Document ID: EPA-HQ-OPP-2007-0513-0005
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-05-07T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

 OFFICE OF

                                                                        
                                    PREVENTION, PESTICIDES AND 

         TOXIC SUBSTANCES

February 06, 2008

MEMORANDUM

SUBJECT:	Environmental Fate Science Chapter for the Triclosan
Reregistration Eligibility Decision (RED) Document

	DP Barcode:  335396		Reregistration Case No.:  2340

FROM:	Srinivas Gowda, Microbiologist/Chemist

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

TO:			Mark Hartman, Branch Chief

Diane Isbell, Team Leader

Heather Garvie, Chemical Review Manager

Regulatory Management Branch II

Antimicrobials Division (7510P)

Timothy McMahon, Risk Assessor

THRU:	Siroos Mostaghimi, Team Leader, Team one

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

Norman Cook, Branch Chief

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

Chemical Name				PC Code	CAS#		Common Name

5-Chloro-2-  (2,4-dichlorophenoxy)phenol	54901		3380-34-5	Triclosan

Attached is the Environmental Fate Science Chapter for the Triclosan RED
Document.

5-CHLORO-2-(2,4-DICHLOROPHENOXY)PHENOL

(TRICLOSAN)

ENVIRONMENTAL FATE SCIENCE CHAPTER

EXECUTIVE SUMMARY

	Triclosan [5-chloro-2-(2,4-dichlorophenoxy)phenol] is used primarily as
a bacteriostat, fungicide/fungistat, and mold/mildewcide.  Use sites for
triclosan include commercial, institutional and industrial premises and
equipment, residential and public access premises, and as a material
preservative.  Four of the required guideline studies for an
environmental fate assessment have been submitted for triclosan;
however, one of the four submitted studies (hydrolysis) was found to be
a preliminary test.  The Agency is using these environmental fate
studies for the assessment of triclosan to fulfill the reregistration
requirements.

	Triclosan is a white crystalline powder with low solubility in water
(12 ppm).  The chemical structures of triclosan (Figure 1) and its
degradate (Figure 2) DCP (2,4-dichlorophenol) are as follows:

 

Figure 1.  Molecular Structure of Triclosan 		Figure 2.  DCP
(2,4-dichlorophenol)

	Triclosan is hydrolytically stable under abiotic and buffered
conditions over the pH 4-9 range based on data from a preliminary test
at 50°C.  Photolytically, triclosan degrades rapidly under continuous
irradiation from artificial light at 25°C in a pH 7 aqueous solution,
with a calculated aqueous photolytic half-life of 41 minutes.  One major
transformation product was identified, DCP (2,4-dichlorophenol), which
was a maximum of 93.8-96.6% of the applied dose at 240 minutes
post-treatment.  Triclosan degrades rapidly in aerobic soils maintained
in darkness at 20 ( 2°C, with calculated half-lives of 2.9-3.8 days. 
One major transformation product was identified, methyl triclosan, at
maximum averages of 13.5-24.0% of the applied at 14-28 days
post-treatment.  In aerobic water-sediment systems maintained in
darkness at 20 ( 2°C, triclosan degraded with calculated nonlinear
half-lives of 1.3-1.4 days in the water, 53.7-60.3 days in the sediment,
and 39.8-55.9 days in the total system.  The major transformation
product, identified as methyl triclosan, was a maximum average of 4.8%
of the applied at 104 days post-treatment (sediment; sandy loam system).
 

	The Agency has used its databases (EPI Suite) and open literature
(TOXNET) to conduct the environmental fate risk assessment.

	In soil, triclosan is expected to be immobile based on an estimated Koc
of 9,200.  Triclosan is not expected to volatilize from soil (moist or
dry) or water surfaces based on an estimated Henry’s Law constant of
1.5 x 10-7 atm-m3/mole.  Triclosan partially exists in the dissociated
form in the environment based on a pKa of 7.9, and anions do not
generally adsorb more strongly to organic carbon and clay than their
neutral counterparts.  In aquatic environments, triclosan is expected to
adsorb to suspended solids and sediments and may bioaccumulate (Kow
4.76), posing a concern for aquatic organisms.  There is also a low to
moderate potential for bioconcentration in aquatic organisms based on a
BCF range of 2.7 to 90.

	Hydrolysis is not expected to be an important environmental fate
process due to the stability of triclosan in the presence of strong
acids and bases.  However, triclosan is susceptible to degradation via
aqueous photolysis, with a half-life of <1 hour under abiotic
conditions, and up to 10 days in lake water.  An atmospheric half-life
of 8 hours has also been estimated based on the reaction of triclosan
with photochemically produced hydroxyl radicals.  Additionally,
triclosan may be susceptible to biodegradation based on the presence of
methyl-triclosan following wastewater treatment.  In the laboratory,
triclosan degraded via aerobic soil metabolism and aerobic aquatic
metabolism, with half-lives of <4 days in soils and half-lives of <1.5
days (water layer) and up to 60 days (sediment and total system) in
water-sediment systems.

  SEQ CHAPTER \h \r 1 From published literature studies on the
occurrence of triclosan in waste water treatment plants, treatment plant
efficiency, and open water measurements of triclosan, the majority
suggest that aerobic biodegradation is one of the major and most
efficient biodegradation pathways (70-80%) through which triclosan and
its by-products are removed from the aquatic environment with actual
efficiencies ranging from 53-99% (Kanda et al., 2003) in activated
sludge plants and trickle down filtration, ranging from 58-86% (McAvoy
et al., 2002).  Another pathway of removing triclosan from water in
wastewater treatment plants is through the sorption of triclosan and
associated by-products to particles and sludge (10-15%) because of the
chemical’s medium to high hydrophobicity (Agüera et al., 2003; Gomez
et al., 2007; Kanda et al., 2003; Lee and Peart, 2002; Bester, 2003 and
2005; Xia et al., 2005).  Benchtop fate testing of triclosan found that
1.5-4.5% was sorbed to activated sludge and 81-92% was biodegraded
(Federle et al., 2002).

Activated sludge and/or sludge samples examined for triclosan residue in
Ohio showed a range of 0.5 to 15.6 μg/g (dry weight) and there were
higher concentrations of triclosan observed in anaerobic sludge as
compared to aerobic sludge (McAvoy et al., 2002).  Other countries where
sludge samples were analyzed for triclosan are as follows: Canada found
370 ng/g (Lee and Peart, 2002); Germany found 1000-8000 ng/g (Bester,
2003 and 2005); Greece found 1,840 ng/g (Gatidou et al. 2007); Spain
found 420-5400 ng/g (Morales et al., 2005); and 19 WWTP were analyzed in
Australia, which had a range of 90 - 16,790 ng/g dry weight and a median
of 2,320 ng/g (Ying and Kookana, 2007).

Effluent concentrations from wastewater treatment plants in the US were
10-21 ng/L in Louisiana (Boyd et al., 2003); 63 ng/L in the upper
Detroit river (Hua et al., 2005); 72 ng/L in Arlington, Virginia (Thomas
and Foster, 2004); 110 ng/L in North Texas (Waltman et al., 2006); and
the highest was 200-2700 ng/L in Ohio (McAvoy et al., 2002). Effluent
concentrations from wastewater treatment plants in other countries were
measured to be 160 ng/L (Lee et al., 2003) or 50-360 ng/L in Canada (Lee
et al., 2005); 50 ng/L (Bester, 2003), 10-600 ng/L (Bester, 2005), or
180 ng/L (Wind et al., 2004) in Germany; 160 ng/L in Sweden (Bendz et
al., 2005); 430 ng/L (31.2 μg/g particulate matter), 1120 ng/L (16.1
μg/g particulate matter), or 230 ng/L (22.4 μg/g particulate matter)
in three different WWTP in Greece (Gatidou et al. 2007); 80-400 ng/L in
Spain (Gomez et al., 2007); 100-269,000 ng/L in Spain (Mezcua et al.,
2004); 0.15±0.08 mg/person in 5 European countries (Paxeus, 2004); 340
or 1100 ng/L, for trickle filtration and activated sludge treatment
plant in England (Sabaliunas et al., 2003); 42-213 ng/L in Switzerland
(Singer et al., 2002); and from 19 WWTP in Australia the range was
23-434 ng/L with a median concentration of 108 ng/L (Ying and Kookana,
2007).

Triclosan was found in approximately 36 US streams (Klopin et al., 2002)
where effluent from activated sludge waste water treatment plants,
trickle down filtration, and sewage overflow are thought to contribute
to the occurrence of triclosan in open water. For this study, the U.S.
Geological Survey surveyed a network of 139 streams across 30 states
during 1999 and 2000.  The selection of sampling sites was biased toward
streams susceptible to contamination (i.e. downstream of intense
urbanization and livestock production). The median concentration was 40
ng/L and the maximum concentration detected was 280 ng/L (Klopin et al.,
2002). In another study, storm water canal measurements over a 6 month
period in Bayou St. John in Louisiana indicated that triclosan ranged
from below the detection level to 29 ng/L (Boyd et al., 2004). Raw
drinking water in Southern California was found to have total mean
concentrations of 56 ng/L triclosan and 49 ng/L triclosan in finished
water and mean concentrations of 734 ng/L of triclosan in raw and
finished drinking water (Loraine and Pettigrove, 2006).   Triclosan was
detected at higher concentrations during dry seasons August to November
in the Southern California water systems.  Other published data on
surface water concentrations of triclosan in the US indicated
concentrations of 4 and 8 ng/L in the upper Detroit river (Hua et al.,
2005) and 56 ng/L in Arlington, Virginia (Thomas and Foster, 2004).
Published data on surface water concentrations of triclosan in other
countries indicated concentrations of <3-10 ng/L in Germany (0.3-10 ng/L
methyl-triclosan) (Bester, 2005); 19±1.4 ng/L in England (Sabaliunas et
al., 2003); 11-98 ng/L in Switzerland (Singer et al., 2002); 30 ng/L in
Germany (Wind et al., 2004); and in Australia 75 ng/L (Ying and Kookana,
2007).

From published literature on the aquatic toxicity of triclosan in
zebrafish, average bioconcentration factors (BCF) for triclosan
following a 5-week accumulation period were 4157 L/kg at 3 (g/L and 2532
L/kg at 30 (g/L (Orvos et al., 2002).  Following 2 weeks of depuration,
average BCF values decreased to 41 L/kg at 3 (g/L and 32 L/kg at 30
(g/L.  Depuration rate constants were 0.142 and 0.141 per day at 3 (g/L
and 30 (g/L, respectively.  The predicted bioconcentration factor for
triclosan was calculated to be ca. 2500.  The lethal body burden was
determined to range from 0.7-3.4 mM/kg, indicating a narcosis mode of
action.

I.	Environmental Fate Assessment

Abiotic

	In the hydrolysis study conducted under abiotic and buffered
conditions, non-radiolabeled 5-chloro-2-(2,4-dichlorophenoxy)phenol
applied at concentrations of 5.2 mg/L (Run 1) and 5.9 mg/L (Run 2), was
stable in heat-sterilized aqueous buffer solutions adjusted to pH 4, pH
7, and pH 9 following incubation in brown glass reaction flasks at 50°C
for 5 days.  After 5 days, triclosan residues in Runs 1 and 2 comprised
5.1-5.4 mg/L and 5.9-6.0 mg/L, respectively, in the pH 4, 7 and 9 buffer
solutions.  The half-lives for triclosan in pH 4, pH 7, and pH 9 buffer
solutions at 50°C were not calculated since the study author determined
that it was hydrolytically stable (<10% degradation).  Furthermore, from
the data at 50°C, the study author concluded that the half-life for
triclosan in pH 4, pH 7, and pH 9 buffer solutions at 25°C was greater
than one year.  This preliminary hydrolysis study has the following
deficiencies: insufficient sampling intervals, no chromatogram data to
confirm the material balance, and generally insufficient details in the
methodology and sampling rational.  Although the preliminary hydrolysis
study still contains few deficiencies as it relates to the OPPTS
Guideline 835.2110, the data are useful and indicate triclosan is
hydrolytically stable at pH 4, 7, and 9 at 50°C, therefore, no
additional hydrolysis data is required.  This hydrolysis study (MRID No.
420279-08) is classified as supplemental and no further hydrolysis
testing is required.

	In a photolysis study conducted under abiotic and buffered conditions,
U-dichlorophenyl-labeled 14C-5-chloro-2-(2,4-dichlorophenoxy)phenol
(triclosan, radiochemical purity > 96%, specific activity 12.7 µCi/mg,
in acetonitrile), at a concentration of 4.42 mg/L, degraded rapidly in
filter-sterilized aqueous pH 7 (phosphate) buffer solutions that were
continuously irradiated under a xenon arc lamp at ca. 25 ± 1C for
240 minutes.  In the irradiated samples, [14C]triclosan declined from
96.6-100.2% of the applied radioactivity at time 0, to 55.2-56.4% at 30
minutes, and was 1.1-1.2% at 240 minutes post-treatment.  In the dark
controls, [14C]triclosan was 98.4% of the applied at time 0 and
94.1-106.1% from 15-240 minutes.  The calculated photolytic half-life
was 41 minutes.  In the irradiated samples, one transformation product
was identified, DCP (2,4-dichlorophenol), which increased from 0.4-1.0%
of the applied radioactivity at time 0, to a maximum of 93.8-96.6% at
240 minutes.  In the dark controls, DCP was observed at a maximum of
1.9% of the applied at 240 minutes.  The photodegradation in water
guideline requirements (OPP 161-2) have been fulfilled by this study
(MRID 430226-08).

	In an aerobic soil metabolism study conducted under abiotic conditions,
[phenoxy-U-14C]-labeled 5-chloro-2-(2,4-dichlorophenoxy)phenol
(triclosan; radiochemical purity 95.8%, specific activity 5.43 MBq/mg),
at a concentration of 0.2 mg/kg, degraded rapidly in sandy loam soil
from Germany, clay loam soil from France, and loam soil from Switzerland
that were maintained in darkness at 20 ( 2(C and a moisture content of
pF 2.0-2.5 for 124 days.  [14C]Triclosan declined from an average
91.9-94.7% of the applied radioactivity at time 0, to 42.3-57.9% at 2-3
days, and was 1.1-4.3% at 61-124 days post-treatment.  [14C]Triclosan
degraded with nonlinear half-lives of 2.9-3.8 days in all soils.  One
major transformation product was identified, methyl-triclosan, which was
a maximum of 13.5-24.0% of the applied 14-28 days post-treatment.  The
aerobic soil biotransformation guideline requirements (OECD 307) have
been fulfilled by this study (MRID 472614-01).

In an aerobic aquatic metabolism study conducted under abiotic
conditions, [phenoxy-U-14C]-labeled
5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; radiochemical purity
96.0%, specific activity 5.43 MBq/mg), at a concentration of 0.1 mg/L,
degraded rapidly in river water-sandy loam sediment and pond water-silty
clay loam sediment systems from Switzerland maintained under aerobic
conditions in darkness at 20 ( 2(C for 104 days.  In the water layer,
[14C]triclosan declined from an average 88.0-92.9% of the applied
radioactivity at time 0 to 48.9-52.8% at 1 day, and was (0.3% at 56-104
days post-treatment.  In the sediment, [14C]triclosan increased from an
average 39.2-40.3% of the applied radioactivity at time 0 to 69.2-74.9%
at 7-14 days, and was 21.3-21.8% at 104 days post-treatment.  In the
total system, [14C]triclosan decreased steadily from 88.0-92.9% of the
applied at time 0 to 52.1-67.9% at 28 days, and was 21.5-21.8% at 104
days post-treatment.  [14C]Triclosan degraded with nonlinear half-lives
of 1.3-1.4 days (water layer), 53.7-60.3 days (sediment), and 39.8-55.9
days (total system) for both water-sediment systems.  One minor
transformation product was identified, methyl-triclosan, which was a
maximum mean of 0.1% of the applied at 28 days post-treatment in the
water and a maximum mean of 3.4-4.8% at 104 days in the sediment and
total system.  The aerobic aquatic biotransformation guideline
requirements (OPP 162-4) have been fulfilled by this study (MRID
472614-02).

In a soil nitrification study conducted under abiotic conditions,
unlabeled 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; purity
99.3%) at application rates of 0.125, 0.25, 0.5, 1.0, and 2.0 mg/kg dry
soil was studied in a German sandy loam soil amended with lucerne meal
and adjusted to 45% MWC that was incubated in the dark for 28 days at 20
( 2(C.  Nitrite was detected at a mean initial concentration of
0.606-0.661 mg NO2-/kg dry soil for Treatments I-V.  After 28 days,
nitrite was not detected in any treatment.  Nitrate was detected at a
mean initial concentration of 94.7-102.4 mg NO3-/kg dry soil for
Treatments I-V.  After 28 days, the mean nitrate concentration increased
in Treatments I, III, IV, and V (105.0-110.1 mg/kg) and decreased in
Treatment II (94.6 mg/kg).  This soil nitrification study is considered
supplemental information (MRID 472614-03).

In a soil respiration study conducted under abiotic conditions,
unlabeled 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; purity
99.3%) at application rates of 0.125, 0.25, 0.5, 1.0, and 2.0 mg/kg dry
soil was studied in a German sandy loam soil adjusted to 45% MWC that
was incubated in the dark for 28 days at 20 ( 2(C.  The mean rate of
respiration at test initiation ranged from 6.12-6.61 mg CO2/h/kg dry
soil for Treatments I-V.  After 28 days, the mean rate of respiration
ranged from 5.85-6.13 mg CO2/h/kg dry soil for Treatments I-V.  This
soil respiration study is considered supplemental information (MRID
472614-04).

In a ready biodegradability study conducted under abiotic conditions,
unlabeled 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; purity
94.8%) at an application rate of 0.206 mg/L was studied in anaerobic
sludge (pH 7.3-7.4) incubated in the dark at 35 ( 1(C for 147 days.  The
concentration of [14C]triclosan was relatively stable and accounted for
78.0-97.4% throughout the study.  This ready biodegradability study is
considered supplemental information (MRID 472614-06).

In a ready biodegradability study conducted under abiotic conditions,
unlabeled 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; purity
94.8%) at an application rate of 0.2 mg/L was studied in a microbial
inoculum of sandy loam soil and activated sludge from an industrial
sewage treatment plant maintained in the dark at 22 ( 3(C for 57 days.  
 SEQ CHAPTER \h \r 1 [14C]Triclosan decreased from an average 78.8% of
the applied at day 0 to 25.6% at 7 days, 20% (single detection) at 14
days, and was below detectable limits at 21 days.  [14C]Triclosan
degraded with an average half-life value of 5.2 ( 1.7 days. This ready
biodegradability study is considered supplemental information (MRID
472614-07).

APPENDIX

Environmental Fate Data for Triclosan 

Parameter	Value	Source

Molecular Weight (g/mol)	289.55	EPI Suite

Molecular Formula	C12H7Cl3O2	EPI Suite

Water solubility (mg/L)	12 ppm

2 ppm	MRIDs 420279-04, 472614-01, 472614-02, 472614-03, 472614-04,
472614-06, 472614-07

Vapor Pressure/volatility (mm Hg)	4 x 10-4 Pa 25°C

3 x 10-4 Pa 20°C

4 x 10-6 mm Hg 20°C	MRIDs 420279-04, 472614-03, 472614-04, 472614-06,
472614-07

Henry’s Law Constant (atm-m3/mol)	1.5 x 10-7 at 25°C	EPI Suite/TOXNET

pKa	7.9	TOXNET

Log Kow (octanol-water partition coefficient)	4.76	MRIDs 420279-02 &
420279-04

Koc (organic carbon ratio in soil)	9,200	TOXNET

Mobility	Immobile	TOXNET

BCF	2.7 to 90	TOXNET

Hydrolysis (hrs)

pH 4

pH 7

pH 9

	Stable at 50°C	MRID 420279-08

Aqueous photolysis half-life

	Half-life = 41 min.

Degradate DCP (2,4-dichlorophenol):  Chemical Formula:  C6H4Cl2O

CAS No.: 120-83-2

	MRID 430226-08

Aerobic soil metabolism	Half-life = 2.9 days, sandy loam soil; 3.8 days,
clay loam soil; 3.7 days, loam soil.

Degradate methyl triclosan.	MRID 472614-01

Aerobic aquatic metabolism	Half-life (River water-sandy loam sediment) =
1.3 days, water; 53.7 days, sediment; 39.8 days, total system.

Half-life (Pond water-silty clay loam sediment) = 1.4 days, water; 60.3
days, sediment; 55.9 days, total system.

Degradate methyl triclosan.	MRID 472614-02

Ready biodegradability	Half-life = 5.2 ( 1.7 days.	MRID 472614-07

A.	Environmental Fate Guideline Studies

	1.	Hydrolysis (OPP Guideline Number 161-1, MRID No. 420279-08)

	This hydrolysis study was reviewed by the Agency and classified as
supplemental due the following deficiencies: insufficient sampling
intervals, no chromatogram data to confirm the material balance, and
generally insufficient details in the methodology and sampling rational.
 Although the hydrolysis study still contains few deficiencies as it
relates to the OPPTS Guideline 835.2110, the data are useful and
indicate triclosan is hydrolytically stable at pH 4, 7, and 9 at 50°C,
therefore, no additional testing is required.  This hydrolysis study
(MRID No. 420279-08) is classified as supplemental and no further
hydrolysis testing is required.

	In this study, non-radiolabeled triclosan
[5-chloro-2-(2,4-dichlorophenoxy)phenol, in ethanol, was added to
heat-sterilized pH 4 (acetate), pH 7 (phosphate), and pH 9 (borate)
aqueous buffer solutions at concentrations of 5.2 mg/L (Run 1) and 5.9
mg/L (Run 2).  Each treated buffer solution was incubated in brown glass
reaction flasks at 50°C for 5 days.  Duplicate samples were prepared
for analysis at 0 and 5 days post-treatment.

 

	Study results indicate that triclosan was stable in sterile pH 4, pH 7,
and pH 9 buffer solutions incubated in brown glass reaction flasks at
50°C for 5 days.  At an application rate of 5.2 mg/L, the parent was
present after 5 days incubation at concentrations of 5.4 mg/L, 5.2 mg/L
and 5.1 mg/L in the pH 4, 7, and 9 buffer solutions, respectively.  At
an application rate of 5.9 mg/L, the parent was present after 5 days
incubation at concentrations of 5.9 mg/L, 6.0 mg/L, and 6.0 mg/L in the
pH 4, 7, and 9 buffer solutions, respectively.

	The half-lives for triclosan in pH 4, pH 7, and pH 9 buffer solutions
at 50°C were not calculated since the study author determined that it
was hydrolytically stable(<10% degradation).  Furthermore, from the data
at 50°C, the study author concluded that the half-life for triclosan in
pH 4, pH 7, and pH 9 buffer solutions at 25°C was greater than one
year. 

	2.	Photodegradation in Water (OPP Guideline No. 161-2, MRID No.
430226-08)

	This study was reviewed by the Agency and satisfies the
photodegradation in water data requirements for triclosan.

	In this study, [14C-U- dichlorophenyl]-labeled triclosan
[5-chloro-2-(2,4-dichlorophenoxy)phenol, radiochemical purity > 96%,
specific activity 12.7 µCi/mg], in acetonitrile, was added to
filter-sterilized pH 7 (phosphate) buffer solution at a concentration of
4.42 mg/L.  Aliquots of the treated solutions were transferred to
sterile, silylated quartz test tubes with Teflon-coated rubber stoppers;
tubes were filled completely with the test solution, leaving no
headspace, to prevent volatile losses.  Dark controls were covered with
aluminum foil and maintained inside a temperature-controlled incubator
at 25.0 ± 0.5(C.  The irradiated test samples were placed in a Suntest
photolysis apparatus, and continuously irradiated with a xenon arc lamp
(wavelengths of 200-300 nm) for 240 days.  The mean irradiation
intensity of the xenon lamp was 0.1139 ± 0.0009 W/cm2, which was
similar to a clear sunny summer day in Frederick, Maryland, with a
natural sunlight intensity of 0.096 W/cm2 to 0.115 W/cm2.  The spectral
distribution and intensity of the artificial and natural light sources,
measured over a wavelength range of 200-700 nm, were also similar.  The
temperature in the photolysis chamber was maintained at ca. 25 ± 1(C.

	Duplicate samples of irradiated solutions and single samples of dark
control solutions were analyzed at time 0 and 15, 30, 60, 120, 180, and
240 minutes post-treatment.  At each sampling interval, aliquots of
irradiated and dark control solutions were analyzed for total
radioactivity by liquid scintillation counting (LSC; limit of detection
was 0.023 ppm).  Additional aliquots of each test solution were analyzed
by HPLC using a Zorbax ODS column (250 x 4.6 mm) and the isocratic
solvent elution of methanol:water (75:25, v:v).  Radioactive areas were
identified by radioscanning; non-radioactive areas were identified by UV
(235 nm).  Quantification of the parent and its transformation products
was performed by LSC analysis of the solutions of the isolated
compounds.  Confirmation of the identity of the parent and its
transformation products was performed by a second HPLC analysis using
the same conditions as described previously, except that the solvent
system was methanol:water:acetic acid (800:200:1, v:v:v).  The volatile
[14C]residues from the irradiated and dark control samples were not
measured.

	In the irradiated samples, [14C] triclosan decreased from 96.6-100.2%
of the applied radioactivity at time 0, to 55.2-56.4% at 30 minutes,
39.4-39.6% at 60 minutes, 12.7-15.7% at 120 minutes, and was 1.1-1.2% at
240 minutes post-treatment.  In the dark controls, [14C] triclosan was
98.4% of the applied at time 0 and 94.1-106.1% from 15-240 minutes. 
Based on first-order linear regression analysis, the calculated
photolytic half-life was 41 minutes, with a rate constant (k) of 1.68 x
10-2/min.

	In the irradiated samples, one transformation product was identified,
DCP (2,4-dichlorophenol), which increased from 0.4-1.0% of the applied
radioactivity at time 0, to a maximum of 93.8-96.6% at 240 minutes.  In
the dark controls, DCP was observed at a maximum of 1.9% of the applied
at 240 minutes.  Two minor unidentified transformation products were
also detected.  In the irradiated and dark controls, Unknown 1 was a
maximum of 7.8% and 1.1%, respectively, and Unknown 2 was a maximum of
5.3% and 1.3%, respectively.

	In the irradiated and dark controls, the material balance was 104.8 ±
3.8% (range, 98.2-111.0%) and 103.6 ± 4.2% (range, 95.7-107.2%) of the
applied, respectively.  Volatilized [14C] residues were not measured.

	3.	Aerobic Soil Metabolism (OPP Guideline No. 162-1 and OECD Guideline
307, MRID No. 472614-01)

	This study was reviewed by the Agency and satisfies the aerobic soil
metabolism data requirements for triclosan.

	In this study, [phenoxy-U-14C]-labeled triclosan
[5-chloro-2-(2,4-dichlorophenoxy)phenol, radiochemical purity 95.8%,
specific activity 5.43 MBq/mg], was added to aliquots of a sandy loam
soil (Speyer 5M, pH 7.1, organic matter 2.4%) from Germany, a clay loam
soil (Senozan, pH 6.85, organic matter 1.79%) from France, and a loam
soil (Gartenacker, pH 7.3, organic matter 2.98%) from Switzerland at a
concentration of 0.2 mg/kg.  The glass metabolism flasks were incubated
for 124 days under aerobic conditions in darkness at 20 ( 2(C and a
moisture content of pF 2.0-2.5.  The flasks were attached to a
flow-through volatile trapping system and moistened air was continuously
drawn through each flask, then through sodium hydroxide and ethylene
glycol traps.

Duplicate samples of each soil were collected at 0, 1, 2, 3, 7, 14, 28,
61, and 124 days posttreatment.  The soils were extracted up to four
times with acetonitrile:water (4:1, v:v), followed by a Soxhlet
extraction with acetonitrile:water (4:1, v:v).  After each extraction,
the supernatants were analyzed for total radioactivity by LSC (limit of
detection was 0.06% of the applied).  The extracts were then combined,
concentrated, re-dissolved in an acetonitrile:water mixture, and
analyzed using LSC.  Day 124 extracts were submitted to a harsh
extraction using acetonitrile:0.1M hydrochloric acid (1:1, v:v) under
reflux conditions and analyzed using LSC.  [14C]Residues in the extracts
were separated and quantified by HPLC using a Kromasil 100-C18 column
(250 x 4.6 mm) and a gradient mobile phase combining (A) 0.1% phosphoric
acid and (B) acetonitrile with UV (224 nm) and radioactive flow
detection.  Quantification of the parent and its transformation products
was performed by LSC analysis of the solutions of the isolated compounds
(limit of detection 0.2% of the applied).  Confirmation of the identity
of the parent and its transformation products was performed by
comparison to unlabeled reference standards.  Identifications were
confirmed by normal phase two-dimensional TLC analysis on pre-coated
silica gel plates (60F254; 0.25 mm thickness; 20 x 20 cm) developed in
ethyl acetate:hexane (50:50, v:v; SS 1; 1st dimension),
chloroform:methanol:water:acetic acid (75:25:2:2, v:v:v:v; SS 2; 2nd
dimension), chloroform:methanol:water:acetic acid (70:30:2:2, v:v:v:v;
SS 3; 2nd dimension), and ethyl acetate:hexane (40:60, v:v; SS 4; 2nd
dimension).  Residues were visualized using UV (254 nm) light with
fluorescence quenching and phosphor imaging using a Fuji BAS 1500
imager.  The sodium hydroxide and ethylene glycol trapping solutions
were analyzed using LSC (limit of detection 0.06% of the applied).  The
presence of carbon dioxide was confirmed by precipitating with barium
hydroxide.  The extracted soil was analyzed using LSC following
combustion (limit of detection 0.62% of the applied).  

In the sandy loam soil, [14C]triclosan decreased from an average 94.7%
of the applied at day 0 to 57.9% at 2 days, 23.1% at 7 days, 12.3% at 14
days, and was 4.3% at 124 days.  Based on linear and nonlinear
regression analyses, [14C]triclosan degraded with half-lives of 30.1 and
2.9 days, respectively.  The observed DT50 value was ca. 2.5 days.

In the clay loam soil, [14C]triclosan decreased from an average 94.3% of
the applied at day 0 to 47.3% at 3 days, 27.3% at 7 days, 12.8% at 14
days, 3.2% at 61 days, and was not detected at 124 days.  Based on
linear and nonlinear regression analyses, [14C]triclosan degraded with
half-lives of 12.5 and 3.8 days, respectively.  The observed DT50 value
was ca. 3 days.

In the loam soil, [14C]triclosan decreased from an average 91.9% of the
applied at day 0 to 42.3% at 3 days, 12.5% at 14 days, 7.6% at 28 days,
and was 1.1% at 124 days.  Based on linear and nonlinear regression
analyses, [14C]triclosan degraded with half-lives of 20.8 and 3.7 days,
respectively.  The observed DT50 value was ca. 2 days.

One major transformation product was detected and identified. 
Methyl-triclosan (M3) was detected at maximum means of 17.5% and 24.0%
of the applied in the sandy loam and clay loam soils, respectively, at
28 days and at a maximum of 13.5% of the applied in the loam soil at 14
days.  One unknown (M1) accounted for a maximum average of 4.1%, 3.4%,
and 3.5% of the applied in sandy loam, clay loam, and loam soils,
respectively, at 0 days.

Overall recoveries averaged 97.6 ( 3% (range 90.4-101.3%) in the sandy
loam soil, 97.5 ( 3% (92.0-100.8%) in the clay loam soil, and 97.5 ( 3%
(91.7-100.9%) in the loam soil.  Extractable [14C]residues decreased
from means of 95.4-98.8% of the applied at day 0 to 12.5-17.3% at 124
days, while nonextractable [14C]residues increased to maximum means of
60.8-75.8% at study termination.  Acidic harsh extraction of select 124
day samples released an average 2.4-2.7% of the applied.  At 124 days
posttreatment, volatilized 14CO2 accounted for 11.5-16.3% of the applied
and organic volatiles were <0.7%.

In a supplementary experiment, sandy loam soil was treated with
[14C]triclosan at 0.2 mg/kg and maintained at 10 ( 2(C.  Duplicate
samples were removed for analysis at 0, 3, 7, 14, 28, 61, and 124 days
posttreatment and analyzed as previously described.  Overall recoveries
averaged 97.3 ( 2.5% (range 91.8-100.6%).  [14C]Triclosan decreased from
an average 93.5% of the applied at day 0 to 17.5% at 124 days.  Major
transformation product methyl-triclosan reached a maximum average of
14.5% of the applied at 61 days.  Two unknowns M1 and M2 accounted for
maximum averages of 3.8% and 1.2% (single replicate), respectively, at 0
days.  Total extractable [14C]residues decreased from an average 97.9%
of the applied at day 0 to 30.8% at 124 days, while nonextractable
[14C]residues increased to a maximum average of 59.7% at 124 days.  At
study termination, an average 5.1% of the applied was present as 14CO2
and volatile organics were (0.1% of the applied.  Based on first-order
linear regression analyses and nonlinear regression analyses,
[14C]triclosan degraded with half-lives of 54.2 and 18.2 days,
respectively.  The observed DT50 value was ca. 7-14 days.

In a second supplementary experiment, aliquots of each soil were treated
with [14C]triclosan at 2.0 mg/kg.  Following treatment, the samples were
incubated as previously described and samples were removed after 23 days
of incubation and immediately stored frozen.

	4.	Aerobic Aquatic Metabolism (OPP Guideline No. 162-4 and OECD
Guideline 308, MRID 472614-02)

	This study was reviewed by the Agency and satisfies the aerobic aquatic
metabolism data requirements for triclosan.

In this study, [phenoxy-U-14C]-labeled
5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; radiochemical purity
96.0%; specific activity 5.43 MBq/mg) was applied to river water-sandy
loam sediment (water pH 7.3, total organic carbon 2.97 mg C/L; sediment
pH 7.29, organic carbon 0.78%) and pond water-silty clay loam sediment
(water pH 7.2, total organic carbon 6.43 mg C/L; sediment pH 7.26,
organic carbon 5.0%) systems from Switzerland for 104 days under aerobic
conditions in darkness at 20 ( 2(C.  [14C]Triclosan was applied at a
rate of 0.1 mg/L.  The sediment:water ratio was ca. 1:3.3 (ca. 2.0 cm
sediment: ca. 6.5 cm water).  The test apparatus consisted of glass
metabolism flasks (ca. 10.6-cm diameter) connected to a continuous
flow-through (moistened air, 30-50 mL/minute) system with 2N NaOH and
ethylene glycol traps.  The sediment and water were acclimated for ca. 2
weeks prior to treatment.

Duplicate vessels per system type were collected after 0, 1, 7, 14, 28,
56, and 104 days of incubation.  The water layers were drawn off via
pipette and concentrated using solid phase extraction (0, 1, and 7 days)
or rotary evaporation (days 56 and 104) or partitioned with ethyl
acetate and acidified with concentrated hydrochloric acid (days 14 and
28).  The concentrated aqueous extracts were subjected to HPLC analysis
using a Kromasil C18 column (250 x 4.6 mm) and three different gradient
mobile phase methods (Methods 2-4) with UV (224 nm) and radioactive flow
detection.  HPLC Method 2 combined (A) 0.1% TFA in water and (B) 0.1%
TFA in acetonitrile and Methods 3-4 combined (A) 0.1% phosphoric acid in
water and (B) acetonitrile.  Confirmation of the identity of the parent
and its transformation products was performed by comparison to unlabeled
reference standards.  Identifications were confirmed by normal phase
two-dimensional TLC analysis on pre-coated silica gel plates (60F254;
0.25 mm thickness; 20 x 20 cm) developed in ethyl acetate:hexane (50:50,
v:v; SS 1) and chloroform:methanol:water:acetic acid (75:25:2:2,
v:v:v:v; SS 2).  Residues were visualized using UV (240 nm) light and
phosphor imaging using a Fuji BAS 1000 imager.  Sediment samples were
extracted up to 3 times with acetonitrile:water (4:1, v:v).  Sediments
from day 1 onwards were additionally submitted to a Soxhlet extraction
using acetonitrile.  The resulting extracts were combined and
concentrated via reduced pressure.  Day 104 extracts were submitted to
an additional harsh extraction using acetonitrile:0.1M hydrochloric acid
(1:1, v:v) under reflux conditions.  Water layers, sediment extracts,
extracted sediment, and trapping solutions were analyzed for total
radioactivity using LSC (limits of detection were 0.11% of the applied
for the water phase, 0.02% for the extractables, 0.04% for the
non-extractables, and <0.01% for volatiles).  The presence of carbon
dioxide was confirmed by precipitating with barium hydroxide.  Water
layer and sediment extract samples were analyzed for the parent and its
transformation products via HPLC and 2-D TLC as previously described.

In the water layers, triclosan decreased from means of 92.9% and 88.0%
in the sandy loam and silty clay loam systems, respectively, at time 0
to 52.8% and 48.9% at 1 day, 11.4% and 12.0% at 7 days, 3.9% and 6.5% at
14 days, and was (0.3% at 56-104 days.  Observed DT50 values for
triclosan in the water layers were ca. 1 day for the sandy loam and
silty clay loam systems with calculated linear half-lives of 11.9 and
7.2 days, respectively, and nonlinear half-lives of 1.3-1.4 days for
both systems.

In the sediments, triclosan increased from means of 39.2% and 40.3% in
the sandy loam and silty clay loam systems, respectively, at time 0 to
69.2% and 74.9% at 7-14 days, then decreased to 51.6% and 65.1% at 28
days, and was 21.3% and 21.8% at 104 days.  In the sediment for the
sandy loam and silty clay loam systems, calculated linear half-lives
were 56.4 and 53.7 days, respectively, and nonlinear half-lives were
53.7 and 60.3 days.

In the total system, [14C]triclosan decreased steadily in the sandy loam
and silty clay loam systems from 92.9% and 88.0%, respectively, at time
0, to 52.1% and 67.9% at 28 days, and was 21.5% and 21.8% at 104 days. 
Observed DT50 values for triclosan in the total sandy loam and silty
clay loam systems were ca. 28 days and 56 days, respectively, with
linear half-lives of 47.8 and 51.0 days, and nonlinear half-lives of
39.8 and 55.9 days.

		No major nonvolatile transformation products were detected and only
one minor product was identified.  Methyltriclosan was detected at a
maximum mean of 0.1% of the applied in the water at 28 days (sandy loam
sediment only) and at a maximum of 4.8% and 3.4% of the applied in the
sandy loam and silty clay systems, respectively, for both the sediment
and total system at 104 days.  Unidentified [14C]residues were total
maximum means of 5.1%, 9.9% and 11.0% of the applied in the water,
sediment and total system, respectively, for the sandy loam systems, and
7.3%, 3.8% and 9.7%, respectively, for the silty clay loam systems.

		Overall recoveries averaged 94.1 ( 2.6% and 95.4 ( 1.4% of applied for
the sandy loam and silty clay loam sediment systems, respectively. 
Extractable sandy loam [14C]residues increased from a mean <0.1% at time
0 to 75.1-78.7% at 7-14 days and were 27.7-34.8% at 104 days. 
Nonextractable [14C]residues were maximum means of 32.4-33.0% at study
termination.  Volatilized 14CO2 was a maximum mean of 21.4-29.2% at
study termination.  Volatile [14C]organic compounds were a maximum of
0.6% at 104 days for both systems.

	5.	Soil Nitrification Study (OECD Guideline 216, MRID No. 472614-03)

		This soil nitrification study was reviewed by the Agency and
classified as supplemental because it could not be determined if the
European soil used in this study was comparable to soils found in a
typical triclosan use area in the United States.  Although the soil
nitrification study contains deficiencies, the data are useful.

	In this study, the effect of unlabeled
5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; purity 99.3%) on soil
nitrification was studied in a sandy loam soil (Speyer 2.3; pH 7.4;
organic carbon 1.02 ( 0.15%) from Germany.  The test system consisted of
incubation flasks (1 L) containing moistened soil that were treated with
triclosan at application rates of 0.125, 0.25, 0.5, 1.0, and 2.0 mg/kg
dry soil.  Following application, the soils were thoroughly mixed,
amended with lucerne meal (ca. 3% nitrogen), and adjusted to 45% MWC by
adding purified water.  The flasks were stoppered with cotton wool plugs
and incubated in the dark for 28 days at 20 ( 2(C.  Control samples were
also prepared and incubated as described.

Triplicate samples were collected at 0 (<3 hours) and 28 days
posttreatment and extracted twice with 2M KCl.  Following each
extraction, the samples were centrifuged and the supernatants were
decanted, filtered, combined, and adjusted with 2M KCl.  The
concentration of nitrite (NO2-) was measured colormetrically at a
wavelength of 550 nm (limit of quantification was 0.09 mg nitrite/kg dry
soil).  The concentration of nitrate (NO3-) was measured by reducing to
nitrite in a cadmium reductor, then measuring colormetrically (limit of
quantification was 0.55 mg nitrate/kg dry soil).

For CO2 evolution measurements, untreated sandy loam soil was sieved,
adjusted to 45% MWC, and subsamples were mixed with varying
concentrations of glucose and talc.  The soils were packed into glass
columns, connected to volatile trapping systems for water and CO2 at the
inlet and to an infrared (IR) gas analyzer at the outlet, and maintained
at 20 ( 2(C for ca. 24 hours.  After an accumulation time, a single
column was flushed with CO2-free air and the CO2 concentration was
measured.  After a 7-second waiting period, the next column was flushed
and measured.

Following amendment with lucerne meal, the mean initial concentrations
of nitrite ranged from 0.606-0.661 mg NO2-/kg dry soil for Treatments
I-V.  After 28 days, nitrite was not detected in any treatment.  The
mean initial concentrations of nitrate were 98.5 mg NO3-/kg dry soil for
Treatment I, 102.4 mg/kg for Treatment II, 94.7 mg/kg dry soil for
Treatment III, 95.4 mg/kg dry soil for Treatment IV, and 96.6 mg/kg dry
soil for Treatment V.  After 28 days, the mean nitrate concentration
increased in Treatments I (105.4 mg/kg), III (105.0 mg/kg), IV (110.1
mg/kg), and V (107.4 mg/kg) and decreased in Treatment II (94.6 mg/kg). 
The calculated deviations to control were -9.3%, -18.6%, -9.7%, -5.4%,
and -7.6% for Treatments I, II, III, IV, and V, respectively.

For control samples, concentrations of nitrite and nitrate were <0.08
mg/kg dry soil and 95.4 mg/kg dry soil, respectively, at day 0 in
untreated and unamended soil.  Following amendment with lucerne meal,
mean concentrations of nitrite and nitrate were 0.645 mg NO2-/kg dry
soil and 99.8 mg NO3-/kg dry soil, respectively.  After 28 days, mean
concentrations of nitrite and nitrate were <0.086 mg NO2-/kg dry soil
and 116.3 mg NO3-/kg dry soil, respectively.  

For untreated sandy loam soil, the maximum rate of initial CO2 evolution
from 100 g dry soil equivalents was 0.326 mL/hour.  The microbial
biomass was calculated to be 134.2 mg microbial carbon/kg dry weight
soil.

In a supplementary experiment, sandy loam soil samples, amended with
lucerne meal and adjusted to 45% MWC, were treated with
2-chloro-6-trichloromethylpyridine (Nitrapyrin Pestanal(; purity 97.5%),
dissolved in acetone, at a concentration of 5 mg a.i./kg dry soil.   
SEQ CHAPTER \h \r 1 The mean initial concentrations of nitrite and
nitrate were 0.450 mg NO2-/kg dry soil and 95.8 mg NO3-/kg dry soil,
respectively.  After 28 days, mean nitrite and nitrate concentrations
were <0.086 mg NO2-/kg dry soil and 20.4 mg NO3-/kg dry soil,
respectively, resulting in a deviation of -82.4% to control for nitrate.
 Based on these results, it was determined that nitrapyrin showed a
strong inhibiting effect.

	6.	Soil Respiration Study (OECD Guideline 217, MRID No. 472614-04)

This soil respiration study has been reviewed by the Agency and
classified as supplemental because it could not be determined if the
European soil used in this study was comparable to soils found in a
typical triclosan use area in the United States.  Although the soil
respiration study contains deficiencies, the data are useful.

	In this study, the effect of 5-chloro-2-(2,4-dichlorophenoxy)phenol
(triclosan; purity 99.3%) on soil respiration was studied in a sandy
loam soil (Speyer 2.3; pH 7.4; organic carbon 1.02 ( 0.15%) from
Germany.  The test system consisted of incubation flasks (1 L)
containing moistened soil that were treated with triclosan at
application rates of 0.125, 0.25, 0.5, 1.0, and 2.0 mg/kg dry soil. 
Following application, the soils were thoroughly mixed and adjusted to
45% MWC by adding purified water.  The flasks were stoppered with cotton
wool plugs and incubated in the dark for 28 days at 20 ( 2(C.  Control
samples were also prepared and incubated as described.  Triplicate
samples were collected at 0 (<3 hours) and 28 days posttreatment.

For CO2 evolution measurements, untreated sandy loam soil was sieved,
adjusted to 45% MWC, and subsamples were mixed with varying
concentrations of glucose and talc.  The soils were packed into glass
columns, connected to volatile trapping systems for water and CO2 at the
inlet and to an infrared (IR) gas analyzer at the outlet, and maintained
at 20 ( 2(C for ca. 18 hours.  After an accumulation time, a single
column was flushed with CO2-free air and the CO2 concentration was
measured.  After a 7-second waiting period, the next column was flushed
and measured.

The mean rate of respiration at test initiation ranged from 6.12-6.61 mg
CO2/h/kg dry soil for Treatments I-V.  The calculated deviations to
control were -4.9%, -6.8%, -7.0%, -10.3%, and -12.0% for Treatments I,
II, III, IV, and V, respectively.  After 28 days, the mean rate of
respiration ranged from 5.87-6.13 mg CO2/h/kg dry soil for Treatments
I-V.  The calculated deviations to control were -9.4%, -11.3%, -12.0%,
-13.5%, and -13.2% for Treatments I, II, III, IV, and V, respectively. 
Based on these results, it was determined that triclosan did not have a
detrimental influence (i.e. ( ( 25%) on soil microbial respiration when
applied to sandy loam soil up to a concentration of 2.0 mg/kg dry soil.

For control samples,   SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1   SEQ
CHAPTER \h \r 1 the mean rate of respiration was 6.95 mg CO2/h/kg dry at
test initiation and 6.77 mg CO2/h/kg dry soil after 28 days.

For untreated sandy loam soil, the maximum rate of initial CO2 evolution
from 100 g dry soil equivalents was 0.326 mL/hour.  The microbial
biomass was calculated to be 134.2 mg microbial carbon/kg dry weight
soil.

In a supplementary experiment, sandy loam soil samples, adjusted to 45%
MWC, were treated with 2-sec-butyl-4,6-dinitrophenyl acetate
(Dinosebacetate Pestanal(; purity 95.6%), dissolved in acetone, at a
concentration of 3.76 mg a.i./1.5 g quartz sand.  The mean rate of
respiration at test initiation was 3.88 mg CO2/h/kg dry soil.  After 28
days, the mean rate of respiration was 2.02 mg CO2/h/kg dry soil.  The
calculated deviations to control were -44.3% at 0 days and -70.2% at 28
days.  Based on these results, it was concluded that dinosebacetate
caused a clear inhibitory effect on soil microbial respiration.

	7.	Ready Biodegradability

		a. (OECD Guideline 311, MRID No. 472614-06)

	This ready biodegradability study was reviewed by the Agency and
classified as supplemental due to the following deviation: the study
author reported that the volume of gas released from the test vessels
was far greater than was theorized and suggested an extraneous source of
carbon may have been present in the test vessels.  Also, the gas
produced by the reference material, ethanol, was far greater than
theorized and the study author suggested that the microbes in the sludge
may have been stimulated by the presence of ethanol, or by the
metabolism of residual organic carbon from organic solvents routinely
used to clean glassware.  Although this study contains deficiencies as
it relates to the OECD Guideline 311, the data are useful.

In this study, the ready biodegradability of
5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; purity 94.8%;
specific activity 15 (Ci/mg) was studied in anaerobic sludge (pH
7.3-7.4) collected from a wastewater treatment plant in Massachusetts. 
The test system consisted of thirty-six Wheaton serum bottles fortified
with [14C]triclosan secondary stock solution at an application rate of
0.206 mg/L that were placed into a glove box and purged with 70:30
N2:CO2.  The bottles were then treated with the inoculated medium,
sealed with parafilm, placed on their sides, and incubated in the dark
at 35 ( 1(C.  Reference material samples (95.8 mg/L ethanol) and control
samples were also prepared and incubated as described.

Triplicate samples were collected at 0, 7, 14, 21, 28, 42, 56, 70, 91,
119, and 147 days posttreatment.  The samples were extracted with ethyl
acetate, then dried, concentrated, and adjusted to volume with
acetonitrile:reagent grade water (80:20, v:v).  The concentrated aqueous
extracts were subjected to HPLC analysis using a Metachem Nucleosil C18
column (250 x 4.6 mm) mobile phase of acetonitrile:reagent grade water
(80:20, v:v) with radioactive flow detection.  Confirmation of the
identity of the parent was performed by comparison to an unlabeled
reference standard.  Gas production measurements were conducted in all
test systems using stainless steel needles attached to gas-tight
syringes.

The concentration of [14C]triclosan was relatively stable and accounted
for 78.0-97.4% throughout the study.  HPLC chromatograms showed 2
unidentified peaks, a “shoulder” peak (ca. 5.5 minutes) and a less
polar peak (ca. 11.3 minutes), that were present in most test and
control samples.  It was determined that these peaks represented matrix
artifacts.  CO2 evolution for [14C]triclosan was not determined and an
anaerobic half-life was not determined.  The volume of the gas released
from the [14C]triclosan treated test vessels was far greater than the
volume of gas which could theoretically be produced and, therefore, was
not reported.  These results indicated that an extraneous source of
carbon was present.

  SEQ CHAPTER \h \r 1 Material balances steadily decreased from an
average of 90.2 ( 2.5% at 0 days to 46.5 ( 15.8% at 147 days. 
Extractable [14C]residues decreased from an average 81.1 ( 3.8% at time
0 to 43.9 ( 16.4% at 147 days.

The cumulative corrected volume of gas produced by the reference
material ethanol was, in all but one replicate, far greater than the
theoretical volume of gas which could have been produced by
mineralization of the ethanol alone, ranging from 69.2-314%.
Explanations for this phenomenon may be the stimulation of the microbes
in the sludge due to the presence of ethanol or the metabolism of
residual organic carbon present in varying amounts since organic
solvents are routinely used in glassware cleaning.

  SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1 For
the control samples, the concentration of [14C]triclosan was relatively
stable and accounted for 85.1-100% throughout the study.  Extractable
[14C]residues accounted for 81.3-112%.

A microbial density of 3.0 x 106 cfu/mL was estimated for the anaerobic
sludge used to inoculate the test medium.  Based on these results, it
can be assumed that the population density of the sludge upon addition
to the nutrient test solution was 3.0 x 105 cfu/mL.  The anaerobic
microbial density ranged from 1.0-1.3 x 104 cfu/mL in the [14C]triclosan
treated test vessels at 63 days posttreatment.  Day 70 blank control
vessels produced 8.0 x 103 cfu/mL.

		b. (OECD Guideline 301B, MRID No. 472614-07)

	This ready biodegradability study was reviewed by the Agency and
classified as supplemental due to the following deviation: the microbial
inoculum used in the study was pre-adapted to the test substances during
a 13-day acclimation period.  Although this study contains deficiencies
as it relates to the OECD Guideline 301B, the data are useful.

	In this study, the ready biodegradability of
5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; purity 94.8%;
specific activity 15 (Ci/mg) was studied in a microbial inoculum
comprised of sandy loam soil [pH 7.5, organic carbon 3.4%] from
Wisconsin and activated sludge from an industrial sewage treatment plant
located in San Juan, Puerto Rico.  Duplicate test and control samples of
the microbial inoculum, combined with sterile mineral salts solution,
were fortified with either [14C]triclosan or nonradiolabeled glucose
solution.  Following a 13-day acclimation period in darkness under
aerobic conditions at 22 ( 3(C, the contents of the flasks were
combined.  Triplicate glass bottles were treated with either
[14C]triclosan at an application rate of 0.2 mg a.i./L or [14C]glucose
solution at an application rate of 25.0 mg a.i./L.  The glass bottles
were connected to a flow-through volatile trapping system and placed
into an environmental chamber maintained in the dark at 22 ( 3(C. 
Moistened, CO2-free air (50-100 mL/min. flow rate) was passed through
duplicate Instagel( and phenethylamine traps.

Triplicate samples were collected from the volatile and carbon dioxide
traps at 0-10, 12, 14, 17, 20, 25, 28, 31, 34, 37, 41, 47, 54, and 57
days posttreatment and analyzed for total radioactivity by LSC.  The
volume of the remaining solution was recorded, then filtered to remove
biomass.  Each test vessel was rinsed with ethanol and the rinsate was
analyzed by LSC.  Biomass-laden filters were analyzed by LSC following
combustion.  Samples were removed from each [14C]triclosan system bottle
and each control bottle at 0, 7, 14, and 21 days and analyzed by HPLC
using a Metachem Nucleosil C18 column (250 x 4.6 mm) mobile phase of
methanol:reagent grade water (80:20, v:v) with radioactive flow
detection (limit of detection was 0.016 mg/L).  Confirmation of the
identity of the parent was performed by comparison to an unlabeled
reference standard.

  SEQ CHAPTER \h \r 1 For the [14C]triclosan systems, the concentration
of [14C]triclosan decreased from an average 78.8% of the applied at day
0 to 25.6% at 7 days, 20% (single detection) at 14 days, and was below
detectable limits at 21 days.  At 57 days posttreatment, the mean
cumulative 14CO2 evolved was 57.1% of the applied and the mean
cumulative [14C]volatile organic products evolved was 10.2% of the
applied.  Based on HPLC data, the study author determined that
[14C]triclosan degraded with an average half-life value of 5.2 ( 1.7
days.  The average half-life for mineralization of triclosan to CO2 was
61 ( 55 days.

For the [14C]glucose systems, at 57 days posttreatment, the mean
cumulative 14CO2 evolved was 81.6% of the applied.  The mean cumulative
[14C]volatile organic products evolved was 0.1% of the applied.

Overall recoveries of [14C]residues averaged 92.1 ( 6.1% (range
85.2-96.6%) and 94.9 ( 2.6% (range 93.3-97.9%) of the applied for the
[14C]triclosan and [14C]glucose systems, respectively.    SEQ CHAPTER \h
\r 1   SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1 Percent recovery was
(89% at all sampling intervals for the control samples.

	The aerobic microbial density ranged from 8.5 x 106 to 1.2 x 107 cfu/mL
in the sludge and from 1.4 x 105 to 4.2 x 106 cfu/mL in the test vessels
at 57 days posttreatment.  Based on these results, it was determined
that a viable aerobic community was present in the test vessels and that
triclosan and its transformation products do not substantially inhibit
aerobic microbial activity.

B.	Summary of Published Literature on Triclosan As Related To
Publicly-Owned Treatment Works (POTW) Concerns

  SEQ CHAPTER \h \r 1 From published literature on the occurrence of
triclosan in waste water treatment plants, treatment plant efficiency,
and open water measurements of triclosan, ccontamination of water can
come directly from   SEQ CHAPTER \h \r 1 public water systems. Triclosan
is ubiquitous in detergents, soaps, and personal care products, which
contribute to the presence of triclosan in water. Published literature
on the occurrence of triclosan in wastewater treatment plants (WWTP),
sewage treatment plants, or wastewater samples for the United States
(Anderson et al., 2004; Boyd et al., 2003 and 2004; Loraine and
Pettigrove, 2006; McAvoy, et al., 2002; Thomas and Foster, 2004 and
2005; Waltman et al., 2006), Canada (Boyd et al., 2003; Hua et al.,
2005), Australia (Ying and Kookana 2007), Japan (Nakada et al., 2006;
Shirashi et al., 1985), Switzerland (Lindstrom et al., 2002; Singer et
al., 2002), and many European countries (Paxeus, 2004) such as England
(Kanda et al., 2003; Sabaliunas et al., 2003; Thompson et al., 2005),
Spain (Agüera et al 2003; Mezcua et al., 2004), Sweden (Bendz et al.,
2005), Greece (Gatidou et al., 2007; Gomez et al., 2007) and Germany
(Bester, 2003 and 2005; Wind et al., 2004) illustrate that triclosan is
removed from wastewater but not completely. The majority of these
studies suggest that aerobic biodegradation is one of the major and most
efficient biodegradation pathways (70-80%) through which triclosan and
its by-products are removed from the aquatic environment.  Another
pathway of removing triclosan from water in wastewater treatment plants
is through the sorption of triclosan and associated by-products to
particles and sludge (10-15%) because of the chemical’s medium to high
hydrophobicity (Agüera et al., 2003; Gomez et al., 2007; Kanda et al.,
2003; Lee and Peart, 2002; Bester, 2003 and 2005; Xia et al., 2005). 
The studies indicated that total removal rates of triclosan from
activated sludge wastewater treatment plants varied from as low as 53%
(Kanda et al., 2003) to as high as 99% (Kanda et al., 2003). Removal
rates for another removal pathway, trickle down filtration, range from
58-86% (McAvoy et al., 2002) and are less effective overall in removing
triclosan than the other pathways previously mentioned. Benchtop fate
testing of triclosan found that 1.5-4.5% was sorbed to activated sludge
and 81-92% was biodegraded (Federle et al., 2002).

 a range of 0.5 to 15.6 μg/g (dry weight) and there was higher
concentrations of triclosan observed in anaerobic sludge as compared to
aerobic sludge (McAvoy et al., 2002).  Other countries where sludge
samples were analyzed for triclosan are as follows: Canada analyzed
concentrations of 370 ng/g (Lee and Peart, 2002); Germany analyzed
concentrations of 1000-8000 ng/g (Bester, 2003 and 2005); Greece
analyzed concentrations of 1,840 ng/g (Gatidou et al. 2007); Spain
analyzed concentrations of 420-5400 ng/g (Morales et al., 2005); and 19
WWTP were analyzed in Australia, which had a range of 90-16,790 ng/g dry
weight and a median of 2,320 ng/g (Ying and Kookana, 2007).

Effluent concentrations from wastewater treatment plants in the US were
10-21 ng/L in Louisiana (Boyd et al., 2003); 63 ng/L in the upper
Detroit river (Hua et al., 2005); 72 ng/L in Arlington, Virginia (Thomas
and Foster, 2004); 110 ng/L in North Texas (Waltman et al., 2006); and
the highest was 200-2700 ng/L in Ohio (McAvoy et al., 2002). Effluent
concentrations from wastewater treatment plants in other countries were
measured to be 160 ng/L (Lee et al., 2003) or 50-360 ng/L in Canada (Lee
et al., 2005); 50 ng/L (Bester, 2003), 10-600 ng/L (Bester, 2005), or
180 ng/L (Wind et al., 2004) in Germany; 160 ng/L in Sweden (Bendz et
al., 2005); 430 ng/L (31.2 μg/g particulate matter), 1120 ng/L (16.1
μg/g particulate matter), or 230 ng/L (22.4 μg/g particulate matter)
in three different WWTP in Greece (Gatidou et al. 2007); 80-400 ng/L in
Spain (Gomez et al., 2007); 100-269,000 ng/L in Spain (Mezcua et al.,
2004); 0.15±0.08 mg/person in 5 European countries (Paxeus, 2004); 340
or 1100 ng/L, for trickle filtration and activated sludge treatment
plant in England (Sabaliunas et al., 2003); 42-213 ng/L in Switzerland
(Singer et al., 2002); and from 19 WWTP in Australia the range was
23-434 ng/L with a median concentration of 108 ng/L (Ying and Kookana,
2007).

Triclosan was found in approximately 36 US streams (Klopin et al., 2002)
where effluent from activated sludge waste water treatment plants,
trickle down filtration, and sewage overflow are thought to contribute
to the occurrence of triclosan in open water. For this study, the U.S.
Geological Survey surveyed a network of 139 streams across 30 states
during 1999 and 2000.  The selection of sampling sites was biased toward
streams susceptible to contamination (i.e. downstream of intense
urbanization and livestock production). The median concentration was 40
ng/L and the maximum concentration detected was 280 ng/L (Klopin et al.,
2002). In another study, storm water canal measurements over a 6 month
period in Bayou St. John in Louisiana indicated that triclosan ranged
from below the detection level to 29 ng/L (Boyd et al., 2004). Raw
drinking water in Southern California was found to have 56 ng/L
triclosan and 49 ng/L triclosan in finished water (Loraine and
Pettigrove, 2006).  Other published data on surface water concentrations
of triclosan in the US indicated concentrations of 4 and 8 ng/L in the
upper Detroit river (Hua et al., 2005) and 56 ng/L in Arlington,
Virginia (Thomas and Foster, 2004). Published data on surface water
concentrations of triclosan in other countries indicated concentrations
of <3-10 ng/L in Germany (0.3-10 ng/L methyl-triclosan) (Bester, 2005);
19±1.4 ng/L in England (Sabaliunas et al., 2003); 11-98 ng/L in
Switzerland (Singer et al., 2002); 30 ng/L in Germany (Wind et al.,
2004); and in Australia 75 ng/L (Ying and Kookana, 2007).

Studies indicated that passive sampling with semi-permeable membrane
devices (SPMDs) were reliable for monitoring low concentrations of
methyl-triclosan in surface water downstream from WWTPs (Wind et al.,
2004; Sabaliunas et al., 2003). The data from these passive samplings
were added to a geo-referenced model GREAT-ER (Geography-Referenced
Regional Exposure Assessment Tool for European Rivers), and the
resulting PEC (Predicted Environmental Concentration) showed very good
accordance to the measured concentrations in the River Itter, in Germany
which were monitored in the same year. The concentrations did not
deviate more than by a factor of 3 (Wind et al., 2004). In England,
GREAT-ER was a useful tool for predicting and visualizing site-specific
concentrations of down-the drain chemicals but a larger volume of data
are needed to make the model more robust (Sabaliunas et al., 2003).

C.	Summary of Published Literature on Triclosan As Related To
Bioaccumulation/Bioconcentration

From published literature on the aquatic toxicity of triclosan, the
bioconcentration of triclosan in zebrafish (Danio rerio) was assessed
according to OECD Guideline 305C (Orvos et al., 2002).  Zebrafish (mean
weight 0.33 g) were acclimated in 30 L glass aquaria containing 20 L of
dechlorinated tap water.  The aquaria were connected to a continuous
flow-through system (5 L/hour) that delivered [14C]triclosan test
solution (purity >98%; specific activity 0.470 MBq/mg) at test
concentrations of 3 and 30 (g/L.  The fish were subjected to an
accumulation period of 5 weeks and a depuration period of 2 weeks. 
Triplicate fish tissues samples were collected weekly and analyzed by
incinerating in an Oxymat SA-101.  The [14C]CO2 was collected and
quantified.

	Average bioconcentration factors (BCF) for triclosan following the
5-week accumulation period were 4157 L/kg at 3 (g/L and 2532 L/kg at 30
(g/L.  The concentration of triclosan was greatest in the digestive
tract of two fish that were separated into muscle (fillet), digestive
system including stomach and intestines, and head.  Following 2 weeks of
depuration, average BCF values decreased to 41 L/kg at 3 (g/L and 32
L/kg at 30 (g/L.  Depuration rate constants were 0.142 and 0.141 per day
at 3 (g/L and 30 (g/L, respectively.  The predicted bioconcentration
factor for triclosan was calculated to be ca. 2500.  The lethal body
burden was determined to range from 0.7-3.4 mM/kg, indicating a narcosis
mode of action.

D.	Contamination of Environmental Compartments and Data Gaps

	Based on the above review of existing literature, the Agency has
concerns with the detection of triclosan and major transformation
products (e.g., methyl triclosan) in various environmental compartments,
including  POTW effluents, surface waters (both fresh and estuarine),
and POTW biosolids which may be applied to soil.  Additionally, some
authors have indicated the occurrence of triclosan and triclosan methyl
in fish and shellfish (Federle and  Schwab, 2003).  The detection of
triclosan and triclosan methyl residues in such compartments has
occurred in various countries and is not unique to the United States.

	The Agency is concerned with such widespread detection of triclosan and
triclosan methyl residues because such residues may result in potential
adverse effects to humans and/or nontarget organisms, including fish,
birds, plants, algae, or other organisms.  This concern is more
pronounced since typically EPA does not perform human and/or
environmental risk assessments for antimicrobial uses such as those for
which triclosan is registered.  However, at the same time the Agency
notes that several authors and/or governmental agencies have performed
screening level risk assessments (Samsoe-Petersen, et. al., 2003; Ying
and Kookana,  2007).  In both of these risk assessments the authors
concluded that under certain circumstances potential risks may exist for
algae and/or soil organisms from surface water discharges (e.g.,
wastewater discharges to surface waters during low flow) or from
biosolids applied to soil.

	Recognizing that these risk assessments are preliminary, but at the
same time noting the extensive literature available on environmental
compartment contamination with triclosan and/or triclosan methyl
residues, the Agency concludes that these contamination issues need to
be addressed by the registrant.  Specifically:

The registrant is required to provide a scientific rationale, including
appropriate modeling (e.g., surface water modeling), that addresses and
quantifies the amounts of triclosan and triclosan transformation
products (e.g., triclosan methyl) occurring in various environmental
compartments (e.g., surface waters, biosolids, soil, fish, shellfish)
from triclosan antimicrobial pesticide uses.

Relative to the above requirement, if the registrant is not able to
provide a satisfactory scientific rationale that determines the
quantities of triclosan and triclosan transformation products in various
environmental compartments, then EPA will assume that the present levels
of triclosan and triclosan transformation products detected in such
compartments occur because of registered antimicrobial use patterns.  In
this case, OPP will require the following environmental fate data:

Environmental Fate Data Requirements for Triclosan

OPP Guideline	Data

 Requirement	MRID

No.	Data Requirement

 Status

161-1

(preferred)	Hydrolysis	420279-08	Supplemental 

(No additional hydrolysis testing required)

161-2 or

835.2240	Photodegradation in Water	430226-08	Satisfied

162-1 or

OECD 307 or 835.4100

	Aerobic soil metabolism	472614-01	Satisfied

OECD 308 or

OPP 162-4 or 

835.4300	Aerobic aquatic metabolism	472614-02	Satisfied

162-3 or

835.4400	Anaerobic aquatic metabolism	N/A	Data Gap

None	Monitoring of representative U.S. surface waters	N/A	Data Gap

REFERENCES

UNPUBLISHED REFERENCES:

   MRID   	                                                  Citation   
                                                     	

420279-08	Pointurier, R. 1990.  Irgasan® DP 300 – Report on
Hydrolysis as a Function of pH.  Unpublished study performed and
submitted by Ciba-Geigy Ltd., Basel, Switzerland.

430226-08	Spare, W. 1993.  Aqueous Photolysis of Triclosan.  Agrisearch
Project No.: 12208.  Unpublished study performed by Agrisearch Inc.,
Frederick, MD; and submitted by Ciba-Geigy Corporation, Greensboro, NC.

472614-01	Adam, D. (2007) (Carbon 14)-Triclosan: Degradation and
Metabolism in Three Soils Incubated Under Aerobic Conditions. Project
Number: B12835. Unpublished study prepared by RCC Umweltchemie Ag.

472614-02	Adam, D. (2006) (Carbon 14)-Triclosan: Route and Rate of
Degradation in Aerobic Aquatic Sediment Systems. Project Number: A33300.
Unpublished study prepared by RCC Umweltchemie Ag.

472614-03	Volkel, W. (2007) The Effects of Triclosan on Soil
Nitrification. Project Number: A89954. Unpublished study prepared by RCC
Umweltchemie Ag.

472614-04	Volkel, W. (2006) The Effects of Triclosan on Soil
Respiration. Project Number: A88312. Unpublished study prepared by RCC
Umweltchemie Ag.

472614-06	Christensen, K. (1994) Triclosan - Determination of Anaerobic
Aquatic Biodegradation. Project Number: 93/12/5076. Unpublished study
prepared by Springborn Laboratories Inc.

472614-07	Christensen, K. (1994) Triclosan - Aerobic Biodegradation in
Water. Project Number: 93/4/4731. Unpublished study prepared by
Springborn Laboratories Inc.

--------------	The Estimation Programs Interface (EPI) Suite.  Windows
based suite of physical/chemical properties and environmental estimation
models developed by the US EPA’s Office of Prevention, Pesticides and
Toxic substances (OPPTS) and Syracuse Research Institute (SRC). 
Physical properties of Triclosan.  EPI Suite Summary (v3.12).  
HYPERLINK "http://www.epa.gov/opptintr/exposure/docs/EPISuitedl.htm"
http://www.epa.gov/opptintr/exposure/docs/EPISuitedl.htm 

-------------	Hazard Substances Data Bank (HSDB).  A Database of the
National Library of Medicine’s TOXNET System.  Triclosan: 
Environmental Fate and Exposure.  HYPERLINK
"Triclosan%20Fate%20Chapter%20for%20RED.updated%2012-21-06.doc"
http://toxnet.nlm.nih.gov 

PUBLISHED (LITERATURE) REFERENCES:

Agüera, A., Fernandez-Alba, A.R., Luis, P., et al. 2003. Evaluation Of
Triclosan And Biphenylol In Marine Sediments And Urban Wastewaters By
Pressurized Liquid Extraction And Solid Phase Extraction Followed By Gas
Chromatography Mass Spectrometry And Liquid Chromatography Mass
Spectrometry. Analytica Chimica Acta 480: 193-205.

Anderson, P.D., D'Aco, V.J., Shanahan, P., et al. 2004. Screening
Analysis of Human Pharmaceutical Compounds in U.S. Surface Waters.
Environmental Science and Technology. 38(3): 838-49.

Bendz, D., Paxeus, N.A., Ginn, .R., et al. 2005. Occurrence And Fate Of
Pharmaceutically  Active Compounds In The Environment, A Case Study:
Hoje River In Sweden.  Journal of  Hazardous Materials. 122: 195-204.

Bester, K. 2003. Triclosan In A Sewage Treatment Process--Balances And
Monitoring Data. Water Research. 37 (16): 3891-6.

Bester, K. 2005.  Fate of Triclosan and Triclosan-Methyl in Sewage
Treatment Plants and Surface Waters. Archives of Environmental
Contamination and Toxicology. 49 (1): 9-17.

Boyd, G.R., Palmeri, J.M., Zhang, S., et al. 2004. Pharmaceuticals And
Personal Care  Products (PPCPs) And Endocrine Disrupting Chemicals
(EDCs) In Stormwater Canals And Bayou St. John In New Orleans,
Louisiana, USA. Science of the Total Environment. 333 : 137-48.

Boyd, G.R., Reemtsma, H., Grimm, D.A., et al. 2003. Pharmaceuticals And
Personal Care Products (PPCPs) In Surface And Treated Waters Of
Louisiana, USA And Ontario, Canada. Science of the Total Environment
(Netherlands). 311 (1-3): 135-49.

Federle, T.W., Kaiser, S.K., and Nuck, B.A. 2002. Fate and Effects of
Triclosan in Activated Sludge.  Environmental Toxicology and
Chemistry/SETAC.  21(7): 1330-7.

Federle, T.W. and E.L. Schwab. 2003. Triclosan Biodegradation in
Wastewater Treatment Plant Effluent Diluted in Various River Wastes.
Abstr. Gen. Meet Am Soc. Microbiol 103. p. 0-017.

 

Gatidou, G., Thomaidis, N.S., Stasinakis, A.S., et al. 2007.
Simultaneous Determination Of The Endocrine Disrupting Compounds
Nonylphenol, Nonylphenol Ethoxylates, Triclosan And Bisphenol A In
Wastewater And Sewage Sludge By Gas Chromatography-Mass Spectrometry.
Journal of Chromatography A. 1138: 32-41.

Gomez, M.J., Martinez Bueno, M.J., Lacorte, S., et al. 2007. Pilot
Survey Monitoring Pharmaceuticals And Related Compounds In A Sewage
Treatment Plant Located On The Mediterranean Coast. Chemosphere. 66 (6):
993-1002.

Hua, W., Bennett, E.R., Letcher, R.J. 2005. Triclosan In Waste And
Surface Waters From The Upper Detroit River By Liquid
Chromatography-Electrospray-Tandem Quadrupole Mass Spectrometry.
Environment International. 31: 621-30.

Kanda, R., Griffin, P., and James, H.A., et al. 2003. Pharmaceutical and
Personal Care Products in Sewage Treatment Works.  Journal of
Environmental Monitoring.  5(5): 823-30.

Kolpin, D.W., Furlong, E.T., Meyer, M.T., et al. 2002. Pharmaceuticals,
Hormones, and Other Organic Wastewater Contaminants in U.S. Streams,
1999-2000: A National Reconnaissance. Environmental Science and
Technology. 36(6): 1202-11.

Lee, H., and Peart, T.E. 2002. Organic Contaminants in Canadian
Municipal Sewage Sludge. Part I. Toxic or Endocrine-disrupting Phenolic
Compounds. Water Quality Research Journal of Canada. 37(4): 681-696.

Lee, H., Sarafin, K., and Peart, T.E., et al. 2003. Acidic
Pharmaceuticals in Sewage: Methodology, Stability Test, Occurrence, and
Removal from Ontario Samples. Water Quality Research Journal of Canada.
38(4): 667-682.

Lee, H., Peart, T.E., and Svoboda, M.L. 2005. Determination of
Endocrine-Disrupting Phenols, Acidic Pharmaceuticals, and Personal-care
Products in Sewage by Solid-phase Extraction and Gas Chromatography-Mass
Spectrometry. Journal of Chromatography. 1094(1-2): 122-9.

Lindstrom, A., Buerge, I.J., Poiger, T., et al. 2002. Occurrence and
environmental behavior of the bactericide triclosan and its methyl
derivative in surface waters and in wastewater. Environmental Science
Technology. 36: 2322-2329. Comment in Environmental Science
Technolology. 36 (11): 228A-230A.

Loraine, G.A., Pettigrove, M.E. 2006. Seasonal Variations In
Concentrations Of Pharmaceuticals And Personal Care Products In Drinking
Water And Reclaimed Wastewater In Southern California. Environmental
Science and Technology. 40(3): 687-95.

McAvoy, D.C., Schatowitz, B., Martin, J., et al. 2002. Measurement of
Triclosan In Wastewater Treatment Systems. Environmental Toxicology and
Chemistry. 21 (7): 1323-9.

Mezcua, M., Gomez, M.J., Ferrer, I., et al. 2004. Evidence of
2,7/2,8-Dibenzodichloro-p-dioxin As A Photodegradation Product Of
Triclosan In Water And Wastewater Samples. Analytica Chimica Acta. 524
(1-2): 241-247.

Morales, S., Canosa, P., and Rodriguez, I., et al. 2005. Microwave
Assisted Extraction Followed by Gas Chromatography with Tandem Mass
Spectrometry for the Determination of Triclosan and Two Related
Chlorophenols in Sludge and Sediments. Journal of Chromatography. 1082:
128-35.

Nakada, N., Toshikatsu, T., and Hiroyuki, S., et al. 2006.
Pharmaceutical Chemicals and Endocrine Disrupters in Municipal
Wastewater in Tokyo and their Removal during Activated Sludge Treatment.
Water Research. 40(17): 3297-303.

Orvos D.R., D.J. Versteeg, J. Inauen, M. Capdevielle, A. Rothenstein and
V. Cunningham. 2002. Aquatic toxicity of triclosan. Environ. Toxicol.
Chem. 21(7): 1338-1349.

Paxeus, N., and Gryaab, K. 2004. Removal Of Selected Non-Steroidal
Anti-Inflammatory Drugs (NSAIDs), Gemfibrozil, Carbamazepine,
Beta-Blockers, Trimethoprim And Triclosan In Conventional Wastewater
Treatment Plants In Five EU Countries And Their Discharge To The Aquatic
Environment. Water Science and Technology. 50 (5): 253-60.

Sabaliunas, D., Webb, S.F., Hauk, A., et al. 2003. Environmental Fate Of
Triclosan In The River Aire Basin, UK. Water Research (England). 37:
3145-54.

Samsoe-Petersen L.,Winther-Nielsen M., Madsen T. Fate and Effects of
Triclosan.

Environment Project No. 861. Copenhagen: Danish Environmental Protection

Agency; 2003.

Shiraishi, H., Otsuki, A., and Fuwa, K. 1985. Identification Of
Extractable Organic Chemicals In Sewage Effluent By Gas
Chromatography/Mass Spectrometry. Biomedical Mass Spectrometry. 12 (2):
86-94.

Singer, H., Muller, S., Tixier, C., et al. 2002. Triclosan: Occurrence
And Fate Of A Widely Used Biocide In The Aquatic Environment: Field
Measurements In Wastewater Treatment Plants, Surface Waters, And Lake
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Thomas, P.M., and Foster, G.D. 2004. Determination of Nonsteroidal
Anti-inflammatory Drugs, Caffeine, and Triclosan in Wastewater by Gas
Chromatography-Mass Spectrometry.2004. Journal of Environmental Science
and Health.  Part A, Toxic/Hazardous Substances & Environmental
Engineering. 39(8): 1969-78.

Thomas, P.M., and Foster, G.D. 2005. Tracking Acidic Pharmaceuticals,
Caffeine, And Triclosan Through The Wastewater Treatment Process.
Environmental Toxicology and Chemistry. 24 (1): 25-30.

Thompson, A., Griffin, P., and Stuetz, R., et al. 2005. The Fate and
Removal of Triclosan during Wastewater Treatment.  Water Environment
Research. 77(1):63-67.

Waltman, E.L., Venables, B.J., and Waller, W.T. 2006. Triclosan in A
North Texas Wastewater Treatment Plant And The Influent And Effluent Of
An Experimental Constructed Wetland. Environmental Toxicology and
Chemistry. 25 (2): 367-72.

Wind, T., Werner, U., Jacob, M., et al. 2004. Environmental
Concentrations Of Boron,  LAS, EDTA, NTA and Triclosan Simulated with
GREAT-ER in the river Itter. Chemosphere (England). 54: 1135-44.

Ying, G. and Kookana, R.S. 2007. Triclosan in Wastewaters And Biosolids
From Australian Wastewater Treatment Plants. Environmental
International. 33 (2): 199-205.

Sign-off Date      :  02/06/08

DP Barcode No.  :  D335396

  The Samsoe-Petersen, et. al., (2003) reference represents a
preliminary risk assessment performed by the Danish Environmental
Protection Agency.

  Note that based on the results of these data additional data (e.g.,
toxicology, ecological effects) may be required in     order for the
Agency to complete human and/or environmental risk assessments.

 Prior to beginning this study the registrant must submit a protocol to
the Agency for approval.

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