**-'.~EO S1"-4~**  

### V"""**~Q\**

### ~ 

# =u UNITED STATES ENVIRONMENTAL PROTECTION AGENCY**~** Z 

### WASHINGTON D.C., 20460



## - w ]) (!J 

# \ ;**~** f\{J

## ~t**PR01~v** OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION



### December 15,2011



### MEMORANDUM

SUBJECT:

FROM:

THRU:

TO: Product Chemistry, Environmental Fate, and Ecological Effects Scoping

Document 

### in Support of Registration Review ofBis (trichloromethyl)

sulfone (BTS).

PC Code: 035601 

### DP Barcode: 394301


### Decision No.: 455121 

### Registration Nos.: See Table 1


### Petition No(s).: NA Regulatory Action: Ecological
Environmental Scoping Document
for Registration Review
Risk Assessment Type: Single chemical Case No.: 2055


### TXRNo.:NA CAS No.: 3064-70-8



### MRID Nos.: See Table 3 & 

### Pg. nos. 7, 40 

### CFR: None 8,9, 10, 11, 12, & 13.



### . " C**~**

# rinivas Gowda,

# MicrObiOIOg**~U"-.cL- ~** **~** James Breithaupt, Agronomist 

### N 

## 6

- 

# I \ t; 

# I**~** - Zoe Layton, Biologist

### ~ 11, '\

Risk Assessment and Sc e S pport Branch (RASSB)

Antimicrobials Division 7510 ) 

# v!1 v ' f t...,?'\

### ~-- 

### Nader Elkassabany, Branch**C~** 

# c::..-**~** 

# . Donna Randall, Peer Reviewer

### ~ .' 

## (JAA..y\a,...Q..O

Risk Assessment and Science Support Branch (

# ~ Antimicrobials Division (7510P)

Mark Hartman, Branch Chief

Lance Wormell, Team Leader

Seiichi Murasaki, Chemical Review Manager Regulatory Management Branch II

Antimicrobials Division (751 

### OP)

Page 1 of40

### Page 2 of 40 Executive Summary

Bis (trichloromethyl) sulfone (BTS) is an or gano

- sulfur compound registered for use as an algicide, bactericide, slimicide and fungicide for use in industrial process and water systems
such as pulp and papermill process water systems, recirculating cooling towers, and oil and gas
field injection water systems ; , and as a material preservative in paper additive system (nonfood contact) such as pastes and adhesive systems, polymers and latex emulsion systems, pigmented
slurries

, coating systems

, in

- container preservative for water

- soluble and water dispersed
adhesives and tackifiers, in

- container preservative for water soluble and water dispersed construction and household products, manufacture and storage preservative for dispersed pigments; and as a fuel preservative

. BTS was first registered in the United States in 1967 as a fungicide. A Reregistration Eligibility Decision (RED) for BTS was completed in September
1996. Currently there are three companies that have nine active registrations. One of these products is registered as a technical with an active ingredient d eclaration of 98%, and two are manufacturing use products with active ingredient declarations of 35 and 39.2%. The remaining six products are end

- use products with active ingredient declarations of 3.3 to 20%; these products consist of soluble ready

- to

- us e solutions and a flowable emulsifiable concentrate. All product chemistry data requirements have been satisfied for th is active ingredient BTS

.

At the time of the RED, risk assessments were not conducted for industrial microbiocides unless products had a once

- through cooling water system use. To regulate these industrial
microbiocide uses and associated risks to the aquatic environment

, the Agenc y required that labels for BTS products require that discharges to aquatic environments comply with a National Pollutant Discharge Elimination System (NPDES) permit. As part of the registration review process, risk assessments for the pulp and papermill p rocess water systems, recirculating cooling

tower, and oil and gas field injection water systems will be conducted. For BTS applied to fuel

, the types of BTS combustion products are expected to be essentially the same as those found
from combustion of fue l alone, and at concentrations that would not be discernable from background level

.

To conduct these assessments, t he Agency data base for evaluating the environmental fate and
transport of BTS is incomplete

. The environmental f ate d ata gaps for this pes ticide include activated sludge sorption isotherm, activated sludge respiration inhibition, and one of four waste biodegradability tests ( ready biodegradability, porous pot test, or one of two simulation tests)

. The purpose of these tests is to address di scharge of fluids from industrial process and water systems, paper additive systems

, and o il and gas field water systems to waste water treatment facilities followed by release to receiving waters and/or direct release to receiving waters

. T he major route of dissipation of BTS in the environment is microbial degradation with an estimated
half

- life of <1 day in aquatic aerobic conditions and <0.5 days in aquatic anaerobic conditions

. Two metabolites are pentachlorodimethylsulfone

, found under anaerobic and aerobic conditions

, and hexachloroethane , found under anaerobic conditions . One aquatic dissipation study was submitted, which measured concentrations of BTS in paper mill effluent. The water going into the paper machine was treated at 484 ppb (0. 484 ppm), with BTS concentrations of 34, 7

- 8, and 2 ppb in machine effluent, water samples from the mill, and lagoon water, respectively. The degradate, pentachlorodimethylsulfone, ranged from 5

- 6 ppb in machine water, mill water, and lagoon water ; hexachloroethane was not detected

.

### Page 3 of 40 B TS is practically non

- toxic to avian species on an acute oral and subacute dietary basis; slightly toxic to small mammals on an acute oral basis; very highly toxic to freshwater fish and
estuarine/marine invertebrates . BTS was classified as highly toxic to freshwater invertebrates
and marine fish , but this is based on supplemental data which is expected to greatly underestimate the toxicity of BTS . In order to perform an ecological risk assessment, including
an endan gered species assessment for all uses, the Agency anticipates requiring several effect studies. This list includes resubmittal of a number of acute aquatic studies (freshwater fish both cold water and warm water; freshwater daphnid; estuarine/marine fish) for the TGAI because BTS would not be stable under the static conditions these studies were conducted, and no analytical measurements were made to document actual exposure concentrations. While the very highly toxic classification under even under these serves for labeling issues, these results are not adequate for assessing risk. Additional TGAI studies include: an estuarine/marine crustacean acute study; a guideline algal toxicity (Tier II) study for a freshwater green alga, Selenastrum capricornutum

, a freshwater diatom, Navicula pelliculosa , a marine diatom, Skeletonema

costatum , and a cyanobacteria study using Anabaena flos

- aqua ; a guideline Lemna toxicity (Tier II) study; a freshwater fish early

- life stage study ; an aquatic freshwater invertebrate life

- cycle study ; and an activated sludge respiration inhibition test

. Because of the short half

- life of BTS, aquatic organisms may also be exposed to the major degradate pentachlorodimethylsulfone of which there is currently no effects data

. To evaluat e risk to total toxic residues of BTS, effects data with this degradate for the following is required: a freshwater acute invertebrate study; a marine/estuarine crustacean and a mollusk acute study; a freshwater fish acute study; an
estuarine/marine invert ebrate life cycle study; a freshwater early life stage study; an algae (Tier II) study using only the most sensitive of the TGAI algae species; a guideline Lemna (Tier II) study; a seedling emergence (Tier II) test using rice; and an activated sludge respi ration inhibition study.

### Page 4 of 40 Introduction

B TS was first registered in the U.S. in 1967 as a fungicide. BTS is registered for use as an algicide, bactericide, slimicide and fungicide in industrial process and water systems such as pulp and papermill process water systems, recirculating cooling towers, secondary oil

- recovery injection water systems, evaporative

- condenser water syst ems, h eat exchanger systems, and as a
material preservative in adhesives , latexes, construction products and household products ( such as caulking materials, mastics, ceramic, glazes, concrete, concrete admixtures, plasters etc.), dispersed pigment preservative, paints coatings and stains, paper coating preservation, photo processing system preservation, polymer latex preservation, and fuel preservation

. Currently nine products are registered for the uses indicated above which are listed in Table 1. A Reregistrat ion Eligibility Decisi on (RED) was issued by EPA for b is(trichloromethyl) sulfone in September
1995 1



### .

Table 1. Registere d Product s of Bis(trichloromethyl) sulfone

Registration
# Registration Name Company

Name Formulation Type % of Active Ingredient

1706

- 177 Nalcon® 7642 Nalco Company Ready

- to

- Use Solution 3.33

67869

- 14 N

- 1386 Technical Verichem, Inc. Technical Chemical 98

67869

- 15 N

- 1386 Hexylene Glycol Verichem, Inc. Formulation
Intermediate 35

67869

- 16 N

- 1386 Naptha Han Verichem, Inc. Manufacturing Use
Product 39.2

67869

- 32 N

- 1386 PEG

- EU 20 Verichem, Inc. Emulsifiable Conc. 20

74655

- 3 Spectrum RX

- 36 Hercules Incorporated Ready

- to

- Use Solution 20

74655

- 6 Spectrum RX

- 38 Hercules Incorporated Ready

- to

- Use Solution 17

74655

- 10 Spectrum RX

- 65 Hercules Incorporated Ready

- to

- Use Solution 18

74655

- 15 Spectrum RX

- 10 Hercules Incorporated Ready

- to

- Use Solution 5.3



### The Agency has conducted a review of the available product chemistry, environmental fate, and ecotoxicity data for BTS

. The primary source of information for this assessment was
the 199 5 b is(trichloromethyl) sulfone RED. The findings are summarized below.

1 http:/www.epa.gov/oppsrrd1/REDs/2055red.pdf

### Page 5 of 40 A. Product Chemistry Summary of Bis(trichloromethyl)sulfone ( 9 8

- 100 % TGAI)

Common Name: Bis(trichloromethyl) sulfone
Chemical Name: Hexachlorodimethyl sulfone Sulfonyl bis(trichloromethane)

Trade and Other Names: N

- 1386 ®



### OPP Chemical Code: 35601

CAS Registry Number: 3064

- 70

- 8

Molecular Formula: C 2 

### Cl 6 

### O 2 

### S

Molecular weight: 301 g/mole

Molecular Structure:

Color: White to Off

- w hite Crystal

Physical State: Solid (Crystals) at 25 ° C

Odor: Pungent aromatic odor

Stability: Relatively s table at room temperature 25 ° C. Does not react
with steel or iron.

Oxidation/Reduction: Not required

. Product does not contain any oxidizing or reducing agents.

Flammability : Not required for products which do not contain combustible liquids.

Explodability: N ot required. Contains no explosive ingredients.

Storage Stability: Ave. % w/w A.I

. Initial: 99.2
After 3 months: 99.0
After 6 months: 99.2 After 1 year: 99.2

Miscibility: Not required. Product is not an emulsifiable liquid and is not intended to be diluted with petroleum solvents.

### Page 6 of 40 Corrosion Characteristics: No degradation or deterioration of the packaging (55

- gallon, epoxy lined steel drum) was observed during or
after the one

- year storage at room temperature. A laboratory immersion testing for corrosivity showed product to be corrosive to stainless steel and cold rolled
steel . Coupons of fiber glass HDPE, LOPE, cross

- linked HDPE and polystyrene were not affected by the product.

Dielectric breakdown voltage: Not required for products not intended to be used around electrical equipment.

pH: Not Applicable for solids

.

UV/Visible absorption: Not Reported

.

Viscosity: Not applicable for solid products

. Melting point: 36

- 38 ° C

.

Boiling Point: Not applicable for solids

.

Density: 2.00 g/ml at 20 ° C

.

Dissociation Constant: N ot applicable

. TGAI Does not dissociate in water.

Log K o/w 

### : 3.3

Solubilit ies : Water: 70 ppm by weight at 20

- 22°C Essentially insoluble in water. Ethylene glycol: 6.2% by weight Dimethyl sulfoxide: 90.0% by weight at 70°F/25° C
82.0% by weight at 4 8 ° F/9 ° C
75.0% by weight at 67 °F/20°C
Acetonitrile: 93.0% by weight at 67°F/20°C 86.0% by weight at 50°F/10°C 81.0% by weight at 41°F/5°C

Vapor Pressure: 0.00108 mm Hg at 2 5 ° C (Source: EPI Suite)

Henry's Law Constant: 1.19 E

- 008 atm

- m 3 

### /mole ( Source: EPI Suite)

Enf orcement Analytical
Method: Gas Chromatograph GC/MS

### Page 7 of 40 All product chemistry data requirements have been satisfied for the active ingredient s BTS

. (Source: MRID s 152324, 152 327, 156932, 162129, 42384501, 42413301, 45614801 , 41888602, 456311

- 01, and 92010003 )

.

B. Environmental Fate Summary

No environmental fate assessment was performed for BTS at the time of the registration. Available environmental fate guideline studies and the results are summarized below.

The Agency's conclusions for the degradation, metabolism, mobility, and dissipation
studies are as follows.

1. Degradation Studies (Abiotic)

a. Hydrolysis (161

- 1)

B TS did not hydrolyze in sterile aqueous buffered solutions at pH 4, 7, or 9 when incubated at 25°C. The study is classified as acceptable (MR ID # 418887

- 01).

b. Photodegradation in water (161

- 2)

B TS photodegraded when irradiated with a non

- specified sunlamp at pH 7 at
25 ° C degraded to bicarbonate, chloride, and sulfate ions. Photodegradation
half

- lives were 3 9 days in water and 6 days in water sensitized with 1% acetone. The study is classified as supplemental (M RID #s 00156819, 00156935 ).

c. Combustion in fuel

No study has been conducted to identify the types and exact amounts of combustion products of BTS that would occur when fuel, with BTS added is burned. However, the combustion by

- product s of BTS that are likely to form
when burned with hydrocarbon fuels i s listed in the following table. This list is by no means complete but provides the ones most likely to form in the greatest quanti ties, and be released to the at mosphere. The active ingredient can extract hydrogen from the hydrocarbon fuel to form some of these by

- products; this can commonly occur in such systems. Quantities provided are estimates for the highest label application rate and assum es that 100% of the BTS is converted to
the designated by

- product . T he highest label application rate is 1.5 gallons of
the formulation (20% a.i.; EPA Registration # 67869

- 32 ) in 10,000 gallons of fuel, which occurs under the worst conditions (system is really fouled), this
translates to 30 ppm 2

2 150 gallons of formulation per 1,000,000 gallons x 0.2 a.i. fraction of formulation = 30 parts per million 

### of the active in fuel

. The levels of sulfur and chlorine
added are within background levels found in crude oils (see the following paragraph), and a majority of the chlorine in fossil fuels is expected to be
released predominately as hydrogen chloride (HCl) and chloromethane (CH 3 

### Cl) (McCulloch et al . 1999; MDNR 1999)

.

### Page 8 of 40 Ta ble 2

. Possible Combustion By

- Products of BTS in Fuel

Combustion By

- Products of BTS Air Emission Levels per gallon of fuel Hexachloroethane (C 2 

### Cl 6 

### ) 30 ppm Chloroform (CHCl 3 

### ) 30 ppm Dichloromethane (CH 2 

### Cl) 30 ppm Sulfur oxides, could be SO 2 

### or SO 3 

### 30 ppm each Hydrochloric acid (6 HCl) 18 0 ppm Thionyl chloride (SO 2 

### Cl) 30 ppm

Sulfur is a natural occurring element in crude oil with reported content in domestic and foreign crude oil ranging from <100 ppm to >20,000 ppm (BLM 1975). The average monthly sulfur content of crude oil in the United States in 2011 ranged from 0.57% (5700 ppm) to 2.28% (22,800 ppm) 3



### . An average
crude oil contains 1

- 3% (10,000

– 30,000 ppm) sulfur 4



### . The level of sulfur that would be added by BTS is within background levels of crude oil. Sulfur content of processed fuel oils will differ based on the origin of the crude oil and the extent upon the methods of refining. For example

, in a 1999 MDNR review of sulfur and chloride content of fuel oils for boilers, the reported sulfu r content for
No. 2 oil and low sulfur No. 6 oil is around 0.41% (4100 ppm) and 0.49% (4900 ppm), respectively, No. 5 oil contained 1.42% (14,200 ppm), and high sulfur
No. 6 oil contained 1.66% (16,600 ppm) (MDNR, 1999). The sulfur content of
fuel oils is regulated in some cases such as diesel fuel which has standards ranging from 15 ppm (ultra low) sulfur content upto 1000 ppm 5 

### ; special processing is needed to obtain the ultra low sulfur content fuels

.

In the 1999 MDNR review of the sulfur and chlorine ( reported as chloride)
content of fuel oils for boilers, No. 2, No. 5 , and No. 6 fuel oil contained
between 0. 02 % ( 2 00 ppm) and 0.05% (500 ppm) chlorine (MDNR, 1999).

2. Metabolism Studies (Biotic)

a. Anaerobic Aquatic Metabolism (162

- 3)

An anaerobic aquatic metabolism study conducted with a sandy loam sediment and pond water shows that the major route of dissipation of BTS is rapid microbial degradation with an estimated half

- life of <0.5 days. The metabolite pentachlorodimethyl sulfone was minor (<10 % of applied parent compound, but hexachloroethane reached 76.3 % of applied by 14 days and degraded to 53% by the end of the study (9 months). The study is classified as acceptable (MRID # 403171

- 01).

3 http://205.254.135.7/dnav/pet/pet_pnp_crq_a_EPC0_YCS_pct_m.htm Website accessed 12/14/2011

4 http://www.osha.gov/dts/osta/otm/otm_iv/otm_iv_2.html

5 http://www.epa.gov/otaq/fuels/dieselfuels/index.htm

### Page 9 of 40 b. Aerobic Aquatic Metabolism (162

- 4)

The calculated aerobic aquatic metabolism half

- life of parent is 0. 7 days. The
carbon

- 14

- labeled ( 14 

### C

- labeled ) residue mass balance accountability had a mean of 97.9% based on initial concentration for the month long study. Extractability decreased from approximately 80% at day 0 to 28% at 1 month. Test water residues increased from approximately 11% at day 0 to 46% at 1 month. There

was n o significant change in non

- extractable residues as a percent of initial
concentration

. Liquid scintillation analysis of trapping solutions shows that 14 

### C

volatiles accounted for a mean of less than 4% of mass balance accountability. The degradates pentachlorodimethyl sulfone and hexachloroethane were formed in significant (>10%) quantiti es. Pentachlorodimethyl sulfone was 1.5 μg/g at the beginning of the study, increased to 4.4 μg/g (100 % of parent compound) by 14 days, and decreased to non

- detectable concentrations by 7

- 14 days. Hexachloroethane was first detected at 7 days, and varie d between 2.4 and 3.6 μg/g (55

- 82 % of applied parent compound) until 21 days. The study is
classified as acceptable (MRID # 40 1932

- 03 ).

3. Mobility Studies

a. Leaching/adsorp tion/desorption (163

- 1)

In a leaching adsorption/desorption study, Freundlich K ads 

### values from five (autoclaved) U.S. soils ranged from 6

- 52 mL/g, which indicates low mobility. The study is classified as acceptable ( M RID #s 00156936, 00162362 ).

4. Dissipation Study

a. Aquatic Field Dissipation Study (164

- 2)

One aquatic dissipation study was submitted. This study followed the dissipation
of bis ( trichloromethyl) sulfone in a pulp/paper mill from paper machine water, to mill water, and further to lagoon water that was then released to a stream. The water going into the paper machine was treated at 4.84 x 10 2 

### ppb (0.484 ppm) bis ( trichloromethyl) sulfone. Effluent from the machine contained 34 ppb, water samples from the mill contained 7

- 8 ppb, and lagoon water contained 2 ppb bis ( trichloromethyl) sulfone. One degradate, pentachlorodime thyl sulfone, ranged
from 5

- 6 ppb in machine water, mill water, and lagoon water. The second degradate, which was referred to as a hydrolysis product, hexachloroethane, was not recovered from any of the samples during the study (MRID # 403171

- 03).

In summary, the registrant has submitted an acceptable hydrolysis study, and an acceptable anaerobic aquatic metabolism study (hydrolysis, MRID # 418887

- 01 ; anaerobic aquatic metabolism, 403171

- 01; aerobic aquatic metabolism study, MRID # 401932

- 03 ) and

ot her studies which are considered to be supplemental that adequately describe the

### Page 10 of 40 environmental fate of BTS and its major degradates . BTS is stable to hydrolysis, but degrades by photodegradation in water with half

- lives of 39 days (corrected) and 6 days ( uncorrected) for

non

- sensitized and sensitized solutions, r espectively (M RID #s 00156819, 00156935 ). A n anaerobic aquatic metabolism study (MRID 403171

- 01) conducted with a sandy loam sediment and pond water shows that the major route of dissipation of BTS is microbial degradation with
an estimated half

- life of <0.5 days. Two metabolites are pentachlorodimethyl sulfone and
hexachloroethane. One aquatic dissipation study (MRID 403171

- 03) was submitted, which measured concentrations of BTS in paper mill effl uent. The water going into the paper machine was treated at 484 ppb (0.484 ppm), with effluent from the machine containing 34 ppb, water samples from the mill containing 7

- 8 ppb, and lagoon water containing 2 ppb BTS. One degradate, pentachlorodimethyl s ulfone, ranged from 5

- 6 ppb in machine water, mill water, and lagoon water. The second degradate, which was referred to as a hydrolysis product, hexachloroethane, was not recovered from any of the samples during the study.

In a leaching adsorption/desorpt ion study, Freundlich K ads values from five (autoclaved) U.S. soils ranged from 6

- 52 mL/g, which indicates relatively low to low mobility in tested soils ( M RID #s 00156936, 00162362 ).

At this time, the Agency did not conduct an environmental fate assessm ent for the material preservatives and industrial process and water systems uses of BTS because of lack of
data on those studies listed on p age 1 1 of this document. Once these studies are submitted, the Agency will then assess the fate and transport of BTS from the uses that create waste products that may pass through waste water treatment plants (WWTPs) and be discharged into terrestrial and aquatic environments. These uses include material preserva tives and industrial slimicides used in recirculating water cooling towers and pulp and paper mills.

Water Quality

B TS is not identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act, based o n information provided at the Agency’s National Pesticides Cause of Impairment of Waters website (searched April 7, 2011) 6 

### . In addition, no Total Maximum Daily Loads (TMDL s ) have been developed for BTS , based on information provided at the Agency’s Nation al Pesticide TMDL web site (searched April 7, 2011) 7 

### . More information on impaired water bodies and TMDLs can be found at http://www.epa.gov/owow/tmdl/ . The Agency invites submission of water quality data for t his pesticide. To the extent possible, data should conform to the quality standards in Appendix A of
the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and Manag ement Process (see: http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1

- sop.pdf ), in order to ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

6

. http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

7 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_ group_name=PESTICIDES

### Page 11 of 40 C. Ecological Effects Summary

No quantitative ecological risk assessment was performed for BTS at the time of the registration. Available e cotoxicity guideline studies and the r esults are summarized in Table 3

. The Agency's conclusions for the terrestrial and aquatic effects studies are as follows.

a. Toxicity to Terrestrial Animals

Birds, Acute and Subacute

In order to establish the toxicity of BTS to birds, the following tests are required
for industrial microbi o cides using the technical grade material: one avian single

dose oral (LD 50 

### ) study on one species (preferably the bobwhite quail or mallard duck) and one subacute dietary study on one species (preferably the bobwhite quail). These studies have been submitted and their results are presented in Table

3 . These results indicate that BTS is practically non

- toxic to avian sp ecies on an acute oral and subacute dietary basis. The acute oral study contained overt signs of toxicity at the highest dose teste d. The guideline requirements are fulfilled (MRID #’s 156817, 156818, and 156820).

Toxicity to Mammals

Wild mammal testing is required on a case

- by

- case basis, depending on the results of the lower tier studies such as acute and subacute testing, intend ed use pattern, and pertinent environmental fate characteristics. In most cases, however, an acute
oral LD 50 

### from an acute oral toxicity study is used to determine toxicity to
mammals. The acute LD 50 

### for rats (small mammal surrogate), discussed in the
Human Health Assessment , was determined to be 535 mg/kg (MRID #152875).
This result indicates that BTS is slightly toxic to small mammals on an acute oral
basis.

b . Toxicity to Aquatic Animals

1. Freshwater Fish

In order to establish the toxicity of BTS to freshwater fish, the minimum data required on the technical grade of the active ingredient for discharge to receiving

waters is one warm water fish toxicity study and one cold water fish toxici ty study. The preferable cold water species is rainbow trout and the preferable warm water species is the bluegill sunfish. Two studies were found in the files, but both
of these studies provide only supplemental information 8

8 These studies were originally cl assified as acceptable, but the issues of stability were not noted or discussed. These studies were downgraded to supplemental because the studies do not document the stability and fate information indicates that stability was not likely. These results a re expected to greatly underestimate the acute sensitivity of BTS to fish. 

### . The studies are
conducted under static conditions and no analytical measurements were made of

### Page 12 of 40 for the test substance. Given that the aquatic aerobic half

- life of BTS is <1 day, the parent was not likely stable under test conditions. To maintain stable exposure concentrations give n the expected half

- life, the tests should have been
conducted under flow

- through conditions and analytical measurements made at a frequency and timing to document stability throughout the study duration

. The results of these supplemental studies are list ed in Table 3 and they are expected to greatly underestimate the acute sensitivity of BTS to fish; however, they still
indicate that BTS can be expected to be very highly toxic to both cold and warm
water fish. The data requirements are not fulfill ed (MRID #s 156814 and 156815).

To establish the toxicity of the major degradate, pentachlorodimethylsulfone , to freshwater fish, one fish acute toxicity study using the most sensitive TGAI species is required . No acute fish toxicity data for this degradate is available. The data requirement for the major degradate, pentachlorodimethylsulfone

, is not
fulfilled.

No chronic data is available for either BTS or its major degradate with freshwater
fish. Because uses of BTS will result in repeated discharge of the antimicrobial
and its major degradate

, pentachlorodimethyl

- sulfone , to aquatic environment a fish early life stage test with TGAI BTS and a test with the degradate is required. There should be an acute toxicity test available for the same species for each of
these.

2. Freshwater Invertebrates

The minimal testing required establishing the acute toxicity of a microbiocide to freshwater invertebrates is a freshwater aquatic invertebrate toxicity test, preferably using first instar Daphnia magna or early instar amphipods, stoneflies, mayflies, or midges. One study was found in the files, but the study provides only supplemental information 9 

### . The stud y was conducted under static conditions and no analytical measurements were made of for the test substance. Given that the aquatic aerobic half

- life of BTS is <1 day, the parent was not likely stable under test conditions. To maintain stable exposure concentrations given the expected
half

- life, the test should have been conducted under at least ren ewal conditions and analytical measurements made at a frequency and timing to document stability throughout the study duration. The classification of BTS as highly toxic to aquatic invertebrates (Table 3 ) based on the supplemental information is likely

an underestimate of the sensitivity of BTS to freshwater invertebrates . The guideline requiremen t is not fulfilled (MRID #156816).

9 The study was originally classified as acceptable, but the issues of stability were not noted or discussed. The study was downgraded to supplemental because it does not document the stability and fate information indicates that stability was not likely. These results are expected to greatly underestimate the acute sensitivity of BTS to
freshwater invertebrates.

### Page 13 of 40 To establish the toxicity of the major degradate, pentachlorodimethylsulfone , to freshwater invertebrates , one freshwater inv ertebrate acute toxicity study using
the same TGAI tested species is required. No acute freshwater invertebrate toxicity data for this degradate

, pentachlorodimethylsulfone

, is available.

No chronic data is available for either BTS or its major degradate with freshwater
invertebrates. Because uses of BTS will result in repeated discharge of the
antimicrobial and its major degradate

, pentachlorodimethyl

- sulfone

, to aquatic
environment a life cycle test with TGAI BTS and a life cycle test with the degradate is required.

3. Estuarine and Marine Animals

For uses where the antimicrobial is expected to reach estuarine or marine environments, one estuarine/marine acute fish toxicity study, one acute crustacean toxicity study, and one mollusk study are required. One sheepshead minnow study was found in the files, but the study provides only supplemental
information 10 

### . The study was conducted under static conditions and no analytical measurements were made of for the test substance. Given that the aqua tic aerobic
half

- life of BTS is <1 day, the parent was not likely stable under test conditions. To maintain stable exposure concentrations given the expected half

- life, the test
should have been conducted under flow through conditions and analytical

measu rements made at a frequency and timing to document stability throughout the study duration. One mollusk embryo larvae study was found in the files, and is acceptable; while the study was conducted under static conditions the mollusk embryo larvae guidelin e study is a static exposure test because of life stage handling limitations

. No acute estuarine/marine crustacean study was found. Based on the embryo larvae mollusk study, BTS i s classified as very highly toxic
to marine/estuarine mollus ks

. The classification of BTS as only high toxic to estuarine/marine fish based on the supplemental information is potentially an underestimate of the sensitivity of BTS to estuarine/marine fish. The guideline requirement is fulfilled for the marine mollusk ( MRID # 40193201 ) but is not
fulfilled for the estuarine/marine fish (MRID # 40193201) or crustacean.

No acute estuarine/marine fish or invertebrate toxicity data for this degradate, pentachlorodimethylsulfone , is available. To establish the toxicity of t he major degradate, pentachlorodimethylsulfone

, which is also expected to reach estuarine or marine environments from discharge of waste waters

, a mollusk embryo larvae study, the most sensitive test and species as indicated by the supplemental data

, is

re quired. A chronic test with a crustacean species is also required (see paragraph below) and to be able to calculate an acute

- to

- chronic ratio for this species, an
acute test with the mysid is also required. Data on an estuarine/marine fish using

10 The study was originally classified as acceptable, but the issues o f stability were not noted or discussed. The study was downgraded to supplemental because it does not document the stability and fate information indicates that stability was not likely. These results are expected to greatly underestimate the acute sensi tivity of BTS to
estuarine/marine fish.

### Page 14 of 40 the same species as that tested with the TGAI is also desired. However, i n the absence of such data, factors derived from a comparison of TGAI and pentachlorodimethylsulfone for freshwater fish and crustacean data will be applied. As the mode of action for mollu sks may differ from that of the fish and crustaceans, there would be a high level of uncertainty in the application of a
factor derived from a fish or crustacean to mollusks.

No chronic data is available for either BTS or its major degradate with
estuarine/marine fish or invertebrates. Because uses of BTS will result in repeated discharge of the antimicrobial and its major degradate

, pentachloro

dimethylsulfone , to aquatic environment

, chronic exposure has the potential to

oc cur. A mysid life cycle test with the major degradate, pentachloro

dimethylsulfone is r equired. This data would allow confirmation that the acute

to

- chronic ratio does not differ between saltwater and freshwater organisms (i.e.,
indication that mode of a ction does not differ greatly between saltwater and freshwater species) for the degradate

. Additionally a fish early life stage test (using the same fish species as used in acute testing) is desired for both BTS and its major degradate pentachlorodimethyl sulfone and an invertebrate (crustacean) life cycle test (using the same species used in the acute test) with BTS is desired.
If these desired BTS and degradate fish early life stage and a BTS invertebrate life cycle test are not submitted the acute

- to

- ch ronic ratios derived from freshwater species will be applied.

c . Toxicity to Aquatic Plants

Algae

No algal toxicity data have been submitted for either BTS or its major degradate pentachlorodimethylsulfone

. For the ecological risk assessment, including an endangered species assessment for all uses, t he Agency anticipates needing the algal toxicity data for BTS with four species : a green alga, a freshwater diatom, a saltwater diatom, and a cyanobacterium

. For the major degradate, pentachlorodim ethylsulfone , a test with the most sensitive of these is required.

Vascular, Nonrooted

No toxicity testing with an aquatic vascular Lemna sp. has been submitted for
either BTS or its major degradate pentachlorodimethylsulfone

. One test with the
TGAI and one test with the major degradate pentachlorodimethylsulfone are required

.

### Page 15 of 40 Vascular Emergent Rooted Plants

No seedling emergence and growth test for BTS or its major degradate is
available. For uses where the antimicrobial is expected to reach aquatic environments, a seedling emergence and growth study with rice is required. Because of the rapid degradation of BTS in the environment, the major degradate pentachlorodimethylsulfone is required

.

Table 3 . Ecotoxicity Data Summary for Bis ( trichloromethyl ) sulfone

Guideline
Number* Common Name/
Taxonomic Name Test Type % a.i. Study
Duration Dose Type Toxicity MRID No./ Study
Classification/

Comments Toxicity
Classification Value Units

Avi an Acute Oral Toxicity

850.2100 (71

- 1) Mallard duck/ Anas platyrhynchos O Tech 14 days LD 50 >2250 mg/kg

- bw 00156817/ Acceptable/ practically

non

- toxic
Avian Subacute Dietary Toxicity

850.2200 (71

- 2b) Mallard duck/ Anas platyrhynchos D Tech 8 days LC 50 > 5000 ppm 00156820/ Acceptable / Overt signs of
toxicity were

observed at the highest

concentration tested (5000 ppm) practically

non

- toxic

850.2200 (71

- 2a) Bobwhite quail/ Colinus virginian us D Tech 8 days LC 50 >5620 ppm 00156818/ Acceptable practically

non

- toxic
Freshwater Fish Acute Toxicity

72

- 1 Rainbow trout/ Oncorhynchus mykiss S 99** 96 hr LC 50 29 ppb 00156814/ Supplemental/ very highly

toxic

72

- 1 Bluegill sunfish/ Lepomis macrochirus S 99** 96 hr LC 50 58 ppb 00156815/ Supplemental very highly

toxic
Freshwater Invertebrate Acute Toxicity

72

- 2 Water flea/ Daphnia magna S 99** 48 hr EC 50 173 ppb 00156816/ Supplemental highly toxic

Estuarine/Marine Acute Toxicity

850.1055 (72

- 3b) Embryo

larvae study Quahog clam/

Mercenaria mercenaria S 99.9 48 hr EC 50 9.2 ppb 40193201/ Acceptable very highly

toxic

72

- 3 Sheepshead minnow/ Cyprinodon variegatus S 99 96 hr LC 50 400 ppb 40138102/ Supplemental highly toxic

Test Type

— O: oral; D: dietary; S: static

. Tox icity Units

— mg / k g

- bw : milligrams per kilogram

- body weight; ppm: parts per million (equivalent to milligrams per kilogram

- diet (mg/kg

diet) for dietary exposure and milligrams per liter (mg/L) fo r aquatic organisms); ppb: parts per billion (equivalent to micrograms per liter (μg/L) for aquatic organisms. Categories of acute toxicity for aquatic organisms (U.S. EPA, 2004) based on E C 50 or LC 50 (mg/L): < 0

. 1 very highly toxic; 0.1

- 1 highly toxic;

### Page 16 of 40 Guideline
Number* Common Name/
Taxonomic Name Test Type % a.i. Study
Duration Dose Type Toxicity MRID No./ Study
Classification/

Comments Toxicity
Classification Value Units

> 1

- 10 moderately toxic; > 10

- 100 slightly toxic; > 100 practically nontoxic. Categories of acute toxicity to terrestrial animals, avian and mammalian (U.S. EPA, 2004). LC 50 (ppm): < 50 very highly toxic; 50

- 500 highly toxic; 501

– 1000 moderately toxic; 1001

- 5000 slightly toxic; >5000 practically non

- toxic. LD 50 (mg/kg

- bw): < 10 very highly toxic; 1 0

- 50 highly toxic; 51

- 500 moderately toxic; 501

- 2000 slightly toxic; >2000 practically non

- toxic. *Brackets indicate the test guideline that the study was conducted under; the non

- brackets identify the current test guideline.
**The % a.i. in the test substance was not given but the same comp ound (N

- 1386) was analyzed in an acute mysid shrimp study and found to
contain 99% a.i.



### Adverse Ecological Incidents

There are no reported incidents in the Agency's Ecological Incident Information System (EIIS) r egarding BTS . The absence of documented incidents does not necessarily mean that
such incidents did not occur.

Ecological Effects Risk Assessment

An ecological risk assessment was not conducted previously on BTS ’s use patterns
described in this document. BTS ’s uses that have potential for environmental exposure are discharges from industrial processes and water systems, specifically: use in pulp and papermill process water systems, recirculating cooling towers, and secondary oil

- recovery injection water systems, and as a preservative in adhesives. The Agency needs to conduct environmental fate and ecological risk assessments for uses that potentially pass through waste water treatment plants (WWTPs) and may be d ischarged into terrestrial and aquatic environments. For this ecological risk assessment, including an endangered species assessment for all uses, t he Agency anticipates needing the ecotoxicity data outlined on page s 17 and 18 of this document

.

The Agency has not conducted previously a n ecological risk assessment for BTS that supports a complete endangered species effects determination. The ecological risk assessment planned during registration review will allow the Agency to determine whether B TS uses have “no effect or “may affect” federally listed threatened or endangered species (listed species) or their designed critical habitats. When an assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical hab itat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries Services (the Services), as appropriate.

Environmental Fate and Ecotoxicity Data Gaps and Anticipated Work

The Agency needs to conduct environmental f ate and ecological risk assessments for material preservatives and industrial slimicides used in recirculating water cooling towers

, pulp and paper mills

, and oil and gas well development water systems that potentially pass through
waste water treatment p lants (WWTPs) and may be discharged into terrestrial and aquatic environments. Therefore, the Agency anticipates needing the proposed environmental fate and ecotoxicity data for BTS and/or any of its major degradation products that are of potential

concer n for all registered uses of BTS . The following environmental fate and ecotoxicity data are needed to conduct an environmental fate and ecological risk assessment:

### Page 17 of 40 **•** The Agency anticipates needing the following data to conduct a complete
environmental fate assessment for pulp and papermill process water system, recirculating cooling tower uses , and oil and gas well development water systems :

o Activated Sludge Sorptio n Isotherm

— TGAI (GLN 835.1110) ;

o Activated Sludge Sorption Isotherm

— major degradate, pentachlorodimethyl

sulfone (GLN 835.1110);

o Ready biodegradability (GLN 835.3110) , Porous Pot Test (GLN 835.3220) , or Simulation Tests to Assess the Biodegradability of Chemicals Discharged to

Wastewater (GLN 835.3280) , or Simulation Test

- Aerobic Sewage Treatment: A. Activated Sludge Units

— TGAI (GLN 835.3240) 11



### o Ready biodegradability (GLN 835.3110), Porous Pot Test (GLN 835.3220), or
Simulation Tests to Assess the Biodegradability of Chemicals Discharged to

Wastewater (GLN 835.3280), or Simulation Test

- Aerobic Sewage Treatment: A. Activated Sludge Units

— major degradate pentachlorodimethyl

- sulfone (GLN 835.3240) 4

. ; and

**•** The Agency anticipates needing the following ecoto xicity data in order to conduct a complete ecological risk assessment, including an endangered species assessment:

o Freshwater invertebrate acute toxicity, Daphnia magna

— TGAI (GLN 850.1010) ;

o Freshwater invertebrate acute toxicity, Daphnia magna

— major degra date, pentachlorodimethylsulfone (GLN 850.1010);

o Estuarine/marine invertebrate acute toxicity

— TGAI (GLN 850.1035);

o Estuarine/marine invertebrate acute toxicity

— major degradate, pentachloro

dimethylsulfone (GLN 850.1035);

o Embyro larvae study using Mercenar ia mercenaria

— major degradate, penta

chlorodimethylsulfone (GLN 850.1055);

o Freshwater fish acute toxicity, coldwater species

— TGAI (GLN 850.1075);

o Freshwater fish acute toxicity, warmwater species

— TGAI (GLN 850.1075);

o Freshwater fish acute toxicity, most TGAI sensitive species

— major degradate, pentachlorodimethylsulfone (GLN 850.1075);

o Aquatic invertebrate life

- cycle, freshwater Daphnia magna

— TGAI (GLN 850.1300) ;

o Aquatic invertebrate life

- cycle, freshwater Daphnia magna

— major degradate, pentachlorodimethylsulfone (GLN 850.13 0 0) ;

11 The results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which of these three biodegradation tests are required. If the ASRI test EC 50 is less than or equal to 20 mg/L, then either the (i) Biodegradation in Activated Sludge Study or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units or (iii) the Porous Pot Test is required. If the ASRI test EC 50 is greater than 20 mg/L, then the applicant must choose either: (i) Read y Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready Biodegradability study is conducted and the test substance passes, then no further testing is required. If, however, the test substance fails the Ready Biodegradability study, then the (i) Biodegradation in Activated Sludge or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units, or (iii) the Porous Pot st udy is required.

### Page 18 of 40 o Aquatic invertebrate life

- cycle, saltwater Americamysis bahia

— major degradate, pentachlorodimethylsulfone (GLN 850.13 5 0) ;

o Fish early

- life stage toxicity test, freshwater species with the most se nsitive TGAI acute species

— TGAI (GLN 850.1400);

o Fish early

- life stage toxicity test, freshwater species with the same species acute toxicity testing was conducted

— major degradate, pentachlorodimethyl

sulfone (GLN 850.1400);

o Seedling emergence (Tier II) w ith rice

— major degradate, pentachloro

dimethylsulfone (GLN 850.4225);

o A quatic plant toxicity test using Lemna spp.

— TGAI (GLN 850.4400) ;

o Aquatic plant toxicity test using Lemna spp.

— major degradate, pentachlorodimethylsulfone (GLN 850.4400);

o A lgal toxicity (Tier II) for a freshwater green alga, Selenastrum capricornutum; for a freshwater diatom, Navicula pelli c ulosa , for a marine diatom, Skeletonema costatum , and for the cyanobacteria species Anabaena flos

- aqua e

— TGAI (GLN 850.5400) ;

o Algal toxicity (Tier II) for the most TGAI sensitive species

— major degradate, pentachlorodimethylsulfone (GLN 850.5400);

o Activated Sludge Respiration Inhibition

— TGAI (GLN 850.6800 or OECD
209 ); and

o Activated Sludge Respiration Inhibition

— major degradate pentachl orodimethylsulfone (GLN 850.6800 or OECD 209 )

.

Facility Emissions to WWTP Modeling

For assessing the fate of BTS and its major degradate, pentachlorodimethylsulfone

, emitted to receiving waters from industrial process water uses of BTS such as at pulp and paper mills, for recirculating cooling towers, and oil and gas well development the Agency anticipates using the a vailable environmental fate information from guideline studies for BTS and its major degradate

, pentachlorodimethylsulfone

, and the following emission scenarios.

**•** Potential environmental releases and associated exposures of concern for antimicrobial uses related to the Pulp, Paper, and Board Industry will be those identified in "Emission Scenario Documents on Pulp, Paper, and Board Ind ustry", Number 23 of OECD Series on Emission Scenario Documents dated July 8, 2009

.

**•** Potential environmental releases and associated exposures of concern for antimicrobial
uses related to the Oil and Gas Well Production Industry will be those identified in the
latest version of the OECD Emission Scenario Document for the Oil Well Production Industry or those identified in the latest version of Generic Scenarios developed by the Chemical Engineering Branch of EPA/OCSPP/OPPT/CEB (Chemical Engineering Branch)

. On

- shore operations assume potential for disposal of drilling fluids and produce water to public or industrial waste treatment facilities and off

- shore operations assume emissions directly to the surrounding water, post

- treatment for removal of oil.

**•** Poten tial environmental releases and associated exposures of concern for uses of antimicrobial uses related to recirculating cooling towers will be assessed using the

### Page 19 of 40 Generic Scenarios for recirculating cooling towers developed by the Chemical Engineering Branc h of EPA/OCSPP/OPPT/CEB and modified for use for antimicrobials by the Antimicrobial Division.

Facility information needed to estimate aquatic exposures from emissions to WWTP for each emission scenario and directly to water from the oil and gas well deve lopment sites include the following:

**•** The number of pulp and paper mill sites using BTS or the maximum annual production
volume of BTS used in pulp and paper mills in the United States and its territories;

**•** The number of recirculating cooling tower sites usi ng BTS or the maximum annual production volume of BTS used in cooling towers in the United States and its territories;

**•** The number of oil and gas well development sites using BTS or the maximum annual production volume of BTS used in oil and gas well devel opment in the United States and its territories;

**•** How many of each of these facilities has on

- site and/or off

- site wastewater treatment.

In the absence of information on the number of these facilities that use BTS and how many of these facilities have on

- site and/or off

- site wastewater treatment, the Agency will assume that all such facilities in the United States have the potential to use BTS

.

In the absence of appropriate test data on biodegradation during wastewater treatment, the Agency will assume that there is no removal of BTS and its major degradate during wastewater treatment and that the amount of BTS and its major degradate released wi th the effluent from a wastewater treatment facility will be the same as the amount entering the wastewater treatment facility. In the absence of data on the percent removal of BTS and its major degradate during drinking water treatment the Agency will as sume there is no removal of

BTS or its major degradate, pentachlorodimethylsulfone

.

D

. References

Maryland Department of Natural Resources (MDNR). 1999. Hydrogen Chloride (HCl) Emissions from Maryland Utility Boilers. Prepared by R. Harkov and J. Ros s , Environmental R esources Management, Annapolis, MD for the Maryland Department of Natural Resources Maryland Power Plant Research Program. Report number PPRP

- 118. 46 pp. http://esm.versar.com/pprp/hcl/pprp

- 118pdf.pdf

McCulloch, A., M. Aucott, C. Benkovitz, T. Graedel, G. Kleiman, P. Midgley, and Y. Li. 1999. Global emissions of hydrogen chloride and chloromethane from coal combustion,
incineration and industrial activit ies: reactive chlorine emissions inventory. Journal of Geophysical Research 104(D7):8391

- 8403.

### Page 20 of 40 

## Appendix A. Environmental Fate Guideline Study Justifications

Study Title: Activated Sludge Sorption Isotherm
Guideline Number: 835.1110
Test Substance: Technical grade active ingredient, bis (trichloromethyl) sulfone Rationale for Requiring the Data Data from this study are needed to determine the sorption potential of activated sludge for the removal of specific chemical compounds in biological wastewater treatment plants (WWTPs). No data is currently available. If the chemical is not sorbed or biodegraded, then it would pass through a biological treatment system unaffected, potentially contaminating surface and drinking waters where it may the n have the potential to adversely affect non

- target organisms. EPA needs activated sludge sorption study data to assess the distribution of the antimicrobial chemical among the solid, aqueous, and vapor phases of WWTPs. Specifically, this study identifie s those chemicals which sorb to sludge
biomass. Practical Utility of the Data

1. How will the data be used?
The data will be used to assess removal of the antimicrobial as a result of sorption to activated sludge. Percent removal via sorption to activated sludge and percent removal via biodegradation are used to determine overall removal of the antimicrobial during wastewater treatment. Over all removal during wastewater treatment is a key input used to determine concentrations of the antimicrobial in surface water immediately downstream of wastewater treatment plants. The concentrations of antimicrobial pesticide immediately downstream of wa stewater treatment plants are used to assess exposure and risk to non

- target endangered and non

- endangered species. Exposure data are integral parts of the risk equation for determining the impact of pesticides to beneficial nontarget organisms through di rect exposure from their
food sources and habitat.

In addition, the data will be used to determine whether or not additional studies and/or label restrictions are needed. If the data indicate that the chemical does not sorb to sludge and instead partitio ns more readily to

water and that the chemical does not biodegrade to an appreciable extent then the chemical has the potential to pass through the WWTP and therefore could be discharged in to the aquatic environment. This determination could trigger furt her data requirements to assess the chemical’s impact upon release. If the data indicates relatively high potential to sorb to sludge, a screening assessment of potential exposure to ecological organisms as a result of biosolids use and disposal would be performed.

2. How could the data impact the Agency’s future decision

- making?
If the data show that removal of the chemical during wastewater treatment is negligible, then the risk
assessments for this chemical would reflect the magnitude of potential risk derived from this chemical’s negligible removal . The risk assessment may result in the Agency requiring label restrictions that would be necessary for the products to meet the “no unreasonable adverse effects” requi rements of FIFRA (e.g., changes to the directions for disposal).

In addition, EPA is required by section 7(a)(2) of the ESA to ensure that any action it authorizes or takes “...is not likely to jeopardize the continued existence of any endangered or threate ned species or result in
the destruction or adverse modification of critical habitat” and to use the best scientific data available” in carrying out this obligation. The data EPA intends to call in are necessary to inform the determination required by the ESA as to whether continued registration of a pesticide is not likely to jeopardize the species or its critical habitat. Absent this data EPA may not be able to conclude that this pesticide will not harm endangered species and may therefore need to consi der other limitations on the use of the pesticide in order to fulfill the Agency’s statutory obligations under the ESA. The lack of these data will limit the flexibility that the Agency and registrants have in coming into compliance with the ESA and could result in

### Page 21 of 40 use restrictions which are unnecessarily severe.

Study Title: Activated Sludge Sorption Isotherm
Guideline Number: 835.1110
Test Substance: D egradate
, pentachlorodimethylsulfone Rationale for Requiring the Data Data from this study are needed to determine the sorption potential of activated sludge for the removal of specific chemical compounds in biological wastewater treatment plants (WWTPs). No data is currently available. If the chemical is not sorbed or bio degraded, then it would pass through a biological treatment system unaffected, potentially contaminating surface and drinking waters where it may then have the potential to adversely affect nontarget organisms. EPA needs activated sludge sorption study da ta to assess the distribution of a major degradate of the antimicrobial chemical among the solid, aqueous, and vapor phases of WWTPs. Specifically, this study identifies those chemicals
which sorb to sludge biomass. Practical Utility of the Data

1. How will the data be used?
The data will be used to assess removal of the major degradate, pentachlorodimethylsulfone, of the antimicrobial as a result of sorption to activated sludge. Percent removal via sorption to activated sludge and percent removal via biodegradation are used to d etermine overall removal of this degradate during wastewater treatment. Overall removal during wastewater treatment is a key input used to determine

conce ntrations of the major degradate in surface water immediately downstream of wastewater treatment plants. The concentrations of the major degradate immediately downstream of wastewater treatment plants
are used to assess exposure and risk to non

- target endangered and non

- endangered species. Exposure data are integr al parts of the risk equation for determining the impact of pesticides and their major degradates to beneficial nontarget organisms through direct exposure from their food sources and habitat.

In addition, the data will be used to determine whether or not additional studies and/or label restrictions are needed. If the data indicate that the chemical does not sorb to sludge and instead partitions more readily to

water and that the chemical does not biodegrade to an appreciable extent then the chemical has the potential to pass through the WWTP and therefore could be discharged in to the aquatic environment. This determination could trigger further data requirements to assess the chemical’s impact upon release. If the data indicates relatively high potenti al to sorb to sludge, a screening assessment of potential exposure to ecological organisms as a result of biosolids use and disposal would be performed.

2. How could the data impact the Agency’s future decision

- making?
If the data show that removal of th e chemical during wastewater treatment is negligible, then the risk
assessments for this chemical would reflect the magnitude of potential risk derived from this chemical’s negligible removal . The risk assessment may result in the Agency requiring label r estrictions that would be necessary for the products to meet the “no unreasonable adverse effects” requirements of FIFRA (e.g., changes to the directions for disposal).

In addition, EPA is required by section 7(a)(2) of the ESA to ensure that any action i t authorizes or takes “...is not likely to jeopardize the continued existence of any endangered or threatened species or result in
the destruction or adverse modification of critical habitat” and to use the best scientific data available” in carrying out thi s obligation. The data EPA intends to call in are necessary to inform the determination required by the ESA as to whether continued registration of a pesticide is not likely to jeopardize the species or its critical habitat. Absent this data EPA may not be able to conclude that this pesticide will not harm endangered species and may therefore need to consider other limitations on the use of the pesticide in order to fulfill the Agency’s statutory obligations under the ESA. The lack of these data will lim it the

### Page 22 of 40 flexibility that the Agency and registrants have in coming into compliance with the ESA and could result in use restrictions which are unnecessarily severe.

Study Titles: Ready Biodegradability ; Porous Pot Test ; Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units; or Simulation Tests to Assess the Biodegradability of Chemicals Discharged to Wastewater (particularly Biodegradation in Activated Sludge) ; or Guideline Numbers: 835.3110, 835.3220, 8 35.3240, or 835.3280 respectively Test Substance: Technical grade active ingredient, bis (trichloromethyl) sulfone Rationale for Requiring the Data For antimicrobial chemicals that go down

- the

- drain and reach a WWTP, as part of its screening

- level environmental fate assessment, EPA will analyze the potential impact of the antimicrobial chemical on the microorganisms in the biological treatment process es of a WWTP. Biodegradation is an important environmental pathway in which the antimicrobial is broken down by bacteria. This study results supply information on the rate of biological breakdown and the completeness of the degradation to carbon dioxide
and water. A ready biodegradability study would allow the Agency to determine whether or not the chemical achieves ‘‘pass levels’’ for ready biodegradability (e.g., 70% removal of dissolved organic carbon). The results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which of these three biodegradation tests are required. If the ASRI test EC 50 is less than or equal to 20 mg/L, then either
the (i) Biodegradation in Activated Sludge Study

, or (ii) Simulation Test

– Aerobic Sewage Treatm ent: A. Activated Sludge Units

, or (iii) the Porous Pot Test is required. If the ASRI test EC 50 is greater than 20 mg/L, then the applicant must choose either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge

, or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units or c) the
Porous Pot Test. If the Ready Biodegradability study is conducted and the antimicrobial passes, then no further testing is required. If, however, the antimicrobial fails the R eady B iodegradability study, then the (i) Biodegradation in Activated Sludge

, or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units, or (iii) the Porous Pot study is required. Practical Utility of the Data

1. How will the data be used? The data from a biodegradation study will be used to determine the percent removal of the antimicrobial as a result of biodegradation of the antimicrobial by activated sludge microorganisms. Percent removal via biodegradation is a key input used to deter mine concentrations of the antimicrobial in surface water immediately downstream of wastewater treatment plants. The concentrations of antimicrobial pesticide immediately downstream of wastewater treatment plants are used to assess exposure and risk to no n

- target endangered and non

- endangered species. Exposure data are integral parts of the risk equation for determining the impact of pesticides to beneficial non

- target organisms through direct exposure from their
food sources and habitat.

In addition, th e data will be used to determine whether or not additional studies and/or label restrictions are needed. If the chemical does not achieve a ‘‘pass level’’ for ready biodegradability, then the Agency would determine that the chemical has the potential to p ass through the WWTP and therefore may be discharged in to the aquatic environment potentially resulting in exposure to non

- target species. This determination would trigger further data requirements to assess the chemical’s impact on the aquatic
environme nt upon release.

2. How could the data impact the Agency’s future decision

- making? If the chemical is found to be readily biodegraded, then activated sludge microorganisms would be identified as highly biodegradable (90% removal via biodegradation). Th is result would be used in conjunction with wastewater treatment plant influent volume and measurement endpoints for aquatic organisms to determine concentrations of antimicrobial pesticide downstream of wastewater treatment plants. If high inhibition of activated sludge microorganisms (i.e., EC 50 less than or equal to 20 mg/L) is

### Page 23 of 40 determined in an activated sludge respiration inhibition test, then higher

- tiered wastewater treatment plant (WWTP) biodegradation studies and/or an activated sludge sorption iso therm study may be triggered. If results of higher

- tier WWTP biodegradation tests indicate low or negligible removal by biodegradation, the risk assessments for this chemical would reflect the magnitude of potential risk derived from the chemical’s
lack o f biodegradability. The risk assessment may result in the Agency requiring label restrictions that would be necessary for the products to meet the “no unreasonable adverse effects” requirements of FIFRA (e.g., changes to the directions for disposal).

In addition, EPA is required by section 7(a)(2) of the ESA to ensure that any action it authorizes or takes “...is not likely to jeopardize the continued existence of any endangered or threatened species or result in
the destruction or adverse modification of c ritical habitat” and to use the best scientific data available” in carrying out this obligation. The data EPA intends to call in are necessary to inform the determination required by the ESA as to whether continued registration of a pesticide is not likel y to jeopardize the species or its critical habitat. Absent this data EPA may not be able to conclude that this pesticide will not harm endangered species and may therefore need to consider other limitations on the use of the pesticide in
order to fulfill the Agency’s statutory obligations under the ESA. The lack of these data will limit the flexibility that the Agency and registrants have in coming into compliance with the ESA and could result in use restrictions which are unnecessarily severe.

Study Titles: Ready Biodegradability; Porous Pot Test; Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units; or Simulation Tests to Assess the Biodegradability of Chemicals Discharged to Wastewater (particularly Biodegradation in Activat ed Sludge); or
Guideline Numbers: 835.3110, 835.3220, 835.3240, or 835.3280 respectively
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

For antimicrobial chemicals and their major degradates that go down

- the

- drain and reach a WWTP, as part of its screening

- level environmental fate assessment, EPA will analyze the potential impact of the major degradate on the microorganisms in the biological treatment processes of a WWTP. Biodegradation is an important environmental pathway in which the major degradate is broken down by bacteria. This study results supply information on the rate of biological breakdown and the completeness of the degradation to
carbon dioxide and water. A ready biodegradabil ity study would allow the Agency to determine whether or not the chemical achieves ‘‘pass levels’’ for ready biodegradability (e.g., 70% removal of dissolved organic carbon). The results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which of these three biodegradation tests are required. If the ASRI test EC 50 is less than or equal to 20 mg/L, then either
the (i) Biodegradation in Activated Sludge Study

, or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units

, o r (iii) the Porous Pot Test is required. If the ASRI test EC 50 is greater than 20 mg/L, then the applicant must choose either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge

, or b) Simulation Test

– Aerobic Sewage Treatment: A. A ctivated Sludge Units or c) the
Porous Pot Test. If the Ready Biodegradability study is conducted and the test substance passes, then no further testing is required. If, however, the test substance fails the R eady B iodegradability study, then the (i) Biodegradation in Activated Sludge

, or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units, or (iii) the Porous Pot study is required.

### Page 24 of 40 Practical Utility of the Data

1. How will the data be used? The data from a biodegradation study will be used to determine the percent removal of the antimicrobial as a result of biodegradation of the antimicrobial by activated sludge microorganisms. Percent removal via biodegradation is a key input used to determine concentrations of the antim icrobial in surface water immediately downstream of wastewater treatment plants. The concentrations of antimicrobial pesticide immediately downstream of wastewater treatment plants are used to assess exposure and risk to non

- target endangered and non

- enda ngered species. Exposure data are integral parts of the risk equation for determining the impact of pesticides to beneficial non

- target organisms through direct exposure from their
food sources and habitat.

In addition, the data will be used to determine whether or not additional studies and/or label restrictions are needed. If the chemical does not achieve a ‘‘pass level’’ for ready biodegradability, then the Agency would determine that the chemical has the potential to pass through the WWTP and therefo re may be discharged in to the aquatic environment potentially resulting in exposure to non

- target species. This determination would trigger further data requirements to assess the chemical’s impact on the aquatic environment upon release.

2. How could the data impact the Agency’s future decision

- making? If the chemical is found to be readily biodegraded, then activated sludge microorganisms would be identified as highly biodegradable (90% removal via biodegradation). This result would be used in conju nction with wastewater treatment plant influent volume and measurement endpoints for aquatic organisms to determine concentrations of antimicrobial pesticide downstream of wastewater treatment plants. If high inhibition of activated sludge microorganisms (i.e., EC 50 less than or equal to 20 mg/L) is determined in an activated sludge respiration inhibition test, then higher

- tiered wastewater treatment plant (WWTP) biodegradation studies and/or an activated sludge sorption isotherm study may be triggered. I f results of higher

- tier WWTP biodegradation tests indicate low or negligible removal by biodegradation, the risk assessments for this chemical would reflect the magnitude of potential risk derived from the chemical’s lack of biodegradability. The risk as sessment may result in the Agency requiring label restrictions that would be necessary for the products to meet the “no unreasonable adverse effects” requirements of FIFRA (e.g., changes to the directions for disposal).

In addition, EPA is required by sec tion 7(a)(2) of the ESA to ensure that any action it authorizes or takes “...is not likely to jeopardize the continued existence of any endangered or threatened species or result in
the destruction or adverse modification of critical habitat” and to use the best scientific data available” in carrying out this obligation. The data EPA intends to call in are necessary to inform the determination required by the ESA as to whether continued registration of a pesticide is not likely to jeopardize the species or i ts critical habitat. Absent this data EPA may not be able to conclude that this pesticide will not harm endangered species and may therefore need to consider other limitations on the use of the pesticide in order to fulfill the Agency’s statutory obligati ons under the ESA. The lack of these data will limit the flexibility that the Agency and registrants have in coming into compliance with the ESA and could result in use restrictions which are unnecessarily severe.

### Page 25 of 40 

## Appendix B: Ecological Guideline Stud y Justifications

Study Title: Aquatic Invertebrate Acute Toxicity Test, Freshwater
Guideline Number: 850.10 10
Test Substance: TGAI Rationale for Requiring the Data No scientifically sound acceptable data are available to assess the potential acute lethal risks of BTS to freshwater invertebrates. There is supplemental information but the study was conducted under static conditions and no analytical measurements were made at any time during the study to document exposure
concentrations. BTS ha lf

- life is <1 day in aquatic aerobic fate studies, so the exposure concentration throughout the supplemental study is unknown. Use of such data would greatly underestimate the sensitivity and underestimate risk for freshwater invertebrates. Scientificall y sound aquatic invertebrate
data for BTS is necessary because freshwater invertebrates may be exposed based on BTS ’s use pattern

and monitoring data

. BTS is used as an 

### algicide, bactericide, slimicide and fungicide for use in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which may result in discharge of BTS and its major degradate, 

### pentachloro

dimethylsulfone to surface waters

. The requested data would allow EPA to estimate risks to

freshwater invertebrates , including defining an action area for endangered species

. Without these data, the Agency is unable to evaluate the potential risks to freshwater invertebrates associated wit h acute exposure to BTS

.

Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The freshwater invertebrate acute study data would allow the Agency to analyze acute lethal effects to freshwater invertebrates from acute exposures due to BTC use.
The effects data would be used to de termine the likelihood that the acute risks can potentially impact aquatic communities, either by direct effects on invertebrates or by indirect effects by reducing food resources to species that rely on invertebrates as a food resource

.

2. How could the data impact the Agency’s future decisi on
- making? Risk estimates (i.e., risk quotients or concentration of concern values) cannot be evaluated without these
data. In the absence of data, acute risks to freshwater invertebrates would use the supplemental data but
this would lead to an underesti mation of risk, and the degree of underestimation would be unknown. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks or having confidence in declaring no affects to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses for BT S which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Aquatic Invertebrate Acute Toxicity Test, Freshwater
Guideline Number: 850.10 10
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

No data are available to assess the potential acute lethal risks of the major toxic degradate penta

chlorodimethylsulfone to freshwater invertebrates. Aquatic invertebrate data for pentachlorodimethylsulfone is necessary because freshwater invertebrates may be exposed based on

BTS ’s use pattern , fate, and monitoring data

. BTS is used as an 

### algicide, bactericide, slimicide and

### Page 26 of 40 fungicide for use in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which can result in discharge of BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. The r equested data would allow EPA to estimate risks

to freshwater invertebrates from exposure to pentachlorodimethylsulfone , including defining an action area for endangered species

.

Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The freshwater invertebrate acute study data would allow the Agency to analyze acute lethal effects to fre shwater invertebrates from acute exposures due to BTC use
and fate

. The effects data with the degradate would be used to de termine the likelihood that the acute risks can potentially impact aquatic communities, either by direct effects on invertebrates or by indirect effects by reducing food resources to species that rely on invertebrates as a food resource

.

2. How could the data impact the Agency’s future decision

- making? Risk estimates (i.e., risk quotients or concentration of concern values) cannot be evaluated without these
data. In the absence of data, if an acute toxicity test is available for BTS the toxicity of the degradate will be assumed to be equivalent to that of the parent BTS otherwise acute risks to freshwater invertebrates would be pr esumed; the Agency would have to assume that BTS and its degradate “may affect” endangered freshwater invertebrates directly (and endangered species from other taxa indirectly)

. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

listed and listed species and in coming into compliance with the Endangered Species Act, and could result
in use restrictions or withdrawal of uses for BT S which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Estuarine/marine invertebrate acute toxic ity test one crustacean species
Guideline Number: 850.10 3 5
Test Substance: TGAI Rationale for Requiring the Data

A c rustacean (mysid) is one of two representative saltwater species used to evaluate acute effects for all
estuarine/marine invertebrates. No acceptable acute study for BTS with an estuarine/marine crustacean species has been submitted ; there is an acceptable acute mollusk study . An acute test using an estuarine/marine crustacean species is required because the active ingredient is expected to reach
estuarine/marine environmen t s based on its use pattern s , monitoring data , and because physiological
differences which allow estuarine/marine inverte brates to live in an estuarine/marine environments may result in this group being more sensitive than freshwater species. Without these data, t here is uncertainty in the representation of the mollusk as the more sensitive species

. Acute risks based on mo llusk data can be calculated, but there would be uncertainty in whether the calculated risk is an underestimate , and the degree of underestimation

.

Practical Utility of the Data

1. How will the da ta be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The estuarine /marine invertebrate acute studies allow the Agency to analyze acute lethal effects to estuar ine/marine invertebrates from acute exposures due to BTS

use. The effects data would be used to de termine the likelihood that the acute risks can potentially impact aquatic communities, either by direct effects on invertebrates or by indirect effects by r educing

### Page 27 of 40 food resources to species that rely on invertebrates as a food resource

.

2. How could the data impact the Agency’s future decision

- making?
In the absence of acute mysid data, acute risks to marine/estuarine invertebrates would be calculated
base d on the mollusk data alone

. But there would be uncertainty in whether the calculated risk is an
underestimate , and the degree of underestimation

. Decisions may be made incorrectly based on these
results.

Study Title: Estuarine/marine invertebrate acute toxicity test
, one crustacean species study and

one embryo larvae mollusk study
Guideline Number: 850.10 3 5 and 850.1055, respectively
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data A crustacean (mysid) and mollusk test are representative saltwater species used to evaluate acute effects for all estuarine/marine invertebrates. No acceptable acute stud ies for the major degradate

, pentachloro

dimethylsulfone

, with an estuarine/marine crustacean species or m ollusk has been submitted. An acute

test using an estuarine/marine mollusk species and crustacean is required because th is major degradate is expected to reach estuarine/marine environmen t s based on BTS use pattern s, fate, and monitoring data

. Additional ly to calculate an acute

- to

- chronic ratio for this degradate for an estuarine/marine invertebrate species, the mysid acute study is required to pair with the chronic study discussed in the Justification Table for Estuarine/marine invertebrate, life cycle t est. The mollusk embryo larvae study is also required because it tentatively appears likely to be the most sensitive of all aquatic organisms, both freshwater and estuarine/marine based on the acceptable BTS mollusk study and the supplemental freshwater f ish and
invertebrate data. The mode

- of

- action to mollusks may be different from that of crustaceans and fish, and therefore any BTS: pentachlorodimethylsulfone ratio or factor derived from crustacean or fish data may underestimate the degradate toxicity to mollusks. In the absence of data, the degradate would be

assum ed to be as toxic as the parent, BTS, for both the crustacean and the mollusk.

Practical Utility of the Data

1. How will the da ta be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The estuarine /marine invertebrate acute studies allow the Agency to analyze acute lethal effects to estuarine/marine invertebrates from acute exposures due to BTS

use. The effects data would be used to de termine the likelihood that the acute risks can potentially impact aquatic communities, either by direct effects on invertebrates or by indirect effects by reducing food resources to species that rely on invertebrates as a food resource

.

2. How could the data impact the Agency’s future decision

- making?
In the absence of acute mysid and mollusk data, acute risks to marine/estuarine invertebrates would be

c alculated assuming that the degradate is as toxic as the parent, and potentially be based on the mollusk alone if acute crustacean data for BTS is not submitted (see the Estuarine/marine inverte brate acute toxicity test one crustacean species Justification Table above) which may result in underestimation of
risk

.

### Page 28 of 40 Study Title: Fish acute toxicity test ( freshwater species , one cold water species study and one warm water species study )
Guideline Number: 850.1075
Test Substance: TGAI Rationale for Requiring the Data No scientifically sound acceptable data are available to assess the potential acute lethal risks of BTS to freshwater fish. There is supplemental information but the studies were conducted under static conditions and no analytical measurements were made at any time during the studies to document exposure concentrations. BTS half

- life is <1 day in aquatic aerobic fate studies, so the exposure concentration throughout t he supplemental studies is unknown. Use of such data would greatly underestimate the sensitivity and underestimate risk for freshwater fish. Scientifically sound freshwater
fish data for BTS is necessary because freshwater fish may be exposed based on BT S ’s use pattern and monitoring data

. A warm water species study and a cold water species study are both necessary to capture and characterize if differences that allow these species to live in such different temperature regimes , such as metabolism and differences in activation and deactivation pathways , result in distinctive
differences in sensitivity to BTS . The most sensitive value of the two is used to screen for risk concerns.

BTS is used as an 

### algicide, bactericide, slimicide and fungicide f or use in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which may result in discharge of BTS and its major degradate, 

### pentachlorodimethylsulfone to surface

waters

. The requested da ta would allow EPA to soundly estimate risks to freshwater fish , including defining an action area for endangered species

. Without these data, the Agency would use the supplemental data which would underestimate risk to an unknown degree

.

Practical Utility of the Data

1. How will the da ta be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The freshwater fish acute study data would allow the Agency

to analyze acute lethal effects to freshwater fish from acute exposures due to BTC use. The effects data
would be used to de termine the likelihood that the acute risks can potentially impact aquatic communities, either by direct eff ects on fish or by indirect effects by reducing food resources to species that rely on fish as a food resource

.

2. How could the data impact the Agency’s future decision

- making? Risk estimates (i.e., risk quotients or concentration of concern values) cann ot be evaluated without these
data. In the absence of data, acute risks to freshwater fish would use the supplemental data but this would lead to an underestimation of risk, and the degree of underestimation would be unknown. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks or having confidence in declaring no affects to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could resu lt in use restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Fish acute toxicity test ( freshwater species, most sensitive of the TGAI species )
Guideline Number: 850.1075
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

No data are available to assess the potential acute lethal risks of the major toxic degradate pentachlorodimethyl

- sulfone to freshwater fish. Fish acute data for pentachlorodimethylsulfone , is

### Page 29 of 40 necessary because freshwater fish may be exposed based on BTS ’s use pattern , fate, and monitoring data

. Only data for the most sensitive of the TGAI species is required, as this should also be the more sensitive species for the degradate. BTS is used as an 

### algicide, bactericide, slimicide and fungicide for use in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which can result in discharge of BTS and i ts major degradate, 

### pentachlorodimethylsulfone to surface waters

. The requested data would allow EPA to estimate risks

to freshwater fish from exposure to pentachlorodimethylsulfone , including defining an action area for endangered species

. Practical Utility of the Data

1. How will the da ta be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The freshwater fish acute study data would allow the Agency

to analyze acute lethal effects to freshwater fish from acute exposures due to BTC use and fate. The
effects data with the degradate would be used to de termine the likelihood that the acute risks can potentially impact aquatic commu nities, either by direct effects on fish or by indirect effects by reducing food resources to species that rely on fish as a food resource

.

2. How could the data impact the Agency’s future decision

- making? Risk estimates (i.e., risk quotients or concentra tion of concern values) cannot be evaluated without these
data. In the absence of data, if an acute toxicity test is available for BTS the toxicity of the degradate will be assumed to be equivalent to that of the parent BTS otherwise if no TGAI or degrada te data is available

acute risks to freshwater fish would be presumed; the Agency would have to assume that BTS and its degradate “may affect” endangered freshwater fish directly (and endangered species from other taxa indirectly)

. T he lack of these data will limit the flexibility the Agency and registrants have in addressing
risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act,
and could result in use restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Fish acute toxicity test ( estuarine/ marine species )
Guideline Number: 850.1075
Test Substance: TGAI Rationale for Requiring the Data No scientifically sound acceptable data are available to assess the potential acute lethal risks of BTS to estuarine/marine fish. There is supplemental information but the study was conducted under static conditions and no analytical measurements were made at any time during the study to document exposure
concentrations. BTS half

- life is <1 day in aquatic aerobic fate studies, so the exposure concentration throughout the supplemental study is unknown. Use of such data would greatly underestimate the sensitivity and underestimat e risk for estuarine/marine fish. Scientifically sound estuarine/marine fish
data for BTS is necessary because estuarine/marine fish may be exposed based on BTS ’s use pattern and monitoring data

. BTS is used as an 

### algicide, bactericide, slimicide and fun gicide for use in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which may result in discharge of BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. The requ ested data would allow EPA to soundly

estimate risks to estuarine/marine fish , including defining an action area for endangered species

. Without these data, the Agency would use the supplemental data which would underestimate risk to an unknown degree

.

### Page 30 of 40 Practical Utility of the Data

1. How will the da ta be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The estuarine /marine fish acute study would allow the Agency

to analyze acute lethal effects to estuarine/marine fish from acute exposures due to BTS use. The effects
data would be used to de termine the likelihood that the acute risks can potentially impact aquatic communities, either by dir ect effects on fish or by indirect effects by reducing food resources to species that rely on fish as a food resource

.

2. How could the data impact the Agency’s future decision

- making? Risk estimates (i.e., risk quotients or concentration of concern values) cannot be evaluated without these
data. In the absence of data, acute risks to estuarine/marine fish would either use the supplemental data
which would lead to an underestimation of risk, with the degree of underestimation unknown, or potentially depending on what results are provided for freshwater fish and invertebrates and their relationship to the supplemental data, some estimate of the degree to which underestimation may be

occur ring could be made or if the data indicates that mollusks are the most sensitive aquatic species of the existing freshwater fish and invertebrate data, then the sensitivity of estuarine/marine fish can be assumed to be equivalent to that of the mollusk res ults. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks or having confidence in declaring no affects to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and co uld result in use
restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily

severe.

Study Title : Aquatic Invertebrate Life

- Cycle (freshwater species )
Guideline Number: 850.13 0 0
Test Substance: TGAI Rationale for Requiring the Data

No chronic life cycle toxicity data for a freshwater invertebrate species ha s been submitted for BTS

. Chronic aquatic invertebrate data for BTS is necessary because based on BTS ’s use pattern , fate, and monitoring data freshwater invertebrates may be repeatedly exposed to BTS and its major degradate, pentachlorodimethylsulfone

. BTS is used as an 

### algicide, bactericide, slimicide and fungicide for use

in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which can result in discharge of BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. The requested data would allow the Agency to estimate

chronic risks to freshwa ter invertebrates from exposure to BTS , including defining an action area for endangered species

. Without these data, the Agency is unable to evaluate the potential chronic risks to
freshwater invertebrates associated with chronic exposure to BTS

. T he Ag ency would have to presume
chronic risk to listed and non

- listed freshwater invertebrates

, but would not be able to quantify the risk.

### Page 31 of 40 Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The aquatic invertebrate life

- cycle study would allow the Agency to analyze chronic effects, including eff ects on reproductive success , survival and growth, to
freshwater invertebrates due to exposure to BTS . The effects data would be used to determine the likelihood that the chronic risks can potentially impact aquatic communities, either by direct effects o n invertebrates or by indirect effects on fish by reducing their food sources.

2. How could the data impact the Agency’s future decision

- making? In the absence of data, chronic risks would be presumed to freshwater invertebrates under chronic exposure

c onditions. T he lack of these data will limit the flexibility the Agency and registrants have in addressing
risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and
could result in use restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily severe.

Study Title : Aquatic Invertebrate Life

- Cycle (freshwater species )
Guideline Number: 850.13 0 0
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

No chronic life cycle toxicity data for a freshwater invertebrate species ha s been submitted for the major degradate pentachlorodimethylsulfone . Chronic aquatic invertebrate data for this degradate is necessary because ba sed on BTS ’s use pattern , fate, and monitoring data freshwater invertebrates may be repeatedly exposed to BTS and its major degradate, pentachlorodimethylsulfone

. BTS is used as an 

### algicide, bactericide, slimicide and fungicide for use in industrial process and water systems, cooling

towers , and it is also used for oil and gas well development water systems which can result in discharge of

BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. The requested data would

allow the Ag ency to estimate chronic risks to freshwater invertebrates from exposure to this degradate

, including defining an action area for endangered species

. Without these data, the Agency would have to assume that the degradate is at least as toxic as the parent , BTS

. However, there is no chronic data for the parent either, so w ithout these data, the Agency is unable to evaluate the potential risks to freshwater invertebrates associated with chronic exposure to BTS or its degradate. T he Agency would have to

pre sume chronic risk to listed and non

- listed freshwater invertebrates

, but would not be able to quantify the
risk.

### Page 32 of 40 Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The aquatic invertebrate life

- cycle study would allow the Agency to analyze chronic effects, including eff ects on reproductive success , survival and growth, to
freshwater invertebrates due to exposure to the degradate, pentachlorodimethylsulfone . The effects data would be used to determine the likelihood that the chronic risks can potentially impact aquatic

c ommunities, either by direct effects on invertebrates or by indirect effects on fish by reducing their food

sources.

2. How could the data impact the Agency’s future decision

- making? In the absence of data, the Agency would have to assume that the degra date is at least as toxic as the parent,
BTS

. However, there is no chronic data for the parent either, so w ithout these data, the Agency is unable to evaluate the potential risks to freshwater invertebrates associated with chronic exposure to BTS or its
d egradate. T he lack of these data will limit the flexibility the Agency and registrants have in addressing
risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and
could result in use restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily severe.

Study Title : Aquatic Invertebrate Life

- Cycle ( estuarine/marine species )
Guideline Number: 850.13 5 0
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

No chronic life cycle toxicity test for an estuarine/marine invertebrate species ha s been submitted for the degradate, pentachlorodimethylsulfone

. Chronic aquatic invertebrate data for this degradate is necessary because based on BTS ’s use pattern , fate, and monitoring data freshwater invertebrates may be repeatedly exposed to BTS and its major degradate, pentachlorodimethylsulfone

. BTS is used as an 

### algicide, bactericide, slimicide and fungicide for us e in industrial process and water systems, cooling

towers , and it is also used for oil and gas well development water systems which can result in discharge of

BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. A chronic study with BTS was not requested because tentatively the mollusk appears to be more sensitive than estuarine/marine fish and freshwater invertebrates. If the acute mysid toxicity data with BTS results in mysid being more sensitive than the mollusk, the acute

- to

- chro nic ratio derived from the degradate and from freshwater invertebrate data for BTS can be used to estimate a BTS chronic value for the mysid. Without the
estuarine/marine life

- cycle data for the degradate

, the Agency is unable to evaluate the potential risks to
estuarine/marine invertebrates associated with chronic exposure to the degradate or the parent

. T he Agency would have to presume chronic risk to listed and non

- listed estuarine/marine invertebrates, but would not be able to quantify the risk.

### Page 33 of 40 Practical Utility of the Data

1. How will the data be used? The aquatic invertebrate life

- cycle study would allow the Agency to analyze chronic effects, including effects on reproductive success , survival and growth, to estuarine/marine invertebrates. The effects data would be used to determine the likelihood that the chronic risks can potentially impact aquatic communities, either by direct effects on invertebrates or by indirect effects to organisms pre ying on
estuarine/marine invertebrates

.

2. How could the data impact the Agency’s future decision

- making? In the absence of data, chronic risks would be presumed to estuarine/marine invertebrates under chronic exposure conditions. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses for TTPC which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Fish Early

- life Stage Toxicity Test (freshwater species)
Guideline Number: 850.1400
Test Substance: TGAI Rationale for Requiring the Data

No fish early

- life stage toxicity test for BTS has been submitted. The fish early

- life stage toxicity test provides the leth al and sublethal effects of a test substance on fish species. The study is necessary for
BTS because the antimicrobial use pattern s and environmental fate characteristics are expected to result in repeated exp osure of freshwater organisms. The requested data would allow the Agency to estimate
chronic risks to freshwater fish from exposure to BTS , including defining an action area fo r endangered species

. Without these data, the Agency is unable to evaluate the potential risks to freshwater fish and aquatic

- phase amphibians (for which fish serve as surrogates) associated with chronic exposure to BTS

. If the test is not conducted with the most acutely sensitive species, an acute toxicity test for the species used in the early life stage test needs to be conducted to allow calculation of an acute

- to

- chronic ratio for use in predicting an early life stage result for the most acutely sens itive species. Practical Utility of the Data

1. How will the data be used? The data from the fish early life stage test will be used to estimate the chronic risks to freshwater fish and amphibians associated with chronic exposures to BTS

. The data will reduce uncertainties associated with
pot ential risks to freshwater fish and amphibians thereby facilitating sound environmental management of natural resources, particularly, freshwater fisheries.

2. How could the data impact the Agency’s future de cision

- making? In the absence of data, chronic risks would be presumed to freshwater fish/amphibians under chronic exposure conditions. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses for TTPC which may otherwise be avoided, or which are unnecessarily severe.

### Page 34 of 40 Study Title: Fish Early

- life Stage Toxicity Test (freshwater species)
Guideline Number: 850.1400
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

No fish early

- life stage toxicity test for the major degradate, pentachlorodimethylsulfone

, has been
submitted. The fish early

- life stage toxicity test provides the leth al and sublethal effects of a test
substance on fish species. Chronic aquatic invertebrate data for this degradate is necessary because based

on BTS ’ s use pattern , fate, and monitoring data freshwater invertebrates may be repeatedly exposed to BTS and its major degradate, pentachlorodimethylsulfone

. BTS is used as an 

### algicide, bactericide, slimicide and fungicide for use in industrial process and water systems, cooling towers , and it is

also used for oil and gas well development water systems which can result in discharge of BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. The requested data would allow the Agency to esti mate chronic risks to freshwater fish from exposure to this degradate , including defining an action area for endangered species

. Without these data, the Agency is unable to evaluate the potential risks to freshwater fish and aquatic

- phase amphibians (for which fish serve as surrogates) associated with chronic exposure to the degradate

. If the test is not conducted with the most acutely sensitive species, an acute toxicity test for the species used in the early life stage test needs to be conducted to allo w calculation of an acute

- to

- chronic ratio for use in predicting an early life stage result for the most acutely sensitive species. Practical Utility of the Data

1. How will the data be used? The data from the fish early life stage test will be used to estimate the chronic risks to freshwater fish and amphibians associated with chronic exposures to BTS and its degradate

. The data will reduce uncertainties associated with pot ential risks to fre shwater fish and amphibians thereby facilitating sound environmental management of natural resources, particularly, freshwater fisheries.

2. How could the data impact the Agency’s future decision

- making? In the absence of data, the toxicity of the degra date would be assumed to be the same as that of the parent, if chronic data for the parent was submitted, or if this data is not available either chronic risks would be presumed to freshwater fish/amphibians under chronic exposure conditions. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species
and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses for TTPC wh ich may otherwise be avoided, or which are unnecessarily severe.

Study Title: Seedling emergence Tier II Test Species: Rice, 

### Oryza sativa

Guideline Number: 850.4 225
Test Substance: D egradate, pentachlorodimethylsulfone Application method: Homogenously mixed into support media Unit of Expression: milligrams per kilogram of bulk support media (dry wt) Rationale for Requiring the Data

No seedling emergence and growth toxicity data for a rooted emergent vascular plant ha s been submitted
for BTS or its major degradate. Based on the fate of BTS, it is not expected to be persistent in the water column or sediment. However, the major degradate is more persistent and may sorb onto organic and inorganic particles in water and depositing with them in sedimentary areas such as lakes, and freshwater
and saltwater marshes. U se s of BTS in industrial process and water systems , cooling towers, and

### Page 35 of 40 discharges from oil and gas well development water systems are expected to lead to exposure of wetland plan ts due to transportation, and deposition of pentachlorodimethylsulfone sorbed onto particles in the
waste stream from use sites. Without this data, the Agency is unable to evaluate the potential risks to rooted vascular emergent plants associated with exp osure to pentachlorodimethylsulfone

. In the study, a minimum of four replicates are necessary to allow a nonparamet ric statistical analysis, if the resulting data fail normality or homogeneity of variance assumptions.

Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. Emergent wetland plants, in association with soil or sediments,
determine the structure and function of wetlands; they provide habitat in the form of nursery areas and cover for wildlife, and regulate the temperature and flow of water. The emergent vascular plant study
would allow the Agency to analyze to a critical component of th e structure and function of an aquatic
ecosystem. A toxicity study on an emergent vascular plant species is used to establish a dose response relationship of BTS with in terms of yield, growth rate, and area under the growth curve . The effects data
would be used to determine the likelihood that losses to emergent plants will occur and that such losses would indirectly lead to loss of other aquatic organisms through impacts such as loss of a food resource, habitat, or habitat quality

.

2. How could the d ata impact the Agency's future decision

- making? In the absence of data, r isks to emergent aquatic plants could not be calculated

. Therefore, until additional data become available, risks to emergent vascular plants (both Federally

- listed and non

- listed species) will be assumed in future BTS risk assessments. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species and in c oming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses
for TTPC which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Aquatic plant growth, floating vascular species ( Lemna sp. ), Tier II
Guideline Number: 850.4 400
Test Substance: TGAI Rationale for Requiring the Data

No non

- rooted vascular aquatic plant toxicity data ha s been submitted for BTS

. BTS is used as an 

### algicide, bactericide, slimicide and fungicide for use in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which can result in discharge of BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. Without these data, the Agency is unable to evaluate the potential risks to non

- rooted vascular aquatic plants
associated with exposure to BTS

.

Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. Mats of floating non

- rooted aquatic plants provide habitat for small invertebrates, food and shelter for f ish and amphibians, and food for waterfowl and marsh birds. The floating vascular aquatic plant study would allow the Agency to evaluate effects to a critical component of the structure and function of the aquatic plant community. A toxicity study on a n on

- rooted vascular aquatic plant species is used to establish a dose response relationship of BTS with effects to non

rooted aquatic plants in terms of yield, growth rate, and area under the growth curve . The effects data
would be used to determine the likelihood that losses to non

- rooted aquatic vascular plants will occur and

### Page 36 of 40 that such losses would indirectly lead to loss of other aquatic organisms through impacts such as loss of a food resource, habita t, or habitat quality

.

2. How could the data impact the Agency's future decision

- making? In the absence of data, risks could not be calculated for aquatic nonrooted macrophytes

. Therefore, until additional data become available, risks to non

- rooted vascular plants (both Federally

- listed and non

- listed species) will be assumed in future BTS risk assessments. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses
for BTS which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Aquatic plant growth, floating vascular species ( Lemna sp. ), Tier II
Guideline Number: 850.4 400
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

No non

- rooted vascular aquatic plant toxicity data ha s been submitted for the major degradate pentachlorodimethylsulfone . BTS is used as an 

### algicide, bactericide, slimicide and fungicide for use

in industrial process and water systems, cooling towers , and it is also used for oil and gas well development water systems which can result in discharge of BTS and its major degradate, 

### pentachlorodimethylsulfone to surface waters

. The requested data would allow the Agency to
estimate risks to aquatic plants from exposure to pentachlorodimethylsulfone , including defining an action area for endangered species

.

Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. Mats of floating non

- rooted aquatic plants provide habitat for small invertebrates, food and shelter for fish and amphibians, and food for waterfowl and marsh birds. The floating vascular aquatic plant study would allow the Agency to evaluate effects to a critical component of the s tructure and function of the aquatic plant community. A toxicity study on a non

- rooted vascular aquatic plant species is used to establish a dose response relationship of pentachlorodimethylsulfone with effects to non

- rooted aquatic plants in terms of yield, growth rate, and area under the growth curve . The effects data would be used to determine the likelihood that losses to

non

- rooted aquatic vascular plants will occur and that such losses would indirectly lead to loss of other aquatic organisms thro ugh impacts such as loss of a food resource, habitat, or habitat quality

.

2. How could the data impact the Agency's future decision

- making? In the absence of data, the toxicity of the degradate would be assumed to be the same as that of the parent,
if data for the parent was submitted, or if this data is not available either risks would be presumed for listed and nonlisted aquatic plants

. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily severe.

### Page 37 of 40 Study Title: Aquatic plant growth, non

- vascular species (one freshwater green alga species, one freshwater diatom species, one estuarine/marine species, and one cyanobacterium species ), Tier II
Guideline Number: 850.5400
Test Substance: TGAI Rationale for Requiring the Data

No nonvascular aquatic plant toxicity data ha s been submitted for BTS. A battery of four species, representing different morphological characteristics and environmental habitats are required for use patterns resulting in emissions to surface waters. U se s of BTS in industrial process and water systems, cooling towers, and discharges from oil and gas well development are expected to lead to exposure of aquatic organisms due to the repeated release and transport of BTS and its major degradate from use sites
int o aquatic ecosystems. Without these data, the Agency is unable to evaluate the potential risks to non

vascular aquatic plants associated with exposure to BTS

. T he Agenc y would have to presume risk to federally listed and non

- listed non

- vascular plants

, b ut would not be able to quantify the risk.

Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The four aquatic nonvascular plant studies would allow the Agency to analyze effects on primary production. A toxicity study on non

- vascular aquatic plant species
is used to establish a dose response relationship of BTC with primary productivity in terms of yield, growth rate, and area under the growth curve . The effects data would be u sed to determine the likelihood
that losses to primary production will occur and that such losses would indirectly lead to loss of other aquatic organisms through impacts such as loss of a food resource, habitat, or habitat quality

.

2. How could the dat a impact the Agency's future decision

- making? In the absence of data, r isks to nonvascular primary productivity could not be calculated

. Therefore, until additional data become available, risks to aquatic non

- vascular plants (both Federally

- listed and non

listed species) will be assumed in future BTS risk assessments. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily severe.

### Page 38 of 40 Study Title: Aquatic plant growth, non

- vascular species ( m ost sensitive of the TGAI tested species ),
Tier II
Guideline Number: 850.5400
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data

No nonvascular aquatic plant toxicity data ha s been submitted for the major degradate pentachlorodimethylsulfone . U se s of BTS in industrial process and water systems, cooling towers, and discharges from oil and gas well development are expected to lead to exposure of aquatic organisms due to the repeated release and transport of BTS and its major degradate from use sites into aquatic
ecosystems. A battery of four non

- vascular tests with the parent BTS have been requested, only a test with the most sensitive of these species is needed to evaluate the toxicity of the degradate relative to the
parent. Without th is degradate data, the Agency would have to assume that the degradate is as toxic as the parent and if there is no parent data the Agency would be unable to calculate risk for BTS and its major degradate

. T he Agenc y would have to pr esume risk to federally listed and non

- listed non

- vascular plants

, but would not be able to quantify the risk.

Practical Utility of the Data

1. How will the data be used? These data are needed for a registration review decision and for an endangered species assessment, which will be conducted as part of that decision. The a quatic nonvascular plant study would allow the Agency to analyze effects on primary production from exposure to the degradate

. A toxicity study on non

vascular aquatic plant species is used to establish a dose response relationship of the degradate with primary productivity in terms of yield, growth rate, and area under the growth curve . The effe cts data
would be used to determine the likelihood that losses to primary production will occur and that such losses would indirectly lead to loss of other aquatic organisms through impacts such as loss of a food resource, habitat, or habitat quality

.

2

. How could the data impact the Agency's future decision

- making? In the absence of data, the toxicity of the degradate would be assumed to be the same as that of the parent, if data for the parent was submitted, or if this data is not available then risks would be presumed to listed and nonlisted aquatic plants

. Therefore, until additional data become available, risks to aquatic non

vascular plants (both Federally

- listed and non

- listed species) will be assumed in future BTS risk

assessments. T he lack of these data will limit the flexibility the Agency and registrants have in addressing risks to non

- listed and listed species and in coming into compliance with the Endangered Species Act, and could result in use restrictions or withdrawal of uses for BTS which may otherwise be avoided, or which are unnecessarily severe.



### Study Title: Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals; Activated Sludge Respiration Inhibition Test
Guideline Number: 850.6800 or OECD 209 , respectively
Test Substance: TGAI , b is (trichloromethyl) sulfone Rationale for Requiring the Data An activated sludge, respiration inhibition test (ASRI) is needed to identify whether this pesticide could harm activated sludge microorganisms found in biological wastewater treatment systems. The Agency
will use these data to determine the potential imp act of this chemical on waste water treatment plants (WWTPs) as a result of respiration inhibition of activated sludge microorganisms. This test is also necessary to enable the Agency to establish correct concentrations for use in the biodegradability tes t, if that test is determined to be adequate for assessing biodegradation potential. Furthermore, the results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which biodegradation test is required.

### Page 39 of 40 If the ASRI test EC 50 is less than o r equal to 20 mg/L, then either the (i) Biodegradation in Activated Sludge Study or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units , or (iii) the Porous Pot Test is required. If the ASRI test EC 50 is greater than 20 mg/L, then t he applicant must choose either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units , or c) the Porous Pot Test. If the Ready Biodegradability study is conduc ted and the antimicrobial passes, then no further testing is required. If, however, the antimicrobial fails the R eady B iodegradability study, then the (i) Biodegradation in Activated Sludge or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units or (iii) the Porous Pot study is required. Practical Utility of the Data

1. How will the data be used? The data will be used to assess potential adverse effects to activated sludge microorganisms from BTS

. In addition, the data will be used to determine whether or not label restrictions are needed. The study will identify the inhibitory effect of this chemical on the treatment plant’s microorganisms’ respiration at
different concentrations of the test subst ance and will identify the EC 50 , the effective concentration of the test substance at which the respiration rate is 50% of that shown by the control under conditions in this guideline. The data will also determine suitable non

- inhibitory concentrations to be used in biodegradability tests.

2. How could the data impact the Agency’s future decision

- making? If the data indicate a high degree of activated sludge respiration inhibition, a more rigorous test for biodegradation in wastewater treatment will be r equired than the R eady B iodegradability test. Also, if a high degree of respiration inhibition is demonstrated and biodegradation and/or sorption is indicated to be negligible, the Agency may require label restrictions or mitigation measures to insure tha t activated sludge microorganisms will not be adversely impacted.



### Study Title: Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals; Activated Sludge Respiration Inhibition Test
Guideline Number: 850.6800 or OECD 209 , respect ively
Test Substance: D egradate, pentachlorodimethylsulfone Rationale for Requiring the Data An activated sludge, respiration inhibition test (ASRI) is needed to identify whether this major degradate could harm activated sludge microorganisms found in biological wastewater treatment systems. The Agency will use these data to determine the potential impact of this chemical on waste water treatment plants (WWTPs) as a result of respiration inhibition o f activated sludge microorganisms. This test is also necessary to enable EPA to establish correct concentrations for use in the biodegradability test, if that test is determined to be adequate for assessing biodegradation potential. Furthermore, the resul ts of the Activated Sludge Respiration Inhibition Test (ASRI) determine which biodegradation test is required. If
the ASRI test EC 50 is less than or equal to 20 mg/L, then either the (i) Biodegradation in Activated Sludge Study , or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units

, or (iii) the Porous Pot Test is required. If the ASRI test EC 50 is greater than 20 mg/L, then the applicant must choose either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge

, or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units , or c) the Porous Pot Test. If the Ready Biodegradability study is conducted and the test substance passes the ready biodegradability study, then no further testing is required. If, however, the test substance fails the R eady B iodegradability study, then the (i) Biodegradation in Activated Sludge

, or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units , or (iii) the Porous Pot study is required.

### Page 40 of 40 Practical Utility of the Data

1. How will the data be used? The data will be used to assess potential adverse effects to activated sludge microorganisms. In addition,
the data will be used to determine whether or not label restrictions are needed. The study will identify the inhibitory effect of this chemical on the treatment plant’s microorganisms’ respiration at different concentrations of the test substance and will identify the EC 50 , the effective concentration of the test substance at which the respiration r ate is 50% of that shown by the control under conditions in this guideline. The data will also determine suitable non

- inhibitory concentrations to be used in biodegradability tests.

2. How could the data impact the Agency’s future decision

- making?
If th e data indicate a high degree of activated sludge respiration inhibition, a more rigorous test for biodegradation in wastewater treatment will be required than the ready biodegradability test. Also, if a high degree of respiration inhibition is demonstrat ed and biodegradation and/or sorption is indicated to be negligible, the Agency may require label restrictions or mitigation measures to insure that activated sludge microorganisms will not be adversely impacted.