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Homopolymer Registration Review Team

Human Health & Environmental Effects

Siroos Mostaghimi 

Jim Breithaupt 

David Bays

Jonathan Chen 

Nate Mottl 

Katelynn King 

Risk Management

Donna Kamarei

Elizabeth Watkins 

Rose Kyprianou

Office of General Counsel

Philip Ross 
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TERMS, ABBREVIATIONS AND SYMBOLS

AD Antimicrobials Division

A.I. or a.i. active ingredient

ASRI activated sludge respiration inhibition

CAS Chemical Abstracts Service 

CFR Code of Federal Regulations 

CMA Chemical Manufacturers Association

COC concentration-of-concern

EC50 median (or 50 percent) effect concentration

ECOTOX ECOTOXicology

EDSP Endocrine Disruptor Screening Program 

E-FAST Exposure and Fate Assessment Screening Tool

EPA Environmental Protection Agency 

FDA Food and Drug Administration 

FFDCA Federal Food, Drug, and Cosmetic Act

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FQPA Food Quality Protection Act 

HPV high production volume

IDS Incident Data System 

Kow octanol-water partition coefficient

LC50 median (or 50 percent) lethal concentration

LD50 median (or 50 percent) lethal dose

Log Kow logarithm of the octanol-water partition coefficient

μg microgram

mg/kg milligram per kilogram

mg/L milligram per liter

mm Hg millimeter of mercury

MRID Master Record Identification Number

MRL maximum residue limit 

N/A not applicable 

nm nanometers

NOAEC no-observed-adverse-effect-concentration

OCSPP Office of Chemical Safety and Pollution Prevention

OPP Office of Pesticide Programs

% percent

PC Code Pesticide Chemical Code

pKa power of the acid dissociation constant or negative base-10 logarithm of the acid 

dissociation constant of a solution

ppb parts per billion 

ppm parts per million

PWP Preliminary Work Plan

RED Reregistration Eligibility Decision

SSTS Section Seven Tracking System

TGAI technical grade active ingredient

TMDL total maximum daily loads

UV/VIS ultraviolet/visible light absorption

WWTPs wastewater treatment plants
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Table of Contents

1 Introduction............................................................................................................................. 6

1.1 Statutory and Regulatory Authority ................................................................................. 6

1.2 Case Overview ................................................................................................................. 7

1.3 Chemical Identification and Properties............................................................................ 7

1.4 Use/Usage Description..................................................................................................... 9

1.4.1 Registrations ............................................................................................................. 9

1.4.2 Summary of Registered Uses.................................................................................... 9

1.4.3 Usage Information .................................................................................................... 9

1.5 Regulatory History ........................................................................................................... 9

1.5.1 Recent/Pending Regulatory Actions....................................................................... 10

1.5.2 Tolerance Information ............................................................................................ 10

1.6 Incidents......................................................................................................................... 10

1.6.1 Human Health ......................................................................................................... 10

1.6.2 Ecological ............................................................................................................... 10

2 Anticipated Data Needs ........................................................................................................ 10

3 Human Health Risk Assessment........................................................................................... 10

3.1 Existing Toxicological Endpoints.................................................................................. 10

3.2 Dietary Exposure............................................................................................................ 11

3.2.1 Food and Drinking Water ....................................................................................... 11

3.3 Occupational and Residential Exposures....................................................................... 11

3.4 Aggregate and Cumulative Exposure............................................................................. 11

3.4.1 Aggregate Exposures.............................................................................................. 11

3.4.2 Cumulative Exposures............................................................................................ 11

4 Environmental Risk Assessment........................................................................................... 12

4.1 Threatened and Endangered Species.............................................................................. 12

4.2 Environmental Fate Assessment .................................................................................... 13

4.2.1 Water Quality.......................................................................................................... 13

4.3 Conceptual Models for Environmental Exposure Pathways.......................................... 13

4.4 Ecological Effects Assessment....................................................................................... 13

4.4.1 Measures of Effect (Ecotoxicology Endpoints)...................................................... 13

4.5 Exposure Analysis Plan.................................................................................................. 14

4.5.1 Aquatic and Terrestrial Wildlife Exposure Estimates ............................................ 14

4.5.2 Screening Level Down-the-Drain Analysis............................................................ 14

5 Endocrine Disruptor Screening Program (EDSP)................................................................. 14

6 Optional Label Changes........................................................................................................ 15

7 Combined Preliminary Work Plan and Proposed Interim Registration Review Decision ... 15

8 Next Steps............................................................................................................................. 15

9 References............................................................................................................................. 16

Appendix A Toxicology Profile............................................................................................... 17

Appendix B Environmental Fate ............................................................................................. 20

Appendix C Ecotoxicology Profile.......................................................................................... 21
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List of Tables

Table 1 – Summary of Anticipated Risk Assessments and Data Needs for Registration Review: 

Homopolymer ................................................................................................................................. 7

Table 2 – Anticipated Registration Review Schedule .................................................................... 7

Table 3 – Chemical Identification of Homopolymer...................................................................... 8

Table 4 – Physical-Chemical and Environmental Fate Properties for Homopolymer.................... 8

Table 5 – Homopolymer Registered Use........................................................................................ 9

Table 6 – Acute Toxicity Studies for Homopolymer.................................................................... 17

Table 7 – Freshwater Fish and Amphibian Toxicity Data............................................................ 21

Table 8 – Freshwater Invertebrate Toxicity Data ......................................................................... 21
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1 Introduction

This document is the Environmental Protection Agency’s (EPA or “the agency”) combined 

Preliminary Work Plan (PWP) and Proposed Interim Registration Review Decision for 2-

Propen-1-aminium, N,N-dimethyl-N-2-propenyl-, chloride, homopolymer herein referred to as 

homopolymer, and is being issued pursuant to 40 CFR Sections 155.50, 155.56 and 155.58. This 

document explains what EPA’s Office of Pesticide Programs knows about homopolymer, noting 

that no additional data nor further assessments are required, and provides an anticipated timeline 

for completing homopolymer’s review. It also includes the agency’s Proposed Interim 

Registration Review Decision for homopolymer. 

A registration review decision is the agency's determination whether a pesticide meets, or does 

not meet, the standard for registration in the Federal Insecticide, Fungicide, and Rodenticide Act 

(FIFRA). The agency may issue, when it determines it to be appropriate, a proposed interim 

registration review decision before completing a registration review. Among other things, the 

proposed interim registration review decision may require new risk mitigation measures, impose 

interim risk mitigation measures, identify data or information required to complete the review, 

and include schedules for submitting the required data, conducting the new risk assessment and 

completing the registration review. 

1.1 Statutory and Regulatory Authority

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All 

pesticides distributed or sold in the United States generally must be registered by the USEPA 

based on scientific data showing that they will not cause unreasonable risks to human health or 

the environment when used as directed on product labeling. The registration review program is 

intended to make sure that, as the ability to assess risk evolves and as policies and practices 

change, all registered pesticides continue to meet the statutory standard of no unreasonable 

adverse effects to human health or the environment. Changes in science, public policy, and 

pesticide use practices will occur over time. Through the registration review program, the agency

periodically reevaluates pesticides to make sure that as change occurs, products in the 

marketplace can be used safely. Information on this program is provided at 

http://www2.epa.gov/pesticide-reevaluation.

The agency is implementing the registration review program pursuant to Section 3(g) of FIFRA

and will review each registered pesticide every 15 years to determine whether it continues to 

meet the FIFRA standard for registration. The regulations governing registration review begin at 

40 CFR 155.40. The agency will consider benefits information and data as required by FIFRA. 

The public phase of registration review begins when the initial docket is opened for each case. 

The docket is the agency’s opportunity to state what it knows about the pesticide and what 

additional risk analyses and data or information it believes are needed to make a registration 

review decision. 
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1.2 Case Overview

The docket for homopolymer (case # 5024) has been established at http://www.regulations.gov

in docket number EPA-HQ-OPP-2015-0255. Documents associated with this registration review 

can be viewed in this docket. Tables 1-2 below summarize the issues relevant to this registration 

review case and the anticipated registration review schedule.

Table 1 – Summary of Anticipated Risk Assessments and Data Needs for Registration 

Review: Homopolymer

Risk Assessment 

Assessment 

Necessary to 

Support 

Registration 

Review

Date of 

Most 

Recent 

Assessment

Type of 

Assessment 

Required 

(New/Updated)

Data Anticipated as Needed

Dietary (food/ drinking 

water ) No N/A None None

Occupational & 

Residential Handler/Post 

Application

No N/A None None

Aggregate No N/A None None

Cumulative No N/A None None

Tolerance Review No N/A None None

Ecological No N/A None None

N/A = Not applicable

Table 2 – Anticipated Registration Review Schedule

Anticipated Activity Target 

Date*

Completion 

Date

Combined Preliminary Work Plan and Interim Registration Review Decision and Implementation 

Open 60-Day Public Comment Period for Combined Preliminary Work Plan and 

Proposed Interim Decision

2015-06 2015-06

Close Public Comment Period 2015-08

Issue Interim Decision 2015-12

Begin Post-Decision Followup 2016

Total (years) 1

*The anticipated schedule will be revised as necessary (e.g., need arising under the Endocrine Disruptor Screening Program with 

respect to the active ingredients in this case).

1.3 Chemical Identification and Properties

Table 3 presents the active ingredient to be assessed in case 5024: homopolymer (PC Code 

128727). The active ingredient has one registered product with the active ingredient composing 

19.8 % (w/w).
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Table 3 – Chemical Identification of Homopolymer

Chemical Name Homopolymer Reference (MRID unless specified)

Comments

Chemical Classification Polymeric quaternary ammonium PAN1

PC Code 128727 None

CAS Number 26062-79-3 (polymer)

7398-69-8 (monomer) PAN

Molecular Formula Polymer: Not applicable

Monomer: C8H16CN None

Molecular Weight (grams/mole) 200,000 (average, polymer)

161.68 (monomer)

Sigma Aldrich (polymer)

Epi-Web 4.1 (monomer)

Molecular Structure

Hess et al., 2003

The homopolymer physical chemistry information is summarized in Table 4. The details of the 

environmental fate information are discussed in Appendix B.

Table 4 – Physical-Chemical and Environmental Fate Properties for Homopolymer

Guideline 

No. Parameter

Homopolymer (EPA Reg. No. 1706-226):

Poly (dimethyldially) ammonium 

chloride

Reference (MRID unless specified)

830.7050 UV/Visible Absorption Stable to sunlight (no conjugation in 

structure) Lyman et al., 1990

830.7370 Dissociation constant 

(pKa)

Not applicable No ionizable functional groups

830.7550

Octanol-water partition 

coefficient at 25 oC (Log 

Kow)

Not applicable (substance is miscible in 

water) 42618401

830.7840 Solubility in water Miscible (10,000 mg/l used in calculations) 42618401

830.7950 Vapor pressure (mmHg) Polymer: None (up to 230 o

C)

Monomer: 15 mm Hg 42618401

None

Henry’s law constant at 

25 oC (atm-m3/mol)

CALCULATED

Polymer: Not applicable (polymer has 

wide range of molecular weights)

Monomer: 3.2 x 10-4

None

atm-m3/mol = atmosphere cubic meter per mole; oC = degrees Celsius; mg/L = milligrams per liter; mmHg = 

millimeters of mercury.

 1 http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35969
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1.4 Use/Usage Description

1.4.1 Registrations

There is one EPA-registered product containing homopolymer as an active ingredient (a.i.).

2 It 

contains 19.8 percent homopolymer in a liquid soluble concentrate formulation.

1.4.2 Summary of Registered Uses

Table 5 presents the registered use of homopolymer as mollusk control (e.g. Zebra mussels) in 

potable water supplies. The product is added to water systems as a concentrated liquid using 

metered pumps. The label states that applications should occur at a point sufficiently inside the 

intake pipe to prevent any release of product into the intake source (5-10 feet). Feed exits must 

be equipped with a pressure check valve at the feed line exit to seal the feed line when the intake 

flow stops. Feed pumps must be designed to shut down when intake pumps stop. Planned 

shutdowns require feed pumps to be stopped half an hour prior to shut down. 

Table 5 – Homopolymer Registered Use

Use Application Method Application Rate

(ppm a.i.)

Industrial Process and Water Systems

Water supplies Metered Pump 25-50

1.4.3 Usage Information

In addition to its use as a pesticide, homopolymer is used as a flocculant in drinking water 

treatment. Based on information provided by the registrant, the pesticidal use of homopolymer is 

minor when compared to the non-pesticidal use. According to the 2004 high production volume 

test plan, homopolymer has been manufactured for at least 40 years in the United States with 

three current manufacturing facilities. The monomer is used almost exclusively in the 

manufacturing of cationic, water-soluble polymers which are used in such industries as water 

treatment plants, paper mills, and textile printing. Using Best Available Technology (BAT) to 

achieve maximum efficacy, the maximum free monomer content of the polymeric products is 

about 1 percent.

3

 

1.5 Regulatory History

The first product containing homopolymer was registered on October 6, 1995 for the use in 

industrial process and water systems. A Reregistration Eligibility Decision (RED) was not 

completed for homopolymer because it was registered after November 1, 1984. 

 2 Veligon TL-M, EPA Reg. No. 1706-226 3 Regnet Environmental Services, 
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1.5.1 Recent/Pending Regulatory Actions

There are no recent regulatory actions for homopolymer.

1.5.2 Tolerance Information

There are no EPA-established tolerances in raw agricultural commodities or processed food and 

feed products for homopolymer under the Federal Food, Drug and Cosmetic Act (FFDCA) 

Sections 408. Additionally, the Federal Food and Drug Administration (FDA) has not established 

any clearances under FFDCA 409. However, Food Contact Notifications (FCNs) have been 

established for homopolymer as part of various polymers. Since these uses are not FIFRAregistered, no dietary exposure assessment is required.

1.6 Incidents

1.6.1 Human Health 

No homopolymer related incidents have been reported in the agency’s Incident Data System 

(IDS) for the time period from 1992 to present, based on a search conducted on March 2015. IDS 

contains reports of incidents from various sources, including registrants, other federal and state 

health and environmental agencies and individual consumers, submitted to OPP since 1992.

1.6.2 Ecological

No homopolymer incidents have been reported in the agency’s Ecological Incident Information 

System (EISS) for the time period spanning 2000 to 2015 based on a search conducted on April 

15, 2015.

2 Anticipated Data Needs

The agency does not anticipate requiring any additional data to support this registration review.

3 Human Health Risk Assessment

With the existing toxicology database, homopolymer appears to have low toxicity (Appendix A). 

The use of homopolymer as a water treatment for control of mollusks in water supplies is not 

expected to pose a hazard to food or drinking water based on the lack of exposure. The 

application system is closed and there is no expected occupational exposure. The agency does 

not anticipate the need to conduct a human health risk assessment for homopolymer.

3.1 Existing Toxicological Endpoints

No toxicological endpoints have been selected for homopolymer.
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3.2 Dietary Exposure

The agency does not anticipate the need to conduct a dietary exposure assessment to support this 

registration review. 

3.2.1 Food and Drinking Water 

A dietary (food and drinking water) exposure assessment is not anticipated to be required for 

homopolymer at this time. The only FIFRA-registered use of homopolymer is as a water 

treatment for the control of mollusks in water supplies. There is only one label use for this 

product, and this use is not expected to result in direct or indirect dietary (food) exposure. The 

use of homopolymer as a water treatment for the control of mollusks in water supplies is not 

expected to result in exposure from groundwater or surface waters; therefore, a drinking water 

assessment is not required at this time.

3.3 Occupational and Residential Exposures

In April of 2015, the registrant amended its label to restrict application to closed metered 

delivery systems; open pouring is prohibited for water treatment. Occupational handler 

exposures are not expected due to closed mixing/loading. Dermal and inhalation post-application 

exposures for the water treatment uses are expected to result in limited exposure contact. No 

additional occupational exposure data or occupational risk assessments are anticipated to be 

required. No residential exposure is expected since applications are only performed in 

occupational settings.

3.4 Aggregate and Cumulative Exposure

3.4.1 Aggregate Exposures 

An aggregate exposure risk assessment will not be conducted for this chemical because of a lack 

of residential exposure due to its use pattern of only being applied in industrial pipes with 

restrictions for controlling backflow into surface water.

3.4.2 Cumulative Exposures 

With respect to cumulative exposure, unlike other pesticides for which EPA has followed a 

cumulative risk approach based on a common mechanism of toxicity, EPA has not made a 

common mechanism of toxicity finding as to homopolymer and any other substances, and 

homopolymer does not appear to produce a toxic metabolite produced by other substances. For 

the purposes of this registration review, therefore, EPA has not assumed that homopolymer has a 

common mechanism of toxicity with other substances. For information regarding EPA’s efforts 

to determine which chemicals have a common mechanism of toxicity and to evaluate the 

cumulative effects of such chemicals, see http://www.epa.gov/pesticides/cumulative/.
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4 Environmental Risk Assessment

The agency has not previously conducted a risk assessment that supports a complete endangered 

species determination for homopolymer. The label states that application to intake water should 

be made 5-10 feet away from the source water intake source to prevent contamination. Based on 

the use in potable water supply systems, the potential pathways of exposure to aquatic organisms 

include transport from in-service use to surface water by way of wastewater treatment plants 

(WWTPs) and any backflow from treated intake water. However, label restrictions prevent 

backflow into surface water, and the environmental fate data indicate strong sorption to 

sediment. Additionally, the pesticidal use of homopolymer is minor when compared to the nonpesticidal use. 

Based on the chemical, physical, and environmental fate properties, homopolymer is miscible in 

water, non-volatile, and stable to hydrolysis and photodegradation. Environmental fate data are 

not anticipated to be required (Table 4 and Appendix B). The acceptable ASRI study (MRID 

49437513) demonstrated an IC50 of 127 mg/L (>20 mg/L) indicating negligible effects on 

WWTP organisms.

4 While data on sorption to soil and sediment (835.1230) have not been 

submitted, the agency considers drinking water exposure to be negligible because, as a 

quaternary ammonium polymer, homopolymer will attach to suspended sediments and organic 

matter and will be removed by flocculation and coagulation of suspended particles in source 

water. Flocculants work by reducing or neutralizing negative charges on suspended particles, 

allowing them to associate and settle in the treatment process.5 If any particles with sorbed 

homopolymer are redeposited into surface water, homopolymer is not expected to desorb and 

enter the water column. The agency does not intend to conduct an environmental risk assessment 

because label restrictions prevent backflow into surface water. 

4.1 Threatened and Endangered Species

There is no reasonable expectation for the registered use of homopolymer to cause direct or 

indirect adverse effects to threatened and endangered species. No adverse modification of any 

designated critical habitat for such species is expected from the use of homopolymer. Exposure 

of terrestrial species is unlikely, because label restrictions prevent backflow into surface water, 

and the environmental fate data indicate strong sorption to sediment. Additionally, the pesticidal 

use of homopolymer is minor when compared to the non-pesticidal use. EPA has made a “no 

effect” determination under the Endangered Species Act (ESA) for all listed species and 

designated critical habitat for such species and has therefore concluded that consultation with the 

Fish and Wildlife Service and the National Marine Fisheries Service under ESA section 7(a)(2) 

is not required.

 4 Breithaupt, James; D427116, Reviewed and accepted on May 5, 2015

5 CIBA, http://www.siltstop.com/pdf/flocculation-theory_application.pdf
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4.2 Environmental Fate Assessment

Based on the chemical, physical, and environmental fate properties, homopolymer is miscible in 

water, non-volatile, and stable to hydrolysis and photodegradation (Table 4 and Appendix B). 

Additional environmental fate data are not anticipated to be required because backflow into 

surface water is not expected to occur based on the use directions specified on the label. 

4.2.1 Water Quality

Homopolymer is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act.

6 In addition, no Total Maximum Daily Loads 

(TMDL) have been developed for homopolymer.

7 More information on impaired water bodies 

and TMDLs can be found at EPA’s website.

8

4.3 Conceptual Models for Environmental Exposure Pathways

The only environmental exposure pathway for the pesticidal use of homopolymer is one of 

potential backflow into the surface water used as source water. As a mitigation measure, the 

labels state that application to intake water should be made 5-10 feet away from the source water 

intake source to prevent contamination. As a result, the agency does not assume that 

environmental exposure will occur and therefore is not including conceptual models for 

exposure. 

4.4 Ecological Effects Assessment

An ecological effects risk assessment will not be conducted for this chemical because of a lack of 

exposure to non-target organisms due to its restricted use pattern of only being applied in 

industrial pipes with restrictions for controlling backflow into surface water. 

4.4.1 Measures of Effect (Ecotoxicology Endpoints)

Ecotoxicity endpoint data are used as measures of effects to aquatic and terrestrial organisms. 

Selected endpoints will not be necessary for this chemical because an environmental risk 

assessment is not anticipated to be necessary. There were six ecotoxicity studies submitted to the 

agency as a condition of registration for two chemicals containing homopolymer as an active 

ingredient. These studies are outlined in Appendix C.

 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

8 http://www.epa.gov/owow/tmdl/
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4.5 Exposure Analysis Plan

4.5.1 Aquatic and Terrestrial Wildlife Exposure Estimates

The agency does not anticipate the need to conduct an ecological risk assessment, because of 

negligible environmental exposure based on the label language to prevent backflow from intake 

pipes and the strong tendency of homopolymer to sorb to negatively-charged particles in intake 

water. 

4.5.2 Screening Level Down-the-Drain Analysis

The Down-the-Drain (DtD) module of E-FAST (Exposure and Fate Assessment Screening Tool) 

was not used to assess homopolymer since the compound is a strong floculant which would be 

removed prior to a wastewater treatment plant. 

5 Endocrine Disruptor Screening Program (EDSP)

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 

chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of its most recent registration decision, for homopolymer, EPA 

reviewed these data and selected the most sensitive endpoints for relevant risk assessment 

scenarios from the existing hazard database. However, as required by FFDCA section 408(p), 

homopolymer is subject to the endocrine screening part of the Endocrine Disruptor Screening 

Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. A second list of chemicals 
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Page 15 of 22

identified for EDSP screening was published on June 14, 20139 and includes some pesticides 

scheduled for registration review and chemicals found in water. Neither of these lists should be 

construed as a list of known or likely endocrine disruptors. For further information on the status 

of the EDSP, the policies and procedures, the lists of chemicals, future lists, the test guidelines 

and the Tier 1 screening battery, please visit our website.10

6 Optional Label Changes

The agency invites comment on any label amendments that could be considered to improve label 

clarity.

7 Combined Preliminary Work Plan and Proposed Interim 

Registration Review Decision

In accordance with 40 CFR Sections 1550.50, 155.56 and 155.58, the agency is issuing this 

combined Preliminary Work Plan and Proposed Interim Registration Review Decision. Based on 

the assumption of no exposure to humans and non-target organisms, no additional data are 

anticipated to be needed and no risk assessments are planned. The agency has made a “no effect” 

finding based on lack of potential exposure for endangered species (see Section 4). Except for 

the EDSP component of the homopolymer registration review case, the agency has made the 

proposed decision that no additional data and no further risk assessments are required.

8 Next Steps

A Federal Register Notice will announce the availability of this combined Preliminary Work 

Plan and Proposed Interim Registration Review Decision for homopolymer and allow a 60-day 

comment period. If there are no significant comments or additional information submitted to the 

docket during the comment period that leads the agency to change its proposed decision, EPA 

may issue an interim decision. The final decision on the registration review for homopolymer 

(case 5024) will occur after an EDSP FFDCA section 408(p) determination is made. See the 

estimated timeline for the completion of homopolymer registration review in Table 2.

 9 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals. 10 http://www.epa.gov/endo/
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9 References 

Breithaupt, James. May 5, 2015. Review of Modified Activated Sludge Respiration Inhibition 

Study (OCSPP 850.3300) for Homopolymer. MRID 49437513, D427116

Ciba (year unknown). Flocculation Theory and Application. 

http://www.siltstop.com/pdf/flocculation-theory_application.pdf

Hess, C.E., Naik, K.N., Paquin, T.J., and Rose, S.J. February 27, 2003. Topcoat compositions, 

substrates containing a topcoat derived therefrom, and methods of preparing the same.

Publication Number: WO2003016045 A1, Application Number: PCT/US2002/026136. 

http://www.google.com/patents/WO2003016045A1?cl=en

MRID 42618401. Oslosky, S. (1992) Product Chemistry: Poly (N,N-dimethyl diallyl 

ammonium chloride): Lab Project Number: DMDAAC. Unpublished study prepared by 

Calgon Corporation. 8 p.

Park, S.H. April, 2008. Effect of Amine-Based Water Treatment Polymers on the Formation of 

N-Nitrosodimethylamine (NDMA) Disinfection By-Product. Georgia Institute of 

Technology. 

https://smartech.gatech.edu/bitstream/handle/1853/22549/park_sanghyuck_200805_phd.

pdf?sequence=1

Pesticide Action Network (PAN). 2014. Diallyl dimethyl ammonium chloride polymers. 

http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35969

Regnet Environmental Services. April 29, 2004. Test Plan for Diallyldimethylammonium 

Chloride (DADMAC): CAS No. 7398-69-8. EPA 201-15208A. 

http://www.epa.gov/chemrtk/pubs/summaries/dialdime/c15208tp.pdf 

Sigma Aldrich Online Catalog. 2014. http://www.sigmaaldrich.com/life-science/life-sciencecatalog.html

U.S. Environmental Protection Agency (EPA). 2002. ECOTOX User Guide: ECOTOXicology 

Database System. Version 3.0. Available: http://www.epa.gov/ecotox/

U.S. Environmental Protection Agency (EPA). 2012. EPI-Suite 4.11. 

http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm

U.S. Environmental Protection Agency. High Production Volume Information System (HPVIS). 

http://www.epa.gov/hpvis/

 
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Appendix A Toxicology Profile

Acute Toxicity for Product Labeling 

As listed in Table 6, homopolymer is a moderate dermal irritant (Category III) and is in Category 

III for acute oral toxicity and Category IV for acute dermal toxicity based on guideline studies. It 

is likely a moderate eye irritant (Category III). However, guideline acute studies are not available 

for acute inhalation acute eye irritation and dermal sensitization. 

Table 6 – Acute Toxicity Studies for Homopolymer

Guideline No./ Study 

Type 

MRID No. Results Toxicity 

Category

870.1100/ 

Acute oral toxicity 42534004 LD50 = 4,100 mg/kg for male and female rat III

870.1200/ 

Acute dermal toxicity 42534005 LD50 ≥ 20,000 mg/kg for male and female rabbit IV

870.1300/ 

Acute inhalation toxicity NA No acceptable Guideline study. This study is considered as a data gap. Unknown

870.2400/ 

Acute eye irritation 42534006 Eye irritation at 24 hours after treatment and clearing in 7 days. III

870.2500/ 

Acute dermal irritation 42534007 Moderate irritation at 72 hours on New Zealand Albino Rabbits III

Note: N/A=Not available

Subchronic Toxicity 

For subchronic oral toxicity, the database includes four studies:

• Roper, J.M. (2009) A 90-day oral (drinking water) toxicity study of 2-Methyl-1,2-

benzisothiazolin-3-one Technical in rats. WIL Research Laboratories, LLC, Ashland, 

OH, USA.WIL-91057, November 9, 2009. MRID 48251534. Unpublished.

• Trautwein and Drommer. (1976). 13 Weeks Oral Toxicity Feeding Study with Monomer 

in Rats. International Bio-Research, Inc. Unpublished.

• Trautwein and Drommer. (1976). 13 Weeks Oral Toxicity Feeding Study with Cat FlocT in Rats. International Bio-Research, Inc. Unpublished.

• Tegeris, A.S. (1976). DADM – Ninety-Day Feeding Study to Dogs. Pharmacopathics 

Research Laboratories, Inc. Laurel, MD. 20810. Sponsored Report No. 76-57. July 2, 

1976. Unpublished.
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Developmental Toxicity 

• Adamik, E. R. (1979). Rabbit Teratology Study with Cat-Floe T. Wil Research 

Laboratories, Inc. Cincinnati, OH 45241. November 29, 1979. MRID 42534016. 

Unpublished.

• Irvine, L.F.H. and Palmer, K. (1990). Poly(Dimethyl Diallyl Ammonium Chloride) 

(PDADMAC) Oral (Gavage) Rat Teratology Study. Toxicol Laboratories Limited. 

Herefordshire, England HR8 lLH . Laboratory Project ID CMA/5/91. November 9, 1991. 

MRID 48437511. Unpublished.

Reproductive Toxicity

• Adamik, E. R. (1979). Multigeneration Study in Rats with Cat-Floe T. Wil Research 

Laboratories, Inc. Cincinnati, OH 45241. Laboratory Project ID WIL-1140-77. 

November 29, 1979. MRID 49437512. Unpublished.

Chronic Toxicity 

There is currently no existing chronic toxicity study for homopolymer. Since there is no chronic 

exposure concern, this is not considered as a data gap.

Carcinogenicity 

There is currently no existing cancer study for homopolymer. Since there are existing 

mutagenicity studies indicating homopolymer is not mutagenic, the absence of a cancer study is 

not considered as a data gap.

Neurotoxicity

There is no neurotoxicity study in the database for homopolymer. 

Mutagenicity 

1. Sun, R.H.C. and Shelton, J.B. (1990). Selmonella/Mammalian-Microsome Plate 

Incorporation Mutagenicity Assay (Amen Test) - Poly (dtaiiyldimethyl ammonium 

chloride). Microbiological Associates, Inc., Rockville, MD 20850. June 21, 1990. 

MRID 42534013. Unpublished. 

2. Putman, D.L. (1990). Micronucleus Cytogenetic Assay in Mice - Poly (dtaiiyldimethyl 

ammonium chloride). Microbiological Associates, Inc., Rockville, MD 20850. June 21, 

1990. MRID 42534014. Unpublished

3. Putman, D.L. (1991). Micronucleus Cytogenctic Assay in Mice. Microbiological 

Associates. Inc. Bethesda, MD 20816. Laboratory Project ID T9143.122. March 27, 

1991. MRID 49437510. Unpublished.
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Dermal Absorption/Penetration

There is no dermal absorption study in the database. However, since homopolymer is applied 

through closed system, there is no occupational exposure. 

Immuntoxicity

There is currently no existing immunotoxicity study for homopolymer. However, since there is 

no exposure concern, immunotoxicity study is not considered as a data gap.

Metabolism

There is no metabolism study available. However, since there is no exposure concern, the 

absence of a metabolism study is not considered as a data gap.
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Appendix B Environmental Fate

Environmental Fate and Transport Properties of Homopolymer

This environmental fate assessment addresses the persistence and mobility of the parent 

compound homopolymer. Based on the chemical, physical, and environmental fate properties, 

homopolymer is miscible in water, non-volatile, and stable to hydrolysis and photodegradation, 

see Table 4. As a flocculant, homopolymer sorbs to organic material, soils and sediment. 

Additional environmental fate data for homopolymer are not anticipated to be required because, 

based on the label language, the agency assumes that backflow into surface water will not occur.

Appendix B References

Breithaupt, James. May 5, 2015. Review of Modified Activated Sludge Respiration Inhibition 

Study (OCSPP 850.3300) for Homopolymer. MRID 49437513, D427116

Ciba (year unknown). Flocculation Theory and Application. 

http://www.siltstop.com/pdf/flocculation-theory_application.pdf

Lyman, W.J., W.F. Reehl, and D.H. Rosenblatt. 1990. Handbook of Chemical Property 

Estimation Methods. American Chemical Society. ISBN O-8412-1761-0

Mostaghimi, Siroos. November 12, 1998. Hydrolysis Waiver Request for CAT-FLOC CL. 

D236082.

MRID 49437513. Licata-Messama, L. March 21, 1995. Test to Evaluate the Inhibition of 

Respiration in Activated Sludge (Test Substance: FL 45 CLV). Unpublished study performed by 

Societe d’Ecotoicologie et de Physico-Chimied, Sarcey, France, and submitted by the SNF, Inc. 

Study No. S.E.P.C. Report No. F065. 
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Appendix C Ecotoxicology Profile

Toxicity to Aquatic Receptors

Freshwater Fish

Table 7 – Freshwater Fish and Amphibian Toxicity Data

Species

Test 

Material 

(% a.i.)

Toxicity EndpointB Value Toxicity 

Category

MRID/

Study Classification/

Comments

Rainbow trout 

(Oncorhynchus 

mykiss)

VeliGon 

L-M

(19.8%)

96-h LC50 =0.077 ppm ai

95% CI = 0.59-0.11 ppm ai

Probit slope = NA

NOAEC = Not determined

Very 

highly 

toxic

44148402/

Acceptable

Fathead minnow

(Pimephales 

promelas)

VeliGon 

L-M

(19.8%)

96-h LC50 = 0.26 ppm ai

95% CI=0.17-0.48 ppm ai

Probit slope = NA

NOAEC = Not determined

Highly 

toxic

44148401/

Acceptable

Rainbow trout 

(Oncorhynchus 

mykiss)

VeliGon 

CL-M

(39.8%)

96-h LC50=0.066 ppm ai 

95% CI=0.043-0.12 ppm ai

Probit slope=NA

NOEAC=0.043 ppm ai

Very 

highly 

toxic

44148405/

Acceptable

Fathead minnow 

(Pimephales 

promelas)

VeliGon 

CL-M

(39.8%)

96-h LC50=0.22 ppm ai 

95% CI=0.19-0.26 ppm ai

Probit slope=5.4

NOAEC=0.11 ppm ai

Highly 

toxic

44148404/

Acceptable

Freshwater Invertebrates

Table 8 – Freshwater Invertebrate Toxicity Data

Species

Test 

Material 

(% a.i.)

Toxicity EndpointB Value Toxicity 

Category

MRID/

Study Classification/

Comments

Waterflea

(Daphnia magna)

VeliGon 

L-M

(19.8%)

48-h EC50 =0.075 ppm ai

95% CI = 0.059 – 0.11 ppm ai

Probit slope= NA

NOAEC= not determined

Very 

highly 

toxic

44148403/

Acceptable

Waterflea

(Daphnia magna)

VeliGon

(39.8%)

48-h EC50 = 2.1 ppm ai

95% CI = 1.8 – 2.6 ppm ai

Probit slope=NA

NOAEC = 0.50 ppm ai

Moderately 

toxic

156044/

Supplemental
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References:

Ward, T.J., J.P. Magazu and R.L. Boeri. 1996. Acute Toxicity of VeliGon L-M to the Fathead 

Minnow, Pimephales promelas. T.R. Wilbury Laboratories, Inc., Marblehead, MA. Lab. Report 

ID: 965-CA. MRID#: 44148401, Unpublished.

Ward, T.J., J.P. Magazu and R.L. Boeri. 1996. Acute Toxicity of VeliGon L-M to the Rainbow 

Trout, Oncorhynchus mykiss. T.R. Wilbury Laboratories, Inc., Marblehead, MA. Lab. Report ID: 

964-CA. MRID#: 44148402, Unpublished.

Ward, T.R., J.P. Magazu and R.L. Boeri. 1996. Acute Toxicity of VeliGon L-M to the Daphnid, 

Daphnis magna. T.R. Wilbury Laboratories, Inc., Marblehead, MA. Lab. Report ID: 963-CA. 

MRID#: 44148403, Unpublished.

Ward, T.J., P. Kowalski and R.L. Boeri, 1996. Acute Toxicity of VeliGon CL-M to the Fathead 

Minnow, Pimephales promelas. T.R. Wilbury laboratories, Inc., Marblehead, MA. Lab. Report 

ID: 962-CA. MRID#: 44148404, Unpublished.

Ward, T.J., P.L. Kowalski and R.L. Boeri. 1996. Acute Toxicity of VeliGon CL-M to the 

Rainbow trout, Oncorhynchus mykiss. T.R. Wilbury Laboratories, Inc., Marblehead, Ma. Lab. 

Report ID: 961-CA. MRID#: 44148405, Unpublished.

Ward, T.J., P.L. Kowalshi and R.L. Boeri. 1996. Acute Toxicity of VeliGon CL-M to the 

Daphnid, Daphnia magna. TR. Wilbury Laboratories, Inc., Marblehead, MA. Lab. Report ID: 

960-CA. MRID#: 44148406, Unpublished.