Page 2 of 32

Executive Summary

Tri-n butyl tetradecyl phosphonium chloride (TTPC) is an algicide, bactericide and 

fungicide for use in industrial processes and water systems. TTPC uses include water treatment 

in recirculating cooling systems, heat exchange water systems, air washing systems, evaporative 

coolers, brewery pasteurizers, pulp/paper/paperboard systems (non-food contact paper and 

paperboard manufacture), and oil and gas well development and production, and enhanced oil 

recovery systems (non-marine use). All product chemistry data requirements have been satisfied 

for this active ingredient. The Agency data base for evaluating the environmental fate and 

transport of TTPC is incomplete. Data gaps for this pesticide include aerobic and anaerobic 

aquatic metabolism, soil adsorption/desorption, 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). No ecological risk assessment 

has been conducted previously for any registered TTPC uses. Based on development of 

exposure scenarios since registration, an ecological risk assessment will be performed for water 

cooling tower emissions, pulp and paper mill emissions, and oil and gas well production 

emissions. TTPC is highly to very highly toxic to freshwater animals and is slightly to

moderately toxic to birds. The Agency data base for evaluating the effects of TTPC and its 

major degradates for these uses is incomplete. Data gaps include aquatic plant tests, fish early 

life stage testing, freshwater and estuarine/marine aquatic invertebrate life cycle test, 

marine/estuarine fish, mollusk, and crustacean acute tests, and sediment toxicity testing with 

benthic invertebrates. 

Introduction

TTPC (Table 2) is an organophosphorous ionic chemical biocide. It was first registered 

on September 22, 2006 as an active ingredient in Bellacide 350 / Bellacide 355 products for 

industrial process water treatments. Specifically, TTPC is registered to control algae, slime 

forming bacteria, sulfate reducing bacteria, and fungi in recirculating cooling tower and process 

water / air washers and industrial scrubbing systems (e.g., commercial and industrial cooling 

towers, evaporative coolers, air washing systems equipped with a mist eliminator); heat transfer 

or exchange systems (e.g., dairy sweetwater systems, brewery pasteurizers, bottle and can 

warmers, hydrostatic sterilizers and retorts); non-food contact pulp, paper and paperboard 

process water (e.g., brown paper, corrugated sheet, kraft paper, newsprint, etc.); enhanced oil 

recovery systems (non-marine use and not registered for use in California) (e.g., injection and 

produced water systems, water disposal systems, and other oilfield water systems); oil and gas 

production and transmission pipelines and systems; gas storage wells and systems; hydro testing 

of pipelines or vessels; pipeline pigging and scraping operations; and to oil and gas well drilling 

and maintenance fluids, packer, completion, workover and fracturing fluids. Uses not registered 

for use in California include: pulp, paper, and paperboard systems, dairy sweetwater system 

applications, brewery pasteurizers, can warmers, hydrostatic sterilizers and retorts, air-washer or 

air scrubber system applications and enhance oil recovery systems.

There is only one registrant for TTPC. Currently three products which are listed in Table 

1 are registered for the uses indicated above. One product (Reg. No. 83451-15) is registered 

both as a manufacturing use product (MUP) and an end use product (EP). Applications to use 
Page 3 of 32

sites are made using a metering-pump system or a closed loading/application system; open 

pouring is prohibited.

A Reregistration Eligibility Decision (RED) was not issued by the Agency for TTPC 

because the initial registration date was after November 1984, the mandated cutoff for initiation 

of the RED process. In the reregistration review an ecological risk assessment will be performed 

for the industrial process and water systems and oil and gas drilling, hydro testing, maintenance 

and oil recovery systems uses.

Table 1. Registered Product of Tri-n butyl tetradecyl phosphonium chloride

Registration

No.

Registration

Name

Company

Name

Formulation

Type

% of Active

Ingredient

83451-15 Bellacide 350 BWA Water Additives US 

LLC

Soluble Concentrate

MUP/EUP 50

83451-16 Bellacide 355 BWA Water Additives US 

LLC

Soluble Concentrate

EUP 5

83451-20 Bellacide 303 BWA Water Additives US 

LLC

Flowable Concentrate

EUP 15

Mode of Action 

The specific mode of action of quarternary alkyl phosphonium salts is not well 

delineated. TTPC belongs to a group of substances that form ionic liquids (ILs). Specifically 

TTPC contains a positively charged long chain hydrocarbon, the long chain hydrocarbon is fat 

soluble and the charged ion portion is water-soluble. A common supposed mechanism of action 

of ILs is membrane disruption, resulting in leakage of cell constituents. 

The Agency has conducted a review of the available product chemistry, environmental 

fate, and ecotoxicity data for evaluating the environmental risk from the above listed uses of 

TTPC and its major degradates. The findings are summarized below.

A. Product Chemistry Summary of TTPC

A Special Note on the Chemistry of TTPC

ILs are a new class of compounds that show some interesting, and a few unique 

characteristics. Some of these IL chemicals were developed to advance the field of green 

chemistry principles; most have been synthesized in the last thirty years, and have been used for

various research and industrial applications.

The biggest rationale to develop these chemicals was to find ‘alternate solvents’ in place 

of more hazardous volatile organic solvents. Some characteristics of these new and modern 
Page 4 of 32

(neoteric) chemicals include: 1) ionic in nature with a positively charged long chain hydrocarbon 

portion which is fat soluble and a negatively charged ion portion ; 2) negligible (low) vapor 

pressure; 3) low melting points, mostly under 100o C; 4) usually nonflammable; 5) low 

mammalian acute toxicity; and 6) some of these ‘solvents’ can initiate reactions, particularly 

when metal-or enzyme-catalyzed, that are different from the conventional solvents. Depending 

on the anion, ILs may or may not be water soluble.

While a number of research publications have appeared in the last 10-15 years about the 

ecotoxicity, environmental fate, and biodegradation properties of some quaternary ammonium 

and phosphonium ionic liquids (Karichkhoff 1981; Wells and Coombe 2006; Lacrama et al. 

2007; Pham et al. 2010; Stojanovic et al. 2011), the environmental fate on quaternary 

phosphonium is still scant.

Ecotoxicity, biodegradation, and environmental fate studies on quaternary phosphonium 

ionic liquids include, but not limited to the following types: a) R-groups attached to central 

phosphorous, where R = C1 through C18 alkyl groups; b) mixed alkyl groups; and c) different 

counter ions like chloride or bromide or more complicated like hexafluorophosphate (F6P-

).

Biodegradation studies have been conducted on quaternary phosphonium alkyl halides, 

(C2 to C18) alkyl groups. All studies show that none of the quaternary phosphonium ILs are 

ready biodegradable, particularly those that have > C4 alkyl groups. None of the studies had the 

chemical under our consideration (TTPC). Some studies have estimated log octanol-water 

partition coefficient (log Kow) values between 6 and 9.

Chemical identity and the physical and chemical properties of a 95% pure grade of the 

active ingredient and the 50% technical grade active ingredient (TGAI) and EP are provided in 

the Tables 2 and 3 below. All product chemistry data requirements have been satisfied for the 

active ingredient TTPC. (Source: MRIDs 133035, 135035, 40680701, 40680703, 40681901, 

46315602, 46333001, 46386901, 46386902, 46386903, 46466801, 46466802, 46466901, 

46466902,46648601, 46648602, 46648603, 46648604, 46662101, 46662102, 46721701, 

46921001, 46921002, 47912005, 47912006, and 48479001).

Table 2. Chemical Identity

Chemical Name: Tri-n butyl tetradecyl phosphonium chloride

Phosphonium, tributyl tetradecyl – chloride

Tetradecyl tributyl phosphonium chloride

Common Name: Tributyl tetradecyl phosphonium chloride (TTPC)

Synonyms Tetra-alkyl-phosphonium chloride

5,6-dibutyloctadecan-5-ylphophanium chloride

IUPAC Name: Tri-n butyl tetradecyl phosphonium chloride

PC Code: 128824

CAS Number: 81741-28-8

Molecular Formula: C26H56

C

Cl P

14H29-P+  ̄ (C4H9)3

CH

Cl ̄

3(CH2)13P(Cl)(CH2CH2CH2CH3)3

Molecular weight: 413.15 g/mole
Page 5 of 32

Molecular Structure:

Table 3. Product Chemistry Data Summary of TTPC

OPPTS 

Guideline 

No.

Physical and Chemical 

Properties TTPC (95% purity) Results TTPC (TGAI and EP, 50% purity, liquid solution) Results

830.1800 Enforcement Analytical 

Method

TTPC

Amperometric titration.

: High Performance Liquid Chromatography (HPLC).

Lauryl sulfate, two-phase titration method.

830.6302 Color White solid at 20°C Clear, colorless liquid at 20°C.

830.6303 Physical State White hygroscopic solid at room temp 

(20°C)

Clear, colorless liquid at room 

temperature (20°C)

830.6303 Odor Slightly sweet odor Very slightly sweet odor.

830.6313 Stability to sunlight, 

normal and elevated 

temperature, metals/metal 

ions

Chemical stability:

Using a thermal gradient of 5 °C per 

minute the test material was stable 

through its melting point (40 - 42 °C) 

and up to elevated temperatures (100 

°C). 

Reported weight losses at very 

elevated temperatures were:

180 °C 2.1% weight loss

280 °C 4.5% weight loss

320 °C 6.8% weight loss

Stable under normal temperature 

conditions and recommended use. 

The concentration of the active 

ingredient remains the same before 

and after exposure to the 

accelerated temperature conditions 

for 30 days at 50 ± 3 °C. For the 

test material packaging, there were 

no signs of puckering, cracking, or 

swelling observed supporting the 

conclusion that the product and its 

packaging materials are stable. 

There was no compromise of the 

HDPE containers observed.

Reactivity to Metal Ions:

Based on its chemical structure TTPC 

will provide a chloride ion source in 

the presence of moisture and may, 

therefore, be potentially corrosive to 

metals which are susceptible to salt 

solution induced corrosion (i.e., mild 

steels, iron, brass, copper but not 

stainless steel or anti-corrosion coated 

metal substrates). TTPC is not 

theoretically reactive with metal ions 

based on its chemical structure. TTPC 

is intended to be packaged in plastic 

drums (HDPE) and not in metal 

containers.

Reactivity to Sunlight:

TTPC has no UV/VIS absorption in 

the range 290 - 800 nm and is 

expected to be photolytically stable.
Page 6 of 32

OPPTS 

Guideline 

No.

Physical and Chemical 

Properties TTPC (95% purity) Results TTPC (TGAI and EP, 50% purity, liquid solution) Results

830.6314 Oxidation/ Reduction:

Chemical Incompatibility

Not an oxidizer or reducing agent. 

Does not contain oxidizing or 

reducing agents and TTPC has no 

reactive oxidizable/reducible groups in 

its structure.

Not an oxidizer or reducing agent. 

Does not contain oxidizing or 

reducing agents.

830.6315 Flammability: Non Flammable. Non-flammable. Not applicable 

because the product is a 50% 

aqueous solution of an ionic solid 

which has no readily oxidizable 

functional groups in its structure 

and cannot, therefore, be 

flammable.

830.6316 Explodability Non-explodable. Contains no 

explosive ingredients.

Not applicable because the product 

is a 50% aqueous solution of an 

ionic solid which has no readily 

reactive functional groups in its 

structure and cannot, therefore, be 

explosive.

830.6317 Storage Stability There was no significant change in the 

active ingredient content of the test 

material during storage at 25 ± 2°C for 

12 months.

Accelerated Storage Stability:

The concentration of the active 

ingredient remains the same before 

and after exposure to the 

accelerated temperature conditions 

for 30 days at 50 ± 3 °C. For the 

test material packaging, there were 

no signs of puckering, cracking, or 

swelling observed supporting the 

conclusion that the product and its 

packaging materials are stable. 

There was no compromise of the 

HDPE containers observed.

There was no significant change in 

the active ingredient content of the 

test material during storage at 25 ± 

2°C for 12 months.

TTPC in aqueous solution will 

have a shelf life in excess of one 

year when stored in its nontransparent packaging.

830.6319 Miscibility Not applicable, because the product is 

not an emulsifiable liquid which is to 

be diluted with petroleum solvents.

Not applicable, not an emulsifiable 

product. Not applicable for 

products not intended to be diluted 

with petroleum solvents.

830.6320 Corrosion Characteristics Not Required. The test material does 

not exhibit corrosion / degradation of 

the HDPE plastic which forms the 

container for its packaging.

Packaged in steel drums (55 kg 

net) with high density polyethylene 

lining. There is no evidence of 

corrosion or breakdown of drums 

with HDPE lining. Does not attack 

HDPE, may slowly corrode steel or 

iron, and does not attack stainless 

steel.
Page 7 of 32

OPPTS 

Guideline 

No.

Physical and Chemical 

Properties TTPC (95% purity) Results TTPC (TGAI and EP, 50% purity, liquid solution) Results

830.6321 Dielectric breakdown Not applicable for products not 

intended to be used around electrical 

equipment.

Not applicable for products not 

intended to be used around 

electrical equipment.

830.7000 pH Not applicable for solids. Undiluted: pH ranges from 7.0 to 

9.0. Average pH is 7.3.

830.7050 UV/Visible absorption TTPC has no UV/VIS absorption in the range 290-800 nm.

830.7100 Viscosity Not applicable for solid products. 53.6 cP at 25 °C and 15 cP at 50 °C

830.7200 Melting point 40-42o Not applicable to this product 

because it is a liquid at room 

temperature.

C

830.7220 Boiling point Not applicable because it is solid at 

room temperature.

100-101°C

830.7300 Density 1.183 g/cc 0.95 - 1.00 g/ml at 20 °C

830.7370 Dissociation Constant Not applicable because the chemical 

structure of TTPC has no dissociable 

groups other than the ion pair shown 

in the structural formula provided 

below:

(n-C4H9)3-P+-C14H29 Cl

Not applicable to MUP or EP 

products.

-

830.7550 Partition coefficient (noctanol/water)Data gap Not applicable to MUP or EP 

products.

830.7840 Solubility in water >50% (w/w) in water at 20°C Not applicable to this product 

because it is already an aqueous 

solution.

Non 

guideline 

study

Solubility in organic 

solvent

Methanol >50%; Isopropanol >50%;

Ethylene glycol >50%

-----

830.7950 Vapor Pressure 3.75 x 10-8 mg Hg at 25 o

Based on the chemical structure of 

TTPC, the vapor pressure is estimated 

to be negligible as the product is an 

ionic solid (substituted phosphonic 

acid chloride salt) with a relatively 

large molecular weight (434.84).

C (nonvolatile).Not applicable to MUP or EP 

products.

Source: EPI 

Suite

Henry’s Law Constant TTPC: 6.57E-002 atm-m3/mole -----

B. Environmental Fate Summary

Available environmental fate guideline degradation and biodegradation studies and the 

results are summarized below.
Page 8 of 32

Degradation Studies (Abiotic)

a. Hydrolysis (161-1)

TTPC did not hydrolyze in sterile aqueous buffered solutions at pH 5, 7, or 9 

when incubated at 25°C for 30 days. The study is acceptable (MRID 40680702) 1

b. Photodegradation in water (161-2)

A study (MRID 40680703) was submitted but was not conducted according to the 

Agency guidelines, and was found to be unacceptable. However, this chemical 

has saturated alky groups with no double bonds (or aromatic components) present, 

and these groups have no tendency to asorb in the UV/visible range (280-800 

nm), so it is expected to be stable to photodegradation. In the absence of a 

scientifically sound study documenting otherwise, TTPC will be assumed to be 

stable to photolysis.

c. Octanol-water partition coefficient (Kow) (OCSPP 830.7550)

Octanol-water partition coefficient (Kow) is a very important indicator for 

bioaccumulative characteristic of a pesticide. The Agency requires registrants to 

provide the numerical value for Kow which is the ratio of the undissociated 

species concentration in the two phases (n-octanol to water) at equilibrium; the 

Agency has test guidelines for the Kow determination. The test guidelines are 

designed to determine Kow for organic chemicals (pesticides) by any of the three 

methods: 1) shake-flask method; 2) column generator and 3) high-performance 

liquid chromatography (HPLC) method. TTPC is an ionic liquid and these 

methods may not provide a meaningful Kow value. The Kow is usually defined as 

the ratio of equilibrium concentrations of the dissolved chemical in n-octanol to 

that in water, and for ionic solutes the intrinsic or true Kow is for the ratio of the 

undissociated species in the two phases. Alternatively where measuring the 

undissociated species in the two phases is difficult, such as that expected for 

TTPC, the apparent Kow, measured as the ratio of the concentrations of 

undissociated and dissociated in the two phases at equilibrium can be used. Ionic 

liquids can be water soluble or water insoluble; either way they present difficulty 

to determine Kow values.

 1 The study was originally accepted by Agency scientists; the Agency reviewed it again, and has concluded that 

hydrolysis study for ionic substances is not applicable. However the Agency considers this data requirement as 

fulfilled.
Page 9 of 32

Biodegradation Studies (Biotic)

a. Activated Sludge Respiration Inhibition Test (OCSPP 850.6800 or OECD 

209)

Inhibitory Effect on the Respiration of Aerobic Waste-Water Bacteria (MRID No. 

00133036): The study does not meet the current guideline standards or data 

requirement for an activated sludge respiration inhibition test (OCSPP 850.6800 

or OECD 209). .

b. Ready Biodegradability (OCSPP 835.3110); or Porous Pot Test (OCSPP 

835.3220); or Simulation Test – Aerobic Sewage Treatment: A. Activated 

Sludge Units (OCSPP 835. 3240); or Simulation Tests to Assess the 

Biodegradability of Chemicals Discharged to Wastewater (OCSPP 835.3280)

Bioelimination in the Simulation Test – Aerobic Sewage OECD Coupled Units 

Test No. 303A (MRID No. 00133037): The study does not meet the current 

guideline standards or data requirement for one of four biodegradation in 

wastewater system studies (OCSPP 835.3110, or 835.3220, or 835.3240, or 

835.3280).

Test for Biodegradability of OECD Closed bottle Test No. 301D (MRID No. 

00133038): The study does not meet the current guideline standards or data 

requirement for one of four biodegradation in wastewater system studies (OCSPP 

835.3110, or 835.3220, or 835.3240, or 835.3280).

The Agency will conduct an environmental fate assessment for registration review. The 

highly important use sites for this fate assessment are: industrial slimicides used in recirculating 

water cooling towers; pulp and paper mills; and oil and gas drilling fluids and process waste that 

potentially pass through waste water treatment plants (WWTPs) and may be discharged into 

terrestrial and aquatic environments. For this assessment the Agency anticipates needing those 

data indicated on page 12 of this document.
Page 10 of 32

Water Quality

TTPC 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 on information provided at the Agency’s 

National Pesticides Cause of Impairment of Waters website (searched April 7, 2011)2

. In 

addition, no Total Maximum Daily Loads (TMDL) has been developed for TTPC, based on

information provided at the Agency’s National Pesticide TMDL web site (searched April 7, 

2011)3

. 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 this 

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 Management Process4

, in order 

to ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

C. Ecological Effects Summary

No ecological risk assessment was performed for TTPC at the time of the registration. 

An ecological risk assessment will be performed for the industrial process and water systems 

which potentially result in discharge to the aquatic environment as part of registration review. 

Available ecotoxicity guideline studies and the results are summarized in Tables 4 & 5 for 

terrestrial and aquatic animals, respectively. 

a. Toxicity to Terrestrial Organisms

A summary of the available toxicity data endpoints from registrant-submitted studies is 

provided in Table 4. TTPC is slightly to moderately toxic to birds. Insect pollinator data are not 

required based on TTPC uses. Mammalian toxicity data for evaluating exposure of mammalian 

wildlife is available for acute oral toxicity and is discussed in the human health scoping 

document.

Table 4. Summary of the Endpoints from Submitted Terrestrial Toxicity Studies for TTPC

Study Type Species Toxicity Value

(a.i.)

Test 

Substance

Toxicity 

Classification MRID & Status

Acute – Avian 

Oral

850.2100

Mallard

(Anas 

platyrhynchos)

LD50 94.3% a.i. : 232 

mg/kg-bw/day

Moderately

toxic

00133051

Acceptable

Acute – Avian 

Dietary

850.2200

Northern Bobwhite 

(Colinus 

virginianus)

LC50 94.3% ai : 4214 

mg/kg-diet Slightly toxic 00133053

Acceptable

Acute – Avian 

Dietary

850.2200

Mallard Duck

(Anas 

platyrhynchos)

LC50 94.3% a.i. : 3663 

mg/kg-diet Slightly toxic 00133052

Acceptable

 2 . http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885 3

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

group_name=PESTICIDES

4 http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf
Page 11 of 32

b. Toxicity to Aquatic Organisms

A summary of acute aquatic ecotoxicity data endpoints from registrant-submitted studies is 

provided in Table 5. TTPC is highly to very highly acutely toxic to freshwater fish and 

invertebrates. Chronic data are required but are not available. Data are not available for 

sediment-dwelling or estuarine/marine organisms. 

Table 5. Summary of the Endpoints from Submitted Aquatic Toxicity Studies for TTPC

Study Type Species Toxicity Value

(a.i.)

Test

Substance

Toxicity 

Classification MRID & Status

Acute –

Freshwater Fish

850.1075

Rainbow trout 

(Oncorhynchus 

mykiss)

96-hr LC50 49.85% a.i. : 

480 μg/L Highly toxic 00133055

Acceptable

Acute –

Freshwater Fish

850.1075

Bluegill sunfish 

(Lepomis 

macrochirus)

96-hr LC50 49.85% a.i. : 59 

μg/L

Very highly 

toxic

00133056

Acceptable

Acute –

Freshwater 

Invertebrate

850.1010

Water flea (Daphnia 

magna)

48-hr EC50 49.85% a.i. : 25

μg/L

Very highly 

toxic

00133057

Acceptable

c. Toxicity to Aquatic Plants

Aquatic plant data (vascular and non-vascular species) are required for the risk 

assessment. No data are available.

Adverse Ecological Incidents

There are no reported incidents in the Agency's Ecological Incident Information System 

(EIIS) regarding TTPC. The absence of documented incidents does not necessarily mean that 

such incidents did not occur.

d. Ecological Risk Assessment

An ecological risk assessment was not conducted previously on the TTPC use patterns described 

in this document. Based on development of exposure scenarios since TTPC was registered, an 

ecological risk assessment will be performed for water cooling tower emissions, pulp and paper 

mill emissions, and oil and gas well production emissions. For this ecological risk assessment, 

which will include an endangered species assessment, the Agency anticipates needing the 

ecotoxicity data outlined on page 12 of this document.

Environmental Fate and Ecotoxicity Data Gaps and Anticipated Work

The Agency has identified a need to conduct environmental fate, environmental effects, 

and ecological risk assessments for recirculating water cooling tower emissions, paper mill

emissions, and oil and gas well production development emissions of TTPC and its major 

degradates to the environment. The ecological risk assessment planned during registration 
Page 12 of 32

review will allow the Agency to make a “no effect” or “may affect” determination for federally 

listed threatened or endangered species (listed species) and their designed critical habitats. When 

an assessment concludes that a pesticide’s use “may affect” a listed species or its designated 

critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National 

Marine Fisheries Services (the Services), as appropriate.

The Agency anticipates needing the environmental fate and ecotoxicity data bulleted 

below for TTPC and/or any of its major degradation products that are of potential concern to 

conduct an environmental fate and effects, and ecological risk assessment:

• The Agency anticipates needing the following fate data to conduct a complete 

environmental fate assessment:

o Aerobic aquatic metabolism (OCSPP 835.4300);

o Anaerobic aquatic metabolism (OCSPP 835.4400);

o Soil adsorption/desorption (OCSPP 835.1230);

o Modified Activated Sludge Respiration Inhibition (OCSPP 850.6800);

o Activated Sludge Sorption Isotherm (OCSPP 835.1110); and

o Ready biodegradability (OCSPP 835.3110), Porous Pot Test (OCSPP 835.3220), 

or Simulation Tests to Assess the Biodegradability of Chemicals Discharged to 

Wastewater (OCSPP 835.3280), or Simulation Test – Aerobic Sewage Treatment: 

A. Activated Sludge Units (OCSPP 835.3240)5

o Octanol/water partition coefficient determination for TTPC by the Shake Flask 

Method (OCSPP 830.7550) modified to use measured TTPC ion pair and cation 

concentrations at equilibrium

.

• The Agency anticipates needing the following ecotoxicity data in order to conduct a 

complete ecological risk assessment, including an endangered species assessment:

o Fish early-life stage toxicity test, freshwater species (most acutely sensitive Blue 

gill sunfish, Lepomis macrochirus) (OCSPP 850.1400)-;

o Aquatic invertebrate life-cycle, freshwater species (OCSPP 850.1300);

o Aquatic plant toxicity test, vascular species (OCSPP 850.4400);

o Aquatic plant toxicity test, non-vascular (4 species: a freshwater green alga, a 

freshwater diatom, a cyanobacterium, and a marine diatom) (OCSPP 850.5400);

o –Sediment chronic toxicity test, freshwater invertebrate Hyallela azteca (Special 

Study); 

o Fish acute toxicity, estuarine/marine species (OCSPP 850.1075

 5 The results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which of these four 

biodegradation tests are required. If the ASRI test EC50 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 the (iii) Porous Pot Test is required. If the ASRI test EC50 is greater than 20 mg/L, then the applicant must 

choose either: (i) Ready Biodegradability or (ii) Biodegradation in Activated Sludge or (iii) Simulation Test –

Aerobic Sewage Treatment: A. Activated Sludge Units or (iv) the Porous Pot Test. If the antimicrobial passes the 

Ready Biodegradability study, then no further testing is required. If, however, the antimicrobial 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 study is required.
Page 13 of 32

o Mysid acute toxicity test (OCSPP 850.1035)

o Mollusc acute toxicity (OCSPP 850.1025 or OCSPP 850.1055)

o Mysid life-cycle toxicity test (OCSPP 850.1350)

o Seedling emergence and growth test for rice (Oryza sativa) (OCSPP 850.4100); 

and

o Sediment chronic toxicity test, freshwater invertebrate Chironomous dilutus

(Special Study).

Facility Emissions to WWTP Modeling

For assessing the fate of TTPC and its major degradates or reaction products emitted to 

receiving waters from industrial process water uses of TTPC such as at pulp and paper mills, for 

recirculating cooling towers, and oil and gas well development the Agency anticipates using the 

available environmental fate information from guideline studies for TTPC and its major 

degradates 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 Industry", 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.

• Potential environmental releases and associated exposures of concern for uses of 

antimicrobial uses related to recirculating cooling towers will be assessed using the 

Generic Scenarios for recirculating cooling towers developed by the Chemical 

Engineering Branch 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 development sites include the 

following:

• The number of pulp and paper mill sites using TTPC or the maximum annual 

production volume of TTPC used in pulp and paper mills in the United States and its 

territories;

• The number of recirculating cooling tower sites using TTPC or the maximum annual 

production volume of TTPC used in cooling towers in the United States and its 

territories; 
Page 14 of 32

• The number of oil and gas well development sites using TTPC or the maximum 

annual production volume of TTPC used in oil and gas well development in the United 

States and its territories; 

• How many of each of these facilities have on-site and/or off-site wastewater 

treatment.

In the absence of information on the number of these facilities that use TTPC 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 TTPC.

In the absence of appropriate test data on biodegradation during wastewater 

treatment, the Agency will assume that there is no removal of TTPC and it’s degradates during 

wastewater treatment and that the amount of TTPC released with 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 TTPC during drinking water treatment the Agency 

will assume there is no removal of TTPC.

Default values for volume of wood treated per day (30 cubic meters per day for vacuum-pressure 

and 15 cubic meters per day for double vacuum facilities) from the emission scenario for wood 

preservatives document (OECD, 2002), the water solubility of TTPC, and label use rate will be 

used to estimate releases to WWTP in units of kilograms per day (kg/site/day).
Page 15 of 32

D. References

Karichkhoff, S.W. 1981. Semi-empirical estimation of sorption of hydrophobic pollutants on 

natural sediments and soils. Chemosphere 10 (8): 833-846.

Lacrama, A., M.V. Putz and V. Ostafe. 2007. A spectral-SAR model for the anionic-cationic 

interaction in ionic liquids: application to Vibrio fischeri ecotoxicity. International 

Journal of Molecular Sciences 8:842-863.

Pham, T.P.T., C. Cho, and Y. Yun. 2010. Environmental fate and toxicity of ionic liquids: A 

Review. Water Research 44 (2):352-372.

Stojanovic, A., C. Morgenbesser, D. Kogelnig, R. Krachler, and B.K. Keppler. 2011. Chapter 

26. Quaternary Ammonium and Phosphonium Ionic Liquids in Chemical and 

Environmental Engineering. In Kokorin, A. (editor), Ionic Liquids: Theory, Properties, 

New Approaches. InTech. http://www.intechopen.com/books/show/title/ionic-liquidstheory-properties-new-approaches

Wells, A.S. and V. T. Coombe. 2006. On the freshwater ecotoxicity and biodegradation 

properties of some common ionic liquids. Organic Process Research & Development. 

10 (4):794-798.
Page 16 of 32

Appendix A. Environmental Fate Study Justifications

Study Title: Sediment and Soil Adsorption/Desorption

Guideline Number 835.1230

Test Substance: Pure active ingredient

Rationale for Requiring the Data

A partition (or distribution) coefficient, Kd, is needed to conduct the environmental fate 

assessment to support the TTPC uses in pulp and papermill process water systems, recirculating 

water cooling systems, and oil and gas well production development process systems. The data 

is not currently available. The Agency has a limited understanding of the potential for TTPC to 

partition and disperse in the aquatic environment by means of sorption to geological materials 

(e.g., soil, sediments, organic or biological matter). A leaching adsorption/desorption study is 

needed in order to determine the Kd , which will allow the Agency to determine whether it will be 

tightly bound to sediments, which in turn will allow the Agency to understand the magnitude of 

TTPC exposure to sediment dwelling organisms. 

Controlled environmental fate and transport laboratory studies are used to determine the 

persistence, mobility, and bioconcentration potential of a pesticide active ingredient and its major 

degradates. The studies offer information on how, or by what mechanism, the pesticide degrades 

or dissipates, the rate at which it degrades or dissipates, where it goes, and what transformation 

products are formed. 

Practical Utility of the Data

1. How will the data be used?

The data would establish the significance of partitioning of TTPC and its major degradates to 

sediment as a route of transport and dispersion. The data would also help establish the Kd , the 

partitioning of TTPC between sediment and water in water/sediment systems. The Kd data from 

the adsorption/desorption study are used as inputs to exposure models. These models estimate 

the expected environmental concentrations of the pesticide and it’s degradates under various 

environmental and use conditions for drinking water and ecological risk assessments. The 

requested data will result in better characterization of TTPC mobility and will allow refined 

exposure estimates for drinking water and ecological risk assessments. 

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

In the absence of acceptable quantitative partitioning data, conservative assumptions about the 

pesticide’s sorption will be used. For the purposes of aquatic water column exposure modeling, 

TTPC will be assumed to be highly mobile, which will lead to conservative aquatic exposure 

estimates that may result in unnecessary mitigation. For sediment exposure modeling, TTPC will 

be assumed to partition primarily to sediment, which will lead to conservative sediment exposure 

estimates. If a direct measure of the partition coefficient were available, it would be used as an 

input for aquatic/sediment modeling which would provide refined aquatic/sediment exposure 

estimates, allowing for more accurate assessments of potential risks in drinking water and to 

ecological receptors, including endangered species.
Page 17 of 32

Study Title: Aerobic Aquatic Metabolism

Guideline Number: 835.4300

Test Substance: Pure active ingredient

Rationale for Requiring the Data

Aerobic aquatic metabolism data is needed to conduct the environmental fate assessment to support the 

TTPC uses in pulp and papermill process water systems, recirculating water cooling systems, and oil and 

gas well production development process systems. Acceptable data on the aerobic aquatic metabolism of 

TTPC in two-sediment systems are required. The data is not currently available. The Agency has limited 

understanding of how TTPC behaves in aerobic aquatic environments after discharge to receiving water. 

The purpose of aerobic aquatic metabolism study is to determine the nature and extent of microbial 

degradation under aerobic conditions in receiving water/sediment systems during the dispersal of the 

biocide throughout the aquatic environment, and to characterize the formation and decline of degradates. 

This information will determine the persistence and concentrations of TTPC and potential degradates over 

the time in representative aerobic water/sediment systems. The results of the study will indicate the 

potential for TTPC to contaminate the aquatic environment since biocide residues may be taken up by the 

sediment biota and passed on to other parts of the aquatic food web. Data are needed for two sedimentwater systems conducted (one each) at neutral and acidic pHs.

Practical Utility of the Data

1. How will the data be used?

The data would establish the significance of aerobic aquatic microbial degradation of TTPC as a route of 

degradation and identify, if possible, the degradation products formed that may adversely affect non-target 

organisms and may contaminate water and food sources of aquatic organisms. The data would also help 

establish the aerobic aquatic aerobic half-life of TTPC in water/sediment systems, and possibly it’s 

degradates, and assist in developing a degradation pathway.

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

The results of this study would indicate the nature and extent of formation and decline under aerobic 

aquatic conditions of TTPC and it’s degradates that may be taken up by sediment biota and passed on to 

other parts of the aquatic food web, and facilitates assessment of potential disposal problems. The study 

helps to determine the degradation rate (half-life) of TTPC in the presence of microorganisms in different 

natural water/sediment systems and establishes what metabolites (degradates) are formed under aerobic 

(oxygen-rich) conditions in the laboratory. If we do not receive this data TTPC would be assumed to be 

stable to aerobic metabolism and we would not know if the chemical breaks down leading to reduced risk 

to human health or the environment or we would not know if more toxic degradates are formed leading to 

increased risk to human health or the environment. 
Page 18 of 32

Study Title: Anaerobic Aquatic Metabolism

Guideline Number: 835.4400

Test Substance: Pure active ingredient

Rationale for Requiring the Data

Anaerobic aquatic metabolism data is needed to conduct the environmental fate assessment to support the 

TTPC uses in pulp and papermill process water systems, recirculating water cooling systems, and oil and 

gas well production development process systems. Acceptable data on the anaerobic aquatic metabolism of 

TTPC in two-sediment systems are required. The data is not currently available. The Agency has limited 

understanding of how TTPC behaves in anaerobic aquatic environments after discharge to receiving water. 

The purpose of an anaerobic aquatic metabolism study is to determine the nature and extent of microbial 

degradation under anaerobic conditions in water/sediment systems during the dispersal of the biocide 

throughout the aquatic environment, and to characterize the formation and decline of degradates. This 

information will determine the persistence and concentrations of TTPC and potential degradates over time 

in representative anaerobic water/sediment systems. The results of the study will indicate the potential for 

TTPC to contaminate the aquatic environment since biocide residues may be taken up by the sediment 

biota and passed on to other parts of the aquatic food web. Additionally, anaerobic conditions are more 

likely to prevail where biocides are found in aquatic environments than in strictly terrestrial environments. 

Data are needed for two sediment-water systems conducted (one each) at neutral and acidic pHs.

Practical Utility of the Data

1. How will the data be used?

Anaerobic aquatic metabolism data will facilitate a better understanding of the fate of TTPC residues in 

water and sediment. The data would establish the significance of anaerobic aquatic microbial degradation 

of TTPC as a route of degradation and identify, if possible, the degradation products formed that may 

adversely affect non-target organisms and may contaminate water and food sources of aquatic organisms. 

The data would also help establish the anaerobic aquatic microbial half-life of TTPC in water/sediment 

systems, and possibly it’s degradates, and assist in developing a degradation pathway.

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

The results of this study would indicate the nature and extent of formation and decline under anaerobic 

aquatic conditions of TTPC and it’s degradates that may be taken up by sediment biota and passed on to 

other parts of the aquatic food web, and would facilitate assessment of potential disposal problems. The 

study helps to determine the degradation rate (half-life) of TTPC in the presence of microorganisms in 

different natural water/sediment systems and establishes what metabolites (degradates) are formed under 

anaerobic (oxygen-poor) conditions in the laboratory. If the data indicate that degradation in anaerobic 

conditions occurs rapidly in acidic and or neutral aquatic systems and produces nontoxic transformations 

products, then the Agency could potentially determine that TTPC residues of concerns do not persist in 

these systems. If data indicate that degradation is not appreciable in aquatic systems or that transformation 

products are similar or higher toxicity than the parent compound, then the Agency could conclude that 

TTPC residues of concern persist in aquatic systems under anaerobic conditions. In the absence of the 

requested data, TTPC anaerobic aquatic metabolism half-lives will be conservatively assumed to be stable 

across the environmental pH range. 

Study Title: Activated Sludge Sorption Isotherm

Guideline Number: 835.1110

Test Substance: Pure active ingredient

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 
Page 19 of 32

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 then 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 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 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. Overall 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 wastewater treatment plants are used to assess exposure and risk to nontarget 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 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 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 potential to sorb to sludge, a screening assessment of potential 

exposure to ecological organimsm 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” 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 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 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. 
Page 20 of 32

Study Title: Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble 

Chemicals or Activated Sludge Respiration Inhibition Test

Guideline Number: 850.6800 or OECD 209, respectively

Test Substance: Pure active ingredient

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 impact 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 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 results of 

the Activated Sludge Respiration Inhibition Test (ASRI) determine which biodegradation test is required. 

If the ASRI test EC50 is less than or equal to 20 mg/L, then either the Biodegradation in Activated Sludge 

Study or the Porous Pot Test is required. If the ASRI test EC50 is greater than 20 mg/L, then the applicant 

must choose either: (i) Ready Biodegradability or (ii) Biodegradation in Activated Sludge or the Porous 

Pot Test. If the antimicrobial passes the ready biodegradability study, then no further testing is required. 

If, however, the antimicrobial fails the ready biodegradability study, then the Biodegradation in Activated 

Sludge or 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. 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 EC50, 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 required than the ready biodegradability 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 that activated 

sludge microorganisms will not be adversely impacted.
Page 21 of 32

Study Titles: Ready Biodegradability; Porous Pot Test; or 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)

Guideline Numbers: 835.3110; 835.3220; 835.3240; or 835.3280, respectively

Test Substance: Pure active ingredient

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 processes of a WWTP. Biodegradation is an important 

environmental pathway in which the antimicrobial is broken down by bacteria. These 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 

four biodegradation tests are required. If the ASRI test EC50 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 the (iii) Porous Pot Test is required. If the ASRI test EC50 is greater than 20 

mg/L, then the applicant must choose either: (i) Ready Biodegradability or (ii) Biodegradation in 

Activated Sludge or (iii) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or (iv) 

the Porous Pot Test. If the antimicrobial passes the Ready Biodegradability study, then no further testing 

is required. If, however, the antimicrobial 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 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 determine 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 nontarget 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, 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 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 

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 

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., EC50 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. If 

results of higher-tier WWTP biodegradation tests indicate low or negligible removal by biodegradation, 
Page 22 of 32

the risk assessments for this chemical would reflect the magnitude of potential risk derived from the 

chemical’s lack of 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 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 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 Title: Octanol/water partition coefficient determination for TTPC by the Shake Flask 

Method

Guideline Number: 830.7550 modified to measure TTPC ion pair and TTPC cation at equilibrium

Test Substance: Pure active ingredient

Rationale for Requiring the Data

The octanol/water partition coefficient (Kow) is a very important and fundamental chemical property. For 

assessing environmental fate and effects of a chemical it is used as an indicator of the bioaccumulative 

characteristic of a pesticide, as well as an indicator of toxicity to a wide variety of aquatic and terrestrial 

organisms. The Kow is usually defined as the ratio of equilibrium concentrations of the dissolved 

chemical in n-octanol to that in water, and for ionic solutes the intrinsic or true Kow is for the ratio of the 

undissociated species in the two phases. Alternatively where measuring the undissociated species in the 

two phases is difficult, such as that expected for TTPC, the apparent Kow

([ ] [ ] ) ([ ] [ ] ) Kow M X o,e o,e M X w,e w,e

+ − + + − + = + M + M

, measured as the ratio of the 

concentrations of undissociated and dissociated in the two phases at equilibrium can be used:

( ). 

where [M+] is the cation concentration and [M+X-] is the undissociated ion pair concentration with the 

subscript o,e designating in the octanol-phase at equilibrium and the w,e subscript designating in the 

water-phase at equilibrium.

For ILs, the partitioning coefficient has been observed to be dependent on the initial concentration. The 

relationship of initial concentration to Kow should be determined over an environmentally relevant range. 

A protocol for measuring the ion pair and cation at equilibrium in the two phases and determination of the 

Kow over an environmentally relevant range is required to be submitted before conduct of the study. To 

facilitate the development of a protocol for Kow determination, the following recently published paper can 

be used as guidance: Sang Hyun Lee and Sun Bok Lee: 2009, J Chem Technol Biotechnol, 84: 202-207. 
Page 23 of 32

Practical Utility of the Data

1. How will the data be used?

The data from this study will be used to assess the potential for adverse effects to aquatic and terrestrial 

organisms from uptake and exposure through the aquatic food web. These effects include screening the 

bioaccumulative tendency of this chemical in aquatic organisms, and transfer to other organisms of the 

aquatic food web. Where a potential of concern is identified the Kow is used to model concentrations in

trophic levels of an aquatic food chain. EECs for a given trophic level are used to assess adverse effects 

to organisms feeding at that trophic level.

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

If Kow from this study is > 1000, or log Kow is 3.2, then a full bioaccumulation fish study will be required 

to ascertain if bioaccumulation is persistent, that is, if depuration does not take place in 14 days after 

ingestion, the a label restriction for its sues around aquatic systems will be imposed. In the absence of 

this data, the Agency will assume that TTPC is bioaccumulative and will impose use restrictions for the 

aquatic medium.
Page 24 of 32

Appendix B: Ecological Study Justifications

Study Title: Fish Early-life Stage Toxicity Test (freshwater species)

Guideline Number: 850.1400

Test Substance: Pure active ingredient

Rationale for Requiring the Data

No fish early-life stage toxicity test for TTPC has been submitted. The fish early-life stage toxicity test 

provides the lethal and sublethal effects of a test substance on fish species. The study is necessary for 

TTPC because the pesticide use patterns and environmental fate characteristics are expected to result in 

repeated exposure of freshwater organisms and TTPC is expected to be persistent in the environment. 

Without these data, the Agency is unable to evaluate the potential risks to freshwater fish and aquaticphase amphibians (for which fish serve as surrogates) associated with chronic exposure to TTPC. 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 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 TTPC. The data will reduce uncertainties associated 

with potential 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 decision-making?

In the absence of data, chronic risks would be presumed to freshwater fish/amphibians under chronic 

exposure conditions. The 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 withdrawl of uses for TTPC which may otherwise be 

avoided, or which are unnecessarily severe.

Study Title: Aquatic Invertebrate Life-Cycle (freshwater species)

Guideline Number: 850.1300

Test Substance: Pure active ingredient

Rationale for Requiring the Data

No chronic life cycle toxicity test for a freshwater invertebrate species has been submitted for TTPC. Uses

of TTPC in industrial process and water systems and discharges from oil and gas well development are 

expected to lead to chronic exposure of aquatic organisms due to the repeated release and transport of 

TTPC from use sites into aquatic ecosystems, and the persistence of TTPC. The data base for ILs is limited 

and insufficient to provide a sound acute-to-chronic ratio for estimating a chronic freshwater invertebrate 

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

invertebrates associated with chronic exposure to TTPC. The Agency would have to presume chronic risk 

to listed and non-listed freshwater invertebrates, but would not be able to quantify the risk.
Page 25 of 32

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 freshwater 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 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 

conditions. The 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 withdrawl of uses for TTPC 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: Pure active ingredient

Rationale for Requiring the Data

No acute study for TTPC with an estuarine/marine fish has been submitted. Acute tests using an 

estuarine/marine species are required because the active ingredient is expected to reach estuarine/marine 

environments based on it’s use patterns and fate, and because physiological differences which allow fish 

to live in an estuarine/marine environments may result in this group being more sensitive than freshwater 

species. Without these data, the Agency is unable to evaluate the potential risks to estuarine/marine fish 

associated with acute exposure to TTPC. The data base for ILs is limited and insufficient to provide a 

sound estimate of sensitivity of estuarine/marine species as compared to freshwater species. Without 

these data, the Agency is unable to evaluate the potential acute risks to estuarine/marine fish associated 

with acute exposure to TTPC. The Agency would have to presume acute risk to listed and non-listed 

estuarine/marine fish, but would not be able to quantify the risk.

Practical Utility of the Data

1. How will the data be used?

The estuarine/marine fish acute study would allow the Agency to analyze acute lethal effects to 

estuarine/marine fish from acute exposures due to TTPC use. The effects data would be used to 

determine the likelihood that the acute risks can potentially impact aquatic communities, 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?

In the absence of data, acute risks to marine/estuarine fish would be presumed or potentially as there are 

acute toxicity for a freshwater fish, applying a safety factor to account for the potential increased 

sensitivity of estuarine/marine species as compared to freshwater species. Because the data base for ILs 

is limited and insufficient to provide a sound estimate of sensitivity of estuarine/marine species as 

compared to freshwater species, an approach such as applying the greatest difference found for any test 

substance as a factor would be considered. The 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 withdrawl of uses for TTPC

which may otherwise be avoided, or which are unnecessarily severe.
Page 26 of 32

Study Title: Estuarine/marine invertebrate acute toxicity test (one crustacean species (mysid) and 

one mollusc (shell deposition or embryo-larval))

Guideline Number: 850.1035 for mysid; 850.1025 or 850.1055, respectively, for mollusc

Test Substance: Pure active ingredient

Rationale for Requiring the Data

Crustacean (mysid) and mollusc (shell deposition or embryo-larval) are representative species used to 

evaluate effects for all estuarine/marine invertebrates. No acute study for TTPC with an estuarine/marine 

crustacean species or with a mollusc species has been submitted. An acute test using an estuarine/marine 

crustacean species and an acute test using a mollusc species are required because the active ingredient is 

expected to reach estuarine/marine environments based on it’s use patterns and fate, and because 

physiological differences which allow estuarine/marine invertebrates to live in an estuarine/marine 

environments may result in this group being more sensitive than freshwater species. Without these data, 

the Agency is unable to evaluate the potential risks to estuarine/marine invertebrates associated with 

acute exposure to TTPC. The data base for ILs is limited and insufficient to provide a sound estimate of 

sensitivity of estuarine/marine species as compared to freshwater species. Without these data, the 

Agency is unable to evaluate the potential acute risks to estuarine/marine invertebrates associated with 

acute exposure to TTPC. The Agency would have to presume acute risk to listed and non-listed 

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

Practical Utility of the Data

1. How will the data be used?

The estuarine/marine invertebrate acute studies would allow the Agency to analyze acute lethal effects to 

estuarine/marine invertebrates from acute exposures due to TTPC use. The effects data would be used to 

determine 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 data, acute risks to marine/estuarine invertebrates would be presumed or potentially as 

there are acute toxicity for a freshwater invertebrate, applying a safety factor to account for the potential 

increased sensitivity of estuarine/marine species as compared to freshwater species. Because the data 

base for ILs is limited and insufficient to provide a sound estimate of sensitivity of estuarine/marine 

species as compared to freshwater species, an approach such as applying the greatest difference found for 

any test substance as a factor would be considered. The 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 withdrawl of uses for 

TTPC which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Aquatic Invertebrate Life-Cycle (estuarine/marine species)

Guideline Number: 850.1350

Test Substance: Pure active ingredient

Rationale for Requiring the Data

No chronic life cycle toxicity test for an estuarine/marine invertebrate species has been submitted for 

TTPC. Uses of TTPC in industrial process and water systems and discharges from oil and gas well 
Page 27 of 32

development are expected to lead to chronic exposure of estuarine/marine organisms due to the repeated 

release and transport of TTPC from use sites into aquatic ecosystems, and the persistence of TTPC. The 

data base for ILs is limited and insufficient to provide a sound acute-to-chronic ratio for estimating a 

chronic estuarine/marine invertebrate NOAEC. While a freshwater invertebrate life cycle and a freshwater 

fish early life stage test is being requested, and for which acute-to-chronic ratios can be derived, there can 

be differences between freshwater and estuarine/marine species which give rise to significantly different 

acute-to-chronic ratios. Without the estuarine/marine life-cycle data, the Agency is unable to evaluate the 

potential risks to estuarine/marine invertebrates associated with chronic exposure to TTPC. The Agency 

would have to presume chronic risk to listed and non-listed estuarine/marine invertebrates, but would not 

be able to quantify the risk.

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 preying 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. The 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 withdrawl of uses for TTPC which may otherwise be 

avoided, or which are unnecessarily severe.

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: Pure active ingredient

Rationale for Requiring the Data

No nonvascular aquatic plant toxicity data has been submitted for TTPC. A battery of four species, 

representing different morphological characteristics and environmental habitats are required for use 

patterns resulting in emissions to surface waters. Uses of TTPC in industrial process and water systems 

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 TTPC from use sites into aquatic ecosystems, and the 

persistence of TTPC. For TTPC, there is evidence in the open literature that effects to algal species may

occur at or below levels resulting on impacts to microbes. Without these data, the Agency is unable to 

evaluate the potential risks to non-vascular aquatic plants associated with exposure to TTPC. The Agency 

would have to presume risk to federally listed and non-listed non-vascular plants, but would not be able to 

quantify the risk.

Practical Utility of the Data
Page 28 of 32

1. How will the data be used?

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 TTPC with primary productivity 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 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?

Because this is the only member of the quaternary phosphonium class of antimicrobials currently 

registered in the U.S., there is no possibility of using submitted toxicity data from closely-related 

surrogate chemicals to fill in potential data gaps. Therefore, until additional data become available, risks 

to aquatic non-vascular plants (both Federally-listed and non-listed species) will be assumed in future 

TTPC risk assessments. The 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 withdrawl 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: 850.4400

Test Substance: Pure active ingredient

Rationale for Requiring the Data

No non-rooted vascular aquatic plant toxicity data has been submitted for TTPC. Uses of TTPC in 

industrial process and water systems 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 TTPC from use sites

into aquatic ecosystems, and the persistence of TTPC. Without these data, the Agency is unable to 

evaluate the potential risks to non-rooted vascular aquatic plants associated with exposure to TTPC. 

Practical Utility of the Data

1. How will the data be used?

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 structure 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 TTPC 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 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?

Because this is the only member of the quaternary phosphonium class of antimicrobials currently 

registered in the U.S., there is no possibility of using submitted toxicity data from closely-related 

surrogate chemicals to fill in potential data gaps. Therefore, until additional data become available, risks 

to non-rooted vascular plants (both Federally-listed and non-listed species) will be assumed in future 

TTPC risk assessments. The 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 withdrawl of uses for TTPC which may otherwise be 

avoided, or which are unnecessarily severe.
Page 29 of 32

Study Title: Seedling emergence and growth, rooted emergent vascular species (Rice, Oryza 

sativa), Tier II

Guideline Number: 850.4100

Test Substance: Pure active ingredient

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 has been submitted

for TTPC. Sediment can be a major sink or reservoir for TTPC and its major degradates, sorbing onto 

organic and inorganic particles in water and depositing with them in sedimentary areas such as lakes, and 

freshwater and saltwater marshes. Uses of TTPC in industrial process and water systems and discharges 

from oil and gas well development are expected to lead to exposure of wetland plants due to 

transportation, and deposition of TTPC sorbed onto particles in the waste stream from use sites, and the 

persistence of TTPC. Without this data, the Agency is unable to evaluate the potential risks to rooted 

vascular emergent plants associated with exposure to TTPC in soil or sediment. In the study, a minimum 

of four replicates are necessary to allow a nonparameteric 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?

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 the 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 TTPC 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 data impact the Agency's future decision-making?

Because this is the only member of the quaternary phosphonium class of antimicrobials currently 

registered in the U.S., there is no possibility of using submitted toxicity data from closely-related 

surrogate chemicals to fill in potential data gaps. Therefore, until additional data become available, risks 

to emergent vascular plants (both Federally-listed and non-listed species) will be assumed in future TTPC

risk assessments. The 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 withdrawl of uses for TTPC which may otherwise be 

avoided, or which are unnecessarily severe.

Study Title: Test Method: 100.5 Life-cycle Test for Measuring the Effects of Sediment-associated 

Contaminants on Chironomus dilutus (formerly known as C. tentans) 

Guideline Number: Agency-wide guideline USEPA 2000b; Non-850 guideline, Special Study

Exposure Method: Spiked whole sediment

Test Substance: Pure active ingredient

Rationale for Requiring the Data

No chronic spiked-sediment toxicity test for a freshwater benthic emergent insect has been submitted for 

TTPC. Use of TTPC in industrial processes and water systems and oil and gas well production systems 

may result in the active ingredient reaching aquatic sediments. Sediment benthos may be exposed to 
Page 30 of 32

sediment associated chemicals via pathways not accounted for in water only studies, such as ingestion of 

sediment. Chemicals that partition to sediment and are persistent in the sediment have the potential to 

pose a chronic risk to sediment benthos. TTPC is assumed to partition to sediment and be persistent 

given the following:

o The half-life of TTPC in aerobic and anaerobic soils is expected to be greater than 10 days based 

on half-life of other ILs; and 

o The organic carbon partitioning coefficient, Koc, of the hydrophilic portion of TTPC is expected 

to be >1000.

For freshwater sediment studies, chronic tests on a benthic emergent insect (Chironomus dilutes, formerly 

Chironomus tentans) and an amphipod (Hyalella azteca) are requested. Although both are freshwater 

species, Hyalella and Chironomus differ substantially in their ecological niche (i.e., infaunal species 

versus epibenthic), physiology, and potential sensitivities to TTPC exposure. Prior to conduct of the 

study, the test design and protocol must be submitted for Agency review and approval. If the half-life is 

found to be <10 days in both aerobic and anaerobic aquatic sediment metabolism studies a 10-day 

survival and growth study for this species using public draft 850.1735 Whole Sediment Acute Toxicity 

Invertebrates, Freshwater. Prior to conduct of the study, the test design and protocol must be submitted 

for Agency review and approval as the there are changes in recommended testing guidance from that 

provided in the public draft.

Practical Utility of the Data

1. How will the data be used? 

Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms 

associated with uses of TTPC. Data from sediment toxicity studies will be compared to estimated 

sediment chronic exposure concentrations to evaluate the potential for TTPC to adversely impact survival, 

emergence, reproduction, and growth of sediment invertebrates.

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

If the data indicates that registered TTPC usage may pose a risk of adverse effects to non-target benthic 

organisms above the Agency Level of Concern, the Agency may explore decision options to mitigate this 

risk. The lack of these data will limit the flexibility the Agency and registrants have in coming into 

compliance with the Endangered Species Act, and could result in use restrictions for TTPC which may 

otherwise be avoided, or which are unnecessarily severe.

Study Title: Test Method: 100.4: Hyalella azteca 42-d test for Measuring the Effects of Sediment 

Associated Contaminants on survival, Growth, and Reproduction

Guideline Number: Agency-wide guideline USEPA 2000b; Non-850 guideline, Special Study

Exposure Method: Spiked whole sediment

Test Substance: Pure active ingredient

Rationale for Requiring the Data

No chronic spiked-sediment toxicity test for a freshwater benthic amphipod has been submitted for TTPC. 

Use of TTPC in industrial processes and water systems and oil and gas well production systems may 

result in the active ingredient reaching aquatic sediments. Sediment benthos may be exposed to sediment 

associated chemicals via pathways not accounted for in water only studies, such as ingestion of sediment. 

Chemicals that partition to sediment and are persistent in the sediment have the potential to pose a chronic 

risk to sediment benthos. TTPC is assumed to partition to sediment and be persistent given the following:

o The half-life of TTPC in aerobic and anaerobic soils is expected to be greater than 10 days based 

on half-life of other ILs; and 

o The organic carbon partitioning coefficient, Koc

For freshwater sediment studies, chronic tests on a benthic emergent insect (Chironomus dilutes, formerly 

, of the hydrophilic portion of TTPC is expected 

to be >1000.
Page 31 of 32

Chironomus tentans) and an amphipod (Hyalella azteca) are requested. Although both are freshwater 

species, Hyalella and Chironomus differ substantially in their ecological niche (i.e., infaunal species 

versus epibenthic), physiology, and potential sensitivities to TTPC exposure. Prior to conduct of the 

study, the test design and protocol must be submitted for Agency review and approval. If the half-life is 

found to be <10 days in both aerobic and anaerobic aquatic sediment metabolism studies a 10-day 

survival and growth study for this species using public draft 850.1735 Whole Sediment Acute Toxicity 

Invertebrates, Freshwater. Prior to conduct of the study, the test design and protocol must be submitted 

for Agency review and approval as the there are changes in recommended testing guidance from that 

provided in the public draft.

Practical Utility of the Data

1. How will the data be used? 

Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms 

associated with uses of TTPC. Data from sediment toxicity studies will be compared to estimated 

sediment chronic exposure concentrations to evaluate the potential for TTPC to adversely impact survival, 

emergence, reproduction, and growth of sediment invertebrates.

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

If the data indicates that registered TTPC usage may pose a risk of adverse effects to non-target benthic 

organisms above the Agency Level of Concern, the Agency may explore decision options to mitigate this 

risk. The lack of these data will limit the flexibility the Agency and registrants have in coming into 

compliance with the Endangered Species Act, and could result in use restrictions for TTPC which may 

otherwise be avoided, or which are unnecessarily severe.

Study Title: Methods for Assessing the Chronic Toxicity of Marine and Estuarine SedimentAssociated Contaminants with the Amphipod Leptocheirus plumulosus

Guideline Number: Agency-wide guideline USEPA 2001c; Non-850 guideline, Special Study

Exposure Method: Spiked whole sediment

Test Substance: Pure active ingredient

Rationale for Requiring the Data

No chronic spiked-sediment toxicity test for an estuarine/marine benthic amphipod has been submitted for 

TTPC. Use of TTPC in industrial processes and water systems and oil and gas well production systems 

may result in the active ingredient reaching aquatic estuarine/marine sediments. Sediment benthos may 

be exposed to sediment associated chemicals via pathways not accounted for in water only studies, such 

as ingestion of sediment. Chemicals that partition to sediment and are persistent in the sediment have the 

potential to pose a chronic risk to sediment benthos. TTPC is assumed to partition to sediment and be 

persistent given the following:

o The half-life of TTPC in aerobic and anaerobic soils is expected to be greater than 10 days based 

on half-life of other ILs; and 

o The organic carbon partitioning coefficient, Koc, of the hydrophilic portion of TTPC is expected 

to be >1000.

Prior to conduct of the study, the test design and protocol must be submitted for Agency review and 

approval. If the half-life is found to be <10 days in both aerobic and anaerobic aquatic sediment 

metabolism studies a 10-day survival and growth study for this species using public draft 850.1740

Whole Sediment Acute Toxicity Invertebrates, Freshwater. Prior to conduct of the study, the test design 

and protocol must be submitted for Agency review and approval as the there are changes in recommended 

testing guidance from that provided in the public draft.

Practical Utility of the Data

1. How will the data be used? 

Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms 

associated with uses of TTPC. Data from sediment toxicity studies will be compared to estimated 
Page 32 of 32

sediment chronic exposure concentrations to evaluate the potential for TTPC to adversely impact survival, 

emergence, reproduction, and growth of sediment invertebrates.

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

If the data indicates that registered TTPC usage may pose a risk of adverse effects to non-target benthic 

organisms above the Agency Level of Concern, the Agency may explore decision options to mitigate this 

risk. The lack of these data will limit the flexibility the Agency and registrants have in coming into 

compliance with the Endangered Species Act, and could result in use restrictions for TTPC which may 

otherwise be avoided, or which are unnecessarily severe.