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P A RT 1 -
Scientific Assessment
1
Triclosan
2 Priority Existing Chemical Assessment Report
1. Introduction
1.1 Declaration
Triclosan (phenol, 5-chloro-2-(2,4-dichlorophenoxy)-), CAS No 3380-34-5, was
declared a Priority Existing Chemical for a full risk assessment under the Industrial
Chemicals (Notification and Assessment) Act 1989 (Cwlth) (the Act) by notice in
the Commonwealth Chemical Gazette of 6 May 2003. The basis for the declaration
was that triclosan has been shown, in laboratory studies, to be toxic to aquatic
species, particularly to algae, which is the most sensitive species. The widespread
use of triclosan in consumer products provides a number of pathways for the
chemical to enter the environment. In addition, the chemical properties of triclosan
indicate that it may be bioaccumulative and persistent in the environment. There
are also reports that suggest incineration of textile products containing triclosan
may result in the formation of dioxin-like substances.
1.2 Objectives
The objectives of this assessment are to:
? identify the extent of use of triclosan;
? characterise the human health hazards and environmental effects of
triclosan;
? determine the potential occupational, public and environmental exposure to
triclosan;
? determine the risk of adverse effects to the environment, workers and the
general public resulting from exposure to triclosan; and
? make recommendations for minimizing environmental, occupational and
public health risks, and for appropriate hazard communication measures,
where applicable.
1.3 Sources of information
Consistent with these objectives, the report presents an extensive and critical
evaluation of relevant information relating to the potential human health effects
and environmental effects from exposure to triclosan.
Importers of triclosan and triclosan-containing products and some formulators
provided relevant scientific data, including information on quantities imported into
Australia, uses, physicochemical properties, human and environmental exposure,
transport, handling, storage, manufacture and disposal, and toxicity (published and
unpublished data). Information was also obtained from published papers identified
in a comprehensive literature search of several online databases up to December
2006, and retrieved from other sources such as the 2002 review of triclosan
antimicrobial resistance undertaken by the European Union (EU) Scientific
Steering Committee (European Commission Health & Consumer Protection
Directorate General, 2002b). With the exception of the studies contained in this
3
Triclosan
overseas report on antimicrobial activity, all primary sources of data were
evaluated.
Data provided by applicants indicated no manufacture of triclosan occurs in
Australia.
Quantities of triclosan in pesticides and veterinary medicines and therapeutic
products were collected for this assessment, but no further assessment of these
products were conducted as they are not within the scope of the ICNA Act. The
Australian Pesticides and Veterinary Medicines Authority (APVMA) provided the
information on pesticides and veterinary medicines containing triclosan imported
into Australia and triclosan imported into Australia as raw material to be used in
pesticide and veterinary medicine manufacture. Quantities of triclosan used for
therapeutic purposes were identified in a survey undertaken by NICNAS in 2004 of
registrants listed on the Australian Register of Therapeutic Goods (ARTG) as
sponsors of products containing triclosan. Of the 30 registrants contacted 27
responded to the initial survey for import data for the calendar years 2001, 2002
and 2003. In contrast, 11 registrants responded to an updated survey for the
calendar years 2004 and 2005 that was conducted in 2006.
Additionally, a telephone survey of companies using triclosan for industrial
purposes in the textile and plastics industry was conducted in 2004. Four
companies using triclosan to treat plastics and 11 companies using triclosan in
textile treatments provided information.
The information obtained on industrial uses of triclosan together with that obtained
on therapeutic, pesticide and veterinary uses resulted in a more accurate estimation
of the total environmental load of triclosan in Australia and, thus, environmental
risk assessment. The characterisation of health risks in Australia was based upon
information on toxicology data, product specifications made by the applicants, and
overseas use patterns and occupational exposure models.
Information to assist in this assessment was also obtained through site visits to
workplaces involved in formulating triclosan into personal care and therapeutic
products, and a workplace using triclosan for textile treatment. This assessment did
not take into account any triclosan imported as part of finished plastic and textile
articles, as no information was provided on the triclosan quantities in imported
articles.
Additionally, NICNAS commissioned two projects for this assessment:
1. Determination of triclosan levels in national breast milk samples, which was
undertaken by the National Centre for Environmental Toxicology, at the
University of Queensland.
2. Evaluation, by a national expert on antimicrobial resistance, of studies on
this issue published in scientific journals from 2002 to December 2005. These
studies have been published since the 2002 EU review of antimicrobial
resistance (European Commission Health & Consumer Protection Directorate
General, 2002b).
4 Priority Existing Chemical Assessment Report
1 .4 Peer review
During all stages of preparation, the report has been subject to internal peer review
by NICNAS and the Australian Government Department of the Environment,
Water, Heritage and the Arts (DEWHA). In addition, the Advisory Group on
Chemical Safety peer reviewed the sections of the report describing the kinetics
and metabolism of triclosan along with the models used to estimate occupational
and public exposure, the methodology used for the human health risk
characterisation, the NICNAS commissioned study to determine triclosan levels in
national breast milk samples, and the potential for triclosan in breast milk to cause
harm to breast-fed babies. The environmental sections of the report were peer
reviewed overseas by Dr Helen Wilkinson of the United Kingdom Environmental
Agency.
1.5 Report structure
Part 1 of this report is the scientific assessment of the available data on triclosan. It
examines the manufacture, importation and use of triclosan, the potential human
and environmental exposure, and the potential human and environmental hazards
associated with triclosan. It also characterizes the human and environmental risks
associated with the use of triclosan and provides information on the current risk
management practices.
Part 2 of the report contains detailed data which support the scientific assessment
of Part 1.
5
Triclosan
2. Background
2.1 International perspective
The first US patent for triclosan was in 1964 (Merck, 1983) and triclosan has been
marketed for over 30 years. The chemical is listed on the Organisation for
Economic Cooperation and Development's (OECD) High Production Volume
Chemicals list (OECD, 2004) and is being sponsored through the OECD SIDS
program by Australia.
Triclosan is not listed under the Rotterdam Convention on the Prior Informed
Consent Procedure for Certain Hazardous Chemicals and Pesticides in
International Trade (Rotterdam Convention, Annex III, 2006). The Convention
enables listed hazardous chemicals to be monitored and their trade controlled on a
global scale. Triclosan is not listed under the Stockholm Convention on Persistent
Organic Pollutants (UNEP, 2005). The Convention is an international treaty that
Australia has ratified, and is aimed at restricting and ultimately eliminating the
production, use, release and storage of persistent organic pollutants (POPs).
Additionally, the World Health Organisation (WHO) has not set guidance values
for triclosan levels in drinking water (WHO, 2006).
In the European Union the Cosmetics Directive (76/768/EEC) has set a maximum
allowable concentration of 0.3% triclosan in cosmetic products (European
Commission, 1999). In Japan, triclosan is included in the Standards for Cosmetics
(as established by the Pharmaceutical Affairs Law, 1960), which sets a maximum
allowable concentration of 0.1% triclosan in cosmetic products (Ministry of Health
and Welfare Notification No. 331, 2000).
In Canada the use of chemicals in cosmetics is regulated via section 16 (Cosmetic
Regulations) of the Food and Drugs Act 1985. Maximum allowable concentrations
of 0.03% triclosan in mouthwash and 0.3% triclosan in other cosmetic products are
allowed. In addition for all triclosan containing products, the concentration of the
impurities 2,3,7,8-tetra-chlorodibenzo-p-dioxin and 2,3,7,8-tetra chloro
dibenzofuran must not exceed 0.1 ng/g, the total concentration of all other
chlorinated dibenzodioxin and dibenzofuran impurities must not be greater than 10
礸/g, and no other individual impurity should be greater than 5 礸/g (Health
Canada, 2005).
Similarly, due to the potential for the formation of dioxins and dibenzofurans as
unwanted low level trace by-products in triclosan (ECB, 2002), the United States
Pharmacopoeia (USP) recommends concentration limits for the following
impurities in triclosan: less than 10 礸/g for monochlorophenols; less than 10 礸/g
for 2,4-dichlorophenol; less than 0.25 礸/g for 1,3,7-trichlorodibenzo-p-dioxin;
less than 0.5 礸/g for 2,8-dichlorodibenzo-p-dioxin; less than 0.25 礸/g for 2,8-
dichlorodibenzofuran; less than 0.5 礸/g for 2,4,8-trichlorodibenzofuran; less than
1 pg/g for 2,3,7,8-tetrachlorodibenzo-p-dioxin; and less than 1 pg/g for 2,3,7,8-tetra
chlorodibenzofuran (USP, 2004). USP recommendations form the basis of
enforcement actions by the U.S. Food and Drug Administration.
6 Priority Existing Chemical Assessment Report
However the basis for the derived European, Japanese and Canadian maximum
allowable concentration of triclosan in cosmetics, and American and Canadian
impurities concentration limits, could not be determined.
2.2 Australian perspective
Triclosan is not manufactured in Australia. Imported triclosan has been reported for
use as an antibacterial ingredient in personal care products; manufacture of carpet
underlay, PVC swimming pool liners, chopping boards and textile fabric. In 1999,
a total of 22 tonnes was notified to NICNAS as having been imported. The
chemical is not reported on the Australian High Volume Industrial Chemicals list.
Triclosan is listed in the Australian Safety and Compensation Council's (ASCC)
List of Designated Hazardous Substances, contained in the Hazardous Substances
Information System (HSIS). Prior to the July 2008 HSIS update triclosan was
classified as a hazardous substance with the risk phrase, `Toxic by inhalation
(R23)'. The source for this listing was a registration report by the Australian
Pesticides and Veterinary Medicine Authority (ASCC, 2005). In July 2008, the
triclosan hazard classification in the HSIS was updated to adopt the changes in
Europe's 29th Adaptation to Technical Progress (ATP) to Directive 67/548/EEC
(April, 2004). Due to this update triclosan is classified in the HSIS as `Irritating to
eyes and skin (R36/38)'.
An atmospheric occupational exposure standard has not been assigned for triclosan
in the ASCC Exposure Standards for Atmospheric Contaminants in the
Occupational Environment as provided by HSIS (ASCC, 2005). Triclosan is not
specifically regulated for transport under the National Road Transport
Commission's Dangerous Goods Code (ADG Code) (FORS, 1998).
Triclosan is not currently regulated for either public health or environmental
purposes. The Australian Drinking Water Guidelines (National Health & Medical
Research Council, 2004) do not stipulate a limit for triclosan in drinking water.
Triclosan is not listed in the Standard for Uniform Scheduling of Drugs and
Poisons (SUSDP No: 23, June 2008).
2.3 Assessments by other national or international bodies
The health and environmental effects of triclosan have recently been evaluated and
its classification and labelling determined under EC Directive 67/548/EEC (Annex
1 of Directive 67548 EEC, 2005). Triclosan is classified in the European Union as
a skin and eye irritant (with risk phrases R38 and R36 respectively) and dangerous
to the environment (risk phrases R50 and R53).
The European Commission's Scientific Steering Committee (SSC) specifically
reviewed antimicrobial resistance to triclosan in 2002 and concluded that "there is
no convincing evidence that triclosan poses a risk to humans or to the environment
by inducing or transmitting antibacterial resistance under current conditions of use"
(European Commission Health & Consumer Protection Directorate-General,
2002a).
No international assessment of the health and/or environmental risk for triclosan
has presently been carried out in the EU. However, in the European Union triclosan
has been `notified' under the Biocidal Products Directive (98/8/EC) in the
following product types (PTs): human hygiene biocidal products (PT1); private and
7
Triclosan
public disinfectants (PT2); veterinary hygiene biocidal products (PT3); film
preservatives (PT7); fibre, leather, rubber and polymerized materials preservatives
(PT9). Under the Directive industry will be required to submit a data-package for
triclosan to support its use in each of these product types. This will include an
assessment of potential risks to human health and the environment. These data
packages were due to be submitted to Denmark (the Rapporteur Member State)
between 1 February and 31 July 2007 for PTs 1, 2 and 3 and between 1 May and
31 October 2008 for PTs 7 and 9 (Commission Regulation [EC] No 2032/2003,
2003).
Currently there are no restrictions in relation to the use of triclosan as a biocide in
the European Union other than those placed on chemicals in relation to their
classification and labelling under EC Directive 67/548/EEC.
A Preliminary Risk Assessment of the pesticide uses of triclosan was released by
the US EPA in April 2008 for public comment. In addition, an aggregated risk
assessment was conducted by the US EPA as part of the Reregistration Eligibility
Decision (RED) Document using biological monitoring data for non-EPA
regulated uses such as toothpaste, hand soaps and deodorants (US EPA, 2008).
8 Priority Existing Chemical Assessment Report
3. Identity, Properties, Analysis,
Manufacture and Use
3.1 Chemical identity
Triclosan is listed on the Australian Inventory of Chemical Substances (AICS) as:
Phenol, 5 chloro-2-(2,4-dichlorophenoxy)-. Synonyms, trade name and formula are
shown in Table 3.1.
Table 3.1 - Chemical identity
Property Value, name or structure
3380-34-5
CAS No.:
222-182-2
EINECS No.:
Triclosan; 2,4,4' ?trichloro-2'-hydroxydiphenyl ether;
Synonyms:
Ether, 2'-hydroxy-2,4,4'-trichlorodiphenyl;
Phenyl ether, 2'-hydroxy-2,4,4'-trichloro-;
2',4',4-Trichloro-2-hydroxydiphenyl ether;
2',4,4'-Trichloro-2-hydroxydiphenyl ether;
2'-Hydroxy-2,4,4'-trichlorodiphenyl ether;
2,2'-Oxybis(1',5'-dichlorophenyl-5-chlorophenol);
2-Hydroxy-2',4,4'-trichlorodiphenyl ether;
3-Chloro-6-(2,4-dichlorophenoxy)phenol;
4-Chloro-2-hydroxyphenyl 2,4-dichlorophenyl ether.
CH 3565; Bacti-Stat soap; DP 300; Irgacare MP;
Trade Names:
Irgacide LP 10; Irgaguard B 1000; Irgasan; Irgasan CH
3565; Irgasan DP 30; Irgasan DP 300; Irgasan DP
3000; Irgasan PE 30; Irgasan PG 60; Microban
Additive B; Microban B; NM 100; TCCP; THDP;
Tinosan AM 100; Tinosan AM 110; Tinosan NW 500;
Tinosan CEL Liquid; Ultrafresh NM 100; Vinyzene
DP 7000; Yujiexin; Zilesan UW
C12H7Cl3O2
Molecular Formula:
Structural Formula:
Cl OH
O
Cl Cl
289.54
Molecular Weight:
9
Triclosan
3.2 Impurities and additives
Commercial grades of triclosan are typically over 99% pure. Impurities that may be
present in trace amounts are:
2,4 Dichlorophenol
3-Chlorophenol
4-Chlorophenol
2,3,7,8 Tetrachlorodibenzo-p-dioxin
2,3,7,8 Tetrachlorodibenzo-furan
2,8-Dichlorbenzo-furan
2,8-Dichlorbenzo-p-dioxin
1,3,7 Trichlorodibenzo-p-dioxin
2,4,8 Trichlorodibenzo-furan
There are no permitted levels of impurities specified for triclosan in the British
Pharmacopoeia (BP). Information on impurities of triclosan imported into Australia
were compared to the maximum permitted levels of impurities in the US and
Canada. The United States Pharmacopoeia (USP) sets a concentration limit for the
following impurities in triclosan: less than 10 礸/g for monochlorophenols; less
than 10 礸/g for 2,4-dichlorophenol; less than 0.25 礸/g for 1,3,7-trichlorodibenzo-
p-dioxin; less than 0.5 礸/g for 2,8-dichlorodibenzo-p-dioxin; less than 0.25 礸/g
for 2,8-dichlorodibenzofuran; less than 0.5 礸/g for 2,4,8-trichlorodibenzofuran;
less than 1pg/g for 2,3,7,8-tetrachlorodibenzo-p-dioxin; and less than 1pg/g for
2,3,7,8-tetra chlorodibenzofuran (USP, 2004). Canada also regulates the dioxins
and dibenzofurans in triclosan (see section 2.1).
From the data submitted, the imported grade of triclosan from the major local
importer meets the specifications of the current edition of the USP. For the
remaining local importers of triclosan, it could not be conclusively determined for
three importers from the data submitted whether the imported grade of triclosan
met the specifications of the current edition of the USP.
Evidence is available that some grades of triclosan traded commercially may not
meet USP specifications. Analysis of triclosan manufactured by five different
producers in India and a producer in China for the presence of 2,3,7,8-tetrachloro-
dibenzo-p-dioxin and 2,3,7,8-tetrachloro-dibenzofuran indicated the samples did
not meet USP specifications (Menoutis and Parisi, 2002). Levels of 2,3,7,8-
tetrachloro-dibenzo-p-dioxin and 2,3,7,8-tetrachloro-dibenzofuran were observed
to range from 17.2 to 1720 pg/g and 0.43 to 207.3 pg/g respectively.
3.3 Physical and chemical properties
3.3.1 Physical state
Triclosan appears as a white to off-white crystalline powder with a faint aromatic
odour (Merck Index, 1983). The chemical is commercially available in solid form.
The purity for triclosan for commercial use is 99% minimum (Ciba Specialty
Chemicals, 2001a).
10 Priority Existing Chemical Assessment Report
3 .3 .2 Physical properties
Few published data on the physical properties of triclosan could be located. Values
derived from data provided by the applicants and where possible, published sources
are summarised in Table 3.2.
Table 3.2 - Physical properties of triclosan
Property Value Reference
540C to 57.3 0C Merck Index
Melting point
(1983)
2800C to 290 0C
Decomposition Fiege et al.
temperature (2000)
1.55 g/cm3 at 22 0C Ciba-Geigy
Density
Limited (1990a)
Ciba Specialty
Specific gravity 1.58 ?0.03
Chemicals
(2001a)
Solubility
0.001g/100g (1x10-5 g /mL) at 20 0C
Water Ciba Specialty
Chemicals
0
8.5 g/100g (0.085 g/mL) at 25 C
n-hexane
(2001a)
0.30 g/100g (0.003 g/mL) at 25 0C
ammonium
hydroxide
acetone > 100 g/100g (> 1.0 g/mL) at 25 0C
PKa (acid Merck Index
7.9
dissociation constant) (1983)
4 x 10 ? mm Hg (4 x 10 ? Pa) at 20 0C Merck Index,
Vapour pressure
(1983)
Fiege et al.
2.6 x 10 ? mm Hg (2.6 Pa) at 100 0C
(2000)
Partition coefficient Ciba-Geigy
4.8
(Log Pow) Limited (1990b)
0.000000005 (estimated) atm/m3 mole
Henry's Law PBT Profiler
at 25 0C (2004)
Constant
> 350 0C
Autoignition Ciba Specialty
temperature Chemicals
(2001a)
3.3.3 Chemical properties
Triclosan is produced by treatment of 2,4,4-trichloro-2-methoxydiphenyl ether
with aluminium chloride in benzene under reflux. Under extreme conditions such
as high alkalinity and heat, conversion to chlorinated dibenzo-p-dioxins can occur
(Fiege et al., 2000). The type and purity of the starting materials in the synthesis of
triclosan will influence the extent of contamination by the impurities dioxins and
dibenzofurans.
11
Triclosan
Triclosan is sparingly soluble in water, moderately soluble in dilute alkaline
solutions, and readily soluble in most organic solvents. While triclosan in powder
form is highly stable to intense radiation, solutions may show instabilities when
exposed to intense UV-light radiation. Additionally, solutions are not stable to
chlorine and have only moderate stability in the presence of oxidising compounds
(Ciba Specialty Chemicals, 2001a).
Triclosan has some volatility in steam. When a suspension of 1000 mg triclosan in
800 ml water is distilled, 180 ?200 mg triclosan are found in the first 500 mL of
the distillate (Ciba Specialty Chemicals, 2001a).
3.4 Methods of detection and analysis
Various methods are described in the literature to analyse triclosan and more
generally, organic halogen compounds and chlorophenols in a variety of media.
Some of the main methods include High Performance Liquid Chromatography
(HPLC) and Gas Chromatography/Mass Spectrometry (GC/MS). The methods of
detection and analysis of triclosan are provided in Part 2, Section 13.
3.5 Manufacture, importation and use
3.5.1 Manufacture and importation
Data provided by applicants indicated no manufacture of triclosan occurs in
Australia. The APVMA provided the information on triclosan imported into
Australia in pesticides and veterinary medicines or as a raw material to formulate
them. Quantities of triclosan used for therapeutic purposes were identified in
surveys undertaken by NICNAS in 2004 and 2006.
In addition, telephone and written surveys of a number of users of triclosan in the
textile and plastics industries were conducted in 2004. Information in this chapter
is based on data from these sources.
Triclosan is imported into Australia both as the raw chemical (>99% powder), as a
liquid solution (10% to <20%), and as an ingredient in various products. Types of
imported products containing triclosan include non-therapeutic personal care and
cosmetic products, therapeutic goods, textile additives, plastics additives, and
grout. In addition, it is probable that finished plastic and textile articles that have
been manufactured with triclosan additives are imported into Australia.
Table 3.3 below shows the total amount of triclosan imported into Australia for the
years 2001-2005. The figures do not take into account any triclosan imported as
part of finished plastic and textile articles, as no information was provided on the
triclosan quantities in imported articles. Articles such as these fall outside the scope
of this assessment.
12 Priority Existing Chemical Assessment Report
Table 3.3 - Importation of triclosan into Australia annually from 2001
to 2005 (approximate)
Year Raw triclosan Triclosan contained in Total
(>99% purity) imported products (tonnes)
(tonnes) (tonnes)
2001 27 3 30
2002 27 4 31
2003 26 2 28
2004 22 1 23
2005 20 1 21
Raw triclosan is imported into Australia as a powder (purity >99%) under the
brand names Irgasan DP 300, Irgacare MP, Irgaguard B1000, Cansan TCH, and
Triclosan USP25 in 20, 25 and 30 kg antistatic polyethylene lined fibreboard
containers. Triclosan is also imported as 10%-<20% aqueous solutions, under the
brand name Irgacide LP 10, in 30 kg blue plastic drums. The containers and drums
are imported by sea freight and transported typically by road and rail within
Australia directly to customers without being opened or re-packed by importers.
Triclosan is occasionally stored in warehouses prior to delivery to customers.
Imported textile and plastic additives containing triclosan are stored by importers
in licensed warehouses and mostly transported to customers unopened, although
one importer formulates a plastic additive product using raw imported triclosan.
Information from one importer indicates that personal care and cosmetic products
are transferred from ships to trucks by cranes and forklifts, transported by road to
the importer's warehouse, and thence to customers.
3.5.2 Uses in Australia
Triclosan is imported into Australia both as the raw chemical and as an ingredient
in various products. In Australia, triclosan is an ingredient in non-therapeutic
cosmetic and personal care products, therapeutic products, veterinary products,
pesticides, household and industrial cleaning products, grouting material, tile paint,
and laminate paint. It is also incorporated in the manufacture of some plastics and
textile products, and is probably present in some imported finished plastic and
textile articles. Triclosan is used for its broad-spectrum anti-microbial activity
against bacteria, as well as moulds and yeast.
3.5.3 Industrial uses
Cosmetic and personal care products
Approximately 200 cosmetic and personal care end products containing triclosan
were imported into Australia from 2001 - 2005. The concentration of triclosan in
these formulations ranges from 0.00125% to 0.87% and equates to approximately 2
tonnes of triclosan imported annually. Cosmetic and personal care products ranging
in size from 5 mL to 500 mL are imported in the form of soaps, creams, gels,
sticks, liquids, and powders, in pre-packaged tubes, jars, and bottles.
13
Triclosan
It is estimated that about 45% ?59% of the total amount of triclosan imported
annually into Australia (as 100% powder or 10% aqueous solution) is used in the
formulation of personal care and cosmetic products. Therefore, the total amount of
triclosan present in personal care and cosmetic products in Australia, from both
imported finished products, and from products formulated within Australia, is
estimated to be approximately 11 ?18 tonnes per annum (see Table 3.4).
Table 3.4 ?Estimated amount of triclosan in cosmetic and personal
care products (non-therapeutic) annually from 2001 to 2005.
Tonnes (approximate)
Present in imported Formulated into TOTAL
Year
finished end products in Australia
products
2001 2.1 15.9 18.0
2002 1.8 14.3 16.1
2003 1.1 15.0 16.1
2004 0.9 9.9 10.8
2005 0.9 11.6 12.5
The following is a list of cosmetic and personal care product types containing
triclosan marketed in Australia, compiled from data provided to NICNAS by
industry for this assessment:
? Body sprays
? Underarm deodorants (spray, stick, roll-on)
? Feminine deodorants
? Colognes
? Foot and shoe deodorant sprays and talc
? Soaps, including liquid hand wash, shower and bath gels
? Face and skin cleansers, moisturisers, toners, exfoliants
? Facial masks
? Eye make-up
? Pre-wax skin wipes
? Baby wipes
? Skin purifying patches
? Anti-acne formulations
? Cuticle and nail conditioners
? Toothpaste
? Mouthwash
? Cotton buds
? Sunscreens
? Insect repellents
Use in household and industrial cleaning products
Triclosan is present in a number of household and industrial-grade cleaning
products formulated in Australia, at concentrations ranging from 0.04% ?0.30%.
No household or industrial-grade cleaning products containing triclosan were
imported into Australia. The total amount of triclosan used in Australia for the
14 Priority Existing Chemical Assessment Report
formulation of these products for the years 2001 ?2003 is estimated to be at least
0.5 tonnes annually. Limited data was provided for 2004 and 2005, and so no
estimates are made for these years. Products notified to NICNAS by industry for
this assessment included:
? Dishwashing detergents
? A wool wash laundry detergent
? Bathroom surface cleaning products
? A commercial kitchen surface cleanser
? A hospital grade disinfectant/cleaner
? Floor mop cartridges
Household cleaning products are packed in 500 mL, 600 mL, 750 mL and 1 L
containers, while the industrial-grade products are packed variously in a 750 mL
trigger container, 500 mL, 1 L, 5 L, 15 L and 25 L containers.
Use in textile manufacture
Textile additives containing triclosan are imported as liquids in 20 L, 25 kg, and 30
kg plastic containers and 200 L drums, and as a powder in 25 kg containers.
Triclosan is used in textiles to impart odour-protection properties to wool,
synthetics, blends, and non-wovens by inhibiting the growth of bacteria and fungi
on these surfaces, and to eliminate house dust mites from material.
Several products containing triclosan for use in textile manufacture have been
imported into Australia from 2001 to 2005. These products contain triclosan at
concentrations ranging from >1% to <20%. It is estimated less than 1 tonne of
triclosan was used annually between 2001 and 2005 in these products. One
formulator of a product for use in textile manufacture has been identified in
Australia. This company uses an imported textile additive solution containing
1.25% triclosan as an ingredient in a chemical product used for coating fabric
subsequently used in the manufacture of vertical blinds. No other formulators of
textile additive products were identified.
The following is a list of textile end-use products manufactured in Australia that
use a triclosan additive in their manufacture:
? Wool bedding
? Quilts (wool filling)
? Pillows (wool filling)
? Doona filling (polyester blend)
? Under-blankets
? Furniture upholstery
? Woollen goods and general textiles
? Towels
? Curtains, blinds
? Fashion, swimwear and sports apparel
? Hosiery
? Socks
? Shoe insoles
15
Triclosan
? Zippers
? Insulation bats
Application of triclosan to textile products is generally by inclusion in a dye bath,
other treatment baths, or by padding. One manufacturer of polyester blend wadding
sprays a triclosan solution on to batches of textile. The chemical coating treatment
for vertical blind fabric is reported to be applied by a knife coating technique.
Generally the products are completely applied and no waste is expected to be
generated.
It is not known how much triclosan is imported into Australia in finished textiles,
such as bedding and clothing. Such products are classed as `articles' under the
Industrial Chemicals (Notification and Assessment) Act 1989 and as such are
outside the scope of this report. A market and internet web page survey by the
Danish Environmental Protection Agency for textile articles (Danish
Environmental Protection Agency, 2003a) containing biocides, including triclosan,
indicates that the following types of imported textile articles may contain triclosan:
clothing for hospital workers, hospital bedding, sports clothing, socks, and tights.
Triclosan is either built-in to the textile fibres during manufacture or applied as a
coating by various techniques (Danish Environmental Protection Agency, 2003a).
A NICNAS search of web pages marketing antibacterial products undertaken in
2004 indicated that the following types of products may also contain triclosan:
mattress pads, pillows, sports clothing, shoes, underwear, socks, tights, gloves,
hats, scarves, sleeping bags, pet beds, non-woven wipes, filters, and surgical type
masks (Sterling Fibres, 2005; Safety and Security Centre, 2003; Manufacturabrasil,
2004).
Use in plastic manufacture
Plastic additives containing triclosan are imported as liquid in 25 kg and 100 kg
plastic drums, as granules in 20 kg plastic bags, and as pellets in 20 kg, 25 kg or 30
kg polyethylene lined fibreboard drums and 200 kg plastic lined drums with seal
system.
Triclosan is used in plastics manufacture as an antimicrobial additive, to protect the
articles from deterioration and from odours and discoloration.
Several products intended for this use have been imported between 2001 - 2005,
containing triclosan at concentrations ranging from >1% - 10%. In addition,
some plastic additive products, containing 5% triclosan, are formulated in
Australia from imported raw triclosan. The total annual amount of triclosan used in
plastics additives annually is estimated to be approximately 0.5 tonne.
Plastic end products manufactured in Australia using triclosan additives include
various household moulded plastic products including:
?Food storage containers
?Wheelie bins
?Toilet seats
?Toilet tidy sets
?PVC carpet backing
?Swimming pool liners
?Toothbrushes, and
16 Priority Existing Chemical Assessment Report
? Pet accessories such as litter trays, food bowls, and Frisbees.
Triclosan is also used in the manufacture of a cling wrap for export, which contains
triclosan at 0.6 % concentration.
It is not known how much triclosan is imported into Australia already incorporated
into finished plastic products. Some of the types of imported plastic products that
could incorporate triclosan include: domestic and commercial kitchenware such as
food storage bins, knives, cutting boards, sponges, appliances, gloves, kitchen and
bathroom fixtures, medical devices, toys and high chairs, and flooring materials
(Ciba Specialty Chemicals, 2001a).
Other industrial uses
A product containing triclosan is being developed in Australia for use as an
antimicrobial treatment agent for air conditioning heat exchange coils. The product,
a spray-on aerosol containing 0.6% triclosan to be used by air conditioning service
contractors, has not yet been released for sale. To date < 1 kg has been used
annually in development.
There is very limited use of triclosan in grout, with one such product containing the
chemical imported into Australia.
Triclosan is added to some oil-based paint formulated in Australia for interior use
on tiles and laminates, as an antimicrobial agent, at a concentration of 1g/L. The
amount of triclosan used annually for this purpose is <0.1 tonne.
3.5.4 Non-industrial uses
Therapeutic uses
In 2003, triclosan was an ingredient in 84 therapeutic goods registered on the
Australian Register of Therapeutic Goods (ARTG). For 56 of these products,
triclosan is the `active' ingredient, meaning that therapeutic claims are being made
with respect to the triclosan as used in that product. For the remainder of the
products (28), triclosan is listed on the ARTG as an `excipient' ingredient, meaning
that triclosan is not the ingredient in the product responsible for the making of
therapeutic claims. Generally the triclosan in these latter products is considered as
a preservative rather than a bacteriocide. The concentration of triclosan in
therapeutic goods ranges from 0.5 mg/g to 20 mg/g.
As stated in Section 1.3, NICNAS conducted two surveys of the registrants of
therapeutic goods containing triclosan listed on the ARTG in 2004 and 2006.
Survey responses indicated that most therapeutic products are formulated in
Australia from locally sourced triclosan. A small number (10) are imported as
finished products. Twenty-eight of the 84 registered products were not being
marketed at the time of the 2004 survey. From the survey responses, it is estimated
that about 39% ?47% of the total amount of triclosan imported either as 100% raw
powder or 10% aqueous solution per annum was utilised in the formulation of
therapeutic products annually in the period 2001 ?2005. Less than one tonne per
annum is imported as an ingredient in finished therapeutic products. Therefore, a
total of approximately 10 - 13 tonnes of triclosan was formulated into therapeutic
products or imported in finished therapeutic goods, per annum, for the period 2001
?2005. This data is presented in Table 3.5.
17
Triclosan
Table 3.5 - Estimated quantities of triclosan present in therapeutic
products annually from 2001 to 2005.
Tonnes (approximate)
Year Imported in Formulated in TOTAL
finished products Australia
2001 0.4 10.5 10.9
2002 0.7 12.3 13.0
2003 0.6 10.7 11.3
2004 0.3 9.2 9.5
2005 0.3 9.3 9.6
The following range of product types are represented:
? Medicated soaps
? Pimple creams
? Burn gels
? Toothpastes
? Insect repellents
? Antiseptic hand washes and barrier lotions
? Bath oil emollient
? Face washes,
? A pre-operative surgical liquid hand wash
? Lip balm
? Sunscreens
? Surface disinfectant
Veterinary uses
Triclosan is an ingredient in 22 products used for veterinary purposes: six pet
shampoos, fifteen insect repellents, and a cattle teat ointment. The approximate
total annual amount of triclosan used in these products is less than 66 kg per year.
3.5.5 Overseas uses
Overseas, triclosan is reported to be used in a similar range of products as reported
in Australia, including cosmetic and personal care products, dermatological and
topical care preparations for the skin, dentifrices and oral rinses, dishwashing and
laundry detergents, fabric softeners, surface cleansers, and in textiles and plastics
(Bhargava and Leonard, 1996; European Commission Health & Consumer
Protection Directorate-General, 2002b; Ciba Specialty Chemicals, 2001b; US
NPIRS, 2005).
Overseas uses reported in the literature but not reported in Australia include as an
ingredient in toilet cleaners and as a biocide in cutting oils (Grattan et al., 1989).
18 Priority Existing Chemical Assessment Report
Information from a technical brochure for a product marketed in Australia
primarily for use as a textile additive states it can be: used as a laundry additive to
be used with softener in the final rinse stage; added to pigment presscakes,
dispersion and inks; used for carpet cleaning; and applied to synthetic and
cellulosic sponges. These uses were not reported as occurring in Australia, and it is
not known whether these are uses that occur overseas.
Summary of uses
A summary of the uses of triclosan (industrial and non-industrial) is presented in
Table 3.6.
Table 3.6 - Estimated average annual distribution of triclosan in
Australia by use category based on information provided for the
assessment
Approximate average
Use (tonnes)
Industrial
Cosmetic/personal care products (non-therapeutic) 15
Household and industrial cleaning products* <1
Textile additives <1
Plastic additives 0.5
Therapeutic goods 11
Veterinary use <0.1
* Based on 2001 to 2003 data. The others are the average of 2001 to 2005 data.
Among the industrial sectors, the cosmetic/personal care sector is the major user of
triclosan (Table 3.6), and the use appears to be declining over time (Table 3.4).
The range of uses of triclosan in Australia is very similar to the uses of triclosan
overseas.
19
Triclosan
4. Human Exposure
4.1 Occupational exposure
Occupational exposure to triclosan may occur during transport, storage, repacking,
formulation of personal care/cosmetic products, therapeutic products, cleaning
agents and paints, treatment of textiles, plastic manufacture and/or during use of
end products containing triclosan.
During occupational use of triclosan powder, solutions and triclosan-containing
end-use products, the main exposure routes are dermal and inhalation, though
ocular exposure may also occur.
In the absence of worker exposure data, exposure to triclosan (except for use of end
products) was estimated using the Estimation and Assessment of Substance
Exposure (EASE) model (version 2.0 for Windows) developed by the United
Kingdom Health and Safety Executive (UK HSE). Occupational exposure during
use of end products containing triclosan was estimated according to the European
Commission's Technical Guidance Document on Risk Assessment (EC, 2003a).
The estimated internal doses resulting from occupational inhalation and dermal
exposure to triclosan and the integrated internal doses are summarised in Table 4.1.
Table 4.1 - Internal dose levels for processes using triclosan
Inhalation Dermal Integrated internal
Occupational
Triclosan
? ? ?br>
Scenario (礸/kg bw/d) (礸/kg/d) dose* (礸/kg bw/d)
100% 0.25-0.64 (with LEV)
Repacking 5.5-55 5.8-55.6 (with LEV)
powder 0.64-6.36(without LEV)
6.1-61.4 (without LEV)
Formulation of 100% 15.9-39.7 (with LEV) 101-895 (with LEV)
85.5-855
end products powder 39.7-397 (without LEV) 125-1252 (without LEV)
13.5% 2.14-5.36 (with LEV) 13.6-120 (with LEV)
Textile 11.5-115
powder 5.36-53.6 (without LEV) 16.9-169 (without LEV)
20%
- ** 17-170 17-170
liquid
Plastic 100% 15.9-39.7 (with LEV) 101-895 (with LEV)
85.5-855
manufacture powder 39.7-397 (without LEV) 125-1252 (without LEV)
10%
- ** 8.6-86 8.6-86
liquid
0.3%
End use - ** 16.7 16.7
maximum
*Integrated internal dose is the total dose following inhalation and dermal exposure for the
activity undertaken.
**Inhalation dose not calculated as considered neglibible.
Although work processes with triclosan in the textile and plastic industry can
involve high temperature heating which could result in vapour formation and an
increased potential for inhalation exposure, most of the equipment used at high
temperatures are closed systems. In addition, inhalation exposure is reduced where
local exhaust ventilation (LEV) is present (Table 4.1). Furthermore, workers are
20 Priority Existing Chemical Assessment Report
not required to perform any tasks around these `heat' zones during these
operations, and thus the potential for exposure to triclosan vapour is considered
minimal.
The EASE model predicts that occupational tasks using 100% powdered triclosan
result in the greatest exposure, and for each major occupational task (i.e.
repackaging, formulation, and plastic manufacture) the EASE scenario that best
describes the process resulted in total internal doses ranging from 5.8 - 895 礸/kg
bw/day with LEV (Table 4.1). For textile treatment using 13.5% triclosan powder,
the integrated internal dose is much lower, 13.6 - 120 礸/kg bw/day with LEV.
Workers handling 10-20%4 liquid forms of triclosan in the textile and plastic
industries and handling end-use products containing triclosan are predicted to have
lower occupational exposure ranging from 8.6 - 170 礸/kg bw/day (Table 4.1).
In the industrial setting, the real exposure level and subsequent internal dose that
workers receive are likely to be lower as the estimations by EASE does not take
into account Personal Protective Equipment (PPE) which were reported to be worn
at all the sites surveyed by NICNAS. Consequently the use of PPE together with
the use of mechanised, closed or partially enclosed work processes mean that the
actual exposures are likely to be lower than that predicted by the EASE model.
A detailed analysis of occupational exposure to triclosan is provided in Part 2,
Section 14. The occupational exposure calculations are detailed in Appendix C.
4.2 Public exposure
4.2.1 Adults
Exposure estimations indicate that of the industrial uses of triclosan, for adults in
the general public the major source of exposure is likely to be from topical
application of cosmetic and personal care products, though inhalation exposure
following the use of household surface sprays can also contribute significantly to
the overall body burden. However, it should be noted that for cosmetic and
personal care products the predicted dermal exposure is based on the combined use
of 17 products. The total maximum internal dose is estimated to be 578.1 礸/kg
bw/day (Table 4.2). This is considered the worst-case scenario and is obtained from
combined exposure through all potential routes of exposure. However, as
individual use and hence exposure to these products will vary widely the actual
exposure is likely to be significantly less in some sub-populations of the public
who do not use these products on a regular daily basis.
In addition to the modelled data, limited measured exposure data are also available
arising from the use of personal care products. Generally exposure to single and
multiple personal care products containing triclosan resulted in steady state plasma
levels of total triclosan less than 40 ng/mL, though higher levels up to 229 ng/mL
were also occasionally seen.
The estimated internal doses in adults in the general public for various exposure
scenarios following the use of products containing triclosan are presented in Table
4.2.
4
Liquid products used in the manufacture of textiles contain >1 % to < 20 % triclosan. For
determining a worst-case exposure scenario for textile manufacture it is assumed that the product
contains 20 % triclosan.
21
Triclosan
Table 4.2 - Summary of internal dose levels in adults using exposure
models
Total
Public
Inhalation Dermal Oral exposure
exposure
? ? ? ?br>
(礸/kgbw/day) (礸/kgbw/day) (礸/kgbw/day) (礸/kg
scenario
bw/day)
Cosmetic &
personal
18.0 - 53.9 145.5 24.4 187.9-223.8
care
products1
Household
cleaning 1.7 ?349.5 0.34 ND 2.04-349.84
products1
Article
3.8 ND ND 3.8
surfaces
Painted
ND2 0.56 ND 0.56
surfaces
Total
23.5 ?407.2 146.5 24.4 194.4-578.1
internal dose
1
Determined for the maximum concentration of triclosan reported for each product type in Australia
2
Included under article surfaces
ND=No data
4.2.2 Children
Babies and young children are likely to be exposed to triclosan through use of
cosmetic, personal care and household products. Furthermore, breast milk
consumption may provide an additional source of exposure. When determining
exposures in this assessment a baby is defined as a child less than one year old and
exposures are determined in young children up to five years old.
No measured exposure data for babies and young children following use of
consumer products containing triclosan was identified in the literature.
Consequently, the same exposure models used to predict adult exposure to triclosan
from consumer products have been used to predict exposure to babies and young
children (see Appendix D). The use data available for these consumer products is
for adults with no use data available in literature for babies and young children.
Therefore, as a rough approximation of exposure and when considered
`reasonable', the adult use data has been used to predict exposure to babies and/or
young children though it is recognised that the predicted values will be over-
estimates and should be regarded as such.
With regards to breast milk consumption mean intake values and body weight are
taken from the interim draft report of the US Environmental Protection Agency
Child-Specific Exposure Factors Handbook (US EPA, 2002).
From the available data it is predicted that in young children the major source of
exposure is likely to be from personal care products and accidental/intentional
ingestion of toothpaste. For a worst-case scenario, where the exposure from all
routes are combined, a maximum total internal dose of 105.3 and 71 礸/kg bw/day
in a two and five year old respectively was estimated. For babies it was observed
that for an exclusively breast-fed baby exposed to the highest concentration of
triclosan detected in an Australian breast milk sample (19 ng/g of milk), the
22 Priority Existing Chemical Assessment Report
internal dose of triclosan received was less (3.04 礸/kg bw/day ?see Appendix D)
than predicted from other sources of exposure in both babies and young children.
A summary of the predicted internal dose level in babies and young children is
shown in Table 4.3.
Table 4.3 -Summary of internal dose levels in babies and young
children
Dermal Total
Inhalation Oral
Public exposure
? ?br>
(礸/kg (礸/kg
scenario1 ? ?br>
(礸/kg bw/day) (礸/kg bw/day)
bw/day) bw/day)
Baby
3.02
<1 year 6.1 90.9 100.0
Young
children
84.5
2 years 5.3 15.5 105.3
5 years 4.3 56.4 10.3 71.0
1
Determined for the maximum concentration of triclosan reported for each product type,
and observed in a breast milk sample, in Australia
2
This is the highest value determined in a 1-month old baby
Maternal and cord blood serum samples received from the Academic Hospital of
Groningen, Netherlands were analysed for selected man-made chemicals including
triclosan (Peters, 2005). Triclosan was detected in approximately half of the
samples analysed (16 out of 39 maternal blood and 8 out of 17 cord blood
samples). In maternal blood the concentration of triclosan ranged from 0.1 to 1.3
ng/g serum and in cord blood from 0.5 to 5.0 ng/g serum (limit of detection <0.1
ng/g serum). The levels of triclosan in cord blood were higher than in maternal
blood.
Three quarters of the urine samples (2517) collected from the US general
population (age 6 years and older from 2003 ?2004) contained free and/or
conjugated triclosan (95th percentile = 459.0 礸/L). Concentrations differed by age
and socio-economic status but not by race/ethnicity and sex. The concentrations of
triclosan appeared to be highest during the third decade of life and among people
with the highest household income (Clafat et al., 2007).
A detailed analysis of the exposure of the general public to triclosan is provided in
Part 2, Section 15.
23
Triclosan
5. Environmental Exposure
Triclosan is widely used in Australia, particularly in consumer applications
(personal care products) and therapeutic products that entail discharge to sewer,
and to natural surface waters after treatment.
5.1 Environmental fate
The water solubility of triclosan is low (10 mg/L) but environmentally significant
as the solubility allows triclosan to be transported in solution. Triclosan is stable to
hydrolysis, but can be regarded as inherently biodegradable in aerobic aquatic
environments because of its susceptibility to microbial metabolism. Degradation of
triclosan in soil incubated under aerobic conditions proceeds primarily via the
formation of methyl triclosan and significant amounts of bound residues. Some
mineralization of the residues is observed. In aerobic aquatic systems, triclosan
dissipates rapidly from the water phase by degradation and adsorption to the
sediment. In both compartments, it degrades to numerous minor metabolites, bound
residues and carbon dioxide. Photolysis also contributes to the loss of triclosan
from sunlit surface waters. In contrast to its degradation in aerobic environments,
triclosan degrades very slowly and is persistent under anaerobic conditions, for
example in soil and sediment.
A minor metabolite, methyl triclosan, forms during aerobic treatment of sewage
and is discharged in sewage effluent together with residues of triclosan. This
metabolite occurs at much lower concentrations than triclosan, but is more
persistent and bioaccumulative.
Consistent with its low water solubility, triclosan can sorb strongly to soils and
sediment.
5.2 Environmental release
The release of triclosn to the sewage system as a result of its use in personal care
products will result in its partitioning to both the aqueous effluent, which is
subsequently discharged to receiving waters, and to sludge (nutrient rich organic
matter, also known as biosolids).
5.2.1 Aqueous environment
A recent Australian screening study determined the concentrations of triclosan in
the effluent from nineteen sewage treatment plants (8 from South Australia (SA), 5
from Queensland, 2 from the Australian Capital Territory (ACT), 1 from Western
Australia (WA) and 3 from Victoria) which ranged from 23 ng/L to 434 ng/L with
mean and median concentration of 142 and 108 ng/L, respectively. A follow up
study on five of these sewage treatment plants in SA and WA indicated substantial
removal (72-93%), with influent concentrations of 573-845 ng/L reducing to 60-
159 ng/L in effluents discharged to surface waters. There is uncertainty as to
whether these data are reflective of larger sewage treatment plants serving major
urban populations, for example in Melbourne and Sydney, but these Australian
data are comparable to or slightly below overseas measurements.
24 Priority Existing Chemical Assessment Report
Recent Australian monitoring in five rivers/estuaries receiving effluents from
sewage treatment plants in Queensland has found triclosan at concentrations up to
75 ng/L near the sewage outfall (Ying and Kookana, 2007). The range of
concentrations detected was 21-75 ng/L in 2004 and 14-60 ng/L in 2005.
Respective effluent concentrations were 51-222 ng/L and 45-187 ng/L.
Concentrations were reduced at upstream and downstream sampling locations, both
about 200 m from the outfall, particularly during 2005 when sampling occurred
under summer conditions conducive to rapid degradation of triclosan. The authors
of this study caution that riverine concentrations could exceed 75 ng/L during
drought conditions as there would be limited dilution of the discharged effluent.
Overseas measurements are comparable to or slightly higher than the Australian
data.
Concentrations of triclosan entering and leaving Australian sewage treatment
plants have been estimated, based on the assumptions that 96% (Ciba Specialty
Chemicals, 1998a) of the import volume is discharged to sewer, and 28-39%
(estimated using the SimpleTreat 3.0 model assuming that triclosan is inherently
biodegradable or not biodegradable, respectively) of this amount discharged in
treated effluent (Table 5.1) for the various levels of sewage treatment possible in
Australia. The estimates obtained are about ten to twenty times higher than the
measured values listed above. This adds to the uncertainty as to whether the limited
available Australian data are truly representative, and indicates a need for further
monitoring.
Table 5.1 - Predicted surface water triclosan concentrations using
SimpleTreat, reported triclosan removal rates, various levels of
wastewater treatment and the estimated Australian triclosan
introduction quantity
Level of Treatment Removal rate PEC Freshwater PEC Marine
(%)* (triclosan, ng/L) (triclosan,
ng/L)
Untreated wastewater --- 14500-17400 1450 - 1740
Primary Treatment 2-96 581-17000 58 - 1700
Secondary Treatment
Trickling Filter 58-96 581-7300 581 - 730
Activated Sludge 55-99 145-7820 14.5 - 782
Activated sludge
61-72 4070-6780 407 - 678
(SimpleTreat)
145-2260 14.5 - 226
Tertiary treatment 87-99
* Removal rate obtained from literature sources. Freshwater and marine PEC values obtained by
dividing the estimated effluent concentration by receiving environment dilution factors of 1 and 10,
respectively.
5.2.2 Terrestrial environment
Triclosan can be substantially removed by adsorption to biosolids during sewage
treatment. The rate of removal is highly variable and dependant on the type and
level of treatment of the effluent. These triclosan containing biosolids may be
added to soil as an ameliorant. The terrestrial environment may also be exposed to
25
Triclosan
triclosan through irrigation using triclosan containing effluent. The predicted
concentrations from these uses are summarized below in Table 5.2.
Recent Australian data from sewage treatment plants in South Australia and
Western Australia indicate that biosolids may contain 0.090-16.790 mg/kg
triclosan on a dry weight basis. Again, there is some uncertainty as to whether
these data are reflective of other parts of Australia, but they are comparable to
overseas measurements. The predicted concentration in soil amended with
biosolids approaches but does not exceed 1 mg/kg, while limited data indicate that
actual levels will be much lower than predicted.
A detailed analysis of the environmental exposure is provided in Part 2, Section
16.
Table 5.2 -Soil PECs resulting from use of biosolids and a soil
conditioner and treated effluent for irrigation
Parameter Environment Australia ASTE (2004) and Dillon
(2003) STP model (2000) model
Estimated quantity of
26000 26000
triclosan to sewer (kg/y)
Estimated quantity of
2.60 ?1010 2.60 ?1010
triclosan to sewer
(mg/y)
Estimated fraction in
55% a 61% b 55% a 61% b
sludge based on
SimpleTreat model (%)
Estimated sludge
95.6 106 79.9 88.6
triclosan conc. (mg/kg
dry wt)
Soil Application Rate
10
(tonnes/ha/year)
PECSoil biosolid
0.735 0.815 0.614 0.681
application
(mg/kg dry wt)
Influent Concentration
17400 17400 14500 14500
(礸/L)
Overall Removal Rate
61% a 72% b 61% a 72% b
(%)
Concentration in
6.78 4.86 5.66 4.07
effluent (礸/L)
Waste water application
1.0
rate to land (m/ha/year)
PECSoil irrigation
0.0521 0.0374 0.0436 0.0313
(mg/kg dry wt)
Notes: The SimpleTreat model output refers only to an activated sludge treatment process. a:
Assumes no biodegradation; b: Assumes inherently biodegradable.
26 Priority Existing Chemical Assessment Report
6. Human Health Hazard Assessment
6.1 Kinetics and metabolism
Numerous human and animal studies are available on the toxicokinetics of
triclosan following both oral and dermal exposure and these are summarized
below.
6.1.1 Oral and dermal route
Absorption
Following oral administration of triclosan, absorption from the gastrointestinal tract
is rapid and extensive in both humans and animals. Data in one study in humans
indicates absorption to be at least 97% while comparative oral and intravenous
studies in rodents indicate absorption to be from 70% to `virtually complete'.
Consequently, for the purposes of this risk assessment, absorption is considered to
be 100% following oral administration in humans. Following dermal application of
triclosan-containing products, absorption in humans was generally at least 3% to
7%, though at least 14% was observed in one volunteer for a 12 h exposure.
Animal data indicates that the extent of triclosan absorption is dependent on the
formulation applied. A number of studies in the rat indicate absorption to be 21%
to 28% following application in ethanol-based, soap suspension and cream
formulations, while skin biopsy and in vitro evidence suggest that the rate of
dermal absorption is less in humans than animals. Thus, it is considered that dermal
absorption in humans is 14%, as this may be observed in some individuals. In vitro
dermal absorption studies using human skin preparations and various formulations
containing triclosan showed dermal absorption values for triclosan ranging from
11-20% in these formulations (US EPA, 2008). Additionally, limited buccal
absorption was also seen in humans. Following normal toothpaste use absorption
was up to 14% of the amount that would be absorbed if an equivalent dosage of
triclosan were ingested.
The US EPA evaluated dermal absorption studies on triclosan or its formulations
and estimateda dermal absorption value of around 20% for rat skin and possibly a
lower value for human skin. The US EPA report stated that additional verification
is needed for determination of dermal absorption of triclosan (US EPA, 2008).
Distribution
Triclosan was rapidly removed from the blood, and metabolism data indicate
extensive first pass metabolism following absorption from the gastrointestinal tract.
The half-life of elimination for orally administered triclosan ranged from
approximately 13 to 29 h in humans compared to 10 to 15 h in rats, 8 to 12 h in
mice and 25 to 32 h in hamsters. In rodents, radioactivity was widely distributed to
organs and tissues following oral or dermal exposure to 14C- or 3H-triclosan. Well-
perfused and excretory organs such as liver, lung, kidney, gastrointestinal tract and
gall bladder showed highest levels following oral and dermal absorption in rodents.
Additionally, evidence is available in the mouse that suggests that the liver is a
specific target organ. Triclosan has also been detected in human breast milk
27
Triclosan
samples at levels ranging from below the limit of quantification to 19 ng/g milk.
However, due to pronounced first pass metabolism the bioavailability of
unconjugated triclosan is likely to be very limited following oral exposure.
Enterohepatic circulation has been demonstrated in rats, while limited evidence is
available for such in mice and hamsters.
Metabolism
The major metabolic pathways in humans and animals involve glucuronide and
sulphate conjugation. Data in rodents indicates that the liver has a high conjugating
capacity for triclosan, while human and animal data demonstrate triclosan is
metabolised to the glucuronide and sulphate conjugate in the skin. The relative
proportion of these metabolites varies depending on plasma steady state of
triclosan and these conjugates combined, with higher concentrations resulting in a
shift from predominantly glucuronide- to predominantly sulphate- conjugates in
rodents and humans. No difference in metabolic patterns was seen between
different human racial groups. In humans and rodents triclosan glucuronide and
triclosan are predominantly found in the urine and faeces respectively.
Excretion
The major route of excretion is via the urine with the faeces being of secondary
importance in humans, hamsters, rabbits and primates following oral exposure,
whilst the reverse was seen in rats, mice and dogs. The available dermal data, in
rats and rabbits, indicates the same predominant routes of excretion. In humans up
to 87% of the administered dose was excreted in the urine and elimination was
relatively rapid; the majority of the dose was excreted by 72 h post dose. Though a
significant difference was observed in the rate of elimination between some
Negroid (black) volunteers compared to Caucasians (white), there are no data
available to explain why this difference was observed. However, the human oral
and dermal data provide no evidence of a bioaccumulation potential. Likewise, the
tissue distribution data in rats and hamsters following single and repeated dosing
provides no evidence of bioaccumulation in these species, though there is limited
evidence in mice that retention of triclosan and/or its metabolites may occur in the
liver.
The observance of triclosan and/or its metabolites in human breast milk indicates
potential excretion in breast milk. However, the data do not allow a reliable
quantitative determination to be made on the potential dose excreted by this route
following exposure to triclosan. The first pass metabolism and relatively rapid
elimination of triclosan, though, suggest that the potential for transfer to the foetus
and bioaccumulation may be limited.
Inhalation route
There are no data on the toxicokinetics of triclosan following inhalation exposure.
However, the observation of clinical signs of toxicity such as muscle spasms seen
in a repeat inhalation study in the rat indicates that absorption via the inhalation
route can occur, but the data do not allow a quantitative estimation of absorption to
be made. Furthermore, because first pass metabolism would not take place
following exposure by this route, bioavailability of triclosan is likely to be
substantially greater than is associated with the oral route, or the dermal route
where metabolism of triclosan to its conjugates has been demonstrated in the skin.
28 Priority Existing Chemical Assessment Report
A detailed analysis of the kinetics and metabolism is provided in Part 2, Section
17.
6.2 Effects on laboratory animals
6.2.1 Acute toxicity
The most recent and well-conducted LD50 study indicates that triclosan has low
acute toxicity by the oral route (LD50 >5000 mg/kg bw), though there is evidence
from older and less well reported studies that it is moderately toxic and produces
nephrotoxicity. No clinical signs of toxicity were observed following a 4 h
exposure to an aerosol of 0.15 mg triclosan/L, which was the highest technically
achievable rat respirable concentration used in this study. The LC50 was greater
than 0.15 mg/L. Due to this very low dose tested in this study it is not possible to
derive a conclusion about the acute inhalation toxicity of triclosan. However, in a
repeat dose inhalation toxicity study in rats, more than 50% rats died after a single
2-h exposure to 1300 mg triclosan/m3 air. Therefore, LC50 for triclosan is
considered as <1300 mg/m3 or <1.3 mg/L. Limited evidence is available that
triclosan is of low acute toxicity by the dermal route (LD50 >9300 mg/kg bw for a
slurry with propylene glycol) and that its acute toxicity is increased if administered
intravenously.
6.2.2 Irritation
The available data shows that triclosan produces both skin and eye irritation in
studies in rabbits but is not phototoxic in a study in guinea-pigs. Respiratory tract
irritation was observed in rats exposed to triclosan in the repeat dose inhalation
toxicity study and therefore, triclosan is considered a respiratory irritant.
6.2.3 Sensitisation
The available data indicate that at most triclosan possesses a very weak skin
sensitisation potential in studies conducted in guinea-pigs.
6.2.4 Repeat dose toxicity
Inhalation
In the only available 21-day inhalation study conducted in rats (2 h/day nose only
exposure), clinical signs of toxicity and death in the high dose animals at 1300 mg
triclosan/m3 air (in 10% ethanol) indicate systemic toxicity. More than 50% rats in
the highest dose group died (11 out of 18) on the first two days of the experiment,
after a single 2 h exposure, compared to no deaths in other treatment groups or the
control group exposed to 10% ethanol. All other observed treatment related effects
are due to local irritation for which a NOAEC of 0.05 mg/L was identified.
Oral
Studies are available in the mouse, rat, hamster, rabbit, dog and baboon.
A NOAEL could not be identified in the 13-week mouse study, although a LOAEL
of 25 mg/kg bw/day was identified based on effects on haematology parameters,
relative liver weight and total cholesterol in both sexes. However, while the mouse
is the most sensitive species, there is evidence that (unlike the rat and hamster) it is
29
Triclosan
sensitive to peroxisome proliferator type effects that are not considered relevant to
a human health risk assessment. Consequently, a NOAEL of 40 mg/kg bw/day (m)
and 56 mg/kg bw day (f) was identified from a two-year carcinogenicity study in
the rat based on clinical chemistry changes, together with histopathological
changes in the liver in males and a trend for reduced body weight gain in females.
Dermal
Local irritant effects have been clearly seen in animal studies. A NOAEL of 7.5
and 3.5 mg/kg bw/day was identified in 14-day studies in male and female rats,
respectively. No systemic toxicity was seen in the rat studies and the only available
robust dog study. However, histological changes to the liver were seen in two 14-
day studies in the mouse, with a NOAEL of 20 and 24 mg/kg bw/day identified in
males and females respectively.
In a 90-day rat study, no treatment related effects were seen on mortality, clinical
signs of toxicity, body weight gain, food or water consumption, haematology,
clinical chemistry or organ weight. Coagulative necrosis of the liver, focal cortical
tubular degeneration of the kidney and microscopic changes to the bladder were
seen at necrospy in a small number of animals. In the absence of a dose response
effect these observations were not considered treatment related. Occult blood was
seen in the urine of 3 to 4 males per group at 40 mg/kg bw/day and above,
including the recovery group, and 2 females in the 40 mg/kg bw/day and recovery
group. However, as the significance of this finding is unknown, it is not considered
to provide reliable evidence of systemic toxicity based on the weight of evidence,
and a NOAEL of 80 mg/kg bw/day is identified. For local irritant effects a NOAEL
could not be identified, and thus the LOAEL was 10 mg/kg bw/day.
6.2.5 Genotoxicity ?in vitro
Negative results have been seen in numerous studies in bacteria, with only a single
weakly positive result seen in a briefly reported study at a very high dose level.
Similarly, no robust evidence of an in vitro mutagenic activity was seen in studies
in fungi or mammalian cells. Both a positive and negative chromosome aberration
study is available, while only negative results were seen in Unscheduled DNA
Synthesis (UDS) assays. Thus, the weight of evidence (a single robust positive
chromosome aberration assay from numerous in vitro studies) does not indicate a
significant genotoxic potential.
6.2.6 Genotoxicity ?in vivo
In vivo, negative results have been seen in a number of bone marrow chromosome
aberration and micronucleus studies. Both a negative and positive result has been
seen in the mouse spot test though there are limitations in the methodology
employed in both studies. Similarly, there are limitations in methodology in the
available studies in germ cells that were all negative. Therefore, there is no robust
evidence of a genotoxic potential in vivo.
6.2.7 Carcinogenicity
Neither of the carcinogenicity bioassay conducted in the rat or hamster provided
evidence of a carcinogenic potential.
30 Priority Existing Chemical Assessment Report
6 .2 .8 Fertility
No evidence of an effect on fertility was seen in a two-generation dietary study in
the rat. Furthermore, data from numerous repeat dose studies of 90-day or longer
duration that examined the reproductive organs support the finding of the only
available fertility study.
6.2.9 Developmental toxicity
No evidence of a developmental effect was seen with triclosan in robust studies in
the rat at doses that produced marked maternal toxicity. Additionally, no evidence
of a postnatal developmental effect was seen in this species. Similarly, no evidence
of a developmental effect was seen at a level that produced marked maternal
toxicity in the only available study in the rabbit. In the mouse, the only treatment
related finding of delayed ossification of forelimb phalanges is considered to be a
secondary non-specific consequence of maternal toxicity. Therefore, the available
data in animals provide no evidence that triclosan has a direct effect on
development. The NOAEL for both developmental and maternal toxicity is 50
mg/kg bw/day.
6.2.10 Antimicrobial resistance
Recent laboratory studies
Data from recent laboratory studies of resistance mechanisms, sometimes in
clinical isolates, more usually with laboratory generated variants, have
demonstrated the following four resistance mechanisms, which have been
manipulated both genetically and biochemically in the laboratory:
? mutational change in gene(s) encoding the target enzyme EAR such that
binding of triclosan and thus inhibition of EAR and fatty acid synthesis
does not occur5;
? mutational changes leading to overproduction of EAR within the cell such
that some molecules of EAR escape the inhibitor and thus remain active5;
? impermeability of the bacterial cell envelope such that triclosan does not
readily penetrate beyond this outer layer of the cell6; and
? effects on efflux pumps that pump triclosan (usually along with other
xenochemicals such as antibiotics and other biocides) from the cell such
that the triclosan concentration does not rise to a damaging level within the
cell5.
Though there is sometimes disagreement as to which mechanism(s) is primarily
responsible for triclosan resistance, and whether more than one may be
functioning, resistance mechanisms involving multidrug efflux pumps and outer
envelope impermeability are likely to give rise to cross resistance towards other
biocides and antibiotics.
5
A form of selected resistance.
6
A form of intrinsic resistance.
31
Triclosan
Studies from clinical or natural settings
Overall these recent environmental studies, and analyses of clinical isolates from
collections taken over the course of time, point to the conclusion that the use of
biocides (including triclosan) in homes and hospitals has not lead to any notable
selection of antibiotic resistance in bacteria, nor where it has been examined, to
cross resistance.
Physiological fitness of bacteria resistant to biocides and antibiotics
By varied measures of physiological fitness, mutants of both Pseudomonas
aeruginosa and Stenotrophomonas maltophilia that overproduce multi-drug efflux
pumps were found to be significantly less fit than their parental wild types in a
number of important regards. The mechanism by which this occurs remains for the
moment a matter for speculation.
Overall conclusions regarding antibiotic resistance
The studies up to 2002 reviewed both by the European Union Scientific Steering
Committee (see EC Health & Consumer Protection Directorate-General, 2002a)
and those studies published between 2002 and 2005 reviewed here, published since
2002, show that triclosan resistance is readily generated in a range of bacterial
species (both gram positive and negative) by selection under laboratory conditions
in partially inhibitory concentrations of triclosan. In contrast, triclosan resistant
mutants are present at low frequency in natural (including clinical) isolates of
gram-positive and gram-negative bacteria. Furthermore, investigations to
determine if the frequency of triclosan resistance has risen as a result of exposure
of natural populations of bacteria to this biocide have shown minor or no change.
Therefore, the data suggest that conditions exist in laboratory experiments that
differ in some important way(s) (unidentifiable from the experiments reported)
from conditions which natural populations experience.
Hence, overall, the new studies available since the EU review provide no evidence
that triclosan poses a risk to humans or to the environment by inducing or
transmitting antibacterial resistance under current conditions of use. Though the
recent limited number of studies do not resolve specific technical/use issues
identified by the SSC (see EC Health & Consumer Protection Directorate-General,
2002a), and therefore the relationship between the use of biocides and the
development of clinically relevant antimicrobial resistance should be kept under
regular review.
A detailed analysis of the effects on laboratory animals and other test systems is
provided in Part 2, Section 18.
6.3 Effects on human health
6.3.1 Skin irritation
There is evidence available that triclosan produces skin irritation in studies
conducted with human volunteers, however, there was no evidence of
phototoxicity.
32 Priority Existing Chemical Assessment Report
6 .3 .2 Sensitisation
Although there is potential widespread consumer exposure to triclosan only a small
number of case studies have been reported where humans who are not atopic have
demonstrated positive reactions to triclosan. The available data indicate that at
most triclosan possesses a very weak skin sensitisation potential.
There is also only very limited evidence for photo-sensitisation by triclosan in
healthy volunteers or those with dermatological conditions.
6.3.3 Repeat dose toxicity
There was no evidence of a treatment related effect in a human tolerance study
with oral doses of triclosan up to 30 mg/day for 15 days and 30 mg/day for 52
days. There has also been no evidence of adverse effects in human studies
examining the use of personal care products containing triclosan.
A detailed analysis of the effects on human health is provided in Part 2, Section
19.
6.4 Regulatory classifications for workplace based hazards
The classification of the health effects of triclosan has been conducted according to
the Approved Criteria for Classifying Hazardous Substances (the Approved
Criteria) (NOHSC, 2004) or, in the case of physicochemical hazards, the
Australian Code for the Transport of Dangerous Goods by Road and Rail (ADG
Code) (FORS, 1998).
The Approved Criteria are cited in the National Model Regulations for the Control
of Workplace Hazardous Substances (NOHSC, 1994c) and provide the mandatory
criteria for determining whether or not a workplace chemical is hazardous.
6.4.1 Physicochemical hazards
Triclosan does not meet the ADG Code (FORS 1998) for classification as a
dangerous good on the basis of physicochemical hazards.
6.4.2 Occupational health hazards
Acute toxicity
Based on the available animal data triclosan does not meet the Approved Criteria
(NOHSC, 2004) for classification for acute oral and dermal toxicity.
The acute inhalation toxicity data in rats is limited. The dose used in the acute
inhalaltion study was low with no deaths reported (LC50 >0.15 mg/L). However,
based on effects seen after a single exposure in a repeat dose inhalation toxicity
study, triclosan meets the Approved Criteria (NOHSC, 2004) for classification as
`Toxic by inhalation (R23)'.
Irritation and corrosive effects
Based on the human and/or animal data triclosan meets the Approved Criteria
(NOHSC, 2004) for classification as irritating to eyes (R36), respiratory system
(R37) and to skin (R38).
33
Triclosan
Sensitising effects
Based on the available human and animal data triclosan does not meet the
Approved Criteria (NOHSC, 2004) for classification as a skin sensitiser.
Effects from repeated or prolonged exposure
Based on the available animal data triclosan does not meet the Approved Criteria
(NOHSC, 2004) for classification as causing serious damage to health by
prolonged exposure through inhalation, ingestion or dermal contact.
Genotoxicity
Based on the available in vitro and animal data triclosan does not meet the
Approved Criteria (NOHSC, 2004) for classification as a mutagen.
Carcinogenicity
Based on the available animal data triclosan does not meet the Approved Criteria
(NOHSC, 2004) for classification as a carcinogen.
Reproductive effects
Based on the available animal data triclosan does not meet the Approved Criteria
(NOHSC, 2004) for classification as a reprotoxicant, as a developmental toxicant,
or for lactational effects.
6.5 Classification and labelling for public health hazards
Scheduling in the SUSDP
The acute oral toxicity of triclosan is greater than 5000 mg/kg bw in rats, and acute
dermal toxicity is >9300 mg/kg bw in rabbits. Triclosan has a LC50 of less than
1300 mg/m3 in rats with 2 h nose-only exposure (expected to be < 650 mg/m3 with
4 h exposure). It is a skin and eye irritant in rabbits. The eye irritation effects were
not completely reversible by day 7 (mean score for cornea opacity = 1 on day 7).
Overall based on the toxicity profile, triclosan meets the Interim Guidelines of the
NDPSC for scheduling (TGA, 2008).
Triclosan is used widely in a number of consumer products. Based on its inhalation
toxicity and irritation effects, inclusion of triclosan in the Standard for the Uniform
Scheduling of Drugs and Poisons (SUSDP) is considered appropriate with cut-offs
and/or exemptions for consumer products.
Details of the hazard classification based on the above are provided in Part 2,
Section 20.
34 Priority Existing Chemical Assessment Report
7. Environmental Hazard Assessment
Ecotoxicity data for several trophic levels (animals and plants) from aquatic and
terrestrial environments were available; however, the data were limited in quantity
in all categories.
7.1 Wildlife
Based on the data available for two standard test species, triclosan is slightly toxic
to birds by the oral route of exposure, with the lowest toxicity data for the bobwhite
quail of LD50 862 mg/kg bw (single oral dose).
7.2 Terrestrial invertebrates
Triclosan exhibited very slight toxicity to earthworms, with a recorded no-
observed-effect concentration (NOEC) of 1026 mg/kg dry wt. Triclosan did not
effect the soil microbial proccesses of respiration and nitrification at concentration
up to 2 mg/kg of dry soil.
7.3 Terrestrial plants
In soils, triclosan is toxic to plants when grown in sandy soil (time-weighted
average (TWA) NOEC for cucumber 65 礸/kg); however, toxicity was less (TWA
NOEC for cucumber 446 礸/kg) when grown in sandy loam. The attenuation of
phytotoxicity is potentially due to the higher organic matter content of the sandy
loam soil binding to the triclosan.
7.4 Aquatic organisms
Triclosan is very toxic to freshwater aquatic organisms with LC50 or EC50 values
<1 mg/L (Mensink et al., 1995). From the limited data available, freshwater algae
are the most sensitive species (lowest NOEC 0.5-0.69 礸/L and 72-96 h EC50 0.7-
1.4 礸/L). Morphological analysis generally indicated enlarged cell sizes when
algae were exposed to concentrations 2.2 礸/L. Data from two algae studies
involving the assessment of recovery post-exposure indicates that algae growth
resumed, hence, triclosan is algistatic rather than algicidal at concentrations up to
13 礸/L.
Data for freshwater algae indicates that ecotoxicity decreases slightly in the
presence of dissolved organic matter (S. subspicatus ErC50 3.5 礸/L), perhaps with
adsorption to organic matter reducing bioavailability.
In both acute and chronic tests with freshwater invertebrates, EC50 values increase
as pH increases, and triclosan is much more toxic to freshwater animals in neutral
or acidic waters than in alkaline waters. For example, in a 7 d test with C. dubia,
the maximum acceptable toxicant concentration (MATC) at pH 7 was ~30 times
less than at pH 8.5. The above mentioned data for freshwater algae were obtained
from toxicity tests performed under alkaline pH conditions (pH 7.5) and given the
higher toxicity of triclosan to other aquatic animals under neutral to acidic
35
Triclosan
conditions, the toxicity values for algae may under-estimate algal toxicity through
the full environmental pH range.
Triclosan was highly toxic to sediment dwelling organisms (the midge Chironomus
tentans and the freshwater amphipod Hyalella azteca) when exposed through the
water column. In contrast, exposure of the the midge Chironomus riparius to
triclosan through spiked sediment showed no effect at concentrations up to 100
mg/kg dry sediment.
Limited data are available for the toxicity of triclosan to marine organisms. The
available data indicates that triclosan is highly toxic to grass shrimp with larvae
being the most sensitive life stage. Triclosan is also very highly toxic to the marine
bacterium Vibio fischeri.
None of the aquatic toxicity tests undertaken investigated or discussed the actual
mode of toxic action of triclosan in the aquatic organisms affected.
Preliminary data indicate that triclosan (or metabolite) is not potently estrogenic to
freshwater fish but it may be weakly estrogenic, anti-estrogenic or androgenic.
7.5 Micro-organisms
Triclosan is an antimicrobial compound to many bacteria, fungi, moulds and
yeasts. Some species are resistant to triclosan and others are able to use it as a sole
carbon source. Effects occur in sensitive micro-organisms at concentrations of
0.01 ppm.
The limited data available indicate that effect levels of triclosan on activated
sewage sludge micro-organisms vary depending on the level of acclimation. A
concentration of 2 mg/L inhibited activated sludge micro-organisms that had not
been acclimated to triclosan; however, the same concentration had no effect on
acclimated organisms. Laboratory-derived IC50 values range from 20-239 mg
triclosan/L based on carbon dioxide (CO2) evolution and glucose utilisation.
Triclosan (2 mg/L) had a slight effect on chemical oxygen demand (COD)
removal under laboratory conditions, but had a major inhibitory effect on the
nitrification process. Anaerobic sludge digestion was significantly inhibited at a
concentration of 10 mg/L. A NOEC for sewage microbes was not available.
A detailed analysis of the effects on organisms in the environment is provided in
Part 2, Section 21.
36 Priority Existing Chemical Assessment Report
8. Human Health Risk Characterisation
8.1 Health risk characterisation methodology
A margin of exposure methodology is used frequently in international assessments
to characterise risks to human health (EC, 2003a). The risk characterisation is
conducted by comparing quantitative information on exposure to the
NOAEL/NOAEC and deriving a Margin of Exposure (MOE) as follows:
1. Identification of critical effect(s).
2. Identification of the most appropriate/reliable NOAEL (if available) for the
critical effect(s).
3. Where appropriate, comparison of the estimated or measured human dose
or exposure (EHD) to provide a Margin of Exposure (MOE):
MOE = NOAEL/EHD
4. Characterisation of risk, by evaluating whether the MOE indicates a
concern for the human population under consideration.
The MOE methodology was used for characterising occupational and public health
risk following exposure to triclosan.
The MOE provides a measure of the likelihood that a particular adverse health
effect will occur under the conditions of exposure. As the MOE increases, the risk
of potential adverse effects decreases. In deciding whether the MOE is of sufficient
magnitude, expert judgment is required. Such judgments are usually made on a
case-by-case basis, and should take into account uncertainties arising in the risk
assessment process such as the completeness and quality of the database, the nature
and severity of effect(s) and intra/inter species variability.
The MOE methodology was used for characterising occupational and public health
risk following exposure to triclosan.
8.2 Occupational risk
8.2.1 Occupational exposures
All triclosan used in Australia is imported either as powder or liquid solution.
Triclosan is also present in imported end-use products. Exposure to triclosan may
occur during:
? Repacking;
? Formulation of personal care/cosmetic products, cleaning agents, and
paints;
? Treatment of textiles;
? Plastics manufacture; and
37
Triclosan
? Use of triclosan-containing end-use products.
Potential routes of exposure to triclosan in the occupational setting are via
inhalation and dermal contact. The likelihood of exposure by ingestion in
occupational settings is expected to be low.
Exposure monitoring data were not available for levels of triclosan in the air for the
different occupational exposure scenarios. Consequently, the UK EASE model
(version II) was used to determine both inhalation and dermal exposure.
8.2.2 Critical health effects
Triclosan is of low acute toxicity via the oral and dermal routes. The limited acute
inhalation toxicity data indicate a LC50 of less than 1300 mg/m3 (equivalent to 1.3
mg/L) in rats for a 2 h exposure period. The critical health effects from acute
exposure to triclosan are skin, eye and respiratory irritation. Skin irritation was
observed in both humans and animals following dermal application. Only data in
experimental animals are available for eye irritation, which was observed following
instillation of triclosan into the eyes of rabbits.
For repeat dose toxicity, the available human data provide no reliable information
to identify a robust NOAEL or profile the systemic toxicity of triclosan. Animal
data are available for the oral, dermal and inhalation routes of exposure. Overall,
the data from rodent studies indicates that the principal effect following ingestion
and topical application of triclosan are hepatic effects, with local irritation often
seen at the site of contact.
While the mouse is the most sensitive species, there is evidence that (unlike the rat
and hamster) it is sensitive to peroxisome proliferator type effects in the liver that
are not considered a risk to human health. Consequently, for ingestion a NOAEL of
40 mg/kg bw/day was identified in the rat for mild clinical chemistry and/or
haematology changes, with hepatocyte hypertrophy and hepatocyte vacuolisation
in cells from males only. In this species no reliable evidence of systemic toxicity
was seen in a dermal study up to the top dose of 80 mg/kg bw/day. Irritation of the
nasal tract and changes in clinical chemistry parameters were seen in rats in the
only repeat dose inhalation study following exposure to an aerosol of triclosan in
10% ethanol at doses more than 50 mg/m3 air.
Triclosan did not cause in vivo genotoxicty, carcinogenicity, reproductive or
developmental toxicity in rodents.
8.2.3 Risk estimates
Physicochemical hazards
Triclosan is a non-flammable powder that does not undergo autoignition and has no
evidence of an explosive property. It has a melting point of 54 oC to 57.3 oC and
decomposition occurs at 280 oC to 290 oC.
Triclosan is stable under normal storage conditions, although solutions are not
stable to chlorine and have only moderate stability in the presence of oxidising
compounds. Triclosan itself has no oxidising properties. Triclosan powder, like
other dusts, may be explosive if ignited when present at a critical concentration in
air.
38 Priority Existing Chemical Assessment Report
Based on the properties of triclosan the risk from physicochemical hazards during
storage and handling of triclosan is considered to be low.
Acute risks due to occupational exposure
The toxicological profile of triclosan indicates that contact with the raw material or
concentrated solutions may result in skin and eye irritation. Inhalation of triclosan
powder may cause toxicity and irritation to the respiratory tract.
Workplace activities related to triclosan are repacking, formulation, use in textile
treatment, plastics manufacture and use of end use products.
Formulation of products containing triclosan is essentially an enclosed, automated
process with closed mixing tanks employed.
Similarly at most workplaces textile treatment is essentially an enclosed, automated
process. Solutions used contain triclosan at less than 20% concentration, with the
exception of one workplace that used a powder containing 13.5% triclosan. At a
wool processing plant site with daily exposure, a solution containing 3% or less
triclosan is used. Similarly, cleaning of baths through which fabrics or articles are
passed in the treatment of textiles is of little concern as the triclosan is very dilute
at this point and the baths are first emptied of solution.
Manufacture of polyolefin masterbatches using raw triclosan occurs on a periodic
basis. Other plastic manufacturing processes use solutions or plastic pellets
containing triclosan. There is little potential for exposure where triclosan is used
encapsulated in a plastic matrix, while when solutions are used the maximum
concentration of triclosan is up to 10%.
The risk of acute effects such as inhalation toxicity, skin, eye and respiratory
irritation during the processes described above is expected to be low due to
periodic rather than daily exposure and use of engineering controls such as local
exhaust ventilation (LEV) at some workplaces. In addition the reported use of PPE,
such as safety goggles and gloves, at some sites would minimise exposure.
Nevertheless, there is the possibility of accidental spills as manual handling
procedures are employed during repacking, at some stages of formulation such as
transfer of raw material to another container or mixing vessel, and during textile
treatment such as transfer of triclosan solutions to another container, mixing vessel
or dye machine. The manual handling stages are of short duration and potential
exposure would normally be minimal. Therefore, overall, the potential for exposure
to triclosan is low. Consequently, the risk to workers from handling triclosan is
considered to be low.
End-use products
Workers may be exposed to triclosan through the use of commercial personal care
and cleaning products containing the chemical. In addition to normal usage, acute
exposure of end users to triclosan may occur following accidental spillage.
Exposure would not be significant as the maximum concentration of triclosan
identified in an occupational end-use product was only 0.3%. Consequently, the
risk of acute effects such as inhalation toxicity, skin, eye and respiratory irritation
is assessed as low.
39
Triclosan
Secondary transfer
Manual handling of triclosan and triclosan products occurred during the majority of
the identified uses. In addition to the risk of inhalation toxicity, skin, eye and
respiratory irritation from acute exposure to triclosan and/or products containing
triclosan following direct skin contact and contact with air borne particles,
secondary transfer from hands or gloves may also occur. The risk of secondary
transfer is expected to be higher in the following situations:
? use of raw material or products containing high percentages of triclosan;
and
? where PPE is not used.
PPE was reported to be used at all sites surveyed, and the risk of acute effects from
secondary transfer is expected to be low.
Chronic risks
There are no Australian or overseas worker health effects monitoring data available
during repacking, formulation, treatment of textiles, and plastic manufacture or for
use of end products. Consequently, the UK EASE model has been used to predict
exposure, and a NOAEL of 40 mg/kg bw/day was selected for effects on the liver
in rats (as described in Section 8.2.2) to calculate MOE for risk assessment. Table
8.1 provides MOEs calculated using the EASE model and the appropriate formulae
are detailed in Appendix C.
In deciding whether the MOE is of sufficient magnitude for these occupational
scenarios expert judgment is required taking into account the risk assessment
process, the nature and severity of effect(s) on which the NOAEL is based, and
intra/inter species variability.
With regards to the nature and severity of effects on which the NOAEL is based,
not only are the critical effects seen in the two-year rat carcinogenicity study
considered minimal but the minor histopathological changes seen in hepatic cells in
males only were not consistently seen at the identified NOAEL (40 mg/kg bw/day)
in interim sacrifice groups throughout the study. Furthermore, no increase in the
severity of these histopathological changes was seen with dose (Part 2, Section
18.4). However, while the effects seen are minimal and the mechanism by which
changes arise and their significance for human health is not clear, they cannot be
dismissed as being of no significance. With regard to inter species variability there
are no data to suggest that humans are more sensitive than animals.
40 Priority Existing Chemical Assessment Report
Table 8.1 ?Calculated margins of exposure (MOE) for effects on the
liver for each occupational exposure scenarios
Process Estimated body burden Combined MOE
from body burden (based on
?br>
Inhalation Dermal (礸/kg bw/day) NOAEL of
exposure exposure 40 mg/kg
? ?br>
(礸/kg (礸/kg
bw/day)
bw/day) bw/day)
Repacking With LEV 0.25 - 0.64 5.8 ?55.6 6897 - 719
5.6 - 55
(100% powder)
Without LEV 0.64 ?6.36 6.1 ?61.4 6557 - 651
Formulation of With LEV 15.9 ?39.7 101 - 895 396 - 44.7
end-use
products 85.5 - 855
Without LEV 39.7 - 397 125 - 1252 320 - 31.9
(100% powder)
Treatment of With LEV 2.14 ?5.36 13.6 ?120 2941 - 333
textiles
(13.5% 11.5 - 115
Without LEV 5.36 ?53.6 16.9 ?169 2367 - 237
powder)
Treatment of With LEV -
textiles
(assumed to be 17 - 170 17 - 170 2353 - 235
Without LEV -
a 20% liquid)1
Plastic With LEV 15.9 ?39.7 101 - 895 396 - 44.7
manufacture
85.5 - 855
(100% powder) Without LEV 39.7 - 397 125 - 1252 320 - 31.9
Plastic With LEV -
manufacture
8.6 - 86 8.6 - 86 4651 - 465
(10% liquid) Without LEV -
Use of end-use With LEV -
products 16.7 16.7 2395
Without LEV -
(0.3%)
1
Liquid products used in the manufacture of textiles contain >1% to < 20% triclosan. For determining a worst-
case exposure scenario/MOE for textile manufacture it is assumed that the product contains 20% triclosan.
A MOE of 100 or greater is usually not considered a flag for concern as it
represents the conservative default uncertainty factors of 10 each for both intra-
and inter- species variability used for risk characterisation.
The MOEs for repacking, treatment of textiles, and plastics manufacture using 10%
triclosan solution, with and without the use of LEV, were all >100 indicating that
the risk of chronic effects to workers from repeated handling of triclosan in these
scenarios is low. The MOE for the use of end-use products was also >100.
Inhalation exposure was not estimated for the use of end-use products. Inhalation
exposure may occur if commercial spray cleaning products are used. However, the
triclosan concentration reported in cleaning products ranged from 0.04 % - 0.30%.
MOEs < 100 were identified for two scenarios. The MOE for formulation ranged
from 44.7 ?396 with LEV and 31.9 ?320 without LEV, as did that for plastic
manufacture when using raw triclosan powder.
41
Triclosan
The lower levels of the MOE in these ranges are considered likely to be
overestimates. However, as the predictive dermal model is less developed than the
inhalation model and its outputs should be regarded as no more than
approximations. Furthermore, the semi-automated processes for formulation and
plastic manufacture mean that dermal exposure is only likely during manual
handling procedures such as transfer of raw material to another container or mixing
vessel in the case of the formulation process and as these procedures are of short
duration exposure would be minimal. Additionally, EASE does not quantify the
actual protection provided by PPE, such as gloves. Risk of chronic effects will
therefore be less at workplaces where PPE are used. Consequently, it is considered
that the MOEs will be at the higher levels of the predicted range (i.e. >100) and the
risk of chronic effects to workers in the formulation and plastics manufacture
industry from repeated exposure to triclosan is low.
8.2.4 Uncertainties in occupational risk estimates
Uncertainties in any risk characterisation process arise from inadequate
information, assumptions made during the process and variability in experimental
conditions. The uncertainties inherent in the characterisation of risk for triclosan
arise mainly from inadequate data and include:
? absence of representative atmospheric monitoring;
? absence of dermal exposure data;
? lack of data on the health effects of triclosan in humans following repeated
exposures; and
? use of a default oral NOAEL for determination of MOE estimates as no
reliable evidence of systemic toxicity was seen in dermal studies in a
suitable animal model.
In addition, the assumptions used in EASE modelling add uncertainties to the risk
characterisation.
8.2.5 Areas of concern
Risk characterisation has indicated that under occupational conditions the risk to
workers of adverse health effects such as inhalation toxicity, skin, eye and
respiratory irritation and chronic effects is low. However, the risk of skin, eye and
respiratory irritation are likely to increase during accidental spills or leaks of
triclosan and/or products containing high concentrations of triclosan, especially
where PPE is not used.
8.3 Public health risk
8.3.1 Public exposure - Adults
Exposure may occur through the use of consumer products containing triclosan.
The major exposure scenarios are:
? Use of cosmetic and personal care products containing triclosan;
? Use of household products containing triclosan; and
? Use of articles containing triclosan.
42 Priority Existing Chemical Assessment Report
Potential routes of exposure are via inhalation and dermal contact. The likelihood
of exposure by ingestion is expected to be low in adults.
Measured exposure data are limited for consumer exposure scenarios. Some data
are available for repeated use of cosmetic and personal care products.
Consequently, exposure models have been used to predict consumer exposure to
triclosan during use of various categories of products (see Part 2, Section 15.3) and,
as conducted for occupational risk, a MOE methodology has been used by
comparing quantitative information on exposure to the NOAEL/NOAEC and
deriving a MOE (see Section 8.1 for further details).
The limited measured data available has been used to undertake risk
characterisation by an alternative method, namely, comparing it with levels of total
triclosan (i.e. triclosan and its metabolites) in the plasma at the identified
NOAEL/NOAEC.
MOE = plasma levels at NOAEL/plasma level following use of consumer product.
As stated previously in sub-section 8.1:
? as the MOE increases the risk of potential adverse effects decreases;
? in deciding whether the MOE is of sufficient magnitude, expert judgment
is required; and
? the critical health effects from acute exposure to triclosan are inhalation
toxicity, skin, eye and respiratory irritation, and hepatic effects from
repeated exposure.
8.3.2 Public health risk estimates - Adults
Acute risks
The potential for acute inhalation toxicity, skin, eye and respiratory irritation could
arise as a result of consumer use of:
? cosmetic and personal care products containing triclosan; and
? household products containing triclosan.
The concentration of triclosan in cosmetics and personal care products ranges from
< 0.01 - 0.5% and in household goods ranges from 0.04 ?0.3%. At these low
concentrations the risk of the irritant effects and inhalation toxicity of triclosan is
not expected.
Additionally, textile and plastic articles containing triclosan do not present a risk
for inhalation toxicity or skin, eye and respiratory irritation.
Risks from repeated exposure
Potential concerns for repeat dose toxicity arise from those consumer exposure
scenarios that involve repeated exposure to triclosan. The use of cosmetic, personal
care and household products and articles containing triclosan can all occur on a
daily basis and so are relevant.
The calculations of consumer exposure for cosmetic and personal products, and
household cleaning products using estimated data (see Part 2, Section15.3 and 15.4
43
Triclosan
respectively) are based on the maximum levels of triclosan in each type of product
in Australia. Furthermore a worst-case exposure scenario has been determined, that
assumed a person was exposed to all possible types of product (e.g. deodorant,
body lotion, facial mask etc) containing triclosan. Consequently, it is recognised
that the determined body burdens and subsequent MOE range presented are
unlikely to be applicable to all consumers (i.e. MOE's would be greater).
Measured plasma levels - cosmetic and personal care products
There is potential for minor hepatic effects to arise as a result of repeated use of
cosmetic and personal care products (see Section 8.2.3 chronic effects). Limited
studies are available measuring plasma levels of total triclosan in volunteers
following repeated use of triclosan-containing cosmetic and personal care products.
Such studies are considered the most appropriate as repeated use allows steady
state plasma levels to be reached. A NOAEL of 41 礸/mL (level in animal plasma)
for hepatic effects was used to estimate MOE for repeated use of cosmetic and
personal care products. A summary of appropriate studies with estimated MOEs
derived from measured data are presented in Table 8.2.
The lowest MOE was 179 in male volunteers following use of a soap containing
1% triclosan. However, a MOE of 1367 ?2050 was obtained following use of an
unspecified bath product containing a comparable amount of triclosan (0.75%).
Similarly, while MOEs of 258 and 311 were seen in female and male volunteers
following use of a toothpaste containing 0.3% triclosan, MOEs of 1595 ?2000
were seen following use of a dentifrice containing 0.28% triclosan.
Thus, considerable variation has been seen in plasma steady state levels of total
triclosan in volunteers following single use of similar products containing similar
concentrations of triclosan. Though the majority of the studies, including a multiple
product use study with triclosan concentrations ranging from 0.28% ?0.75%,
indicate MOEs >1000 which are considered satisfactory, there is evidence of
MOEs of approximately 180 ?310 in some studies. Considering the nature of the
health effect used to derive the NOAEL (minor histopathological changes in
hepatic cells in male rats that were not consistently seen in interim sacrifice groups
throughout a carcinogenicity study), all the derived MOEs are considered to
indicate a low risk of chronic effects following repeated use of consumer products
containing triclosan.
However, the above data does raise a potential concern, namely, that MOEs lower
than those observed may be possible in some individuals through combined use of
many products containing triclosan, and/or products containing relatively high
concentrations of triclosan.
44 Priority Existing Chemical Assessment Report
Table 8.2 ?Calculated margins of exposure (MOE) in adults for effects
on the liver from measured exposure to cosmetic and personal care
products
Product Plasma level of total MOE based on
plasma levels1
triclosan in humans
(ng/mL)
Single product use
2292
Hand wash (1%) 179
1583 259
Unspecified bath product (0.75%) Approx 20 - 30 2050 - 1367
Dentifrice (0.2%) 26.7 1536
22.74
Dentifrice (0.28%) 1806
25.75 1595
20.56 2000
1322
Toothpaste (0.3%) 311
1593 258
Multiple product use
36.74 1117
Soap bar (0.75%) Deodorant (0.39%)
34.35 1195
Dentifrice (0.28%)
1
Calculation based on animal plasma level of total triclosan at the NOAEL: plasma level of
41 礸/mL which is the combined average of male and female values observed at 3, 6, 12,
18 and 24 months.
2
Maximum level observed in male volunteers
3
Maximum level observed in female volunteers
4
Maximum level observed in Caucasian (white) volunteers
5
Maximum level observed in Negroid (black) volunteers
6
Maximum level observed in Mongoloid (oriental) volunteers
Risks from repeated exposure to cosmetic and personal care products
using estimated exposure data
Information on triclosan concentrations in cosmetic and personal care products was
available, however, there was no information on Australian use patterns.
Consequently, use patterns and exposure models were adopted from the EU
technical guidance document on risk assessment (EC, 2003a) and guidance note for
the testing of cosmetic ingredients and their safety evaluation (SCCNFP, 2003).
The estimated MOEs are presented in Table 8.3.
Table 8.3 ?Calculated margins of exposure (MOE) in adults for effects
on the liver from estimated exposure to cosmetic and personal care
products
Combined
Inhalation Dermal MOE (based on
Oral body burden
? ? NOAEL of 40
(礸/kg (礸/kg
? ?br>
(礸/kg bw/day) (礸/kg
mg/kg bw/day)
bw/day) bw/day)
bw/day)
18.0 - 53.9 145.5 24.4 187.9 - 223.8 212.9 - 178.7
45
Triclosan
The body burden level used to estimate MOE is derived from a worst-case
scenario, where exposure is assumed to all products containing triclosan by all
exposure routes. The estimated MOE range is therefore, a worst-case range. It is
expected that for the majority of the population the MOE will generally be at the
higher end of the predicted range. However, there may be a subgroup of consumers
who repeatedly use multiple products containing triclosan. In this subgroup the
MOE may be at the lower end of the predicted range. The estimated MOE range is
considered to indicate a low risk by chronic effects following repeated use of
consumer products containing triclosan in the majority of the population.
Estimated risk from repeated exposure - household cleaning products
Information was only available on triclosan levels in Australian household cleaning
products, and the use patterns and exposure models were adopted from the EU
technical guidance document on risk assessment (EC, 2003a). These estimated
MOEs are presented in Table 8.4.
Table 8.4 ?Calculated margins of exposure (MOE) in adults for effects
on the liver from estimated exposure to household cleaning products
Dermal Oral Combined
Inhalation MOE (based on
body burden
? NOAEL of 40
? ?br>
(礸/kg (礸/kg (礸/kg
mg/kg bw/day)
?br>
bw/day) bw/day) bw/day) (礸/kg bw/day)
1.7 - 349.5 0.34 ND 2.04 - 349.84 19608 - 114.3
The estimated MOE range is a worst-case scenario based on exposure to a number
of household cleaning products and is unlikely to be reflective of normal use.
Exposure to all the cleaning products is also unlikely to occur on a daily basis. It is
therefore considered that the realistic MOE is likely to be at the higher end of the
predicted range. Consequently, the risk of chronic effects from the use of
household products containing triclosan is low.
Estimated risks from repeated exposure ?articles
Minimal data on triclosan levels in articles in use in Australia is available.
Furthermore, potential dermal and oral exposure from articles containing triclosan
could not be determined as no data on the migration of triclosan from such are
available. Dermal exposure is based only on contact with painted surfaces.
Inhalation exposure was calculated using the OECD Environmental Directorate
model (OECD, 1993) and is likely to be an overestimate. However, the derived
MOE (see Table 8.5) still indicates that the risk of chronic effects from the use of
articles containing triclosan is low.
46 Priority Existing Chemical Assessment Report
Table 8.5 ?Calculated margins of exposure (MOE) in adults for effects
on the liver from estimated exposure to articles
MOE (based
Inhalation Combined
Dermal on NOAEL of
Oral
? body burden
(礸/kg
? 40 mg/kg
(礸/kg ?br>
?br>
bw/day) (礸/kg bw/day)
(礸/kg bw/day) bw/day)
bw/day)
3.8 0.56 No Data 4.4 9090
Summary of estimated risks from repeated exposure in adults
Table 8.6 below provides a summary of the data including an overall body burden
and MOE when major exposure scenarios are combined. In determining an overall
total body burden and MOE for cosmetic and personal care products estimated
exposure data has been used, as values are reported in 礸/kg bw/day as for other
scenarios. Additionally for cosmetic and personal care products, though the MOEs
derived from measured data were generally >1000 some studies had values similar
to the estimated range.
Table 8.6 ?MOEs in adults for exposure scenarios to triclosan
MOE (based on
Public exposure scenario Combined body
? NOAEL of 40 mg/kg
burden (礸/kg
bw/day)
bw/day)
Cosmetic & personal care products 187.9 - 223.8 212.9 - 178.7
Household cleaning products 2.04 - 349.84 19608 - 114.3
Article surfaces 4.4 9090
193.7 - 577.4 206.5 - 69.3
All exposure scenarios combined
Individual public exposure scenarios showed MOE ranges greater than 100,
indicating low risk (Table 8.6). The higher value in the predicted MOE range for
all exposure scenarios combined is similar to that for cosmetic and personal care
products, indicating that the greatest contributor to the overall body burden are
from the use of such products. The lower MOE value less than 100 in the
predicted MOE range for combined scenario (MOE = 69.3) indicates that there
could be risks when using cosmetic and personal care products, and household
cleaning products together with exposure to article surfaces by the same person.
8.3.3 Public exposure - children
This section focuses on babies and young children up to five years old. Exposure to
this sub-group may occur from direct contact with consumer products containing
triclosan. The major exposure scenarios are:
? Use of personal care products containing triclosan; and
? Use of articles containing triclosan.
In addition, exposure to triclosan may also occur via breast milk in breast-fed
babies.
47
Triclosan
Potential routes of exposure are via inhalation and dermal contact, and the oral
route from the sucking or mouthing of textile articles and/or breast-feeding.
As for consumer exposure to adults, measured exposure data is limited and
exposure models have been used to predict exposure to various categories of
products. Additionally, a MOE methodology was undertaken.
8.3.4 Risk estimates - children
Acute risks
As for adults (see Section 8.3.1) the risk of inhalation toxicity, skin, eye and
respiratory irritation as a result of exposure to personal care products is low.
Articles containing triclosan present a low risk.
Risks from repeated exposure
Limited data are available on the concentration of triclosan and patterns of use for
triclosan containing products that may be used on children. In determining
exposure to these products assumptions have been made regarding application
volume to children (see Section 4.2.2 for more details). Consequently, it is likely
that the predicted exposure levels may be over-estimates.
Estimated risks from repeated exposure - personal care products
Dermal exposure was estimated for use of a body lotion on babies and children up
to five years old. Additionally, oral exposure was estimated from use of toothpaste
in children between one and five years. The data is presented in Table 8.7.
Table 8.7 -Calculated margin of exposure (MOE) in children for effects
on the liver from estimated exposure to cosmetic and personal care
products
Age Dermal Oral Combined MOE (based on
? ?br>
(years) body burden NOAEL of 40
(礸/kg (礸/kg
? mg/kg bw/day)
bw/day) bw/day) (礸/kg bw/day)
<1 85 N/A 85 471
2 84 15.5 99.5 402
5 56 10.3 66.3 603
The estimated MOEs are for a worst-case scenario, as the maximum concentration
of triclosan in Australian consumer goods likely to be used by children have been
taken to determine body burdens. The estimated MOEs for all the age groups are
>100 and are based on the minor health effects observed in animals at the selected
NOAEL of 40 mg/kg bw/d. Thus, these MOEs for children are considered to
indicate a low risk of chronic effects following repeated use of multiple consumer
products containing triclosan.
48 Priority Existing Chemical Assessment Report
Estimated risks from repeated exposure ?articles
The OECD Environmental Directorate model (OECD, 1993) was used to
determine exposure from a textile or plastic article based on the chemical's vapour
pressure. However, no data is available on the leaching of triclosan from articles
that would allow potential oral or dermal exposure to be predicted. It is considered
that oral and dermal exposure to triclosan through use of articles containing
triclosan will be low and, thus, the contribution to the total body burden is likely to
be negligible. Dermal exposure to triclosan through contact with painted surfaces
has been estimated based on 100% availability from the thin films. The data is
presented in Table 8.8 and the derived MOEs indicate that the risk of chronic
effects from exposure to articles containing triclosan is low.
Table 8.8 - Calculated margin of exposure (MOE) in children for effects
on the liver from estimated exposure to articles
Body Body MOE (based on
Age Body
burden burden NOAEL of 40 mg/kg
(years) burden
- inhalation - inhalation - total - bw/day)
? ? ?br>
(礸/kg (礸/kg (礸/kg
bw/day) bw/day) bw/day)
Infant
<1 7.40 5.90 13.30 3007
Children
2 5.27 0.46 5.73 6981
5 4.28 0.42 4.70 8511
Estimated risks from repeated exposure ?breast milk
Exposure was determined in exclusively breast-fed babies based on the maximum
level of total triclosan observed in an Australian breast milk study (see Appendix
E). The data is presented in Table 8.9 and the derived MOEs indicate that the risks
of chronic effects from exposure through breast milk containing triclosan is low.
Table 8.9 - Margin of exposure (MOE) in children for effects on the
liver from the maximum level of total triclosan measured in Australian
breast milk
Body burden MOE (based on NOAEL of
- oral - 40 mg/kg bw/day)
Age (month)
?br>
(礸/kg bw/day)
1 3.04 13 158
2 2.46 16 260
3 2.22 18 018
4 2.10 19 048
49
Triclosan
Summary of estimated risks from repeated exposure in children
Table 8.10 below provides a summary of the data including an overall body burden
and MOE when major exposure scenarios are combined. As stated previously the
derived MOEs are likely to be overestimates. As for adults, it can be seen that the
predicted MOE for all exposure scenarios combined is similar to that for cosmetic
and personal care products, indicating that the greatest risk by far comes from the
use of cosmetic and personal care products. Furthermore, Table 8.10 also indicates
that the lowest risk for children is from exposure through breast-milk containing
triclosan.
Table 8.10 ?MOEs in children for exposure scenarios to triclosan
Source of exposure Age Combined body MOE (based on
(years) NOAEL of 40
burden
mg/kg bw/day)
?br>
(礸/kg bw/day)
<1
Cosmetic & personal 85 471
care products
2 99.5 402
5 66.3 603
Breast milk <1 3.04 13 158
Article surfaces <1 13.30 3007
2 5.73 6981
5 4.70 8511
<1 95.44 395
All sources of
exposure combined 2 104.77 380
5 70.58 564
8.3.5 Uncertainties in public risk estimates
Uncertainties involved in the public health risk characterisation for both adults and
children result from database limitations. There is a lack of Australian data on the
use patterns of consumer products containing triclosan to allow a realistic exposure
assessment. Additionally there is very limited measured data, meaning that
generally exposure models have been used to determine the sources of exposure
that represent the greatest risk to consumers. Such models are not as reliable as
measured data as they mostly use conservative assumptions.
8.3.6 Areas of concern
The available information indicates that public use of triclosan products and hence
potential exposure is widespread. The risk characterisation has indicated that under
normal conditions of consumer use the risk of adults and children being exposed to
levels of triclosan that would lead to adverse health effects such as inhalation
toxicity, skin, eye and respiratory irritation and chronic effects is low. Of all the
sources of exposure the risk estimation indicated that the lowest MOEs, using
modelled data, were from combined use of triclosan containing products (cosmetic
and personal care products, cleaning products and exposure to article surfaces).
50 Priority Existing Chemical Assessment Report
However, the use patterns of triclosan-containing products vary greatly among
individuals.
Some studies in humans show a high level of exposure following use of a single
cosmetic or personal care product. This raises concerns that chronic health effects
may potentially occur in some individuals through the combined use of a range of
cosmetic and personal care products containing triclosan, or use of certain products
containing relatively high concentrations of triclosan. However, these limited
incidences are not reflective of general consumer exposure.
8.4 Biological monitoring data
The population-based biological monitoring data are believed to be a more accurate
predictor of aggregate exposure because not only are the data triclosan specific,
they are also based on actual consumer use of the various triclosan products as they
naturally co-occur (Us EPA, 2008). However, there are uncertainties in the
biological monitoring data.
In the US EPA aggregated risk assessment, the population-based biological
monitoring data based on spot urine concentrations were obtained from the
National Health and Nutrition Survey. Based on the results at the mean and 99th
percentile, the aggregated risk to triclosan from all uses did not trigger a risk of
concern (using an oral NOAEL of 30 mg/kg bw/d in baboons MOEs were >100
even for the most conservative dose and conversion method) (US EPA, 2008).
51
Triclosan
9. Environmental Risk Characterisation
9.1 Environmental release and degradation
This section provides a characterisation of risks to the Australian environment from
use of triclosan as an anti-microbial agent. A risk quotient (RQ) approach has been
used to predict the risk to aquatic organisms, terrestrial (soil-dwelling) organisms,
and wildlife associated with aquatic and terrestrial environments. To predict an
acceptable environmental risk using the RQ approach, the quotient of the predicted
environmental concentration (PEC) divided by the predicted no effect
concentration (PNEC) needs to be 1 or less (i.e. RQ 1).
9.1.1 Environmental release of triclosan
Environmental release of triclosan is unlikely during importation, storage and
transportation. Containers of triclosan will be transported directly from port
facilities to several industrial facilities throughout Australia for use in the
manufacture of various products. In addition, triclosan in finished products will be
imported (in ready-to-use products and articles) and distributed throughout
Australia for consumer use. Accidental spills, leaks and catastrophic mechanical
failure during a transport accident are the most likely reasons for environmental
release. Engineering controls (e.g. container specifications) and emergency clean-
up procedures (i.e. spill response instructions on Material Safety Data Sheet and
label) will limit the impact on the environment of such incidents.
Triclosan is incorporated into cosmetics and personal care products that after
application may wash off directly into natural surface waters, such as during
bathing and primary aquatic recreational activities. Due to the uncertainty in
estimating environmental release by this pathway, no predicted environmental
concentration (PEC) in surface waters has been derived. Greater risks to the aquatic
environment would be more likely in populated areas during peak usage times, and
in surface waters with limited flow or longer hydraulic residence time (e.g. ponds,
lakes).
9.1.2 Wastewater treatment plant systems
The majority of triclosan used in Australia will eventually be washed off or
otherwise enter the Australian sewerage system where it will mix with a wide
range of chemical and biological constituents typically found in wastewater. Most
wastewater treatment plants (WWTPs) and sewage treatment plants (STPs) rely on
microbial processes to enable treatment and degradation of wastewater
constituents. In general, wastewater with inhibitory levels of contaminants may
reduce or cease the treatment plant's ability to degrade wastewater constituents,
potentially resulting in the release of poorly treated wastewater into the
environment in effluent and sludge with potential adverse impacts.
Although triclosan has anti-microbial properties, the international literature
indicates that microbial biodegradation processes (e.g. secondary treatment) enable
significantly greater treatment and degradation of triclosan relative to primary
treatment processes. This indicates that the communities of sewage
microorganisms within the STPs tested were capable of treating some if not most
52 Priority Existing Chemical Assessment Report
of the triclosan during operational conditions. In addition, variable rates of
biodegradation of triclosan, particularly through mineralisation to CO2, have been
demonstrated over time in laboratory tests involving sewage sludge micro-
organisms exposed to triclosan at concentrations in the range of 10-5000 礸/L, and
in one long-term study with a triclosan concentration of 500 000 礸/L (Table 16.3).
Furthermore, specific microorganisms have been identified in sewage sludge that
are capable of partially mineralising triclosan through a series of co-metabolic
steps.
However, biodegradation studies indicate that the rate of biodegradation of
triclosan is generally proportional to exposure time and inversely proportional to
triclosan concentration, and the degradation rate probably also depends on the
microbial community and whether it has been acclimatised to triclosan as well as
the environmental conditions (e.g. aerobic versus anaerobic; Table 16.3). At
elevated concentrations, triclosan may potentially inhibit sewage microbes, species
or communities. At concentrations of up to 20000 礸/L, triclosan was not readily or
inherently biodegradable under aerobic conditions and the inability to degrade
triclosan is attributed to inhibition of microbial growth as a 3-hour IC50 of 20000
礸/L has been reported. Inhibition of growth, CO2 evolution and nitrification have
been reported under aerobic conditions at concentrations 600 礸/L; however,
some studies show that inhibition at an exposure concentration of 2000 礸/L may
be relatively minor if microbes have been pre-exposed to low concentrations of
triclosan. A lag phase before degradation has also been demonstrated in some
microbial degradation studies.
For triclosan, anaerobic microbial degradation, a process used in many STPs, is
slow relative to aerobic biodegradation. In one study, ~91% of the extractable
residues remained as 14C-triclosan after 147 days of incubation with anaerobic
inoculum and anaerobic conditions (Springborn Laboratories Inc., 1994a).
Microbial analysis of the sludge during the study indicated that the sludge microbes
remained viable.
Based on the estimated use and disposal pattern for triclosan in Australia, a mean
annual wastewater concentration for triclosan in the Australian sewerage system of
14500-17400 ng/L (see Section 16.5) has been estimated. Recently, triclosan levels
have been measured in the influent of five Australian STPs in concentrations
ranging from 573 to 845 ng/L, and triclosan concentrations in secondary and
tertiary treated effluents have been observed in the range 23-434 ng/L (with a
median measured concentration of 108 ng/L and a mean of 142 ng/L) from 19
STPs (Ying and Kookana, 2007). This compares with a range of <100-740 ng/L in
effluent from three primary treated STPs measured in the mid 90s. As a
comparison, the available monitoring data from international sources indicate
triclosan concentrations in untreated wastewater in the range of <100-562000 ng/L
and secondary and tertiary treated effluents of 10-2700 ng/L (see Table 16.54).
Hence, estimated concentrations of triclosan in Australian sewage systems are at
the lower end of the range of concentrations measured internationally. However
the study by Ying and Kookana (2007) did not cover many urban STPs (none in
the largest urban areas in Australia) and as a result the full range of triclosan
concentrations in influent and effluent across Australia is not yet clear.
STP monitoring studies indicate that a relatively high rate of removal of triclosan
(95%) can be achieved after secondary (activated sludge and trickling filter)
treatment processes even when the influent triclosan concentration was 7500-
53
Triclosan
21900 ng/L (Sabaliunas et al., 2003). However, in another STP, removal efficiency
of only 35%-42% was achieved after secondary treatment (aerobic digestion) of
influent containing triclosan in the range of 30100-37800 ng/L, though at the same
STP, a lower influent triclosan concentration of 1300-2600 ng/L resulted in a
higher treatment efficiency (69%). At relatively low influent concentrations, the
available data from STP monitoring do not indicate a particular trend of decreasing
treatment efficiency with increasing triclosan concentration; however, at higher
influent concentrations, treatment efficiency apparently declines. Although this
apparent trend may potentially be related to inhibition of the microbial processes
by triclosan (as discussed above), it is not possible to extrapolate between STPs
due to the different treatment processes and environmental conditions and other
factors may have also resulted in the lower treatment efficiency of triclosan when
at relatively high influent concentrations. The available data has been collected
from a range of treatment processes across a number of countries. The measured
removal rate for five STPs (3 tertiary and 2 secondary) ranged between 72-93%.
However, given that this is a small sample of the nearly 900 STPs across Australia
it is uncertain how representative this would be of the wider Australian sewage
treatment system. Consequently, the following assessment has been conducted
based on the ranges removed that have been observed in international data.
9.2 Aquatic risk
9.2.1 Predicted No Effect Concentration (PNEC) for triclosan
Although triclosan has been used in Australia and internationally for many years,
and has been discharged into aquatic receiving environments (freshwater,
estuarine, marine) in treated wastewaters and other products, no published
freshwater or marine water or sediment quality guidelines were available from the
Australian or international literature for triclosan for the protection of aquatic
ecosystems. Consequently, predicted no effect concentrations (PNECs) have been
derived in this assessment from the ecotoxicity data available using recognised
Australian methodology for deriving guidelines (ANZECC and ARMCANZ,
2000).
While no published guidelines are available, several other authors/agencies have
also derived PNECs or equivalent values for triclosan for the protection of
freshwater organisms:
? The Danish Environmental Protection Agency (Danish EPA, 2003b), using
the European Union principles for derivation of Predicted No Effect
Concentrations (PNECs), derived a PNECaquatic of 0.05 礸/L for triclosan
by dividing the lowest available NOEC, for a freshwater alga (0.5 礸/L;
RCC, 1995), by a safety factor of 10.
? The quality and reliability of the algae toxicity data available for triclosan
have been reviewed elsewhere by Hanstveit and Hamwijk (2003) and the
NOEC of 0.69 礸/L (S. subspicatus; ABC Laboratories, 1997a) was
considered the most reliable value in their view, stating that the lower
NOEC of 0.5 礸/L (RCC, 1995) was from a test which had discrepancies
between the control and acetone control that cast doubt on the incubation
conditions used. A PNEC of 0.069 礸/L was derived by dividing this
NOEC by an assessment factor of 10.
54 Priority Existing Chemical Assessment Report
? The abovementioned PNECfreshwater of 0.069 礸/L (~0.07 礸/L) is also
referred to in a Briefing Note prepared by the Environment Agency (2004)
and a report of the fate of triclosan in wastewater treatment (Thompson et
al. 2005).
Recent work by Veldhoen et al. (2006) on the effects of triclosan on the
development of tadpoles of the North American bullfrog, Rana catesbeiana
demonstrated alterations in gene expression at concentrations of 0.03 礸/L
triclosan. Precocious hormonally-induced metamorphosis was recorded after
exposure to concentrations of 0.15 ?.03 礸/L triclosan. In isolation, this work is
not considered sufficient demonstration that exposure to such concentrations
during development in the wild would result in lasting adverse effects such as
reduced survivorship. Nevertheless, these early results do indicate the potential for
interference with thyroid hormones at extremely low concentrations.
While this study in isolation is considered insufficient to determine the regulatory
endpoint, these data contribute to the weight of evidence that adverse effects are
likely to occur at concentrations below those measured in the field.
9.2.2 Risk to freshwater ecosystems
Aquatic toxicity data are available for four freshwater taxa with 13 species (acute
studies) and three taxa with 10 species (chronic studies).
The aquatic toxicity data available indicate that the green algae (Scenedesmus
subspicatus) and the cyanobacterium (Anabaena flos-aquae) are relatively sensitive
to the adverse effects of triclosan (refer Table 21.5). A PNECfreshwater of 0.05 礸/L
(50 ng/L) is adopted for this assessment based on dividing the NOEC, for the
freshwater alga Scenedesmus subspicatus (0.5 礸/L; RCC, 1995), by a safety factor
of 10, in line with the Danish Environmental Protection Agency (Danish EPA,
2003b). This is in agreement with the PNEC of 58 ng/L determined using the
protective concentration of 0.29 礸/L to protect 95% of species derived using
BurrliOZ modelling and applying an assessment factor of 5 in line with the EC
Technical Guidance Document (Appendix H). It is also a compromise with the
PNEC of 20 ng/L which would be derived from the lowest reported NOEC for
green alga (0.2 礸/L for the green alga Pseudokirchneriella subcapitata) and
applying the same assessment factor of 10.
The derived risk quotients in Table 9.1 based on the predicted environmental
concentrations near STP outlets indicate that the current use rate of triclosan
presents an unacceptable risk to freshwater organisms. A risk to aquatic organisms
is indicated for each type of wastewater treatment considered, from primary to
tertiary; moreover, in each case this is so even at the lowest predicted
concentration. It should be noted that higher levels of wastewater treatment are
applied where the receiving water is freshwater. Unacceptable risk quotients are
also predicted based on the limited Australian measured triclosan levels for
untreated wastewater, treated effluent and surface waters. The risk quotients for the
measured Australian data are much lower than those for the predicted
concentrations.
55
Triclosan
Table 9.1 - Risk Quotients (PECFreshwater/PNECFreshwater) for freshwater
ecosystems based on removal rates for sewage treatment levels
Level of Treatment Removal PECFreshwater PNECFreshwater PECFreshwater
rate (%) a (triclosan, (triclosan,
PNECFreshwater
礸/L) 礸/L)
Untreated wastewater --- 14.5-17.4 0.050 290-347
Primary Treatment 2-96 0.581-17 0.050 12-341
Secondary Treatment
Trickling Filter 58-96 0.581-7.3 0.050 12-146
Activated
55-99 0.145-7.82 0.050 3-156
Sludge
Activated
61-72 4.07-6.78 0.050 81-136
sludge (SimpleTreat)
Tertiary treatment 0.145-2.26 0.050 3-45
87-99
Measured Australian Data
PNECFreshwater PECFreshwater
PECFreshwater
(triclosan,
(triclosan 礸/L) PNECFreshwater
礸/L)
Untreated Effluent 0.573-0.845 0.050 11-17
Treated Effluent 0.023-0.740 0.050 0.46-14.8
Surface Waters 0.014-0.070 0.050 0.28-1.4
International surface b
0.050 <46
<2.300
waters
a Removal rate obtained from literature sources (see Section 16.5). Freshwater PEC values obtained
by dividing the estimated effluent concentration by receiving environment dilution factors of 1. Data
are from Table 16.6.
b excludes levels near manufacturing facility
9.2.3 Risk to marine ecosystems
Many large sewerage systems discharge into marine environments, but there is a
paucity of aquatic toxicity data for triclosan to marine organisms. In the absence of
adequate marine toxicity data, the PNECfreshwater of 0.05 礸/L is adopted as a PNEC
for marine waters for this assessment. This approach is supported by a preliminary
review of comparative freshwater and marine ecotoxicity data by ECETOC (2003).
56 Priority Existing Chemical Assessment Report
Table 9.2 - Risk Quotients (PECMarine/PNECMarine) for marine
ecosystems based on removal rates for sewage treatment levels
Level of Treatment Removal PECMarine PNECMarine PECMarine
rate (%)* (triclosan, (triclosan,
PNECMarine
礸/L) 礸/L)
Untreated wastewater --- 0.050
1.5-1.7 29-34.7
Primary Treatment 2-96 0.050
0.058-1.7 1.2-34.1
Secondary Treatment
Trickling Filter 58-96 0.050
0.058-0.73 1.2-14.6
Activated Sludge 55-99 0.050
0.015-0.78 0.3-15.6
Activated sludge
61-72 0.050
0.41-0.68 8.1-13.6
(SimpleTreat)
0.015-0.23 0.050
Tertiary treatment 87- 99 0.3-4.5
Measured Australian Data
PNECMarine PECMarine
PECMarine
(triclosan,
(triclosan 礸/L) PNECMarine
礸/L)
Untreated Effluent 0.0573-0.0847 0.050 1.1-1.7
Treated Effluent 0.0023-0.0740 0.050 0.046-1.48
Surface Waters 0.0014-0.0070 0.050 0.028-0.14
* Removal rate obtained from literature sources (see Section 16.5.2). Marine PEC values obtained by
dividing the estimated effluent concentration by receiving environment dilution factors of 10.
The derived risk quotients in Table 9.2 based on the predicted environmental
concentrations indicate that the current use rate of triclosan also presents an
unacceptable risk to marine organisms, though the risk quotients are significantly
lower than the corresponding freshwater situation. Risk is only marginal from
treated effluent based on the available although quite limited Australian figures.
While significant quantities of Sydney's wastewater (~75%) are discharged to the
marine environment after receiving only high flow primary treatment, Table 9.2
includes data from three of the major plants, including Malabar STP which is
responsible for the highest value. However, the risk is acceptable to the Australian
marine environment once a minimum level of dilution has taken place.
9.2.4 Risk to sediment dwelling organisms
Toxicity data are available for two freshwater taxa with 2 species. The most
sensitive organism is the amphipod Hyalella azteca which has a reported LC50 of
200 礸/L (Dussault et al. 2008). Based on this endpoint and applying an assessment
factor of 1000 (based on the lack of data) the PNECsediment for sediment dwelling
organisms has been determined to be 0.2 礸/L. It is inappropriate to use the result
of 100 mg/kg for exposure to spiked sediment as aquatic organisms will be
exposed through the water column and also the triclosan used in this study was
strongly bound to the sediment. The derived risk quotients in Table 9.3 based on
the predicted environmental concentrations near STP outlets indicate that the
current use rate of triclosan presents an unacceptable risk to sediment dwelling
57
Triclosan
organisms. A risk to sediment dwelling organisms is indicated for each type of
wastewater treatment considered, from primary to tertiary; moreover, in each case
this is so even at the lowest predicted concentration. Once again, it should be noted
that higher levels of wastewater treatment are applied where the receiving water is
freshwater. Unacceptable risk quotients are also predicted based on the limited
Australian measured triclosan levels for untreated wastewater and treated effluent.
However, the risks based on the measured levels in Australian surface waters are
acceptable.
Table 9.3 - Risk Quotients (PECSDO/PNECSDO) for Sediment Dwelling
Organisms (SDO) based on removal rates for sewage treatment levels
Level of Treatment Removal PECSDO PNECSDO PECSDO
rate (%) a (triclosan, (triclosan,
PNECSDO
礸/L) 礸/L)
Untreated wastewater --- 14.5-17.4 0.2 72-87
Primary Treatment 2-96 0.581-17 0.2 2.9-85
Secondary Treatment 0.2
Trickling Filter 58-96 0.581-7.3 0.2 2.9-36
Activated
55-99 0.145-7.82 0.2 0.72-39
Sludge
Activated
61-72 4.07-6.78 0.2 20-34
sludge (SimpleTreat)
0.145-2.26
Tertiary treatment 0.2 0.72-11.3
87-99
Measured Australian Data
PNECSDO PECSDO
PECSDO
(triclosan,
(triclosan 礸/L) PNECSDO
礸/L)
Untreated Effluent 0.573-0.845 0.2 2.86-4.22
Treated Effluent 0.023-0.740 0.2 0.115-3.7
Surface Waters 0.014-0.070 0.2 0.07-0.35
International surface b
0.2 2.86-4.22
<2.300
waters
a Removal rate obtained from literature sources (see Section 16.5). Sediment Dwelling Oraganisms
PEC values obtained by dividing the estimated effluent concentration by receiving environment
dilution factors of 1. Data are from Table 16.6.
b excludes levels near manufacturing facility
Sediment dwelling organisms also include microbial populations that have been
shown to play an important role in the recycling of essential elements such as
carbon, nitrogen and phosphorus (Alongi 1994 and Costanzo et al. 2005). The
continual discharge of triclosan has the potential to disrupt these microbial
populations possibly affecting the recycling of these nutrients.
In addition, there are data to suggest that triclosan accumulates in sediments that
are distant from catchment sources (Singer et al., 2002), as well as the persistence
of triclosan in sediments.
58 Priority Existing Chemical Assessment Report
9 .3 Terrestrial risk
Most of the triclosan used each year will, after use, be sent to sewer where
treatment in STPs is expected to account for degradation of much of the triclosan
present. However, a fraction entering the sewerage system is expected to partition
in the sludge phase with a proportion remaining in the treated water. This is
supported by international monitoring data from a range of unit processes. Hence,
terrestrial organisms may be exposed to triclosan through contact with STP sludge
or treated water containing triclosan. The following sections look at the risk
associated with exposure to these sources of triclosan in the environment.
9.3.1 Risk associated with sludge and biosolids from STPs containing
triclosan
Traditionally, sewage sludge was disposed of to landfill or incinerated and these
practices continue in parts of Australia (e.g. incinerated in the Australian Capital
Territory). However, an increasing proportion is being reclaimed as biosolids and
re-used for soil conditioning (see Appendix A). For example, in Sydney in 2002-3,
Sydney Water Corporation captured solids to the equivalent of ~51000 dry tonnes
of biosolids of which 100% was used for soil conditioning applications in
agriculture (60%), forestry (20%-35%), land rehabilitation, landscaping and
horticulture (5%-20%). The use of biosolids as a soil conditioning agent results in
the exposure of soil dwelling organisms such as earthworms as well as crops
through their roots and seeds, to triclosan.
Limited data is available for soil dwelling organisms; NOEC values are available
for six plant species (Table 21.2) and earthworms (1026 mg/kg dry wt; Section
21.2). Based on this data, an assessment factor of 50 has been adopted for this
assessment. The lowest available NOEC is for cucumber of 96 礸/kg (dry wt) (see
Table 21.2) resulting in a PNEC of 1.92 礸/kg dry wt. This endpoint is less
conservative than the PNECsoil of 0.096 礸/kg (dry wt) derived by the Danish
Environmental Protection Agency (2003b), based on dividing the lowest available
NOEC by a safety factor of 1000. This PNEC was considered preliminary due to
the lack of soil ecotoxicity data available.
The predicted soil (PECsoil) concentrations outlined in Section 16.5.7 (Table 16.63)
derived for use of STP biosolids as a soil conditioner have been used to estimate
the risk to soil dwelling organisms resulting from this practice (Table 9.3).
The calculated PECsoil/PNECsoil ratios presented in Table 9.3 for the predicted
biosolids concentrations indicate potential risks to soil dwelling organisms through
the use of sewage sludge contaminated with triclosan as a soil conditioner when
used at a rate of 10 tonnes of biosolids per hectare per annum. The PECsoil/PNECsoil
ratios derived from the Australian measured data range from an acceptable risk at
the lowest measured concentration (0.07 礸/kg dry weight) to an unacceptable risk
at the highest measured concentration (129 礸/kg dry weight), with the large range
reflecting that of the measured concentrations. Ying and Kookana (2007) reached a
similar conclusion based on their data, but with an assessment factor of 1000 (RQ
<1360).
59
Triclosan
Table 9.4 - Risk Quotients (PECSoil/PNECSoil) for soil dwelling
organisms based on the use of sewage sludge as a soil conditioner.
Parameter Environment ASTE (2004) and
Measured
Dillon (2000) model a
Australia (2003)
Australian Datad
STP model
Estimated fraction in
b c b c
sludge based on - -
55% 61% 55% 61%
SimpleTreat model (%)
PECSoil (biosolid
application) 735 815 614 681 0.07 129
(礸/kg dry wt)
Lowest NOEC
96 96 96 96 96 96
(礸/kg dry wt)
Assessment Factor 50 50 50 50 50 50
PNECsoil (礸/kg dry wt) 1.92 1.92 1.92 1.92 1.92 1.92
PECsoil/PNECsoil 383 424 320 355 0.36 67
Notes: The SimpleTreat model output refers only to an activated sludge treatment process. a. Based on a
sludge generation rate of 100 kg/ML of wastewater. b. Assumes inherently biodegradable. c. Assumes
no biodegradation. d. Ying and Kookana (2007).
Consequently, the calculated risk quotients for both the predicted and some of the
measured levels of triclosan in biosolids indicate an unacceptable risk when
biosolids from STPs are used as soil ameliorants. Given the small amount of the
Australian data available it is unclear how representative this is of the levels in
biosolids produced across Australia.
9.3.2 Risk associated with triclosan containing effluent from STPs for
irrigation
The irrigation of crops with sewage effluent containing triclosan will also result in
exposure to soil dwelling organisms. The risk to soil dwelling organisms as a result
of this practice has been determined based on the PECsoil for irrigation presented in
Table 16.63 and the PNECsoil determined above. These are summarised below in
Table 9.5.
Table 9.5 - Risk Quotients (PECSoil/PNECSoil) for soil dwelling
organisms based on the use of treated effluent for irrigation.
Measured
Parameter Environment ASTE (2004) and
Australian Data
Australia (2003) Dillon (2000)
model d
STP model
PECSoil (irrigation)
52.1 a 37.4 a 43.6 a 31.3 a 0.18 b 5.7 b
(礸/kg dry wt)
PNECSoil (礸/kg dry wt) 1.92 1.92 1.92 1.92 1.92 1.92
PECsoil/PNECsoil 27.1 19.5 22.7 16.3 0.09 2.97
a. b.
See Table 16.63 Determined in an analogous manner to the values derived in Table
16.63 with the range of measured triclosan effluent concentrations of 0.023-0.740 礸/L
from Ying and Kookana (2007).
60 Priority Existing Chemical Assessment Report
Once again the generated PECsoil/PNECsoil of Table 9.5 indicate that there is a
potential risk to soil dwelling organisms at a total application rate of 1 m depth
irrigation water per hectare per annum, including the higher end of the range of
measured Australian data. The peak soil concentration is likely to be significantly
reduced by degradation between irrigation events and deeper movement into the
soil. While a potential risk is still indicated (risk quotients approximately 2-3) if it
is assumed the triclosan from a single irrigation event delivering 10 cm is adsorbed
in the surface 10 cm of soil, based on PECs estimated from modelling, the risk
would be acceptable based on PECs estimated from measured Australian biosolid
levels. Recent studies indicate that triclosan will degrade relatively rapidly in
aerobic soils which would mitigate potential risks. However, triclosan will persist
if the soil is anaerobic.
9.3.3 Risks to water-associated wildlife
Derivation of the toxicity reference values (TRVs) for birds and
mammals
Effects on algae and other aquatic organisms indicated above (Table 9.1) may be
sufficient to indirectly impact higher organisms through reduction in their food
supply. The potential for direct toxicity from exposure to triclosan to arise in
wildlife should also be considered. This may arise from dietary exposure
(exacerbated by bioaccumulation in the food chain), from drinking surface water,
or from incidentally or accidentally ingesting sediment.
Due to data limitations, avian and mammalian oral toxicity reference values
(TRVs) have been derived using an assessment (safety) factor (AF) approach rather
than more sophisticated and accurate statistical approaches that are data intensive.
The Approximation Approach of United States Army Center for Health Promotion
and Preventive Medicine (USACHPPM, 2000) has been adopted for this
assessment to derive TRVs as this method is applicable to small sets of toxicity
data. The methodology is scientifically based, and is an important internationally
published guide that describes the rationale and methods for deriving wildlife
TRVs.
Studies are available for the mouse, rat, hamster rabbit, dog and baboon. The data
indicate that the mouse is the most sensitive species to the systemic toxicity of
triclosan. A LOAEL of 25 mg/kg bw/day was identified from a 13-week study in
mice for effects on haematology parameters, relative liver weight and total
cholesterol in both sexes.
An avian repeat dose oral toxicity data of adequate quality is available for triclosan
and has been used to derive the avian TRV. The five day repeat dose in diet oral
NOAEL of 179 mg TCS/kg bw/day for Bobwhite quail, based on the study by Bio-
Life Associates (1993c), has been selected to derive the avian TRV for triclosan as
this was the highest dose tested that resulted in no adverse effects (mortality).
Oral TRVs derived for the assessment of risks from exposure to triclosan by
mammals and birds and the aquatic TRV have been presented in Table 9.6. A high
level of confidence of wildlife health protection is afforded by the derived TRVs
for triclosan.
61
Triclosan
Wildlife TRVs are expressed as an acceptable dose of chemical by a specific
exposure route (e.g. oral, inhalation, or dermal) or as an acceptable environmental
media concentration (e.g. mg/kg of soil). The derived TRVs have been used in an
analogous manner to PNEC values in the risk quotient approach to predict the risks
to mammalian and avian wildlife.
Table 9.6 - Derived mammalian and avian oral TRVs for triclosan
(TCS)
Derived TRV
Taxa and Toxicity Data Reference AF
(mg TCS/kg
bw/day)
Mammals (mg TCS/kg bw)
Sub-Chronic LOAEL: Chapter 18 20 1.25
25 mg TCS/kg bw/day
Birds (mg TCS/kg bw)
Acute NOAEL (Bobwhite Bio-Life Associates 30 6.0
mortality): (1993c)
179 mg TCS/kg bw/day
AF = Assessment Factor
Wildlife exposure
In general, wildlife may potentially be exposed to one or more environmental
media (e.g. surface waters, sediments, soils, air), each of which may potentially
contain triclosan, and multi-media exposure may occur concurrently (e.g. oral,
dermal and/or inhalation). Triclosan has a high affinity to lipids and a high
propensity for bioaccumulation, as indicated by biological tissue residue
monitoring conducted in other parts of the world, and wildlife may be exposed to
triclosan through consumption of foods (food chain or secondary exposure).
Total exposure to environmental media by wildlife may be estimated using the
following model equation:
Exposure total = Exposure oral + Exposure dermal + Exposure inhalation (Eq. 1)
In the above equation, oral exposure routes are considered more likely to occur or
be relatively more significant for triclosan. Although all potential pathways for
exposure to triclosan have been considered in this assessment, oral exposure routes
are of greatest importance (e.g. food consumption, drinking water, incidental
sediment ingestion). Triclosan is not volatile and inhalation exposure is unlikely to
be a significant exposure pathway for wildlife. Although dermal absorption of
triclosan can potentially occur, there is considerable uncertainty in estimation of
dermal uptake rates by wildlife from exposure to solutions containing triclosan. In
general, features such as oily fur and feathers and toughened skin, are likely to
reduce the potential for skin contact with environmental media and absorption
(Sample et al., 1997).
62 Priority Existing Chemical Assessment Report
For this assessment, it is assumed that wildlife obtain all of their food and water
within the area of contamination based on the calculated PEC values (Appendix B
Tables B-2 to B-5). The derived PECs for food intake are based on the
consumption of biota allowing for a BCF of 5000 based on data for fish (see
Section 16.4.2), which may be different for the organisms in the wildlife diet.
Further, wildlife that have home ranges of size greater than the area of
contamination will likely have less exposure than animals with smaller home
ranges. Exposure may be seasonal or intermittent for migratory species of wildlife
relative to sedentary species. In addition, their prey may move in and out of
contaminated areas, thereby the potential for bioaccumulation of triclosan in prey
may be less than for sedentary prey.
Avian and mammalian risk
The risk to birds and mammals for the ingestion of triclosan through the intake of
water, food and sediment has been estimated by comparing the PECs for the
various routes of exposure (See Appendix B Tables B-3, B-4, B-5 and B-6) with
the TRVs of 6.0 and 1.25 triclosan/kg bw/day derived for birds and mammals
respectively.
As a worst case, wildlife triclosan intake rates by birds and mammals during
drinking have been estimated using the upper value PEC surface water values
(17.4 礸/L) and the wildlife exposure model equations for surface water ingestion
(see Appendix B). Using this method, the maximum bird and mammal intake rates
of triclosan by the drinking water exposure route are 0.005 mg/kg bw/day.
Wildlife triclosan intake rates by birds and mammals from incidental or intentional
sediment ingestion have been estimated using PEC sediment and the wildlife
exposure model equations for sediment ingestion (see Appendix B). Using this
method, the maximum bird and mammal intake rates of triclosan by the sediment
exposure route are 3.6 mg/kg bw/day.
Triclosan in the aquatic environment has the potential to bioaccumulate in aquatic
organisms and food chain exposure by wildlife may occur. Estimated wildlife
dietary intake of triclosan has been presented in Tables B-2, B-3, B-4 and B-5
(Appendix B) based on a BCF of 5000 (derived from fish data). This is considered
to be highly protective. Dietary exposure for birds to triclosan is estimated in the
range of 3.3-126 mg/kg bw/day (freshwater) and 0.3-12.6 mg/kg bw/day (marine)
depending on taxa, weight and the discharge source. The food chain potentially
provides a significantly greater level of exposure than other routes of exposure
evaluated. A similar scenario may be expected for mammals.
The calculated risk quotients (PEC/TRV) for the total oral intake (sum of the water,
food and sediment exposure routes) are presented below (Table 9.7). The risk
quotients for the various modes of intake are presented in Appendix G. The risk
quotients for drinking water of various levels of water treatment are all below 0.01
and the maximum risk quotient for sediment intake was 0.6, indicating that these
modes of intake are not expected to present a risk to wildlife.
63
Triclosan
The risk quotients in Table 9.7 indicate that at worst-case predicted concentrations
for each type of sewerage treatment, there is a potential risk for birds and mammals
ingesting biota from downstream of STP outfalls at all levels of treatment except
for those exposed to tertiary treated wastewater discharging to the marine
environment. Calculations based on the maximum measured concentration in
Australian surface waters indicate there is not a potential risk for birds that are
solely dependent on the aquatic compartment for their food and water intake.
Similar calculations for mammals indicate a potential risk for mammals that are
solely dependent on the freshwater aquatic environment for their food and water
intake. However, most Australian mammals are not solely dependent on the
freshwater aquatic compartment for both their food and water intake and are
therefore unlikely to reach the above levels of exposure. The exception to this may
be the platypus.
The potential risk to platypuses has been evaluated using the mammalian TRV and
the potential exposure as determined in Section 16.5.10. The risk quotients for total
exposure (water, sediment and biota) are in the range 4.6-7.6 for the predicted
secondary treatment effluent scenarios, the minimum level of treatment expected
for discharges to inland rivers suggesting potential risk to platypuses. However,
calculations based on the maximum measured concentration in surface waters of
0.070 mg/L (Ying and Kookana 2007) yields risk quotients of 0.5-0.7 indicating no
potential risk to platypus. It should be noted that the PECs derived for food
exposure are based on extrapolating a BCF of 5000 from fish data to the freshwater
invertebrates that make up the bulk of the platypus diet.
64 Priority Existing Chemical Assessment Report
Table 9.7 - Estimated Risk Quotients (PEC/TRV) for birds and
mammals (0.01-1.0 kg bw) potentially exposed to freshwater and
marine ecosystems containing triclosan released in STP effluent, based
on removal rates for sewage treatment levels
Effluent Body Birds Total Oral Mammals Total Oral
Source weight PEC/TRV PEC/TRV
(kg live Freshwa Freshwa
Marine Marine
wt) ter ter
Untreated 0.01 kg 21.6 2.2 54.8 5.5
wastewater 0.1 kg 9.7 1.0 43.5 4.3
1.0 kg 4.3 0.4 34.5 3.5
Primary 0.01 kg 21.2 2.1 53.7 5.4
Treatment 0.1 kg 9.5 0.9 42.6 4.3
1.0 kg 4.2 0.4 33.9 3.4
Trickling 0.01 kg 9.1 0.9 23.0 2.3
Filter 0.1 kg 4.1 0.4 18.3 1.8
1.0 kg 1.8 0.2 14.5 1.5
Activated 0.01 kg 9.7 1.0 24.6 2.5
Sludge 0.1 kg 4.4 0.4 19.6 2.0
1.0 kg 2.0 0.2 15.5 1.6
Activated 0.01 kg 8.4 0.8 21.4 2.1
sludge 0.1 kg 3.8 0.4 17.0 1.7
(SimpleTreat) 1.0 kg 1.7 0.2 13.5 1.3
Tertiary 0.01 kg 2.8 0.3 7.1 0.7
treatment 0.1 kg 1.3 0.1 5.7 0.6
1.0 kg 0.6 0.06 4.5 0.4
Measured 0.01 kg 0.9 0.09 2.3 0.2
Australian 0.1 kg 0.4 0.04 1.9 0.2
Data
1.0 kg 0.2 0.02 1.5 0.1
9.4 Risk from degradation products
Little or no toxicity data is available for the triclosan degradation products. Hence,
it is not possible to quantify the risks associated with these compounds. However,
these compounds are only formed in small quantities from triclosan and any steps
put in place to mitigate the potential risks posed by triclosan will mitigate any
potential risks associated with the degradation products.
9.5 Data gaps
The following significant data gaps were identified when undertaking the risk
characterisation.
Monitoring data
Triclosan has been used in Australia for many years with most eventually being
disposed to sewer. There is some local monitoring data (Ying and Kookana, 2007)
which indicates that it is found in sewage influent (five samples; 573 to 845 ng/L),
effluent (19 samples; 23 to 434 ng/L) and in surface waters near STP outfalls (five
rivers, 14 to 75 ng/L) at levels exceeding the freshwater PNEC of 50 ng/L. Earlier
65
Triclosan
data indicate levels of <100-740 ng/L in primary treated effluents from three major
Sydney STPs. However, apart from these the identities as well as details of sewage
treatment and receiving waters are not known. There is also limited Australian STP
monitoring data, and environmental monitoring data, for the methylated or
chlorinated derivatives of triclosan. A survey during this assessment found that
none of the major Australian wastewater utilities routinely monitor wastewaters,
effluent or receiving environments/ecological receptors (e.g. shellfish, fish) for
triclosan.
Triclosan has a high affinity to sediments, where it may be stable in anaerobic
conditions in the long term based on international sediment core dating research,
and biota; however, no sediment or tissue monitoring studies have been undertaken
for triclosan or methyl-triclosan in Australia.
Triclosan has a high affinity to STP sludge; however, limited monitoring data are
available on the concentration of triclosan in these sludges, or in biosolids, used as
a soil fertility conditioner in Australia.
Triclosan is known to photolyse to various chlorinated derivatives including
2,7/2,8-dichlorodibenzo-p-dioxin (DCDD). No STP or field monitoring data were
available on the occurrence of these dioxins in effluent or surface waters in the
aquatic environment. Very limited toxicity data are available for these compounds
as well.
Microbial effects
Triclosan is widely used due to its known anti-microbial properties. However, there
is a paucity of microbial toxicity data or field monitoring data on the ecological
effects of triclosan.
Toxicity data
While there are toxicity data for triclosan for a few species of mammals and birds
(none for reptiles or amphibians), there is a paucity of data for native Australian
wildlife for triclosan, and no toxicity data for the methylated product of triclosan.
Ethical constraints on vertebrate testing will mean this gap is unlikely to be filled.
International studies indicate that the methylated product of triclosan, has a higher
affinity to bioaccumulate and is present in biota at comparatively higher
concentrations. Further, comparisons between Australian native species and
standard test species have shown that where data is available the variation is within
a factor of 10. Therefore, this would be accounted for within the interspecies
variation allowed for in the assessment factors applied in determining the PNECs.
There is also a lack of data available for the toxicity of triclosan and methyl-
triclosan to sediment dwelling organisms. There have been triclosan related effects
observed on the development of tadpoles of the North American bullfrog, Rana
catesbeiana although the biological significance of these results is unknown.
Further investigation of the effects of triclosan on soil micro-organisms and
nutrient recycling should be carried out given the potential for significant quantities
of triclosan to find its way into the terrestrial environment due to the use of
biosolids for soil amelioration.
66 Priority Existing Chemical Assessment Report
9 .6 Conclusions
The annual import volume and use pattern of triclosan has been used to estimate
potential levels of triclosan entering Australian STPs. The estimated potential
levels between 14.5-17.4 礸/L are 17-20 times higher than the highest observed
influent concentration (0.845 礸/L), but these data are quite limited. The estimated
concentrations are at the lower end of those observed overseas (<0.10-562 礸/L).
These influent levels have been used to derive PECs for Australian freshwater and
marine environments based on varying levels of wastewater treatment. For
freshwater, the predicted levels range between 0.1-15.2 礸/L, are consistent with
the observed levels overseas of 0.01-269 礸/L, but higher than the limited
Australian effluent data (0.023-0.74 礸/L) that are available. Measurements of
triclosan in Australian surface waters have found triclosan levels between 0.014
and 0.075 礸/L.
Based on the predicted concentrations and the use of triclosan and subsequent
release to the Australian sewage system at current levels of use, is likely to result in
concentrations of the chemical within natural waterways which indicate potential
risk to aquatic ecosystems at all levels of wastewater treatment. Algae and aquatic
plants are the most susceptible organisms. However, if the levels obtained close to
the outfall from five Australian rivers are representative of all Australian
conditions then the risk is only marginal. Given the significant difference between
the predicted and limited measured levels it is important to determine how
reflective the measured data is of the wider Australian environment. However,
based on the limited measured Australian data it is likely that the growth of
sensitive algal species downstream of some sewage outfalls is inhibited by
exposure to triclosan residues in the discharged effluent. As the distance from the
outfall increases, the level of triclosan is expected to be reduced through a
combination of photolysis and absorption (see Section 16.5.5), and at least with
ocean outfalls through further dilution of the effluent plume. The distance
downstream of the point of release triclosan before levels fall below harmful levels
has not been estimated in this assessment, but it is noted that in Europe triclosan
has been detected at levels >50 ng/L approximately 20 km downstream (see Figure
16.13).
There is potential for indirect effects on birds and mammals to occur near STP
outlets resulting from effects of triclosan on their food supply, and also direct
toxicity arising primarily through food consumption based on the predicted levels
of triclosan in surface waters. However, the endpoint on which the mammalian
wildlife TRV value is based is a sub-chronic endpoint and therefore highly
protective, and the avian value is also considered conservative. Furthermore, direct
toxicity has been assessed assuming bioaccumulation occurs in the entire diet to a
similar extent to that found in laboratory studies with fish, and that triclosan
concentration in water is at the upper end of predicted concentration ranges for
various types of sewage treatment, which results in a very conservative assessment.
When the highest measured concentration in Australian surface waters is used the
potential effects are predicted for mammals and not for birds. However, as noted
above, the predictions are based on the mammals being solely dependent on the
freshwater aquatic environment for food. This is unlikely to be the case for most
Australian mammals with the exception of the platypus. Calculations based on
platypus specific data and the maximum measured Australian surface water
67
Triclosan
concentration indicate that there is an acceptable level of risk to platypuses living
in the vicinity of a sewage outfall.
A potentially unacceptable risk toward soil dwelling organisms as a result of the
use of biosolids (as soil conditioners) or effluent (for irrigation) from STP has also
been indicated based on the levels of triclosan potentially present in the sludge and
effluent.
68 Priority Existing Chemical Assessment Report
10. Current Human Health Risk
Management
10.1 Occupational health and safety
10.1.1 Assessment of current control measures
According to the National Model Regulations for the Control of Workplace
Hazardous Substances (NOHSC, 1994c), exposure to hazardous substances should
be prevented or, where this is not practicable, adequately controlled so as to
minimise risks to health and safety. The National Code of Practice for the Control
of Workplace Hazardous Substances (NOHSC, 1994) provides further guidance in
the form of a hierarchy of control strategies, namely:
? Elimination;
? Substitution;
? Isolation;
? Engineering controls;
? Safe work practices; and
? Personal protective equipment (PPE).
These measures are not mutually exclusive and effective control usually requires a
combination of these strategies.
Elimination and substitution
Elimination is the removal of a chemical from a process and should be the first
option considered in minimising risks to health. In situations where it is not
feasible or practical to eliminate the use of a chemical, substitution should be
considered. Substitution includes replacing with a less hazardous substance or the
same substance in a less hazardous form.
Triclosan is not manufactured in Australia but is imported both as the raw chemical
and as an ingredient in products. Of all the applicants providing data, only one was
actively seeking to replace triclosan in their product with a less hazardous
chemical. Therefore, elimination and substitution do not appear to be being locally
pursued. Substitution and elimination of triclosan may not have been considered as
it is less hazardous than a number of other antimicrobial agents.
Isolation
Isolation as a control measure involves separation of the process from employees
by distance or the use of barriers or enclosure to prevent exposure. In this regard,
the following controls were identified for triclosan and products containing
triclosan:
? Stored in original containers in a cool dry ventilated chemical storage area,
not segregated and no special storage precautions taken;
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Triclosan
? Polymer pellets are stored above ground, with restricted access to
employees; and
? All raw materials, triclosan included, are stored in a bunded dangerous
goods area segregated from the rest of the site.
Engineering controls
Engineering controls are plant or processes which minimise the generation and
release of hazardous substances. They include enclosure or partial enclosure, local
exhaust ventilation and automation of processes.
The engineering controls in place to prevent exposure to triclosan vary and include:
? Triclosan is delivered to site in 25 kg fibre drums and dispensed from a
laminar flow dispensing booth into plastic bags, which are then dispensed
as needed to be mixed with other ingredients to make bulk product;
? Weighing of triclosan in a ventilated and extracted dispensing area. At the
manufacturing area material are added to the mixer under local extraction
and the batch is filled into containers through a sealed system;
? Mechanical air extraction at point of weighing and point of addition of
triclosan to product;
? During weighing and dispensing activities, a stand-alone dust extraction
system is used to collect air-borne particles; and
? Automated mixing systems.
Safe work practices
Safe work practices have an important role in reducing exposure to triclosan. Work
practices vary and include:
? Restricted access to triclosan, reducing the number of employers exposed;
? The mixture is left to stand for 24 h before transport by road to contract
filler. Safety and emergency procedures are detailed in the relevant
Material Safety Data Sheet (MSDS) located within the dispensary;
? Triclosan is weighed out in a ventilated room;
? For weighing out and dispensing, a plastic bag is placed into another
plastic bag and the chemical is dispensed into this double plastic bag
arrangement to minimise the risk of puncturing and hence exposure; and
? Workers follow written standard operating procedures, which cover receipt
and storage, dispensing, cleaning equipment and waste disposal. The
chemical's MSDS is required to have been read and understood by those
handling triclosan. Following weighing and/or dispensing, overalls and
gloves are immediately disposed of as hazardous waste.
Personal protective equipment (PPE)
PPE is used to minimise exposure to or contact with chemicals. PPE should be
used in conjunction with other controls and not as a replacement. Where other
control measures are not practicable or adequate to control exposure, then PPE
70 Priority Existing Chemical Assessment Report
should be used. From the information submitted some companies used PPE alone
whilst others used PPE in combination with engineering controls. Furthermore,
submitted details on PPE varied with some companies simply advising wearing of
"appropriate" PPE whilst other detailed the type of equipment to be used.
For workers handling triclosan the PPE used are mainly to protect the hands, face
and eyes. In addition, inhalation of dusts is also minimised by appropriate PPE.
Instructions given for PPE were:
? Waterside transport and warehouse workers wear coats, overalls and heavy
duty gloves;
? During weighing, operators wear overalls, safety glasses, gloves and
appropriate respiratory protections (e.g. a face mask or dust mask fitted
with particulate dust cartridge);
? Workers wear overalls, protective eyewear, footwear, face masks etc in
accordance with Workcover requirements;
? Workers wear PPE including overalls, PVC gloves, safety glasses and
appropriate respiratory protection. Handled as per supplier's MSDS;
? Workers follow written standard operating procedures and wear P3
Powered Air Purifying Respiratory protection which includes a hood,
disposable overalls, and impervious gloves; and
? Prior to formulation of the product, workers wear gloves, eyeglasses,
protective clothing, boots and organic respirator. After formulation,
workers wear all these PPE except for the respirator.
10.1.2 Hazard communication
Labels
The National Code of Practice for the Labelling of Workplace Substances
(NOHSC, 1994a) is applicable to labels for workplace substances. Labels of
consumer products are required to comply with the Standard for the Uniform
Scheduling of Drugs and Poisons (SUSDP) (NDPSC, 2003). Triclosan is currently
not listed in the SUSDP. Triclosan is classified as a hazardous substance in the
Australian Safety and Compensation Council (ASCC) Hazardous Substances
Information System (HSIS).
Labels submitted for assessment were assessed for requirements under the National
Code of Practice for the Labelling of Workplace Substances (NOHSC, 1994a). The
assessment took the form of a qualitative appraisal, which included the following
categories of information:
? Substance identification;
? Hazard category/signal word;
? ADG Code classification/packaging group;
? Details of manufacturer or supplier;
? Risk information (or phrase);
? Safety information (or phrase);
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Triclosan
? Information on spills/leaks or fires; and
? Reference to MSDS.
Triclosan is classified as a hazardous substance in HSIS, and depending on the
concentration, labels for products containing triclosan should contain the following
hazard classification, risk and safety phrases based on the HSIS classification prior
to July 2008:
Classification of mixtures containing triclosan as presented in HSIS prior to
July 2008:
Triclosan Concentration Risk Phrases Classification of Mixtures
> 25% R23 Toxic
3% < conc < 25% R20 Harmful
The most appropriate safety phrases are:
? S38: In case of insufficient ventilation, wear suitable respiratory equipment
? S45: In case of accident or if you feel unwell seek medical advice
immediately (show the label where possible)
? S60: This material and its container must be disposed of as a hazardous
waste
This assessment supports the additional classification for triclosan.
Additional risk and safety phrases may be applicable in products depending on the
presence of other hazardous ingredients.
The labels provided by applicants were assessed against the classification
appearing in the HSIS prior to July 2008. No safety phrases were given under the
HSIS for triclosan prior to July 2008.
A total of four labels for triclosan raw material were provided (two for different
grades from the same company). One label gave the concentration though all
identified the substance. Three labels included the UN number of 3077 and of
those, two gave a packaging class of 9. The EU risk phrases (for skin and eye
irritation) were given in three and no label gave the risk phrase as provided in HSIS
prior to July 2008 (toxic by inhalation). Therefore, the ADG Class for toxicity (6.1)
or the relevant UN number was not provided on any label. Although no safety
phrases are mandated all labels presented adequate safety precautions/instructions.
Information on spills was provided on three labels.
MSDS
Under NOHSC National Model Regulations for the Control of Workplace
Substances (NOHSC 1994c) and the corresponding State and Territory legislation,
suppliers are required to provide MSDS to their customers for all hazardous
substances. Employers must ensure that a MSDS, prepared in accordance with the
NOHSC National Code of Practice for the Preparation of Material Safety Data
Sheets (NOHSC 1994b), is readily accessible to employees with potential exposure
to triclosan used in the workplace. A sample MSDS for triclosan prepared in
accordance with this Code is provided in Appendix I. This sample MSDS is for
72 Priority Existing Chemical Assessment Report
guidance only. Under the NOHSC MSDS Code, manufacturers and importers have
the responsibility of compiling their own MSDS and to ensure information is up-to-
date and accurate.
In April 2003, NOHSC declared under the NOHSC Act, the National Code of
Practice for the Preparation of Material Safety Data Sheets 2nd Edition (NOHSC,
2003) (MSDS Code). The MSDS Code forms part of the Hazardous Substances
Framework and the revision addressed various technical elements and facilitates
Australia remaining consistent with international approaches to hazard
communication. The major focus of the revised MSDS Code however is to
incorporate the information provisions of the National Standard for the Storage
and Handling of Workplace Dangerous Goods (NOHSC, 2001). Notification of the
declaration appeared in the Commonwealth Government Notices Gazette of 23rd
July 2003 and the Commonwealth Chemical Gazette of 5th August 2003.
In declaring the MSDS Code, NOHSC decided that it should not come into effect
under Commonwealth, State and Territory regulations until 24 April 2006 to
minimise the impact on industry and allow time for the Commonwealth, States and
Territories to amend their regulations. The 2nd Edition of the MSDS Code is
available on the ASCC web site at:
http://www.ascc.gov.au/ohslegalobligations/nationalstandards/COP_MSDS.htm
A number of MSDS for triclosan and triclosan-containing products were provided
for assessment. MSDSs provided for assessment fall into four main categories:
1) Triclosan raw chemical
2) Triclosan containing industrial products
3) Triclosan containing consumer products; and
4) Triclosan containing articles.
The content and format of MSDSs for raw chemical were assessed according to
NOHSC National Code of Practice for the Preparation of Material Safety Data
Sheets 2nd Edition (NOHSC, 2003). This assessment focused on the adequacy of
the information provided in relation to the `core' elements; product identification,
health hazard information; precautions for use and safe handling information. The
quality/adequacy of information presented in MSDS for triclosan is summarised in
Appendix J.
Numerous types of products containing triclosan at varying concentrations are
available. Due to the large number of product MSDS and the inability to identify a
product reflective of standard use containing a `typical' concentration of triclosan,
no assessment was undertaken on MSDSs for triclosan containing products.
MSDS for products containing other hazardous substances in addition to triclosan
should address the hazards of all ingredients/residues, taking into account
combined/additive effects of chemicals where relevant.
Assessment of MSDS for triclosan raw material
A total of seven MSDS from five suppliers were provided for assessment.
Appendix J provides a summary of this assessment against `core' elements as
described above. In general all but one MSDS attempted to cover the majority of
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Triclosan
core elements but there was inconsistency in the information provided between the
MSDSs. One supplier produced two MSDSs for the raw material under different
product names. In these MSDSs differences between the two documents were
found in the following sections: materials to avoid, ingredients, health effects, first
aid, precautions for use, personal protection, storage and transport, spills and
disposal, fire/explosion hazard. In most cases the differences were that one MSDS
provided more detailed information than the other, however in the first aid section,
one document stated that vomiting should not be induced whilst the other
document provided no statement on vomiting.
Another importer had simply copied the MSDS produced by their overseas supplier
and that MSDS was totally inadequate (see MSDS number 6 at Appendix J). In
terms of the core elements, only product identification and formulation were
adequately addressed in this MSDS.
With regard to the hazardous nature triclosan was classified in Australia in the
ASCC HSIS prior to July 2008 as:
R23 ?Toxic by inhalation.
The source for this listing was an assessment by the Australian Pesticides and
Veterinary Medicine Authority (APVMA).
All MSDS addressed health effects, however, they were inadequate in that none
indicated the then Australian classification as in the HSIS prior to July 2008.
Instead, the EU classification `Irritating to eyes and skin (R36/38)' was provided.
ASCC updated the HSIS in July 2008 to adopt the EU classification of R36/38 for
triclosan.
The following is a discussion of the key findings of this assessment.
Product identification
This was adequately covered in all but two MSDSs, one of which provided only
the product name.
Triclosan is not specifically listed in the ADG Code. Due to its moderate inhalation
toxicity (HSIS classification prior to July 2008 and NICNAS classification in this
report), triclosan powder (100%) falls under Class 6.1 (Toxic substances),
packaging class III (Substances presenting low danger) and UN number 2811
(toxic, solid, organic) (see recommendation 2a).
The other forms of triclosan imported to Australia (liquids and pellets) should have
the appropriate UN number (solid or liquid) depending on the concentration of
triclosan. Class 6.1 applies only if the estimated LC50 value (1 hour) falls within
the ADG Code (2007) classification range for inhalation toxicity (< 4.0 mg/L).
Triclosan is highly toxic (acute and chronic) to some aquatic species. If the LC50
value (1 hour) of triclosan liquids or solids falls outside the Class 6.1 classification
range for inhalation toxicity (> 4 mg/L), Class 9 (Miscellaneous dangerous
substances and articles) and UN number 3077 (environmentally hazardous
substance, liquid, not otherwise specified) or 3082 (environmentally hazardous
substance, solid, not otherwise specified) is applicable to triclosan (ADG Code,
2007).
74 Priority Existing Chemical Assessment Report
Health hazard information
This information was poorly covered in that the ASCC classification (prior to July
2008) (R23)) was not given in any MSDS. One MSDS gave no risk phrases whilst
the remaining MSDSs listed the EU classification, with one MSDS including the
additional risk phrase R37: `Irritating to respiratory system'.
Precautions for use
Overall the information on personal protective equipment was considered
satisfactory but again one MSDS gave no information under this element.
Safe handling information
Adequate information was provided on storage and transport. Handling of spills
and disposal and fire/explosion hazards was adequately covered in five of the seven
MSDS.
10.1.3 Education and training
Guidelines for the induction and training of workers exposed to hazardous
substances are provided in the National Commission's National Model Regulations
for the Control of Workplace Hazardous Substances (NOHSC 1994c) (the Model
Regulations). Under these regulations, employers are obliged to provide training
and education to workers handling hazardous substances.
The Model Regulations stipulate that training and induction should be appropriate
for the workers concerned. It is important that each workplace implement a
program that is suitably designed to accommodate the needs of different workers.
It is important that training be given to the workers at induction and repeated at
regular intervals to reinforce the information. Review of training and education
needs for workers on a regular basis is useful.
Information obtained for assessment indicates that very few importers and/or
formulators of triclosan or triclosan containing products have written instructions
or formal training for workers, as only six companies have a training program in
place. Furthermore, while ongoing training reinforces what was taught at initial
induction it appears from the data submitted that training was not ongoing.
Information provided stated:
? Staff are trained generally in good manufacturing practice under the
supervision of the Quality Assurance Manager;
? Staff using triclosan are instructed to wear protective clothing and follow
good hygiene practices;
? Storemen, samplers and operators are trained in chemical and manual
handling and records of training kept;
? Workers receive training in accessing information from MSDSs and on
safe handling of chemicals;
? Workers are trained in safe handling of hazardous substances; and
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Triclosan
? Written standard operating procedures mandate training that is supervised
by the Training Team Leader but no further details are provided.
10.2 Occupational monitoring and regulatory controls
10.2.1 Atmospheric monitoring
Under the NOHSC Model Regulations (NOHSC, 1994c), employers are required to
carry out an assessment of the workplace for all hazardous substances, the
methodology of which is provided in the NOHSC Guidance Note for the
Assessment of Health Risks Arising from the Use of Hazardous Substances in the
Workplace (NOHSC, 1994d). When assessment indicates that the risk of exposure
via inhalation is significant, atmospheric monitoring should be conducted to
measure levels of the hazardous substances in the workplace as a precursor to the
implementation of suitable control measures to reduce exposure. Subsequent
monitoring is also required to ensure that such measures are effective. No
atmospheric monitoring programs for triclosan in the workplace have been
identified. Triclosan was classified as Toxic by inhalation (i.e. R23) in the ASCC
HSIS prior to July 2008.
10.2.2 Occupational exposure standards
Triclosan is not listed in the NOHSC Exposure Standards for Atmospheric
Contaminants in the Occupational Environment (NOHSC, 1995) nor do any
overseas exposure standards exist.
10.2.3 Health surveillance
In accordance with NOHSC Model Regulations (NOHSC, 1994c), employers have
a responsibility to provide health surveillance in those workplaces where the
workplace assessment indicates that exposure to a hazardous substance may lead to
an identifiable substance-related disease or adverse health effect. Triclosan is not
listed in Schedule 3 (list of substances requiring health surveillance) and as such
there are no formal requirements for health surveillance programs for exposed
workers.
10.2.4 National transportation regulations
The Australian Dangerous Goods Code (ADG Code) (FORS, 1998) sets out
various requirements relating to the transport of dangerous goods by road or rail.
Triclosan is not specifically listed in the ADG Code. According to the MSDSs
from three suppliers, the solid form of the chemical fits into the ADG Code
category of "environmentally hazardous substance, solid, n.o.s." and has the UN
Number 3077 associated with it.
However, due to its inhalation toxicity (HSIS classification prior to July 2008 and
NICNAS classification in this report), triclosan powder (1-h LC50 of 2.6 mg/L
estimated from 4-h LC50 of 0.65 mg/L) falls under ADG Code Class 6.1 and UN
number 2811 ?toxic, solid, organic.
The other forms of triclosan imported to Australia (liquids and pellets) should have
the appropriate UN number (solid or liquid) depending on the concentration of
triclosan. Class 6.1 applies only if the estimated LC50 value (1 hour) falls within
the ADG Code (2007) classification range for inhalation toxicity (< 4.0 mg/L).
76 Priority Existing Chemical Assessment Report
Triclosan is highly toxic (acute and chronic) to some aquatic species. If the LC50
value (1 hour) of triclosan liquids or solids falls outside the Class 6.1 classification
range for inhalation toxicity (> 4 mg/L), Class 9 (Miscellaneous dangerous
substances and articles) and UN number 3077 (environmentally hazardous
substance, liquid, not otherwise specified) or 3082 (environmentally hazardous
substance, solid, not otherwise specified) is applicable to triclosan (ADG Code,
2007).
Considering that liquid triclosan formulations imported to Australia contains only
<20% triclosan, those would fall under UN number 3082 (Class 9) based on the
acute and chronic toxicity to aquatic life.
10.3 Public health regulations
Australian Drinking Water Guidelines and SUSDP
Triclosan is not listed in the Australian Drinking Water Guidelines (NHMRC,
2004) or in the Standard for the Uniform Scheduling of Drugs and Poisons
(SUSDP) (NDPSC, 2003). However, given the acute toxicity profile of triclosan
and the potential for consumer exposure to products containing triclosan, some
public health regulatory controls may be warranted.
Cosmetics
The majority of cosmetic products used in Australia contain 0.3% or less of
triclosan. However, some products, such as shower/bath gels, body washes, face
washes and face masks, can contain up to 0.5% triclosan. There is no Australian
standard limiting the amount of triclosan allowed in cosmetic products. In contrast
the EU, Canada and Japan have all set maximum allowable concentrations for
triclosan in cosmetic products (see sub-section 2.1).
Labels for consumer products
Forty-five companies submitted data on consumer products containing triclosan,
which fell into three broad categories and amounted to 383 products. The
categories were:
1. Cosmetics, including toothpastes, deodorants/antiperspirants, perfumes,
body washes and moisturisers;
2. Disinfectants and surface cleaners, including bathroom cleaners and
anti-mould products; and
3. Articles, including cling wrap and cotton buds
The number of cosmetic products by far exceeded the numbers of other products.
Labels for consumer products were provided by 19 companies and covered 114
cosmetics and 4 surface cleaners. Of these 118 labels provided, 77 listed triclosan
as an ingredient. As triclosan is not listed in the SUSDP there are no specific
labelling requirements for consumer goods that contain the chemical (as opposed to
industrial products containing triclosan which must be labelled according to the
classification in the HSIS).
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Triclosan
11. Current Environmental Risk
Management
11.1 Environmental regulatory controls
This section provides information with reference to international initiatives on the
environmental regulatory controls in Australia applicable to triclosan.
In summary, the management of environmental pollution and waste in Australia is
regulated through individual State and Territory regulatory systems rather than at a
national level and each State and Territory has legislative frameworks and
strategies for managing emissions and environmental pollution to air, land and
waters.
11.2 Control of major hazard facilities
According to the National Standard for the Control of Major Hazard Facilities
(NOHSC, 2002), triclosan is not one of the specifically identified chemicals that
must be considered when determining whether a site is a major hazard facility.
11.3 Aquatic ecosystems management
The Australian water quality guidelines (ANZECC/ARMCANZ, 2000), established
under the National Water Quality Management Strategy, provide water and
sediment quality guidelines (trigger levels) for freshwater and marine ecosystems
throughout Australia. The guidelines provide a decision-tree framework for the
assessment and management of risks from chemicals to water and sediment quality.
Although no Australian trigger values are available for triclosan or its methylated
or chlorinated products, aquatic toxicity data are available for triclosan and have
been utilised in this assessment to develop water quality benchmark level
(predicted no effect concentrations, PNECs). Each State and Territory has
legislative frameworks and strategies for managing water and sediment pollution.
11.4 Disposal and waste treatment
Each Australian State and Territory provides statutory controls on waste generation
and management. Triclosan-containing materials classified as wastes should be
sent to licensed waste disposal contractors in accordance with State and Territory
requirements. No specific waste disposal guidelines, standards or management
issues were identified for triclosan wastes. Due to the ecotoxicity of triclosan
product, care should be exercised in disposing of contaminated wastes to avoid
pollution of the environment.
In some States/Territories, waste disposal licences are required to be held by waste
contractors managing triclosan wastes. In NSW, transporters conveying triclosan
waste in quantities greater than 200 kg per load or waste facilities treating triclosan
wastes require a licence under the Protection of the Environment Operations Act
1997 issued by the NSW Environment Protection Authority.
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Although no specific waste disposal guidelines, standards or management issues
were identified for triclosan, 11 companies provided detailed disposal information.
Most companies indicated that there was no routine disposal of waste chemical, as
batch sizes are determined so as to use full containers of triclosan. If disposal was
needed the following were given as the methods used:
? Cardboard packaging is recycled and inner empty triclosan plastic bag
disposed of at approved landfill. If product waste occurred it is disposed of
as condemned stock, that is collected by a waste collection agency and
taken to an EPA licensed waste facility;
? Mixing vessels and filling machines are routinely washed. The washings
are processed in a waste treatment plant, the treated water pumped to the
sewer and sludge disposed of by a licensed waste operator;
? Waste is released to sewers (estimated total annual release 20 kg);
? Spills swept up and then flushed to an onsite liquid waste treatment plant
and;
? Workers follow written standard operating procedures. Spills are treated as
hazardous waste. The chemical is swept and placed in a plastic bag that is
sealed and then encased in a fibre container. A label identifying the
hazardous waste is affixed to the outside of the fibre container and an
outside contractor is called to collect and dispose of the waste by high
temperature incineration. The waste is tracked by giving the contractor a
hazardous waste handover certificate and after destruction the contractor
must supply a Certificate of Destruction that is filed on site. The empty
cardboard drums in which triclosan was shipped are recycled and the
plastic liner is disposed of at approved landfill.
11.5 Emergency procedures
Handling and storage incidents
Recommendations for dealing with spills involving solids and aqueous solutions
are provided in MSDSs and are similar for both forms and state:
? Shovel into approved disposal container;
? Vacuum contaminated area;
? Avoid creating dusty conditions;
? Spills to be promptly removed;
? Prevent material from entering sewers, waterways or low areas; and
? Report large spills to local environmental authorities.
However, one importer of triclosan raw material provided specific procedures for
spills on site:
? Isolate spill or leak area immediately;
? Warn other personnel;
? Wear appropriate PPE before touching damaged containers;
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Triclosan
? If safe to do so, for liquids, contain with suitable absorbent material and
prevent spilled material from spreading to drain, watercourse or soil. Use
sand or earth to make a dam to contain spill;
? If safe to do so, for powders, dampen down first, scoop up, then
absorb/vacuum up all remaining residue using small quantities of water
and detergent if necessary;
? Place collected spilled material into a sealable container and label "Waste
Environmentally Hazardous Solid, UN No3077";
? Do not wash down residue to drains. Dampen down area and repeat clean-
up and containerization of spilled material until all residue is collected; and
? Dispose as chemical waste according to State/Territory waste disposal
regulations.
Recommendations for fighting fires involving solids and aqueous solutions are
provided in MSDSs and are the same for both forms and state:
? Use self contained breathing apparatus; and
? Extinguish using carbon dioxide, dry chemical, foam, or water.
Road transport incidents
Procedures provided by an importer of the raw chemical for spills during road
transport include the following:
? Stop vehicle engine and turn off electrical equipment;
? No smoking, no naked lights, or sources of ignition in immediate area;
? Warn other traffic;
? Send message to fire brigade and police. Tell location, material, UN No.,
quantity, condition of vehicle and emergency contact;
? Inform emergency services (e.g. Fire Brigade, Police, Environment
Protection Agency) of incident location, substance, UN Number, quantity,
container type, condition of vehicle and emergency contact;
? Stop leak if safe to do so, wear chemical resistant gloves, boots and
protective clothing;
? Prevent spilled material from spreading to drain, watercourse or soil. Use
sand or earth to make a dam to contain spill. Absorb liquid to suitable
absorbent material (e.g. dry sand or earth). Collect spilled substance in a
sealable container and label waste with the UN number;
? Do not wash down residues to drains. Dampen down area and repeat clean-
up and containerization of spilled material until all residues are collected;
and
? Dispose of waste according to instructions from EPA
Procedures provided by an importer of the raw chemical for fires during transport
are:
80 Priority Existing Chemical Assessment Report
? Carry out actions described for full emergencies;
? If a minor fire extinguish using dry powder or foam extinguisher; and
? Major fire handled by emergency services - wear chemical resistant gloves,
boots and protective clothing. Use dry powder, foam or water fog. Use
sand or earth to make a dam. Prevent contaminated fire fighting water from
spreading to drain, watercourse or soil.
Maritime incidents
For managing spills and leaks of triclosan during maritime transportation, the
procedures followed will depend on the type, extent and location of the spill
incident and whether the spill is contained within the ship or released to the marine
environment. Recommendations include the following:
? Initiate ship chemical emergency procedures;
? Identify the source of the spill or leak and isolate the area immediately;
? Stop the leak if safe to do so, (e.g. reposition the container). Wear
chemical-resistant gloves, boots and protective clothing. Clean-up spill as
per above recommendations (Handling and storage incidents);
? Prevent spilled material from spreading. Use sand or earth to make a dam
to contain spill. Absorb liquid to suitable absorbent material (e.g. dry sand
or earth). Collect spilled substance in a sealable container and label waste
with the UN number. Do not wash down residues;
? If product has been released off-ship, identify the location of the spill or
leak (e.g. GPS co-ordinates), quantity, container type, weather conditions
and current. Warn other shipping traffic in the area;
? Inform emergency services (e.g. Dockyard chemical safety officer, Fire
Brigade, Police, Australian Maritime Safety Authority, Environment
Protection Agency) of incident location, substance, UN Number, quantity,
container type, condition of ship and emergency contact; and
? Dispose of any containerised waste in accordance with state/territory waste
disposal regulations by incineration.
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12. Discussion and Conclusions
12.1 Importation and use
Triclosan is not manufactured in Australia. It is imported into Australia in various
forms, such as the raw chemical (>99% powder), a liquid solution (10% to <20%),
plastic pellets and as an ingredient in various products (see below). The total
amount of triclosan imported annually into Australia has decreased each year from
30 tonnes in 2001 to 21 tonnes in 2005.
The main occupational use of triclosan in Australia is in the formulation of
personal care and cosmetic products, therapeutic products and cleaning agents.
Other major uses of triclosan are in the treatment of textiles and plastics
manufacture. A minor use is in the formulation of some oil-based paints for interior
use on tiles and laminates. Triclosan is included in many consumer products
because of its antimicrobial activity. Consumer uses of triclosan in Australia
include cosmetic and personal care products, therapeutic products, veterinary
products, pesticides, household and cleaning products.
It is possible that several polychlorodibenzo-p-dioxins and polychloro-
dibenzofurans may be found as low-level trace by-products in triclosan. The trace
levels are dependent on the starting materials and reaction conditions. This led to
the United States Food and Drug Administration (via the United States
Pharmacopoeia) and Health Canada to set concentrations limits for these impurities
in triclosan.
The European Union, Canada and Japan have set maximum allowable
concentration limits for triclosan in cosmetic products.
A summary of the health and environmental hazards, and the potential risk to
workers and the public are discussed in the following sections.
12.2 Human health hazards and risks
12.2.1 Human health hazards
In humans, triclosan is rapidly and completely absorbed from the gastrointestinal
tract while a lower rate is seen for dermal absorption. It is also rapidly removed
from the blood, and extensive first pass metabolism occurs following oral
administration. The major metabolic pathways in humans and animals involve
glucuronide and sulphate conjugation, and metabolism to these conjugates has also
been observed in the skin. In humans, excretion is relatively rapid. Though a
significant difference was observed in the rate of elimination between some
Negroid (black) volunteers compared to Caucasians (white), there are no data
available to explain this difference. The major route of excretion being the urine,
while the faeces is of secondary importance. The human oral and dermal data
provide no evidence of a bioaccumulation potential. Additionally, enterohepatic
circulation has been demonstrated in rats, while limited evidence is available in
mice and hamsters.
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Triclosan has low acute oral and dermal toxicity in animals. The limited inhalation
toxicity data in rats indicate moderate toxicity. Both animal and human data
indicate it is a skin irritant, and a study in rabbits indicates it is an eye irritant. The
repeat dose inhalation toxicity study in rats showed irritation effects to the
respiratory tract. Data from both humans and animals indicate that triclosan has at
most a very weak skin sensitisation potential. No data on respiratory sensitization
are available.
Systemic toxicity was observed following repeated exposure to triclosan in oral
and dermal animal studies. No reliable human data are available. Animal data
indicates that the liver is the target organ following ingestion of triclosan, with
hepatocyte hypertrophy and hepatocyte vacuolization in cells observed. While the
mouse is the most sensitive species there is evidence that (unlike the rat and
hamster) it is sensitive to peroxisome proliferator type effects in the liver that are
not considered a risk to human health. Similar effects on the liver were seen in
dermal studies.
A number of in vitro and in vivo genotoxicity studies are available, and, although
some positive results were obtained, overall, there is no evidence of an in vivo
genotoxic potential. Oral carcinogenicity studies in the rat and hamster provide no
evidence of a carcinogenic potential. No effects on fertility were seen in a 2-
generation study in the rat, and there was no evidence of teratogenicity in
developmental toxicity studies conducted in rats and rabbits.
Triclosan is listed in the Office of the Australian Safety & Compensation Council's
(ASCC) List of Designated Hazardous Substances, contained in the Hazardous
Substances Information System (HSIS). Prior to July 2008, triclosan was classified
as a hazardous substance in the HSIS with the risk phrase, `Toxic by inhalation
(R23)'. ASCC updated the HSIS in July 2008 to adopt the Europe's 29th
Adaptation to Technical Progress (ATP) to Directive 67/548/EEC (April, 2004).
With this update in July 2008, triclosan is now on the HSIS with the risk phrase,
`Irritating to eyes and skin (R36/38)'. Based on the current assessment and
according to the Approved Criteria for Classifying Hazardous Substances
(NOHSC, 2004), triclosan is classified as `Toxic by inhalation (R23)' and
`Irritating to eyes, respiratory system and skin (R36/37/38)'.
Triclosan is not listed in the Standard for Uniform Scheduling of Drugs and
Poisons (SUSDP). However, the acute toxicity profile of triclosan suggests that it
could be considered for listing in the SUSDP.
12.2.2 Occupational health and safety risks
Workers may be potentially exposed to triclosan by skin and eye contact and
inhalation. The likelihood of exposure by ingestion in occupational settings is
expected to be low. Similarly, the low vapour pressure of triclosan means that the
main route of exposure is likely to be via the dermal route. However, there is
potential for inhalation exposure when using triclosan powder.
Exposure during importation and storage is unlikely except in the case of
accidental breakage of containers and spillage of triclosan powder or liquid. The
potential for exposure following accidental spillage of plastic pellets containing
triclosan is low, as the triclosan itself is encapsulated in the plastic matrix. The
major occupational exposure scenarios are formulation of personal care, cosmetic
and cleaning products, treatment of textiles and plastics manufacture. In these
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Triclosan
scenarios, enclosed automated processes are reported to be used. Exposure is
expected to be low as generally the process is periodic, engineering controls such
as local exhaust ventilation are reported to be in place at most work sites and
personal protective equipment (PPE), such as safety goggles and gloves, are
reported to be worn at some sites. Consequently, the risk of acute effects such as
inhalation toxicity, skin, eye and respiratory irritation is low, though the risk would
increase for accidental spills or leaks of triclosan and/or products containing high
concentrations of triclosan, especially where personal protective equipment is not
used in the clean up of spills. Exposure would not be significant during use of
commercial cleaning products containing triclosan, as the maximum concentration
of triclosan identified in an occupational end-use product was 0.3%.
However, no occupational monitoring data for triclosan are available in Australia
or reported in the literature. Therefore, the Estimation and Assessment of
Substance Exposure (EASE) model was used to predict inhalation and dermal
exposure. For chronic effects, a Margin of Exposure (MOE) approach was
undertaken for risk characterisation using a NOAEL of 40 mg/kg bw/day identified
in a 2-year study for effects on the liver in the rat. The lowest MOE ranges
determined were 32?20 for formulation/plastic manufacture with 100% triclosan.
However, it is considered that the MOEs for these scenarios will be at the higher
end of the predicted range (i.e. > 100 for formulation/plastic manufacture) and the
risk of chronic effects to workers from repeated exposure to triclosan is low. The
determination of a low risk is based on the nature and severity of effects seen in
repeated dose studies in animals. The histopathological changes observed in
hepatic cells were minor and seen only in male rats. In addition, these changes
were not seen consistently throughout the carcinogenicity study and, there are no
data to suggest that humans are more sensitive than animals. Additionally, EASE
does not take into account the use of PPE and it is considered that the use of closed
or partially enclosed automated work processes and other engineering controls and
PPE mean that the actual exposures are likely to be lower than that predicted by the
EASE model.
MSDS and labels for imported raw triclosan were assessed qualitatively against the
NOHSC MSDS and Labelling Codes. In general, labels were lacking information
on the concentration (i.e. purity) of triclosan. No label gave the risk phrase for
inhalation toxicity as provided in the HSIS, but all except one label gave the risk
phrases for eye and skin irritation. All labels provided adequate safety
precautions/instructions. There was inconsistency in the information provided
between the MSDS, generally relating to the level of detailed information
provided. However, overall, information on product identification, precautions for
use, and safe handling were adequate. The risk phrases for eye and skin irritation
were provided in all but one MSDS, though one included the additional risk phrase
R37: `irritating to respiratory system'. A sample MSDS for triclosan is included in
Appendix I.
Due to the large number of product MSDS and the inability to identify a product
reflective of standard use containing a `typical' concentration of triclosan, no
assessment was undertaken on MSDS for triclosan containing products.
12.2.3 Public health risks
Public exposure can occur through the use of consumer products containing
triclosan. The major exposure scenarios are from the use of consumer products
84 Priority Existing Chemical Assessment Report
containing triclosan such as cosmetic and personal care products, household
cleaning products and from textile articles containing triclosan. Given the types of
triclosan containing products available to the public the main route of exposure is
likely to be dermal, though oral exposure may occur through accidental or
incidental ingestion of lip balm, toothpaste or mouthwash formulations, and
inhalation exposure may occur through breathing aerosols generated from the use
of cosmetic, personal care or cleaning products. Additionally, oral exposure may
potentially occur in young children and babies through the sucking or mouthing of
textile/plastic articles. The detection of triclosan and/or its metabolites in human
breast milk samples indicates a further potential source of exposure in breast-
feeding babies.
For acute health effects such as inhalation toxicity, skin, eye and respiratory
irritation the risk is considered to be low due to the low concentration of triclosan
in consumer products. Additionally, accidental ocular exposure is expected to
occur only infrequently. Textile and plastic articles do not present a risk for
irritation.
Measured exposure data are limited for the consumer exposure scenarios. Some
data are available for repeated use of cosmetic and personal care products.
Consequently, various exposure models have been used to predict consumer
exposure to various categories of products. The absence of data on the leaching of
triclosan from articles prevents the potential dermal and oral exposure to be
determined from such. As for occupational risk characterisation, an MOE approach
was undertaken for chronic effects. A worst-case exposure scenario was
determined with the exposure models and MOEs were determined using the
maximum level of triclosan detected for each type of product in Australia and with
exposure to all possible types of products for that exposure scenario.
All MOE ranges derived from exposure models indicated that the risk of chronic
effects from repeated exposure to consumer products containing triclosan is low, as
in addition to being worse-case scenarios and thus likely to be overestimates, the
nature and severity of the effects seen in animals are minor and there are no data to
suggest that humans are more sensitive than animals. The lowest MOE ranges in
both adults and young children/babies using modelled data, and hence greatest
potential risk of an adverse effect, was for exposure to cosmetic and personal care
products: 179-213 in adults; 471 in babies less than 1 year old; 402 in 2 year old
children; and 603 in 5 year old children. In adults, similar MOE ranges were seen
in some volunteer studies (i.e. measured data) using a single cosmetic or personal
care product containing triclosan: 179?117. This measured data raise a concern
that cannot be completely dismissed, that is, the risk of chronic effects may
potentially increase to levels that cause concern in some individuals through
combined use of many cosmetic and personal care products containing triclosan,
and/or use of such products containing relatively high concentrations of triclosan.
This assessment indicates that the lowest potential source of exposure to babies,
and hence the lowest risk of an adverse effect, is from triclosan in breast milk.
7
For the measured data, the majority of MOEs following use of a single cosmetic or personal care
product were greater than 1000.
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12.3 Environmental hazards and risks
12.3.1 Environmental hazards
Limited ecotoxicity data were available for several trophic levels (animals and
plants) from aquatic and terrestrial environments.
In the aquatic environment, triclosan is very toxic to freshwater aquatic organisms
such as Daphnia and fish. From the limited data available, freshwater algae are the
most sensitive species (NOEC = 0.2-0.69 礸/L and 72-96 h EC50 = 0.53-1.44
礸/L). Recent research has indicated that effects on hormonally-induced
metamorphosis of tadpoles can occur at concentrations around the predicted no
effect concentration (PNEC). However, the biological significance of these effects
is currently unclear, particularly as higher concentrations showed no effect.
In both acute and chronic tests with freshwater invertebrates, EC50 values increase
as pH increases, and triclosan is much more toxic to freshwater animals in neutral
or acidic waters than in alkaline waters. There was a paucity of data for marine
organisms, which precludes conclusions on toxicity for this compartment.
Both triclosan and its methylated derivative methyl-triclosan have a high potential
to bioaccumulate in aquatic organisms (Log Pow values of 4.8 and 5.2,
respectively, indicating partitioning to lipids). Bioaccumulation potential is also
evident from laboratory-scale bioconcentration factor (BCF) studies and field
monitoring studies. However, no data were available that correlate tissue
concentrations with effect levels.
In the terrestrial environment, data for two standard test species indicates that
triclosan is slightly toxic to birds by the oral route of exposure, with a LD50 of
862 mg/kg bw in bobwhite quail. In soils, triclosan is toxic to plants when grown in
sandy soil (time-weighted average (TWA) NOEC for cucumber 65 礸/kg);
however, toxicity was less (TWA NOEC for cucumber 446 礸/kg) when grown in
sandy loam. The attenuation of phytotoxicity is potentially due to the higher
organic matter content of the sandy loam soil binding to triclosan.
Triclosan is also slightly toxic to earthworms. No other terrestrial invertebrate
toxicity data were available, and no data were available on the effects of triclosan
on soil microbial process (e.g. respiration, nitrification).
The limited data available indicate that effect levels of triclosan on activated
sewage sludge micro-organisms can vary depending on the level of acclimation,
but can significantly reduce their ability to remove ammonia as well as their
nitrification capacity for several days at least.
For assessing potential risks to the environment, the annual import volume and use
pattern of triclosan was used to estimate potential levels of triclosan entering
Australian STPs. The estimated amount is between 14.5-17.4 礸/L. The estimated
concentrations are consistent with those observed overseas (<0.10-562 礸/L).
These influent levels were used to derive predicted environment concentrations for
Australian freshwater and marine environments based on varying levels of
wastewater treatment. For freshwater, the predicted levels range between 0.1-
15.2 礸/L, which are consistent with the observed levels overseas of 0.01-
269 礸/L. However, limited measured Australian data for the levels of triclosan in
some sewage effluent and biosolids indicate that measured levels are at the lower
end of internationally observed values. Notably, the measured data do not include
86 Priority Existing Chemical Assessment Report
the larger STPs or any NSW STPs. Consequently, it is difficult to extrapolate these
data to all freshwater ecosystems in Australia.
12.3.2 Environmental risks from release to the aquatic environment
There is potential for indirect effects on birds and mammals to occur near STP
outlets as a consequence of the effects of triclosan on their food supply, and also
direct toxicity arising primarily through food consumption based on the predicted
levels of triclosan in surface waters. Based on exposure and toxicity data, the risks
to birds and most Australian mammals (with the possible exception of the platypus)
are considered to be acceptable. Modelled data indicate potentially unacceptable
risks to mammals such as the platypus that subsist exclusively on water璪ased
organisms such as fish (from bioaccumulation in food). To refine the risk estimate,
platypus specific data was compared to the maximum measured Australian surface
water concentration taken from five rivers in Queensland, and indicated that there
is an acceptable level of risk to platypuses. However, these surface water
measurements were only conducted in Queensland and do not cover the full range
of urban STPs in Australia, particularly the larger STPs.
Modelled data indicate a potentially unacceptable risk to freshwater organisms for
each type of wastewater treatment. Available data for concentrations of triclosan
in surface waters near STPs in five rivers in Queensland indicate that
concentrations are likely to be lower than those predicted through modelling, but
confirms that triclosan is still present at levels which could potentially result in
adverse effects on algae. These surface water measurements are unlikely to be
representative of broader environmental concentrations, which could potentially be
much higher around other, larger STPs. Because no data were submitted for
sediment-dwelling organisms, it is not possible to determine potential effects in this
particular compartment. As dilution is high in ocean outfalls, risks to marine
species are considered acceptable.
12.3.3 Environmental risks from release to the terrestrial environment
Both modelled and measured data indicate that triclosan is present in biosolids at
levels which, when applied to soil, may result in adverse effects on plants. While
some evidence is also available which points to its persistence in treated soils, a
standard laboratory study indicates that triclosan degrades rapidly in aerobic soils.
Although modelled data indicate potential risks to soil dwelling organisms from
irrigation by effluent water, limited measured data indicate that risks to plants from
irrigation are acceptable.
Overall, in the absence of additional data indicating concentrations downstream of
representative STPs in Australia, it is not possible currently to exclude the
possibility of unacceptable risks to certain species such as algae. Algae form an
important food source for numerous other organisms. Potentially unacceptable
risks to soil dwelling organisms from the use of biosolids (as soil conditioners) or
effluent (for irrigation) from STPs also currently cannot be excluded.
12.4 Data gaps
For the purposes of human health and environmental risk assessment, this report
identified a number of data gaps.
The environmental assessment identified the following monitoring data gaps:
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Triclosan
? lack of comprehensive Australian data on the concentration of triclosan in
representative STP effluents and surface waters;
? lack of Australian data on the concentration of methylated or chlorinated
derivatives of triclosan in representative STP effluents and surface waters;
? lack of measured data on the concentration of triclosan and its methylated
or chlorinated derivatives in aquatic sediments;
? lack of comprehensive data on the concentration of triclosan and its
methylated or chlorinated derivatives in STP sludge, or in biosolids, used
as soil conditioners in Australia; and
? lack of field monitoring and microbial toxicity data on the ecological
effects of triclosan.
The environmental assessment identified the following data gaps for toxicity:
? lack of toxicity data for triclosan for native Australian wildlife, and no
toxicity data for the methylated products of triclosan;
? limited data on the toxicity of triclosan and no data for methyl-triclosan to
sediment dwelling organisms;
? lack of data on the effects of methyl-triclosan on soil micro-organisms and
nutrient recycling; and
? limited data regarding effects of triclosan on marine organisms and no data
for methyl-triclosan.
The human health assessment identified the following monitoring and toxicity data
gaps:
? absence of representative atmospheric monitoring in formulation plants;
? absence of dermal exposure data;
? absence of data on the leaching of triclosan from textile and plastic articles;
? lack of data on the health effects of triclosan in humans following repeated
exposure; and
? use of a default oral NOAEL for determination of MOE estimates as no
reliable evidence of systemic toxicity was seen in dermal studies in a
suitable animal model.
The assumptions used in EASE modelling also add uncertainties to the human risk
characterisation.
Furthermore, while it is concluded that there is no risk to humans or the
environment with regard to antimicrobial resistance to triclosan, it is recognized
that there is limited information on:
? The prevalence of triclosan resistant organisms in clinical environments;
? The exact mechanisms of antibacterial action of triclosan;
? The kinetics of triclosan antibacterial resistance mechanisms and their
possible transferability; and
88 Priority Existing Chemical Assessment Report
? The fate of triclosan in the environment, the rate and extent of degradation
of triclosan and the anti-microbial activity of degradates or low
concentrations in the environment.
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