2

Problem Formulation for the Environmental Fate, 

Ecological Risk, Endangered Species, and Drinking 

Water Exposure Assessments in Support of the 

Registration Review of Hydramethylnon

HN NH

CF3 C

H

C

H

C C

H

C

H

CF3

N

N

H3C CH3

CAS: 67485-29-4

PC Code: 118401

Prepared by:

Edward Odenkirchen, Ph.D., Sr. Science Advisor

He Zhong, Ph.D., Biologist

U.S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch I

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

Anita Ullagaddi, Biologist

Christopher Koper, Chemist

November 15, 2012
3

Table of Contents

Executive Summary........................................................................................................................ 4

1. Purpose........................................................................................................................................ 4

2. Problem Formulation .................................................................................................................. 5

2.1. Nature of Regulatory Action................................................................................................ 5

2.2. Previous Assessments.......................................................................................................... 6

2.2.1. Ecological Risk Assessments........................................................................................ 6

2.2.2. Drinking Water Exposure Assessments........................................................................ 6

3. Stressor Source and Distribution ................................................................................................ 7

3.1. Mechanism of Action.......................................................................................................... 7

3.2. Overview of Pesticide Use and Usage ................................................................................ 7

3.3. Environmental Fate and Transport...................................................................................... 7

3.4. Clean Water Act................................................................................................................ 10

4. Receptors.................................................................................................................................. 11

4.1. Effects to Aquatic Organisms........................................................................................... 11

4.2. Effects to Terrestrial Organisms....................................................................................... 14

4.3. Incident Databases Review............................................................................................... 16

4.4. Ecosystems Potentially at Risk ......................................................................................... 16

5. Assessment Endpoints ............................................................................................................. 17

6. Conceptual Model.................................................................................................................... 17

6.1. Risk Hypothesis................................................................................................................. 17

6.2. Conceptual Diagram .......................................................................................................... 17

7. Analysis Plan ............................................................................................................................ 20

7.1. Stressors of Concern .......................................................................................................... 20

7.2. Measures of Exposure........................................................................................................ 20

7.3. Measures of Effect ............................................................................................................. 22

7.4. Integration of Exposure and Effects .................................................................................. 23

7.5. Endangered Species Assessments...................................................................................... 23

7.6. Endocrine Disruptor Screening.......................................................................................... 24

7.7. Drinking Water Assessment .............................................................................................. 25

7.8. Preliminary Identification of Data Gaps............................................................................ 25

7.8.1. Environmental Fate Data ............................................................................................ 25

7.8.2. Ecological Effect Data ................................................................................................ 27

8. References................................................................................................................................ 31

APPENDIX A. Submitted Environmental Fate and Effects Studies......................................... 432

APPENDIX B. SIP v.1.0 and STIR v. 1.0 Descriptions, Assumptions, Inputs and Outputs...... 43

APPENDIX C. Physical and Chemical Properties of Hydramethylnon Major Degradates...... 437

APPENDIX D. Toxicity Data of ECOSAR estimation (EPI V4.10) ....................................... 438
4

Executive Summary

Hydramethylnon, tetrahydro-5,5-dimethyl-2(1H)-pyrimidinone [3-[4-(trifluoromethyl)phenyl]-1-

[2-[4trifluoromethyl)phenyl]ethenyl]-2 -propenylidene] hydrazone, (CAS 67485-29-4; PC Code 

118401), is a slow acting stomach toxicant registered for the control of ants, fire ants and 

cockroaches in grasses/non-crop lands and non-food use area in domestic dwellings and 

commercial establishments.

The Agency has concluded that the stressor of concern is the parent hydramethylnon. Two 

known major degradates 1,5-bis(alpha, alpha, alpha-trifluoro-p-tolyl)-1,4-pentadien-3-one (CL98,724, 

28%) and 4H-pyrimido [2-1-c]as-triazio-4-one1,6,7,8-tetrahydro-7,7-dimethyl-3-[p-

(trifluoromethyl)-styryl] (CL247,176, 25.2% and 30.5%) will not be assessed further because of 

the low toxicity based on the ECOSAR analysis. However, several unknown degradates from 

photolysis and anaerobic degradation studies will be assumed as the parent hydramethylnon 

unless the unknowns are properly identified. 

The drinking water (DW) from surface water source will be assessed as hydramethylnon may 

move horizontally through soil runoff, e.g. an aerial granular application following by a rain fall 

event. Hydramethylnon appears to have a low potential for groundwater contamination due to 

the lack of movement of hydramethylnon in the soil profile under most conditions. Therefore, 

DW assessment from the ground water source will not be conducted. 

Data gaps of the environmental fate and potential ecological effects are identified and included in 

a data call-in (DCI) section. The following is a brief summary, 1). Environmental Fate Data: 

Aquatic photodegradation (835.2240), anaerobic aquatic metabolism (835.4400) studies, and 

aerobic aquatic metabolism study (835.4300). 2). Ecological Effect Data: Avian acute oral 

toxicity for passerine species (850.2100), saltwater invertebrate life cycle (850.1350), fresh water 

an saltwater fish early life stage (850-1400), plan toxicity (850.4100, and 850.4150) and growth 

(850.5400 and 850.4400). The value of the above data to the risk assessment and how 

uncertainty will be addressed in lieu of data are discussed in detail in section 7.8.2. 

1. Purpose

The purpose of this problem formulation is to provide an understanding of what is known about 

the environmental fate and ecological effects of hydramethylnon considering its currently 

registered uses. Hydramethylnon (CAS 67485-29-4; PC Code 118401) is a slow acting stomach 

toxicant registered for the control of ants in grasses and non-crop lands such as lawns, turfs, and nonbearing nursery stocks. It is also registered for the control of ants and cockroaches in non-food use 

areas in domestic dwellings and commercial establishments and for control of imported fire ants in 

areas of the southern United States where infestations occur. The registered granular or baits

formulation may be applied via broadcast or spot treatment. Currently, 37 active labels are 

registered (USEPA 2012a) and among them, several formulations (Reg# 241-260, 241-261, 241-

322 and 2724-496) are labeled for aerial broadcast application at 0.0176 lb a.i. /acre in 

airport/landing fields, animal housing premises, commercial/industrial lawns, golf course turf, 
5

nonagricultural uncultivated lands, ornamental lawns and turf, pastures, rangeland and 

recreational areas etc. (USEPA 2012b). In addition, the AMDRO granular formulation is also 

registered at 0.0219 lb a.i. /acre (not exceed 0.0876 lb a.i. /acre per year) for control of bigheaded 

ants on pineapples in Hawaii (USEPA 2003). The impregnated formulation may be applied as a 

bait to control household ants and cockroaches. Hydramethylnon is also used for control of 

subterranean termites in a bait package that is sold to and only for use by certified pest control 

operators (PCOs). The above uses establish a complete environmental exposure pathway. 

Therefore, a comprehensive ecological risk assessment and characterization is warranted for the 

hydramethylnon usage. Mitigation as a result of the Re-registration Eligibility Decision (RED) 

(USEPA, 1998) required that all labels need to comply with worker protection standards (WPS) 

for occupational and residential use. In addition, the Agency has developed a program (the 

“Endangered Species Protection Program”) to identify pesticides whose use may cause adverse 

impacts on endangered and threatened species, and to implement mitigation measures that will 

eliminate the adverse impacts. This document provides a plan for analyzing data relevant to 

hydramethylnon and for conducting environmental fate, ecological risk, endangered species, and 

drinking water exposure assessments for its registered uses. Additionally, this problem 

formulation identifies data gaps, uncertainties, and potential assumptions used to address those 

uncertainties relative to characterizing the potential ecological risk associated with the registered 

uses of hydramethylnon. 

2. Problem Formulation

2.1. Nature of Regulatory Action

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), all pesticides distributed 

or sold in the United States generally must be registered by the Environmental Protection 

Agency (Agency). In determining whether a pesticide can be registered in the U.S., the Agency 

evaluates its safety to non-target species based on a wide range of environmental and health 

effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act, and the 

Agency was mandated to implement a new program for the periodic review of pesticides, i.e., 

Registration Review (http://www.epa.gov/oppsrrd1/registration_review/). The Registration 

Review program is intended to ensure 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 and the environment. Changes in science, public 

policy, and pesticide use practices will occur over time. Through the new Registration Review 

program, the Agency periodically reevaluates pesticides to make sure that as change occurs, 

products in the marketplace can be used safely. 

As part of the implementation of the new Registration Review program pursuant to Section 3(g) 

of FIFRA, the Agency is beginning its evaluation of hydramethylnon to determine whether it 

continues to meet the FIFRA standard for registration. This problem formulation for the 

environmental fate, ecological risk, endangered species, and drinking water assessment chapter 

in support of the registration review of hydramethylnon will be posted in the initial docket which 

will open the public phase of the review process.
6

2.2. Previous Assessments

2.2.1. Ecological Risk Assessments 

Hydramethylnon was developed by American Cyanamid in 1977 and first registered in the 

United States in 1980. The reregistration eligibility decision (RED) assessed nonfood use for 

indoor and outdoor residential and agricultural areas for the control of ants, cockroaches, 

termites and other domestic insects such as crickets, silverfish, palmetto bugs and water bugs 

(USEPA 1998). Based on the negligible residues from the grass and rangeland use, the RED 

concluded that the hydramethylnon uses pose minimal risk to freshwater and terrestrial nontarget organisms. However, certain confirmatory data for avian reproduction were needed 

(USEPA 1998). 

In 2003, a Section 3 new use assessment was completed for use of hydramethylnon on 

pineapples in Hawaii for control of bigheaded ants (PC Code Number: 118401, DP Barcode: 

D249596)”. This assessment estimated that the risk quotients exceed levels of concern for acute 

risk, acute restricted use, and acute endangered species risk presumption categories for 20-g 

birds and 15-g and 35-g mammals. Also the risk quotients exceeded the levels of concern for 

acute restricted use and acute endangered species risk presumption categories for freshwater fish. 

The following studies were identified as data gaps: estuarine/marine fish LC50 (850.1075), 

estuarine/marine invertebrate EC50 ( 850.1035), sediment toxicity testing (850.1735 and 

850.1740), aquatic photodegradation (835.2240), aerobic aquatic metabolism (835.4300), and 

terrestrial field dissipation (835.6100). In addition, the same assessment recommended label 

revisions to specify the number of applications and the minimum interval between applications

(USEPA 2003). 

2.2.2. Drinking Water Exposure Assessments

Previously conducted drinking water exposure assessments are listed in Table 1. Based on the 

negligible residues from the grass and rangeland use, the RED concluded that hydramethylnon 

residues in drinking water were unlikely (USEPA 1998). However, in a Section 3 new use 

assessment conducted since RED, Tier -1 FIRST modeling showed the peak (acute) and annual 

average (chronic) concentrations of 76.09 ppb and 1.45 ppb, respectively. The ground water 

concentrations are not likely to exceed 0.035 ppb by SCI-GROW modeling (USEPA 2003). 

Table 1. Previous Hydramethylnon Drinking Water Assessments

Date References Purpose

03/2003 DP 249596 Section 3 New Crop Use Registration of Hydramethylnon on 

Pineapples in Hawaii for Control of Bigheaded Ants

12/1998 EPA 738-R-98-023 Reregistration Eligibility Decision (RED) Hydramethylnon
7

3. Stressor Source and Distribution

Hydramethylnon is a slow acting stomach toxicant registered in early 1980 for the control of ants 

in grasses and non-crop lands such as lawns, turfs, and non-bearing nursery stocks. The active 

ingredient of hydramethylnon is formulated for 37 end use products, primarily as baits, to control 

ants and cockroaches in non-food use areas in domestic dwellings and commercial 

establishments, fire ants in areas of the southern United States and subterranean termites. 

3.1. Mechanism of Action

Hydramethylnon is a trifluoromethyl aminohydrazone and is metabolic inhibitor blocking the 

biological process in the insect that makes adenosine triphosphate (ATP). Hydramethylnon acts 

upon the mitochondria where it disrupts cellular respiration by inhibiting the electron transport 

chain (ETC) at the cytochrome b-c1 complex.

3.2. Overview of Pesticide Use and Usage 

The use sites and usages on the registered hydramethylnon are summarized by the Biological and 

Economic Analysis Division at the Agency (USEPA 2012a,b). The active ingredient of 

hydramethylnon is formulated for 37 end use products (USEPA 2012a) such as: Amdro, Combat, 

Maxforce, Sensible, and Siege, TC-250, Grants Kills, Liquid Ant Bait, RF-2018 Magma, and 

Raid registered, and sold in the United States by the registrants: BASF, Bayer Environmental 

Sciences, Whitmire Micro-Gen Research Laboratories, Grant Laboratories, Wellmark 

International, S.C. Johnson & Son Inc, Bell laboratories, Combat Insect Control Systems, and 

Ambrands. Hydramethylnon is formulated as a granular, pelletted/tabletted, impregnated 

materials and solution-ready to use as well as bait for control of imported fire ants, harvester 

ants, and leafcutting ants in rangeland and pastures. The registered granular formulation may be 

applied via broadcast or to individual mounds for ant and fire ant control. Several formulations 

(Reg# 241-260, 241-261, 241-322 and 2724-496) are labeled for aerial broadcast application at 

0.0176 lb a.i. /acre in airport/landing fields, animal housing premises, commercial/industrial 

lawns, golf course turf, nonagricultural uncultivated lands, ornamental lawns and turf, pastures, 

rangeland and recreational areas etc. (USEPA 2012b). The maximum registered field broadcast 

application rate is 0.0219 lb a.i. /acre and not exceed 0.0876 lb a.i. /acre per year (USEPA 

2012b). The impregnated formulation may be applied as a bait to control household ants and 

cockroaches. In addition, hydramethylnon is also used for control of subterranean termites in a 

bait package that is sold to and only for use by certified PCOs. 

3.3. Environmental Fate and Transport

Technical hydramethylnon (Fig. 1) is a yellow to tan crystalline solid with a characteristic 

vegetable oil odor and melting point of 189-191 oC. The compound is insoluble in water (7-9) 

ppb (USEPA 1998), slightly soluble in alcohols, and soluble in acetone, chlorobenzene, and 1,2-

dichloroethane. Hydramethylnon vapor pressure is 2x10-8 mm of Hg @ 25 oC with an average 

n-octanol and water partition coefficient (Kow) 27,965 (or Log Kow = 4.45) (MRID 416125-02). 
8

Two technical hydramethylnon products are registered by BASF Corporation (with 98% 

technical formulation 241-270) and Bell Laboratories Inc. (with 99.5% technical formulation 

12455-134). 

The major degradation routes of hydramethylnon are abiotic photolysis and soil binding. 

Hydramethylnon's photolytic half-life in water is ≤1 hour (MRIDs 42238201 and 42473301). A 

major degradate CL247,176, (4H-pyrimido [2-1-c]as-triazio-4-one1,6,7,8-tetrahydro-7,7-

dimethyl-3-[p-(trifluoromethyl)-styryl]), represented 25.2% and 30.5% of the recovered 14Cphenyl and 14C-pyrimidine radioactivity, respectively. Another major degradate CL98,724, (1,5-

bis(alpha, alpha, alpha-trifluoro-p-tolyl)-1,4-pentadien-3-one), represented 28.0% of recovered 

phenyl labeled material. In addition, four unidentified compounds were discernible in the 

pyrimidine radiolabeled and the phenyl radiolabeled samples, ranging from 29.6% to 7.6% of 

recovered radioactivity (MRIDs 42238201 and 42473301). Hydramethylnon soil photolysis is 

biphasic, with half-lives of 4 days for the first phase and in about 30 days for the second phase 

with two unidentified degradates making up 10% of the applied radioactivity (MRIDs 42113401 

and 42353801). Submitted mobility study shows that hydramethylnon adsorb strongly to soils: 

loamy sand, sandy loam, loam, and silt loam soils with reported Kd values ranged from 1039-

1782 mL/g and Kdes values ranged from 3330 to 5630 mL/g (MRID 41888302). Aerobic soil 

metabolism study indicates that hydramethylnon appears to dissipate very slowly by biotic 

processes with 385 days half-life for (MRID 00061709). The half-lives of 445 - 552 days were 

reported for anaerobic aquatic metabolism (MRID 43102701). The compound is stable to 

hydrolysis at pH 5, pH 7, and pH 9 (MRID 42194701).

Field dissipation data showed hydramethylnon has 3 days and 55 days half-lives in Florida 

and Texas field environments respectively (MRIDs 43293101 and 43293102). Therefore, 

hydramethylnon on soil surfaces appears to be non-persistent (MRID 42353801) and immobile 

(MRID 41888302). However, below the soil surface hydramethylnon appears to be more 

persistent (MRID 43102701). Due to the lack of movement of hydramethylnon in the soil profile 

under most conditions, hydramethylnon appears to have a low potential for groundwater 

contamination, but may move horizontally on the soil surface through runoff, e.g. a broadcast 

granular application following by a rain fall event.

Hydramethylnon showed some tendency to accumulate in fish tissues with reported 

bioconcentration factors of 1300X in whole fish, 780X in fillet, and 1900X in viscera. Slow 

depuration (48 to 63% of residues depurated after a 14-day clearance period) was observed. The 

current limited outdoor use patterns of hydramethylnon combined with its low aqueous 

solubility, tendency to rapidly photodegrade in water, and high soil sorption affinity suggest low 

potential for bioaccumulation in the environment. Appendix A includes a complete list of 

submitted studies. The physical, chemical and environmental fate properties of hydramethylnon 

are listed in Table 2, and of hydramethylnon major degradates are listed in Appendix C. 
9

Table 2. Physical, Chemical, and Environmental Fate Properties of Hydramethylnon (PC 

118401).

Parameter Value Reference Comments

Parent

Chemical Hydramethylnon Hydramethylnon

RED

USEPA (1998)

Chemical Name Tetrahydro-5,5-dimethyl2(1H)-pyrimidinone [3-[4-

(trifluoromethyl)phenyl]-1-[2-

[4trifluoromethyl)phenyl]ethen

yl]-2 -propenylidene]hydrazone 

Hydramethylnon

RED

USEPA (1998)

Chemical Family amidinohydrazone Hydramethylnon

RED

USEPA (1998)

Empirical Formula C25H24F6N4 MRID 41612502 Product Chemistry

SMILES N1CC(C)(C)CNC1=NN=C(

C=Cc2ccc(C(F)(F)F)cc2)C=

Cc3ccc(C(F)(F)F)cc3

EPI V4.10

CAS Number 67485-29-4 MRID 41612502 Product Chemistry

Structure MRID 41612502 Product Chemistry

Selected Physical/Chemical Parameters

Molecular mass 494.5 MRID 41612502 Product Chemistry

Solubility (25°C) 7-9 ppb Hydramethylnon

RED

USEPA (1998)

Kow 27,965 MRID 41612502 Product Chemistry

Vapor pressure (23.1°C) < 2×10-8 mm Hg MRID 41612502 Product Chemistry

Henry’s law constant (25°C) 8.21×10-11 atm·m3/mol EPI Suite 4.10

Persistence

Hydrolysis pH 5

835.2120 pH 7

 pH 9

Stable MRID 42194701 Acceptable

Aqueous Photolysis (t 1⁄2 ) 

835.2240

< 1hr MRID 42238201

MRID 42473301

Supplemental

Soil Photolysis (t 1⁄2 ) 

835.2410

30 (Pyrimidyl labeled) and 

35 (Phenyl labeled) days

MRID 42113401

MRID 42353801 Acceptable
10

Parameter Value Reference Comments

Photodegradation in Air

835.2370

N/A (Waived)

Aerobic Soil Metabolism (t 1⁄2 ) 

835.4100

391 (Pyrimidyl labeled) and 

375 (Phenyl labeled) days

MRID 42320801 Supplemental

Anaerobic Soil Metabolism (t 1⁄2 ) 

835.4200

Stable (Not reported) MRID 00061709 Supplemental

Anaerobic Aquatic Metabolism (t 1⁄2 ) 

835.4400

455 (Pyrimidyl labeled) and 

552 (Phenyl labeled) days

MRID 43102701 Supplemental

Aerobic Aquatic Metabolism (t 1⁄2) 

835.4300

N/A

Bioaccumulation in Fish (Depuration 

half-life) 850.1730

14 days

(BCFs in bluegill sunfish 

of 780 in fillet, 1300 in 

whole fish and 1900 in 

viscera)

MRID 00101611 Acceptable

Mobility

Kd

835.1230

835.1240

Loam sand 1039 mL/g

Sandy loam 1669 mL/g

Loam soil 1715 mL/g

Silt loam 1717 mL/g

MRID 41888302 Acceptable

Laboratory Volatility

835.1410

N/A (Waived)

Field Volatility

835.8100

N/A (Waived)

Field Dissipation

Terrestrial Field Dissipation (t 1⁄2 ) 

835.6100

3 days (Florida)

&

55 days (Texas)

 

MRID 43293101

&

MRID 43293102

Supplemental

&

Supplemental

3.4. Clean Water Act

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

impaired under section 303(d) of the Clean Water Act1. No total maximum daily loads (TMDL) 

have been developed2. The Impaired Waters and Total Maximum Daily Loads website can be 

consulted for more information3. The Agency invites submission of water quality data for 

hydramethylnon. To the extent possible, data should conform to the quality standards in 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.

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

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

group_name=PESTICIDES

3 http://www.epa.gov/owow/tmdl/

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

4. Receptors

Consistent with the process described in the Overview Document (USEPA, 2004), the risk 

assessment for hydramethylnon relies on a surrogate species approach. Toxicological data 

generated from surrogate test species, which are intended to be representative of broad 

taxonomic groups, are used to extrapolate the potential effects on a variety of species (receptors) 

included under these taxonomic groupings.

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the 

available open literature will be used to evaluate the potential direct and indirect effects of 

hydramethylnon to aquatic and terrestrial receptors. This includes toxicity on the technical grade 

active ingredient, degradates, and when available, formulated products (e.g., “Six-Pack” studies). 

The open literature studies are identified through EPA’s ECOTOXicology (ECOTOX) 

database5

, 

which employs a literature search engine for locating chemical toxicity data for aquatic life, 

terrestrial plants, and wildlife. The evaluation of both sources of data may also provide insight 

into the direct and indirect effects of hydramethylnon on biotic communities from loss of species 

that are sensitive to the chemical and from changes in structure and functional characteristics of 

the affected communities. Data from an ECOTOX run for hydramethylnon will be evaluated for 

possible quantitative and/or qualitative inclusion in the risk assessment in support of Registration 

Review.

Data requirements to support registration of a pesticide are typically for toxicity of the technical 

grade active ingredient and in certain cases toxicity of degradation products and formulations. 

Studies submitted by the registrant are listed in Appendix A. The ECOTOX database will be 

searched when the risk assessment for hydramethylnon is prepared. At that time, endpoints more 

sensitive than available guideline studies will be reviewed from the open literature studies.

A summary of data representing non-target organisms exposed to hydramethylnon in aquatic and 

terrestrial habitats is provided in Sections 4.1 and 4.2. A summary of ecological incidents 

associated with hydramethylnon and a description of ecosystems potentially at risk are provided 

in Section 4.3. 

4.1. Effects to Aquatic Organisms

Acute toxicity data indicate that technical grade hydramethylnon is highly toxic to fish 

(freshwater and marine/estuarine) and freshwater invertebrates. No data are currently available 

(pending review of public literature) for hydramethylnon toxicity to marine/estuarine 

invertebrates, algae, or multicellular plants. Data are not available that evaluate chronic toxicity 

to any aquatic organisms. Table 6 summarizes the effects from the available studies which will 

be considered in the risk assessment. Appendix A includes a complete list of submitted studies. 

 5 http://cfpub.epa.gov/ecotox/
12

Table 6. Summary of Toxicity of Hydramethylnon (TGAI) to Aquatic Organisms

Species Exposure 

Scenario

% 

AI

Toxicity MRID Toxicity 

Category

Classification

Rainbow trout

(Oncorhynchu

smykiss)

96 hour

850.1075

92 LC50 = 0.157 mg 

a.i./L

35279 Highly toxic acceptable

Bluegill 

sunfish

(Lepomis 

macrochirus)

96 hour

850.1075

92 LC50 = 1.67 mg 

a.i./L

35279 Moderate

toxic

acceptable

Channel 

catfish

(Ictalurus 

punctatus)

96 hour

850.1075

92 LC50 = 0.090 mg 

a.i./L

52858 Very highly 

toxic

acceptable

Waterflea

(Daphnia 

magna)

48 hour

850.1010

92 EC50 = 1.14 mg 

a.i./L

35877 Moderate

toxic

acceptable 

Mysid Shrimp 

(Americamysis

Bahi)

48 hour

850.1035

97.8 LC50 = 0.0544 

mg a.i./L

46684802 Very highly 

toxic

acceptable

Sheepshead 

Minnow, 

(Cyprinodon

variegatus)

96 hour

850.1075

97.8 LC50 = >0.976 

mg a.i./L

46684803 Highly toxic acceptable

Midge larvae 

(Chironomus

dilutus)

850.1735 97.8 Pore water 

LC50 = >0.079 

mg a.i./L

NOAEC 0.079 

mg a.i./L

Sediment

LC50 = >929 mg 

a.i./kg-dw

NOAEC 929 mg 

a.i./kg-dw

Overlying Water

LC50 = >0.015 

mg a.i./L

NOAEC 0.015 

mg a.i./L

46684805 Very highly 

toxic

Practically 

non-toxic

Very highly 

toxic

acceptable

Marine 

amphipod, 

(Leptocheirus

plumulosus)

850.1740 97.8 LC50 = 2.2 mg 

a.i./L

NOAEC 0.504 

mg a.i./L

46684804 Moderately

toxic

acceptable
13

No empirical data for the primary degradates identified in environmental fate studies are 

available. The OPP/Health Effects Division used the potential toxicity concern prediction tool 

DEREK to conclude that neither of the two degradates (CL98,724 and CL247,176) is likely to be 

toxic as the parent hydramethylnon. In addition, ECOSAR analysis by EFED estimated much 

less toxic potency of the two degradates than that of the parent compound (Appendix D). 

Therefore, degradates CL98,724 and CL247,176 will not be warranted for further assessment.

Aquatic Animal

Acute Effects

Freshwater Fish

Of the three species tested, rainbow trout, bluegill sunfish, and channel catfish, the latter species 

is the most sensitive and that endpoint, pending review of public literature, would serve as the 

effects basis for acute freshwater fish risk assessment. Data acceptable for risk assessment are 

not available for formulations or degradation products. 

Freshwater Invertebrates

Only one species is available, pending public literature review. The daphnid endpoint would 

serve as the basis for acute freshwater invertebrate risk assessment.

Marine-Estuarine Fish

Only one tested species, sheepshead minnow has been tested and this endpoint would serve as 

the estuarine/marine fish acute risk assessment effects endpoint, pending public literature review.

Marine-Estuarine Invertebrates

One species of estuarine/marine invertebrates has yielded a valid acute toxicity test result (mysid 

shrimp) and would be used in the acute risk assessment, pending public literature review.

Chronic Effects

No freshwater or estuarine/marine fish nor estuarine marine invertebrate chronic data are 

available, pending public literature review. 

A supplemental study with Daphnia magna is available. The study was found to exhibit a 

statistically significant effect in the solvent control versus water control. Therefore, the study is 

incapable of providing a reliable estimate of a no effect concentration for hydramethylnon and 

cannot be used quantitatively in risk assessments. While the study is useful to demonstrate 

effects it cannot be reliable used quantitatively.
14

Sediment Dwelling Organisms

Two species of benthic invertebrates have been tested (a marine amphipod and a chironomid 

midge). Pending further data from the literature, both studies provide acceptable acute lethal 

endpoints and no effect endpoints for sediment risk assessment. 

Aquatic Plants

Pending a public literature review, no data are available for assessing the effects of 

hydramethylnon to aquatic plants.

4.2. Effects to Terrestrial Organisms

Acute toxicity data indicate that technical grade hydramethylnon is slightly toxic to birds and 

mammals. 

Table 7 summarizes the effects from the available studies which will be considered in the risk 

assessment. Appendix A includes a complete list of submitted studies. 

Table 7. Summary of Toxicity of Hydramethylnon (TGAI) to Terrestrial Organisms

Species Test Type % AI Toxicity MRID Toxicity 

Category

Classification

Mallard duck 

(Anas 

platyrhynchos)

850.2100 92 LD50 = 2510 mg 

a.i./kg-bw

64575 Slightly toxic Acceptable 

(“Core”)

Bobwhite quail

(Colinus 

virginianus)

850.2100 92 LD50 = 1828 mg 

a.i./kg-bw

32038 or 

64576

Slightly toxic Acceptable 

(“Core”)

Mallard duck 

(Anas 

platyrhynchos)

850.2200 96 LC50 = 4355 mg 

a.i./kg-diet

32039 or 

85931

Slightly toxic Acceptable 

(“Core”)

Bobwhite quail 

(Colinus 

virginianus)

850.2200 92 LC50 = 1780 mg 

a.i./kg-diet

32040 or 

64577

Slightly toxic acceptable 

(“Core”)

Mallard duck 

(Anas 

platyrhynchos)

850.2300 97.8 NOAEC: 28.5 mg 

a.i./kg diet

LOAEC: 57.0 mg 

a.i./kg diet

Based on 14 days 

survival

45449702 Not 

Applicable

acceptable

Bobwhite quail

(Colinus 

virginianus)

850.2300 97.8 NOAEC 57 mg 

a.i./kg diet

LOAEC ≥ 57 mg 

a.i./kg diet

45449701 Not 

Applicable

acceptable

Laboratory rat Oral dose 95 LD50 41612503 acceptable 
15

Species Test Type % AI Toxicity MRID Toxicity 

Category

Classification

(acute) (males) = 817 mg 

a.i./kg-bw

(females) = 1502 mg 

a.i./kg-bw

Moderately 

toxic

Slightly toxic

(“Core”)

Laboratory rat 3-generation 

reproduction 

study

93.3 NOAEL = 50 mg 

a.i./kg diet

LOAEL = 100 mg 

a.i./kg diet

based on male 

infertility

35525, 

35526, 

101575

Not 

Applicable

acceptable

Honey bee (Apis 

mellifera

850.3020 96.8 LD50

68 ug a.i./bee

41607801 Practically 

nontoxic

acceptable

Terrestrial Animals

Acute Effects

Birds

Of the two species of birds tested in single oral dose and subacute dietary dose experiments 

(mallard duck and bobwhite quail) the quail provides the most sensitive acute and subacute 

endpoints for use in risk assessment.

Data are not available on acute oral toxicity to a passerine species. In addition, data are not 

available for formulations. 

Insects

Acute toxicity to honeybee data is available from one study and will be used in the risk 

assessment.

 

Mammals

Acute toxicity testing indicates that technical hydramethylnon produced an LD50 of 817 mg/kgbw in males and 1502 mg/kg-bw in females. 
16

Chronic Effects

Two species of birds (mallard duck and bobwhite quail) have been studies in a long-term 

reproduction test. Of the two species, the mallard duck was the most sensitive (survivors of 

hatchlings) and this endpoint will be used in the risk assessment.

A 3-generation reproduction study is available for rats exposed to technical hydramethylnon and 

the male infertility NOAEC and will serve as the reproduction endpoint in the risk assessment.

Terrestrial Plants

Pending literature review, no data are available for effects on terrestrial plants.

4.3. Incident Databases Review

A preliminary review on August 22, 2012, of the Ecological Incident Information System (EIIS, 

version 2.1.1), which is maintained by the Agency’s Office of Pesticide Programs, and the Avian 

Monitoring Information System (AIMS), which is maintained by the American Bird 

Conservancy, indicates there are no reported ecological incidents associated with the use of 

hydramethylnon. 

However, incidents have been reported to the Agency in aggregated incident reports. Pesticide 

registrants report certain types of incidents to the Agency as aggregate counts of incidents 

occurring per product per quarter. Ecological incidents reported in aggregate reports include 

those categorized as ‘minor fish and wildlife’ (W-B), ‘minor plant’ (P-B), and ‘other non-target’ 

(ONT) incidents. ONT incidents include reports of adverse effects to insects and other terrestrial 

invertebrates. For hydramethylnon, registrants have reported 4 minor fish and wildlife incidents, 

no minor plant incidents, and no other non-target incidents. Unless additional information on 

these aggregated incidents becomes available, they will be assumed to be representative of 

registered uses of hydramethylnon in the risk assessment.

.

4.4. Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in scope; therefore, it may not be possible to identify 

specific ecosystems during the development of a nation-wide ecological risk assessment. 

Terrestrial ecosystems potentially at risk could include the treated site and immediately adjacent 

areas that may receive spray drift or runoff. Aquatic ecosystems potentially at risk from 

hydramethylnon due to granular broadcast application, runoff, or erosion include water bodies 

adjacent to or downstream from the treated area and could include impounded bodies such as 

ponds, lakes and reservoirs, or flowing waterways such as streams or rivers. For uses in coastal 

areas, aquatic habitat also includes marine ecosystems, including estuaries. 
17

5. Assessment Endpoints

Assessment endpoints represent the actual environmental value that is to be protected, defined by 

an ecological entity (species, community, or other entity) and its attribute or characteristics 

(USEPA, 1998). For hydramethylnon, the ecological entities may include the following: birds, 

mammals, terrestrial-phase amphibians, reptiles, freshwater fish and invertebrates, aquatic-phase 

amphibians, estuarine/marine fish and invertebrates, terrestrial plants, terrestrial invertebrates, 

and aquatic plants. The attributes for each of these entities include growth, reproduction, and 

survival.

6. Conceptual Model 

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves in the 

environment from a source to an ecological receptor. For an ecological pathway to be complete, 

it must have a source, a release mechanism, an environmental transport medium, a point of 

exposure for ecological receptors, and a feasible route of exposure. The conceptual model for 

hydramethylnon provides a written description and visual representation of the predicted 

relationships between hydramethylnon, potential routes of exposure, and the predicted effects for 

the assessment endpoint. A conceptual model consists of two major components: risk hypothesis 

and a conceptual diagram (USEPA, 1998).

6.1. Risk Hypothesis

A risk hypothesis describes the predicted relationship among the stressor, exposure, and 

assessment endpoint response along with the rationale for their selection. For hydramethylnon, 

the following ecological risk hypothesis is being employed for this national-level ecological risk 

assessment:

Hydramethylnon, when used in accordance with current labels, can result in offsite movement of 

the compound via runoff, leading to exposure of non-target plants and animals. Application of 

hydramethylnon to outdoor areas may serve as a major source of hydramethylnon exposure to 

wildlife. When used in accordance with the labels, hydramethylnon use may cause adverse 

effects upon the survival, growth, and reproduction of non-target terrestrial and aquatic 

organisms. These non-target organisms include federally-listed threatened and endangered 

species. 

6.2. Conceptual Diagram

The formulations employed and the environmental fate properties of hydramethylnon indicate 

that broadcast application and runoff, represent potential transport mechanisms to aquatic and 

terrestrial habitats where non-target organisms may be either directly or indirectly exposed. 

These transport mechanisms (i.e., sources) are depicted in the conceptual diagrams below 

(Figures 1, and 2) along with the receptors of concern and the potential attribute changes in the 

receptors due to hydramethylnon exposure. Solid arrows depict the most likely routes of 
18

exposure and effects; dashed lines depict potential routes of exposure that are not considered 

likely for hydramethylnon. Figure 1 represents the expected aquatic exposure pathways; Figure 

2 focuses on exposure pathways for terrestrial plants, terrestrial invertebrates, and dietary routes 

of exposure for terrestrial vertebrates. Drinking water and inhalation risks for terrestrial wildlife 

were not considered in the conceptual diagram based on the “no concern” conclusions drawn 

from screening model runs for theses pathways described elsewhere in this document. At the 

present time, the Agency does not have a method to quantify the dermal routes of exposure to 

terrestrial wildlife, and data are limited to quantify the contribution of such exposures to the toxic 

burden an organism experiences. 

Figure 1. Conceptual model for exposure and effects of hydramethylnon to aquatic organisms. 

Dotted lines indicate exposure pathways that have a low likelihood of contributing to ecological 

risk.

*Route of exposure includes only ingestion of fish and aquatic invertebrates

Stressor

Source

Receptors

Attribute

Change

Hydramethylnon Applied to Use Site

Spray drift

Aquatic animals

Invertebrates 

Vertebrates

Piscivorous mammals 

 and birds* 

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae and 

 vascular plants

Reduction in prey

Modification of PCEs 

 related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

 habitat

Surface water/

Sediment

Runoff

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Uptake/gills 

or integument

Ingestion Ingestion

Atmospheric 

transport

Soil Leaching to

Groundwater

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake/cell, 

roots, leaves Riparian plants

terrestrial 

exposure 

pathways see 

Figure 2

Off-Gassing

Wet/dry 

Deposition
19

Figure 2. Conceptual model for exposure and effects of hydramethylnon to terrestrial organisms. 

Dotted lines indicate exposure pathways that have a low likelihood of contributing to ecological 

risk.

Irrigation 

water

Stressor

Source

Attribute

Change

Hydramethylnon Applied to Use Site

Direct

application Spray drift

Terrestrial 

vertebrates*

Terrestrial 

Inverts*

Individual 

organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey and 

food

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Terrestrial 

plants

grasses/forbs,

 

Runoff

Terrestrial 

vertebrates* 

Exposure Media 

& Receptors Soil

Ingestion

Ingestion

Dermal uptake/Ingestion

Atmospheric 

transport

 Root uptake/contact

 Wet/dry deposition

Ingestion

Leaching to

Groundwater

Off-gassing
20

7. Analysis Plan

In order to address the risk hypothesis, the potential for adverse effects on the environment is 

estimated. The use, environmental fate, and ecological effects of hydramethylnon are 

characterized and integrated to assess the risks. 

This analysis plan will be revisited and may be revised depending upon a full review of the data 

available in the open literature and the information submitted by the public in response to the 

opening of the Registration Review docket.

7.1. Stressors of Concern

The stressor of concern is the parent hydramethylnon. Four unidentified compounds were 

discernible in the pyrimidine radiolabeled and the phenyl radiolabeled samples, ranging from 

29.6% to 7.6% of recovered radioactivity found from aqueous photolysis studies (MRIDs

42238201 and 42473301) and two unidentified degradates making up 10% of the applied 

radioactivity from soil photolysis studies (MRIDs 42113401 and 42353801) will be treated as the 

parent unless the unknowns are identified and the toxicities are assessed. Two major degradates 

CL98,724 (28%) and CL247,176 (31%) are not warranted for further assessment based on

DEREK and ECOSAR estimation (Appendix D). In addition, the Agency will review open 

literature to identify degradate(s) of potential toxicological concern. Data sources that will be 

used in the future assessment include: 1) registrant submissions in support of registration review; 

2) publicly available literature on ecological effects; 3) monitoring data for freshwater streams, 

lakes, reservoirs, and estuarine areas; and 4) incident reports of adverse effects on aquatic and 

terrestrial organisms associated with the use of hydramethylnon. 

7.2. Measures of Exposure

Hydramethylnon exposures in aquatic and terrestrial environments will be evaluated by 

available standard models. The risk conclusions in perspective scenarios will need to be based 

on maximum labeled application rate, number of applications, and minimum application 

intervals and application methods that have the greatest potential for off-site transport for the 

currently registered use. 

Aquatic Exposure 

The expected environmental concentrations (EECs) are modeled based on parent 

hydramethylnon only. The EECs of surface water source will be used to calculate the risk 

quotient (RQ) for assessing the acute and chronic risks to aquatic organisms. A Tier-II 

PRZM/EXAM models coupled with the input shell PE5.pl (August, 2007) will be used to 

generate EECs for acute and chronic exposure, e.g., peak for acute, 21 days average for chronic 

invertebrate and 60 days average for chronic fish exposures. More specific model information 

in Office of Pesticide Programs, USEPA is available online 

(http://www.epa.gov/oppefed1/models/water/index.htm).
21

Terrestrial Exposure

There is potential exposure to non-target organisms through consumption of contaminated food 

items (e.g. treated insects or vegetation), direct application, and runoff.

EEC values used for terrestrial vertebrate exposure will be derived from the Kenaga nomograph 

(Hoerger and Kenaga, 1972) as modified by Fletcher et al. (1994) using the T-REX model 

(version 1.5.1). The upper limit values from the nomograph represent the 95th percentile of 

residue values from actual field measurements. The Fletcher et al. (1994) modifications to the 

Kenaga nomograph are based on measured field residues from 249 published research papers, 

including information on 118 species of plants, 121 pesticides, and 17 chemical classes. For 

input into T-REX, the default foliar dissipation half-life of 35 days will be used due to 

insufficient foliar dissipation rate data on hydramethylnon. Hydramethylnon-only EECs will 

cover risk from the degradation products given the labeled maximum application rate is for a 

single annual application if degradation products are not more toxic than hydramethylnon.

If terrestrial plant toxicity data become available, TerrPlant (version 1.2.2, 12/26/2006) will be 

used to calculate EECs for characterizing exposure to terrestrial and semi-aquatic plants. This 

model estimates pesticide concentrations in runoff and in spray drift. EECs are based upon 

application rate, solubility, incorporation depth, and application method and form. 

SIP

The Screening Imbibition Program (SIP v.1.0, Released June 15, 2010) was used to calculate an 

upper bound estimate of bird and mammal exposure to hydramethylnon in drinking water. The 

estimate is calculated using the solubility limit of hydramethylnon in water (0.009 mg/L at 

25°C). Risk is assessed using the most sensitive acute and chronic avian toxicity endpoints and 

the most sensitive acute and chronic mammalian toxicity endpoints (data summarized elsewhere 

in this document). Appendix B provides a description of the model, assumptions in deriving an 

upper bound exposure estimate, and model results. Detailed information about SIP v.1.0, as well 

as the tool, can be found on the EPA’s website at 

http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial.

Drinking water exposure alone was not determined to be a potential acute concern for mammals 

or birds.

STIR

STIR v.1.0, Screening Tool for Inhalation Risk, is used to provide an upper bound estimate of 

exposure of birds and mammals to pesticides through inhalation of spray drift or vapor. The 

upper bound exposure estimate requires a number of input parameters including the vapor 

pressure and molecular weight for the vapor-phase pesticide; additionally it requires the 

application rate and method of application (i.e., ground or aerial) for spray drift. The toxicity 

aspect of the tool requires an avian acute oral LD50 value (the model provides an estimate of 

avian inhalation toxicity in the absence of such data), the chemical specific avian allometric 

scaling factor to adjust toxicity based on body weight for the chemical (if available), the weight 
22

of the tested bird, a rat acute oral LD50 value, a rat acute inhalation LC50 value, the duration of 

the rat inhalation study, and the weight of the tested rat. This tool was designed for use in the 

Problem Formulation phase of the ecological risk assessment process to quantitatively evaluate 

the need for further analysis of inhalation as a potential pathway of concern for birds and 

mammals. 

STIR was used to evaluate the potential for significant avian risk from inhalation of 

hydramethylnon using an assumed vapor pressure of 2 X 10-8 mm Hg (this value is conservative 

as reported vapor is less than the value). Acute oral toxicity for birds and rats was derived from 

values posted elsewhere in this document and an acute inhalation value for rats was from MRID 

42871101 as 2.9 mg/L over 4 hours of exposure. The STIR results did not indicate that the 

inhalation pathway should be of concern even under conservative assumptions of exposure for 

hydramethylnon for the highest broadcast application rate of 0.0176 lb a.i./acre. Appendix B 

provides a description of the model, assumptions in deriving an upper bound exposure estimate, 

and model results. 

7.3. Measures of Effect

Ecological effects data are used as measures of direct and indirect effects to biological receptors. 

As discussed previously, data are obtained from registrant-submitted studies or from literature 

studies identified by ECOTOX. The ECOTOX database provides more ecological effects data in 

an attempt to bridge existing data gaps. ECOTOX is a source for locating single chemical 

toxicity data and potential chemical mixture toxicity data for aquatic life, terrestrial plants, and 

wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research and 

Development, and the National Health and Environmental Effects Research Laboratory's MidContinent Ecology Division.

Also as discussed previously, information on the potential effects of hydramethylnon on nontarget animals will be collected from the Ecological Incident Information System (EIIS),

aggregate incident reports, and the Avian Incident Monitoring System (AIMS). 

Where available, sub-lethal effects observed in both registrant-submitted and open literature 

studies will be evaluated qualitatively. Such effects may include behavioral changes (e.g. 

lethargy and changes in coloration). Quantitative assessments of risks are limited to those 

endpoints that can be directly linked to the Agency’s assessment endpoints of impaired survival, 

growth, and reproduction.

The assessment of risk for direct effects to non-target organisms makes the assumption that 

toxicity of hydramethylnon to birds is similar to terrestrial-phase amphibians and reptiles. The 

same assumption is made for fish and aquatic-phase amphibians. 

The acute measures of effect used for animals in this assessment are the LD50, LC50, and EC50. 

LD stands for "Lethal Dose", and LD50 is the amount of a material, given all at once, that is 

estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration” 

and LC50 is the concentration of a chemical that is estimated to kill 50% of the test organisms. 

EC stands for “Effective Concentration” and the EC50 is the concentration of a chemical that is 

estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic 
23

measures of exposure for listed and non-listed animals are the NOAEL/NOAEC and NOEC. 

NOAEL stands for “No Observed-Adverse-Effect-Level” and refers to the highest tested dose of 

a substance that has been reported to have no harmful (adverse) effects on test organisms. The 

NOAEC (i.e., “No-Observed-Adverse-Effect-Concentration”) is the highest test concentration at 

which none of the observed effects were statistically different from the control. The NOEC is 

the No-Observed-Effects-Concentration. Only acute exposures are assessed for plants. Non 

listed plants are assessed using the EC25 (terrestrial plants) or EC50 (aquatic plants) and listed 

plants (terrestrial and aquatic) are assessed using either the NOAEC or EC05.

7.4. Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effect characterizations to 

determine the potential ecological risk from the use of hydramethylnon and the likelihood of 

direct and indirect effects to non-target organisms in aquatic and terrestrial habitats. The 

exposure and effects data are integrated in order to evaluate potential adverse ecological effects 

on non-target species.

Typically the risk quotient (RQ) method is used to compare exposure and measured toxicity 

values. EECs are divided by acute and chronic toxicity values. The resulting RQs are then 

compared to the Agency’s Levels of Concern (LOC) (USEPA, 2004). These criteria are 

typically used to indicate when a chemical’s use, as directed on the labels, has the potential to 

cause adverse direct or indirect effects to non-target organisms. In addition, incident data from 

EIIS, aggregate incident reports, and AIMS will be considered as part of the risk 

characterization. 

7.5. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to Federally-listed threatened and endangered (listed) species from 

registered uses of hydramethylnon. This assessment will be conducted in accordance with the 

Overview Document (USEPA, 2004), provisions of the ESA, and the Services’ Endangered 

Species Consultation Handbook (USFWS and NMFS, 1998).

The assessment of effects associated with the registration of hydramethylnon is based on an 

action area. The action area is used to identify all listed (threatened and endangered) species and 

designated critical habitat that could be affected by the Federal action. The Federal action is the 

authorization or registration of pesticide use or uses as described on the label(s) of pesticide 

products containing a particular active ingredient. The action area is defined by the Endangered 

Species Act as, “all areas to be affected directly or indirectly by the Federal action and not 

merely the immediate area involved in the action” (50 CFR §402.2). Based on an analysis of the 

Federal action, the action area is defined by the actual and potential use of the pesticide. 

In the case of nationwide ecological risk assessment conducted for hydramethylnon under 

Registration Review, the action area will encompass the entire U.S. and its territories. The 

purpose of defining the action area as the entire U.S. and its territories is to ensure that the initial 

area of consideration encompasses all areas where hydramethylnon may be used now and in the 

future that are subject to the ESA, including the potential for off-site transport via spray drift 
24

(unlikely given formulations used) and downstream dilution. Additionally, the concept of a 

nationwide action area takes into account the potential for direct and indirect effects and any 

potential modification to critical habitat based on ecological effect measures associated with 

reduction in survival, growth, and reproduction, as well as the full suite of sublethal effects 

available in the effects literature. It is important to note that the nationwide action area does not 

imply that direct and/or indirect effects and critical habitat modification are expected to or are 

likely to occur over the full extent of the action area, but rather to identify all listed species and 

critical habitat that may potentially be affected by the action. The Agency will use more 

rigorous analysis including consideration of available land cover data, toxicity data, and 

exposure information to determine areas where individual listed species and designated critical 

habitat may be affected or modified via endpoints associated with reduced survival, growth, or 

reproduction.

7.6. Endocrine Disruptor Screening

As required by FIFRA and the Federal Food, Drug and Cosmetic Act (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 registration 

review, 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), hydramethylnon 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 and data call-ins for the first group of 

67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. EPA 

published the second list of chemicals for Tier 1 Screening on November 17, 2010. 

Hydramethylnon is not among the group of pesticide active ingredients on the first or second 
25

lists to be screened under the EDSP. Accordingly, as part of registration review, EPA will issue 

future EDSP orders and data call-ins, requiring the submission of EDSP screening assays for 

hydramethylnon. For further information on the status of the EDSP, the policies and procedures, 

the list of chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit 

our website: http://www.epa.gov/endo/.

7.7. Drinking Water Assessment

A Drinking Water Assessment (DWA) from the surface water source will be conducted based on 

the updated application rates and the latest input parameter guidelines since the previous DWA 

(USEPA 2003). Concentrations of the residue in surface waters will be estimated using a Tier II 

PRZM/EXAMS model (http://www.epa.gov/oppefed1/models/water/index.htm). DWA from the 

ground water source will not be conducted. The reason is that hydramethylnon appears to have a 

low potential for groundwater contamination due to the lack of movement of hydramethylnon in 

the soil profile under most conditions.

7.8. Preliminary Identification of Data Gaps

Available studies submitted to fulfill environmental fate and ecological effects guideline 

requirements, as well as outstanding data gaps for hydramethylnon, are defined in Sections 7.8.1 

and 7.8.2, respectively. Studies are identified that offer data for each guideline requirement, as 

well as study classifications and whether or not further data are needed in order to support risk 

assessment.

7.8.1. Environmental Fate Data

Table 10 lists submitted fate studies with MRID, data classification and existing data gaps for 

parent hydramethylnon. In summary of the hydramethylnon environmental fate data, it appears 

that the photolysis is potentially a major degradation pathway. However, one of the uncertainties

is the several unknown degradates formed through the photolysis pathway. In aquatic 

photolysis, four unidentified compounds were discernible in the pyrimidine radiolabeled and the 

phenyl radiolabeled samples, ranging from 29.6% to 7.6% of recovered radioactivity (MRIDs 

42238201 and 42473301). Hydramethylnon soil photolysis is biphasic, with half-lives of 4 days 

for the first phase and in about 30 days for the second phase with two unidentified degradates 

making up 10% of the applied radioactivity (MRIDs 42113401 and 42353801). In addition, two 

major degradates (15% and 12.7%) were not identified in anaerobic aquatic metabolism study 

(MRID 43102701). Proper identification of the above unknowns is very critical to help to 

characterize the hydramethylnon environmental fate. In absence of these data, a conservative 

approach will be used to assume the unknown degradates are the parent hydramethylnon. 

Finally, the aerobic aquatic metabolism (835.4300) study is not submitted and without the data, a 

conservative stable half-life will be assumed.
26

Table 10. Environmental Fate Data Gaps for Hydramethylnon

Guideline Description MRID Classification Data Gap Comments

835.2120 Hydrolysis 42194701 Acceptable No 1Four degredates were 

not identified. In 

absence of the data, 

the unknowns will be 

treated as the parent.

2

Waived

3

Data are required 

under on 40CFR Part 

158 . In absence of the 

data, a conservative 

stable assumption will 

be used.

4

Two major degradates 

(15% and 12.7%) were 

not identified. In 

absence of the data, 

the unknowns will be 

treated as the parent.

5

Study conducted in 

Florida

6

Study conducted in 

Texas

7

Detection of the 

residue in soil

835.2240 Photodegradation in 

Water

42238201

42473301 Supplemental Yes1

835.2410 Soil Photolysis 42353801 Acceptable No

835.2370 Photodegradation in Air None N/A No2

835.4100 Aerobic Soil Metabolism 42320801 Supplemental No

835.4200 Anaerobic Soil 

Metabolism 00061709 Supplemental No

835.4300 Aerobic Aquatic 

Metabolism None N/A Yes3

835.4400 Anaerobic Aquatic 

Metabolism 43102701 Supplemental Yes4

835.1230

835.1240

Leaching

Adsorption/Desorption 41888302 Acceptable No

835.1410 Laboratory Volatility None N/A No2

835.8100 Field Volatility None N/A No2

835.6100

Terrestrial Field 

Dissipation

432931015 Supplemental No

432931026 Supplemental No

Hydramethylnon ECM 433452017 N/A No

850.1730 Accumulation in Fish 00101611 Acceptable No

 

Aerobic Aquatic Metabolism 

Guideline 835.4300, aerobic aquatic metabolism data are not available for hydramethylnon; 

these are required under the 40 CFR Part 158 data requirements for outdoor terrestrial uses of 

conventional pesticides

Aquatic photolysis and Anaerobic Aquatic Metabolism

Both aquatic photolysis (835.2240) and soil photolysis (835.4400) studies are classified as 

supplemental because of several major degradates (>10%) were not identified and the data 

requirement were not satisfied for environmental fate characterization. 
27

7.8.2. Ecological Effect Data

Several data gaps for hydramethylnon ecological effects remain across all taxonomic groups 

(Tables 12, 13, and 14). 

TABLE 12. Ecological Effect Data Gaps for Terrestrial Animals Exposed to 

Hydramethylnon

Guideline Description MRID Classification Data Gap? Comments

850.2100

Avian acute oral toxicity

(upland game or 

waterfowl species)

32038 or 

63576

and 

64575

Acceptable 

(“Core”) No

1

Avian acute oral toxicity data 

are not available for passerines,

which are now required under 

the most recent 40 CFR Part 

158. Avian acute oral toxicity 

(passerine species) N/A Not applicable Yes1

850.2200

Avian dietary toxicity 

(upland game species)

32040 or 

64577 Acceptable No

Avian dietary toxicity 

(waterfowl species)

32039 or 

85931 Acceptable No

850.2300

Avian reproduction 

(upland game species)

45449701

Supplemental No

Avian reproduction 

(waterfowl species)

45449702 Acceptable 

(“Core”) No

850.3020 Honeybee acute contact 

toxicity

41607801 Acceptable No
28

TABLE 13. Ecological Effect Data Gaps for Aquatic Animals Exposed to Hydramethylnon 

Guideline Description

MRID

Classification Data 

Gap? Comments

850.1075

Acute freshwater fish 

toxicity

52858

Acceptable No 1

These data are required under 40 

CFR part 158 for terrestrial 

outdoor uses.

2

These data are required under 40 

CFR part 158 based on potential 

exposure and acute 

marine/estuarine fish and 

invertebrate RQs. EFED has 

previously requested these studies 

and they were made a condition of 

registration for the product 

Instinct (EPA Reg. Number 

62719-583).

Acute freshwater fish 

toxicity

35279

Acceptable No

Acute estuarine/

marine fish toxicity

52857

Acceptable No

Acute estuarine/

marine fish toxicity 

with flow-through

46684803 Supplemental No

850.1010 Acute toxicity to 

freshwater invertebrates

35877 Acceptable No

850.1025 Acute estuarine/

marine mollusk toxicity

46684801 Invalid Yes2

850.1035

Acute estuarine/

marine invertebrate 

toxicity

46684802 Acceptable No

850.1300 Freshwater invertebrate 

life cycle

101610 Supplemental Yes2

850.1350 Saltwater invertebrate 

life cycle Not applicable Not applicable Yes2

850.1400

Freshwater fish early 

life stage Not applicable Not applicable Yes1

Saltwater fish early life 

stage Not applicable Not applicable Yes2

850.1735

Whole sediment acute 

fresh water 

invertebrates

46684804 Acceptable No

850.1740

Whole sediment acute 

marine water 

invertebrates

46684805 Acceptable No
29

TABLE 14. Ecological Effect Data Gaps for Plants Exposed to Hydramethylnon

Guideline Description Classification Data 

Gap? Comments

850.4100

Terrestrial plant toxicity 

(Tier I&II seedling 

emergence)

Not submitted Yes1

1 These data are required under 40 

CFR part 158 and are not available. 

2 A Tier I study is triggered. A Tier 

II study may be conducted in lieu of 

a Tier I if it is suspected that an 

adverse effect will be detected at 

the limit dose. If a Tier I study is 

conducted and any adverse effects 

are observed this would necessitate 

conduct and submission of a Tier II 

study as well. 

850.4150

Terrestrial plant toxicity 

(Tier I&II vegetative 

vigor)

Not submitted Yes1,2

850.5400

Aquatic plant growth

(freshwater green alga) Not submitted Yes1,2

Aquatic plant growth 

(freshwater diatom) Not submitted Yes1,2

Aquatic plant growth 

(saltwater diatom) Not submitted Yes1,2

Aquatic plant growth 

(Cyanobacteria) Not submitted Yes1,2

850.4400 Aquatic plant growth 

(vascular plants) Not submitted Yes1,2

Avian Acute Oral and Dietary Toxicity

Acute avian oral toxicity data are not available for a passerine species. Avian acute oral toxicity 

data on passerines are now required under the current 40 CFR Part 158. Avian acute oral toxicity 

data will be used to determine the lethal dose of hydramethylnon to birds on a body weight basis. 

Passerine species may be more or less sensitive to hydramethylnon because they have higher 

metabolic rates than the tested species (mallard duck, Beltsville small white turkey poults, and 

white leghorn cockerel chicks) due to their smaller sizes and because they may utilize different 

metabolic pathways. EFED will assume risk to birds on an acute oral basis in the absence of 

these data
30

Estuarine/Marine Mollusc Acute Toxicity

Data are invalid for an acute mollusc endpoint. These data are important for in that they provide 

close taxonomic surrogacy for a variety of Federally listed mollusks. There are no toxicity 

surrogates for hydramethylnon and this acute is required under 40 CFR Part 158 for pesticides 

expected to enter estuarine/marine systems. Hydramethylnon is expected to reach these systems.

Freshwater Fish and Marine/Estuarine Fish Chronic Toxicity (Early-Life Stage)

A study is not available on chronic toxicity to freshwater fish or marine/estuarine fish (early-life 

stage). Under the 40 CFR Part 158 data requirements for conventional pesticides, this data is 

conditionally required (OCSPP Guideline 850.1400) for outdoor terrestrial uses. 

Because chronic data are lacking for both fish types it is not possible to assign an acute to 

chronic ratio from one acute/chronic paired data set to the other fish type. Consequently, at the 

minimum either a freshwater fish or an estuarine/marine fish (of a species presently tested in 

acute testing protocols) should be performed and the resulting ACR applied to other fish. 

Optimally, both a freshwater and estuarine species (of species presently tested in acute testing 

protocols) should be tested using early life stage testing protocols.

Freshwater and Marine/Estuarine Invertebrate Chronic Toxicity (Life Cycle)

Acceptable studies are not available on chronic toxicity to freshwater and marine/estuarine 

invertebrates. Data are required for both invertebrates under the 40 CFR Part 158 data 

requirements for outdoor terrestrial uses of conventional pesticides. Potential exposure to 

hydramethylnon is expected for both freshwater and estuarine/marine environments, and EFED 

has previously requested the marine/estuarine study in earlier risk assessments. 

Terrestrial Plant Toxicity

Guideline terrestrial plant data are not available for hydramethylnon; these are required because 

of hydramethylnon’s outdoor uses. 

Aquatic Plant Toxicity

Aquatic plant toxicity studies are required for pesticides with outdoor terrestrial uses (four nonvascular plant studies and one vascular plant study. No data are available on unicellular or 

vascular species. Exposure to hydramethylnon is possible and the different species are likely to 

show a range of sensitivity to hydramethylnon. A Tier I plant study may be conducted in lieu of 

a Tier II study with the understanding that any adverse effects observed by the Tier I study 

would necessitate conduct and submission of a Tier II study as well. 
31

8. References

USEPA. 1998. Reregistration Eligibility Decision (RED) Hydramethylnon. 143 pp 

USEPA. 2003. Section 3 New Crop Use Registration of Hydramethylnon on Pineapples in

Hawaii for Control of Bigheaded Ants (PC Code Number: 118401, DP Barcode: 

D249596) 45 pp.

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs. U.S. Environmental Protection Agency, Office of Prevention, 

Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. 

January 23, 2004.

USEPA. 2012a. 118401 Hydramethylnon Full LUIS Label Tracking, BEAD 7/18/2012 

USEPA. 2012b. 118401 Hydramethylnon EFED label data report, BEAD 7/18/2012

 
32

APPENDIX A. Submitted Environmental Fate and Effects Studies

SUBMITTED ENVIRONMENTAL FATE STUDIES

161-1 Hydrolysis

MRID Citation 

31307 Reichert, B.L.; Stout, S.J.; Pasarela, J. (1980) Amdro Fire Ant In- secticide CL 

217,300: The Hydrolysis of Carbon-14 Labeled CL 217,300: Project No. 0420. 

(Unpublished study received Apr 24, 1980 under 241-EX-93; submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:242308-G) 

62328 Kapoor, I.P. (1979) Letter sent to T. Wang dated Feb 27, 1979: The hydrolysis of 

carbon-14 labeled CL 217,300 in an aqueous system. (Unpublished study received 

Mar 21, 1979 under 241-EX- 93; submitted by American Cyanamid Co., Princeton, 

N.J.; CDL: 237848-N) 

98491

ACC 247235

Barringer, D.F.; Stanley-Millner, P. (1982) Amdro^(TM)I Fire Ant Insecticide (CL 

217,300): The Hydrolysis of Carbon-14 CL 217,300. (II) Studies at Concentrations 

in the ppb Range without Cosolvent: Report No. C-2005. (Unpublished study 

received Apr 9, 1982 under 241-260; submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:247235-A) 

42194701 Beckman, K.; Cranor, W. (1992) Hydrolysis of Hydramethylnon as a Function of pH 

at 25 C: Lab Project Number: 38960. Unpubli- shed study prepared by ABC Labs., 

Inc. 67 p. 

161-2 Photodegradation-water

MRID Citation 

42238201 Cranor, W.; Beckman, K. (1992) Determination of the Aqueous Photolysis Rate of 

Hydramethylnon (Interim Report): Lab Project Number: 38961. Unpublished study 

prepared by ABC Labs, Inc. 51 p. 

42473301 Cranor, W. (1992) Determination of the Aqueous Photolysis Rate of 

Hydramethylnon: ?Final Report|: Lab Project Number: 38961. Unpublished study 

prepared by ABC Labs, Inc. 79 p. 

70924 Lee, A.; Mallipudi, M.; Stanley, P.A.; et al. (1980) Amdro^(TM)I Fire Ant 

Insecticide (CL 217,300): Photolysis in Distilled Wa- ter: Project No. 0420. Final 

rept. (Unpublished study received Mar 16, 1981 under 241-260; submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:244585-A) 

161-3 Photodegradation-soil

MRID Citation 

61703 Kapoor, I.P. (1979) Letter sent to T. Wang dated Sep 13, 1979: The Photolisis of 
33

Carbon-14 Labelled CL217,300. (Unpublished study received Jul 1, 1980 under 241-

260; submitted by American Cyan- amid Co., Princeton, N.J.; CDL:099777-B) 

ACC 098985 CL 217,300: The Photolysis of CL 217,300 Bait Formulation on

Several Carriers. A. Markantonates. Acc. #095985,

71014 Barringer, D.F., Jr.; Stanley, P.A. (1981) Amdro^(TM)I Fire Ant In- secticide (CL 

217,300): Photolysis on Soil Thin-layer Plates (Benzylic Carbon-14 Labeled): PDM 

18-1:1-23. Final rept. (Un- published study received Mar 18, 1981 under 241-260; 

submitted by American Cyanamid Co., Princeton, N.J.; CDL:244605-A) 

101609 Barringer, D. (1981) Amdro Fire Ant Insecticide (CL 217,300): Photolysis on Soil 

Thin-layer Plates (Pyrimidine Carbon-14 Labeled): Report No. PD-M 18-22:1-18. 

(Unpublished study re- ceived May 14, 1982 under 241-260; submitted by American 

Cyanamid Co., Princeton, NJ; CDL:247502-B) 

42113401 Melcer, M. (1991) Hydramethylnon (...): Photodegradation on Soil: Interim Report: 

Lab Project Number: E-91-9. Unpublished study prepared by American Cyanamid 

Co. 47 p. 

42353801 Melcer, M. (1992) Hydramethylnon (AC 217,300): Photodegradation on Soil: Lab 

Project Number: E-91-9. Unpublished study prepared by American Cyanamid 

Comp. 192 p 

162-1 Aerobic soil metabolism

MRID Citation 

42320801 Gorman, M. (1992) Aerobic Soil Metabolism of Hydramethylnon: Lab Project 

Number: 38977. Unpublished study prepared by ABC Laboratories, Inc. 86 p. 

35282 Reichert, B.L.; Gatterdam, P.E.; Miller, K.; et al. (1980) Amdro Fire Ant Insecticide 

(CL 217,300): Metabolism in Soil under Aer- obic Conditions: Project No. 0420. 

Final rept. (Unpublished study received Jul 1, 1980 under 241-260; submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:099488-

125752 Reichert, B.; Gatterdam, P.; Miller, K.; et al. (1980) Amdro Fire Ant Insecticide (CL 

217,300): Metabolism in Soil under Aerobic Conditions: PD-M Volume 17-5. Final 

rept. (Unpublished study received Feb 18, 1983 under 241-260; submitted by 

American Cyanamid Co., Princeton, NJ; CDL:071409-J) 

ACC 098985 Preliminary Aerobic Soil Metabolism of CL 217,300. I .P.

Kapoor, Acc. #098985, Section D2, Exhibit 6.

Al'rlDRO Fire Ant I n s e c t i c i d e (CL 217,300): . Metabolism of Surface Applied 

Compound under Field Conditions, P. Gatterdam, Report No. C-1743. American 

Cyanamid Company, Product Development, Princeton, N. J., Accession No. 241-

260, 241-261.
34

162-1 Anaerobic Soil Metabolism

MRID Citation 

35878 Reichert, B.L.; Knoll, B. (1979) CL 217,300: Anaerobic Soil Metabolism: Project 

No. 0420. (Unpublished study received Jul 1, 1980 under 241-260; submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:099488-E) 

61709 Reichert, B.L.; Knoll, B.A. (1979) CL 217,300: Anaerobic Soil Me- tabolism: PD-M 

16-26. Progress rept. from 1/29/79 to 5/31/79. (Unpublished study received Jul 1, 

1980 under 241-260; submitted by American Cyanamid Co., Princeton, N.J.; 

CDL:099778-E) 

61710 Gatterdam, P.; Miller, K. (1980) Amdro Fire Ant Insecticide (CL 217,300): 

Metabolism of Surface Applied Compound under Field Conditions: Report No. C1743. (Unpublished study received Jul 1, 1980 under 241-260; submitted by 

American Cyanamid Co., Princeton, N.J., CDL:099778-F) 

162-3 Anaerobic aquatic metab.

MRID Citation 

43102701 Cady, C. (1994) Anaerobic Aquatic Metabolism of Hydramethylnon: Final Report: 

Lab Project Number: ENV/94/002: 38978. Unpublished study prepared by ABC 

Lab., Inc. 68 p. 

163-1 Leach/adsorp/desorption

MRID Citation 

32045 Reichert, B.L.; Knoll, B.A. (1979) CL 217,300: Determination of Mobility in Soil: 

Project No. 0420. (Unpublished study received Jun 11, 1980 under 241-260; 

submitted by American Cyanamid Co., Princeton, N.J.; CDL:099457-C) 

62329 Kapoor, I.P. (1979) Letter sent to T. Wang dated Feb 28, 1979: Mobility of CL 

217,300. (Unpublished study received Mar 21, 1979 under 241-EX-93; submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:237848-O) 

41888302 Mangels, G. (1990) Hydramethylnon (AC217,300): Adsorption/Desorpti- on: Lab 

Project Number: E-90-21. Unpublished study prepared by American Cyanamid Co. 

35 p. 

164-1 Terrestrial field dissipation

MRID Citation 

35283 Gatterdam, P.E.; Miller, K. (1980) Amdro Fire Ant Insecticide (CL 217,300): 

Metabolism of Surface Applied Compound under Field Conditions: Report No. C1743. (Unpublished study received Jul 1, 1980 under 241-260; submitted by 
35

American Cyanamid Co., Princeton, N.J.; CDL:099488-F) 

61803 Manuel, A.J.; Wang, T.; Muzyk, K.R.; et al. (1980) Amdro(TM)I Fire Ant 

Insecticide (CL 217,300): Residues of CL 217,300 in Soil (Grass; GND; FL, 1979) 

(C-1646): Report No. C-1706. (Compilation; unpublished study received Jul 1, 1980 

under 241-260; submitted by American Cyanamid Co., Princeton, N.J.; CDL: 

099775-H) 

43293101

Wrong PC on 

DER

York, C. (1994) CL 217,300 (hydramethylnon/G): Rate of Dissipation of CL 

217,300 Residues in Soil after Treatment with AMDRO Fire Ant Insecticide (FL; 

1992): Lab Project Number: RES/94/051. Unpublished study prepared by American 

Cyanamid Co., Huntingdon Analytical Services. 120 p. 

43293102

Wrong PC on 

DER

York, C. (1994) CL 217,300 (hydramethylnon/G): Rate of Dissipation of CL 

217,300 Residues in Soil after Treatment with AMDRO Fire Ant Insecticide (TX; 

1992): Lab Project Number: RES/94/065. Unpublished study prepared by American 

Cyanamid Co., Huntingdon Analytical Services. 119 p. 

43636701 Fletcher, J. (1995) CL 217,300: Freezer Stability of Residues of CL 217,300 in Soil: 

Lab Project Number: RES 94-070: AM92PT03: A011.071. Unpublished study 

prepared by American Cyanamid Co. and Huntingdon Analytical Services. 40 p. 

165-0 Accumulation Studies -- General

MRID Citation 

31304 or 

61705

Caballa, S.H.; Knoll, B. (1979) CL 217,300: Biodegradability, Environmental Fate 

and Ecological Magnification of Carbon-14 Labeled CL 217,300 in a Model 

Ecosystem: Project No. 0420. (Unpublished study received Apr 24, 1980 under 241-

EX-93; submitted by American Cyanamid Co., Princeton, N.J.; CDL:242308-C) 

61705 Caballa, S.H.; Knoll, B. (1979) CL 217,300: Biodegradability, Envi- ronmental Fate 

and Ecological Magnification of Carbon-14 La- beled CL 217,300 in a Model 

Ecosystem: PD-M 16-11. Final rept. (Unpublished study received Jul 1, 1980 under 

241-260; submitted by American Cyanamid Co., Princeton, N.J.; CDL:099777-H) 

62331 Kapoor, I.P. (1979) Letter sent to T. Wang dated Feb 23, 1979: Comparative 

biodegradability, environmental fate and ecological magnification of carbon-14 

Mirex and carbon-14 CL 217,300 in a model ecosystem. (Unpublished study 

received Mar 21, 1979 under 241-EX-93; submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:237848-Q) 

164252 American Cyanamid Co. (1979) Residues of AC 217, 300: [in or on Grass and Fate 

in the Environment]. Unpublished compilation. 349 p. 

165-1 Confined rotational crop

MRID Citation 

92163029 Lee, A. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00061706. AMDRO Fire Ant Insecticide (CL 217300): Uptake and Residues of 

Radioactivity in Follow-Crops Grown in Soil Containing Aged Residues of Carbon-
36

14 Labeled CL 217,300: Report No. PD-M Volume 17-3. Prepared by AMERICAN 

CYANAMID CO. 35 p. 

61706 Gatterdam, P. E. 1979. AMDRO fire ant insectidide (CL 217300): Uptake and 

Residues of Radioactivity in Fallow-Crops Grown in Soil Containing Aged Residues 

of carbon-l4 Labeled CL 217,300. performed and submitted by American Cyanamid 

Company Princeton, NJ.

ACC 098985 Gatterdam, , P.E. CL 217,300: Residues of CL 217,300 i n Range Grass Grown i 

nSoil Treated w i t h Carbon-14 labeled compound a t Gainesville,

Florida. Acc 8098985, Section 02, Exhibit 9.

165-4 Bioaccumulation in fish

MRID Citation 

92163030 Lee, A. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00101611. AMDRO Fire Ant Insecticide (CL 217,300): Identification and 

Characterization of CL 217,300 and Its Metabolite in Bluegill Sunfish Exposed to 

1.8 ppb of CL 217,300 in Water. Prepared by AMERICAN CYANAMID CO. 21 p. 

31305 Kuc, W.J. (1980) 14C-AC217,300: Channel Catfish, Ictalurus punctatus 

(Rafinesque): Bioconcentration Study: UCES Project No. 11507-51. (Unpublished 

study received Apr 24, 1980 under 241-EX-93; prepared by Union Carbide Corp., 

submitted by American Cyanamid Co., Princeton, N.J.; CDL:242308-D) 

31306 Kuc, W.J. (1980) 14C-AC 217,300: Bluegill Sunfish, Lepomis macro- chirus 

Rafinesque: Bioconcentration Study: UCES Project No. 11507-54. (Unpublished 

study received Apr 24, 1980 under 241-EX-93; prepared by Union Carbide Corp., 

submitted by Ameri- can Cyanamid Co., Princeton, N.J.; CDL:242308-E) 

35280 Reichert, B.L.; Knoll, B.; Koc, W.J.; et al. (1980) Amdro Fire Ant Insecticide (CL 

217,300): Identification and Characterization of CL 217, 300 and Its Metabolites in 

Bluegill Sunfish: Project No. 0420. Final rept. (Unpublished study including UCES 

Proj- ect No. 11507-54, received Jul 1, 1980 under 241-260; prepared in cooperation 

with Union Carbide Corp., submitted by American Cyanamid Co., Princeton, N.J.; 

CDL:099488-A) 

61707 Vilkas, A.G.; Kuc, W.J. (1980) American Cyanamid Company ^14IC- AC217,300: 

Channel Catfish,~Ictalurus punctatus~(Rafinesque) Bioconcentration Study: UCES 

Project No. 11507-51. (Unpublished study received Jul 1, 1980 under 241-260; 

prepared by Union Car- bide Corp., submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:099777-J) 

61708 Reichert, B.; Knoll, B. (1980) Amdro Fire Ant Insecticide (CL 217,300): 

Identification and Characterization of CL 217,300 and Its Metabolites in Bluegill 

Sunfish: PD-M 17-14. Final rept. (Unpublished study received Jul 1, 1980 under 

241-260; submitted by American Cyanamid Co., Princeton, N.J.; CDL:099778-C) 

101611 Barringer, D.; Stanley-Millner, P. (1982) Amdro Fire Ant Insecti- cide (CL 

217,300): Identification and Characterization of CL 217,300 and Its Metabolite in 

Bluegill Sunfish Exposed to 1.8 ppb of CL 217,300 in Water: Report No. PD-M 19-

6:1-185. (Unpub- lished study received May 14, 1982 under 241-260; submitted by 
37

American Cyanamid Co., Princeton, NJ; CDL:247502-D) 

Non Guideline Selections

MRID Citation 

34022 Tondreau, R.E.; Manuel, A.J. (1980) CL 217,300: Validation of GC Method M-1045 

for the Determination of CL 217,300 Residues in Soil: Report No. C-1646. Includes 

method dated Jan 3, 1980. (Unpublished study received Jun 11, 1980 under 241-260; 

submit- ted by American Cyanamid Co., Princeton, N.J.; CDL:099454-C) 

34023 Manuel, A.J.; Wang, T.; Williams, D.; et al. (1980) Amdro Fire Ant Insecticide (CL 

217,300): Residues of CL 217,300 in Soil (Grass; GND; FL, 1979) (C-1646): Report 

No. C-1706. (Unpublished study received Jun 11, 1980 under 241-260; prepared in 

cooperation with U.S. Dept. of Agriculture, Science and Education Adminis- tration, 

submitted by American Cyanamid Co., Princeton, N.J.; CDL:099454-D) 

34028 American Cyanamid Company (19??) Stability Information. (Unpub- lished study 

received Jun 11, 1980 under 241-260; CDL:099450-C) 

34029 Lopata, R.J. (1980) CL 217,300: High Pressure Liquid Chromatograph- ic Assay of 

Tetra-hydro-5,5-dimethyl-2(?~H~?)-pyrimidinone, ?3-?4-(Trifluoromethyl)-phenyl|-

1-|2-?4-trifluoromethyl)phenyl| ethenyl3-2-propenylidene|-hydrazone. Methods M935 dated Nov 22, 1978 and M-1068.1 dated Apr 21, 1980. (Unpublished study 

received Jun 11, 1980 under 241-260; submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:099450-D) 

34030 Markantonatos, A. (1979) CL 217,300: HPLC Determination of CL 217,300 Content 

in Oil Formulations and Defatted Pregel Corn Bait Formulations. Method M-1040.1 

dated Nov 20, 1979. (Unpub- lished study received Jun 11, 1980 under 241-260; 

submitted by American Cyanamid Co., Princeton, N.J.; CDL:099450-E) 

61802 Tondreau, R.E. (1980) Recommended Method of Analysis: CL 217,300: GC Method 

for the Determination of CL 217,300 Residues in Soil. Method M-1045 dated Jan 3, 

1980. (Unpublished study received Jul 1, 1980 under 241-260; submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:099775-G) 

63869 Metz, W.A.; Conley, J.M. (1980) Hydrazine: High-Pressure Liquid 

Chromatographic Method of Analysis for Residual Hydrazine in CL 217,300. 

Method M-1087 dated Jun 24, 1980. (Unpublished study received Jul 1, 1980 under 

241-260; submitted by American Cyana- mid Co., Princeton, N.J.; CDL:099768-B) 

71016 Atlas, R.M. (1980) Effects of the Insecticide AC 217,300 on Soil Microorganisms. 

(Unpublished study received Mar 18, 1981 under 241-260; prepared by Univ. of 

Louisville, Dept. of Biology, sub- mitted by American Cyanamid Co., Princeton, 

N.J.; CDL:244603-A) 

71024 Lopata, R.J. (1978) CL 217,300: High Pressure Liquid Chromatograph- ic Assay of 

Tetrahydro-5,5-dimethyl-2(1~H~)-pyrimidinone, ?3- ?4-(trifluoromethyl)-phenyl|-1-

?2-?4-(trifluoromethyl)phenyl| ethenyl|-2-propenylidene|-hydrazone. Method M-935 

dated Nov 22, 1978. (Unpublished study received Mar 16, 1981 under 241-EX-97; 

submitted by American Cyanamid Co., Princeton, N.J.; CDL: 244587-B) 

71025 DeLuccia, S. (1981) Proposed Analytical Method for Determination of AC 217,300 
38

Formulations. Undated method. (Unpublished study received Mar 16, 1981 under 

241-EX-97; submitted by American Cyanamid Co., Princeton, N.J.; CDL:244587-C) 

79263 Gatterdam, P.E. (1981) Amdro^(TM)I Fire Ant Insecticide (CL 217,300): Recovery 

of Carbon-14 CL 217,300 from Water Stored in Glass Vessels: Report No. C-1875. 

(Unpublished study re- ceived Jul 24, 1981 under 241-260; submitted by American 

Cyanam- id Co., Princeton, N.J.; CDL:245593-A) 

125750 Vander Meer, R.; Williams, D.; Lofgren, C. (1982) Degradation of the toxicant AC 

217,300 in Amdro Imported Fire Ant Bait under field conditions. J. Agric. Food 

Chem. 30(6):1045-1048. (Also In unpublished submission received Feb 18, 1983 

under 241-260; submitted by American Cyanamid Co., Princeton, NJ; CDL:071409-

H) 

125751 Gatterdam, P.; Miller, K. (1980) Amdro Fire Ant Insecticide (CL 217,300): 

Metabolism of Surface Applied Compound under Field Conditions: Report No. C1743. (Unpublished study received Feb 18, 1983 under 241-260; submitted by 

American Cyanamid Co., Princeton, NJ; CDL:071409-I) 

43345201 Fletcher, J. (1994) AMDRO (CL 217,300): Validation of HPLC Method M 2266 for 

the Determination of CL 217,300 Residues in Soil: Addendum to Terrestrial Field 

Dissipation Studies with CL 217,300: Lab Project Number: RES/93/142. 

Unpublished study prepared by American Cyanamid Co. 32 p. 

ACC 098985 Caballa, S.H. CL 21'7,-300: ~determination of Par t i t ion Coefficient i n nOctanolWater Solvent System. Acc #098985, section D2,

43345202 Fletcher, J. (1994) CL 217,300: Independent Laboratory Validation of HPLC 

Method M 2266 for the Determination of CL 217,300 Residues in Soil by 

Huntingdon Analytical Services, Inc.: Addendum to Terrestrial Field Dissipation 

Studies with CL 217,300: Lab Project Number: RES/94/071: A011/066. 

Unpublished study prepared by American Cyanamid Co. and Huntingdon Analytical 

Services, Inc. 57 p. 

32046 Caballa, S.H. (1979) CL 217,300: The Effect of Soil Microorganisms on Carbon-14 

Labeled CL 217,300: Project No. 0420. Includes un- dated method. (Unpublished 

study received Jun 11, 1980 under 241-260; submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:099457-D) 

41888301 Mangels, G. (1990) Hydramethylnon (AC217,300): Soil Thin-Layer 

Chromatography: Lab Project Number: E-89-31. Unpublished study prepared by 

American Cyanamid Co. 15 p. 

SUBMITTED EFFECTS STUDIES

71-1 Avian Single Dose Oral Toxicity

MRID Citation 

32038 or 

64576

Beavers, J.B.; Fink, R.; Brown, R. (1979) Final Report: Acute Oral LD50--Bobwhite 

Quail: Project No. 130-126. (Unpublished study received Jun 11, 1980 under 241-
39

260; prepared by Wildlife Inter- national, Ltd. in cooperation with Washington 

College, submit- ted by American Cyanamid Co., Princeton, N.J.; CDL:099456-C) 

64575 Fink, R.; Beavers, J.B.; Grimes, J.; et al. (1979) Final Report: Acute Oral LD50--

Mallard Duck: Project No. 130-127. (Unpub- lished study received Jul 1, 1980 under 

241-260; prepared by Wildlife International Ltd. and Washington College, submitted 

by American Cyanamid Co., Princeton, N.J.; CDL:099779-E) 

92163003 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00064575. AC 217,300 - Acute Oral LD50 - Bobwhite Quail: Project No. 130-126; 

June 14, 1979. Prepared by WILDLIFE INTERNATIONAL, LTD. 11 p. 

92163004 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00064576. AC 217,300 - Acute Oral LD50 - Mallard Duck: Project No. 130-127; 

June 14, 1979. Prepared by WILDLIFE INTERNATIONAL, LTD. 12 p. 

71-2 Avian Dietary Toxicity

MRID Citation

32039 or 

85931

Beavers, J.B.; Fink, R.; Grimes, J.; et al. (1979) Final Report: Eight-Day Dietary 

LC50--Mallard Duck: Project No. 130-125. (Un- published study received Jun 11, 

1980 under 241-260; prepared by Wildlife International, Ltd. in cooperation with 

Washington Col- lege, submitted by American Cyanamid Co., Princeton, N.J.; CDL: 

099456-D) 

32040 or 

64577

Beavers, J.B.; Fink, R.; Grimes, J.; et al. (1979) Final Report: Eight-Day Dietary 

LC50--Bobwhite Quail: Project No. 130-124. (Unpublished study received Jun 11, 

1980 under 241-260; prepared by Wildlife International, Ltd. in cooperation with 

Washington College, submitted by American Cyanamid Co., Princeton, N.J.; 

CDL:099456-E) 

92163005 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00064577. AC 217,300 - Acute Oral LC50 - Bobwhite Quail: Project No. 130-124; 

July 13, 1979. Prepared by WILDLIFE INTERNATIONAL, LTD. 11 p. 

92163006 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00085931. AC 217,300 - Acute Oral LC50 - Mallard Duck: Project No. 130-125; 

July 12, 1979. Prepared by WILDLIFE INTERNATIONAL, LTD. 12 p. 

71-4 Avian Reproduction

MRID Citation

45449701 Frey, L.; Martin, K.; Beavers, J. et al. (2001) Avian Reproduction Test with 

Hydramethylnon (AC 217300) in Northern Bobwhite (Colinus virginianus): Lab 

Project Number: ETX-00-186: 130-191. Unpublished study prepared by Wildlife 

International, Ltd. 286 p. {OPPTS 850.2300} 

45449702 Frey, L.; Martin, K.; Beavers, J. et al. (2001) Avian Reproduction Test with 

Hydramethylnon (AC 217300) in Mallard (Anas platyrhynchos): Lab Project 

Number: ETX-00-187: 130-192. Unpublished study prepared by Wildlife 
40

International, Ltd. 284 p. {OPPTS 850.2300} 

72-1 Acute Toxicity to Freshwater Fish

MRID Citation

164246 Union Carbide Corp. (1979) The Acute Toxicity of AC 217,300 to the Channel 

Catfish: Ictalurus punctatus (Rafinesque): UCES Project No. 11506-20-20. 

Unpublished study. 9 p. 

164247 Union Carbide Corp. (1979) Acute Toxicity of AC 217,300 to Bluegill Sunfish, 

Lepomis macrochirus Rafinesque: UCES Project # 11506- 20-19. Unpublished 

study. 10 p. 

32037 Schneider, C.E. (1979) Acute toxicity of AC 217,300 to the Rainbow Trout,~Salmo 

gairdneri~Richardson: UCES Project # 11506-20- 18. (Unpublished study received 

Jun 11, 1980 under 241-260; prepared by Union Carbide Corp., submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:099456-A) 

35279 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of AC 217,300 (Lot No. AC 

3196-99B, 91.6% Active Ingredient) to the Bluegill Sunfish,~Lepomis 

macrochirus~Rafinesque: UCCES Project No. 11506-20-31. (Unpublished study 

received Jul 1, 1980 under 241-260; prepared by Union Carbide Corp., submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:099492-B) 

52857 Vilkas, A.G.; Schupner, J.K. (1980) The Acute Toxicity of AC 217,300 to the 

Rainbow Trout,~Salmo gairdneri~Richardson: UCES Project No. 11506-20-34. 

(Unpublished study received Oct 8, 1980 under 241-260; prepared by Union Carbide 

Corp., submitted by American Cyanamid Co., Princeton, N.J.; CDL:243466-B) 

52858 Vilkas, A.G.; Schupner, J.K. (1980) The Acute Toxicity of AC 217,300 to the 

Channel Catfish,~Ictalurus punctatus~(Rafin- esque): UCCES Project No. 11506-

20-32. (Unpublished study re- ceived Oct 8, 1980 under 241-260; prepared by Union 

Carbide Corp., submitted by American Cyanamid Co., Princeton, N.J.; CDL: 

243466-C) 

92163007 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00035279. AC 217,300 - Acute LC50 - Bluegill Sunfish: Project No. 11506-20-31;

June 23, 1980. Prepared by UNION CARBIDE CORP. 12 p. 

92163008 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00052858. AC 217,300 - Acute LC50 - Channel Catfish: Project No. 11506-20-32; 

August 6, 1980. Prepared by UNION CARBIDE CORP. 13 p. 

92163009 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00052857. AC 217,300 - Acute LC50 - Rainbow Trout: Project No. 11506-20-34; 

August 5, 1980. Prepared by UNION CARBIDE CORP. 13 p. 

72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation
41

164248 Morrissey, A. (1979) The Acute Toxicity of AC 217,300 to the Water Flea: Daphnia 

magna Straus: UCES Project No. 11506-20-21. Unpublished study prepared by 

Union Carbide Environmental Services, Union Carbide Corp. 10 p.

92163010 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00099779. AC 217,300 - Acute LC30 - Daphnia: Project No. 11506-20-33; June 23, 

1980. Prepared by UNION CARBIDE CORP. 12 p. 

35877 Vilkas, A.G.; Browne, A.M. (1980) The Acute Toxicity of AC 217,300 (Lot No. AC 

3196-99B, 91.6% Active Ingredient) to the Water Flea, Daphnia magna Straus: 

UCCES Project No. 11506-20-33. (Unpublished study received Jul 1, 1980 under 

241-260; prepared by Union Carbide Corp., submitted by American Cyanamid Co., 

Prince- ton, N.J.; CDL:099492-C) 

72-3 Acute Toxicity to Estuarine/Marine Organisms

MRID Citation

46678301 Hughes, C.; Holmes, C. (2005) BAS 315 I: Acute Toxicity to the Mysid Shrimp, 

Americamysis bahia, Determined Under Flow-Through Test Conditions. Project 

Number: 49244, 132203, 2005/5000091. Unpublished study prepared by ABC 

Laboratories, Inc. 31 p.

46684801 Hicks, S.; Holmes, C. (2005) BAS 315 I: Effect on New Shell Growth of the Eastern 

Oyster (Crassostrea virginica). Project Number: 49245, 132200, 2005/5000173. 

Unpublished study prepared by Analytical Bio-Chemistry Labs., Inc. 43 p.

46684802 Hughes, C.; Holmes, C. (2005) BAS 315 I: Acute Toxicity to the Mysid Shrimp, 

Americamysis bahia, Determined Under Flow-Through Test Conditions. Project 

Number: 49244, 132203, 2005/5000091. Unpublished study prepared by Analytical 

Bio-Chemistry Labs., Inc. 31 p.

46684803 Warbritton, R.; Holmes, C. (2005) BAS 315 I: Acute Toxicity Test with the 

Sheepshead Minnow, Cyprinodon variegatus, Determined Under Flow-Through Test 

Conditions. Project Number: 49243, 132197, 2005/5000124. Unpublished study 

prepared by Analytical Bio-Chemistry Labs., Inc. 33 p.

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID Citation

101610 Forbis, A.; Boudreau, P.; Thompson, C.; et al. (1982) Chronic Toxicity of 14C-AC 

217,300 to Daphnia magna under Flow-through Test Conditions: ABC #28568. 

Final rept. (Unpublished study received May 14, 1982 under 241-260; prepared by 

Analytical Bio- chemistry Laboratories, Inc., submitted by American Cyanamid Co., 

Princeton, NJ; CDL:247502-C) 

92163011 Gagne, J. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00101610. AC 217,300 - Invertebrate Life - Cycle Test, Daphnia: Project No. 

28568; April 26, 1982. Prepared by ANALYTICAL BIOCHEMISTRY LABS, INC. 

14 p. 
42

72-6 Aquatic org. accumulation (see Fate Studies 165-4)

MRID Citation

92163030 Lee, A. (1990) American Cyanamid Company Phase 3 Summary of MRID 

00101611. AMDRO Fire Ant Insecticide (CL 217,300): Identification and 

Characterization of CL 217,300 and Its Metabolite in Bluegill Sunfish Exposed to 

1.8 ppb of CL 217,300 in Water. Prepared by AMERICAN CYANAMID CO. 21 p. 

101611 Barringer, D. 1982. Identifiaction and Characterization of CL 217,300 and It's 

Metabolite in Bluegill Sunfish Exposed to 1.8 ppb of CL 217,300 in Water.

performed by ABC Laboratory, Columbia MO and American

Cyanamid, Princeton NJ. sponsored by American Cyanamid

Company, Princeton NJ. Received by EPA 4/4/90. MRID 101611.

141-1 Honey bee acute contact

MRID Citation

41607801 Thompson, M.; Hoxter, K.; Smith, G. (1990) AC 217,300: An Acute Contact 

Toxicity Study with the Honey Bee: Lab Project Number: 130-151B. Unpublished 

study prepared by Wildlife International Ltd. 26 p. 

35281 Gillespie, J.M.; Atkins, L. (1977) Toxicity of Experimental Com- pounds AC 

217,300 and AC 206,859 to Honey Bees: Experiment No. 60904-77-Z3E. 

(Unpublished study received Jul 1, 1980 under 241-260; prepared in cooperation 

with Univ. of California--Riv- erside, Dept. of Entomology, submitted by American 

Cyanamid Co., Princeton, N.J.; CDL:099488-C) 

Acute Toxicity to Aquatic Insects

850.1735 Whole sediment: acute freshwater invertebrates

MRID Citation

46684804 Warbritton, R.; Holmes, C. (2005) BAS 315 I: Acute Toxicity to the Midge Larvae, 

Chironomus dilutus, in Whole Sediment. Project Number: 132206, 49246, 

2005/5000123. Unpublished study prepared by Analytical Bio-Chemistry Labs., Inc 

and Agvise Inc. 66 p.

850.1740 Whole sediment: acute marine invertebrates

MRID Citation

46684805 Hughes, C.; Holmes, C. (2005) BAS 315 I: Acute Toxicity to the Marine Amphipod, 

Leptocheirus plumulosus, in Whole Sediment. Project Number: 49247, 132209, 

2005/5000174. Unpublished study prepared by Analytical Bio-Chemistry Labs., Inc 

and Agvise Inc. 45 p 
43

APPENDIX B. SIP v.1.0 and STIR v. 1.0 Descriptions, Assumptions, Inputs and Outputs

SIP v.1.0

SIP v.1.0 provides an upper bound estimate of exposure of birds and mammals to pesticides through 

drinking water alone. This model is intended for use in problem formulation to determine whether or not 

drinking water exposure alone is a potential pathway of concern. This does not aggregate drinking water 

exposure with other exposure routes (i.e., diet, inhalation, dermal).

SIP employs the following conservative assumptions to derive upper bound exposure 

estimates:

1) The chemical concentration in drinking water is at the solubility limit in water (at 25oC).

2) The assessed animals obtain 100% of their daily water needs through drinking water.

3) The daily water need is equivalent to the daily water flux rate as calculated by Nagy and 

Peterson (1988).

4) The body weight of the assessed bird is equivalent to the smallest generic bird modeled in 

T-REX (i.e., 20 g). This assumption results in the highest ratio of exposure to toxicity for the 3 

assessed avian body weights of T-REX (i.e., 20, 100, 1000 g).

5) The body weight of the assessed mammal is equivalent to the largest generic mammal 

modeled in T-REX (i.e., 1000 g). This results in the highest ratio of exposure to toxicity for the 

3 assessed mammalian body weights of T-REX (i.e., 15, 35, 1000 g). 

Parameter Value

Chemical name hydramethylnon

Solubility (in water at 25oC; mg/L) 0.009

Mammalian LD50 (mg/kg-bw) 817

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Mammalian NOAEL (mg/kg-bw) 50

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Avian LD50 (mg/kg-bw) 1828

Avian test species mallard duck

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 28.5

Bobwhite quail NOAEC (mg/kg-diet) 57

NOAEC (mg/kg-diet) for other bird species

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird 

species

Body weight (g) of 2nd other avian species
44

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.0015 0.0015

Adjusted toxicity value (mg/kg-bw) 628.4042 38.4580

Ratio of exposure to toxicity 0.0000 0.0000

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.0073 0.0073

Adjusted toxicity value (mg/kg-bw) 949.1440 1.4140

Ratio of exposure to acute toxicity 0.0000 0.0052

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for birds

Drinking water exposure 

alone is NOT a potential 

concern for birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. 

Therefore, when aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through 

drinking water may contribute to a total exposure that has potential for effects to non-target animals.

STIR v1.0 

Inhalation is a potentially important route of exposure to pesticides for mammalian and avian 

wildlife (Driver et al. 1991; USEPA 2004a). STIR is a screening tool used at the Problem 

Formulation phase to assess the potential for risk to bird and mammals from inhalation exposure. 

The exposure pathways that are assessed by this tool include both droplet inhalation and vapor 

phase inhalation. Allometric equations that relate inhalation rate to body weight are used to 

derive an estimated inhalation dose of either droplets or vapor for a 0.020 kg bird and a 0.015 kg 

mammal (Mineau et al. 1996; Sample and Arenal 1999; USEPA 1993). 

Results from acute inhalation toxicity studies for mammals from the "six-pack" that are routinely 

submitted to the Registration Division of the Office of Pesticide Programs can be directly 

compared with the estimated inhalation doses from vapor and droplets. In most cases however, 

avian inhalation data are lacking. STIR uses the avian oral toxicity data together with both the 

mammalian oral and inhalation toxicity data to derive an estimate of avian inhalation toxicity. 

Based on the findings of the 2004 Science Advisory Panel (USEPA 2004), an adjustment factor 

is applied to these data to adjust the estimate of avian inhalation toxicity for differences in 

diffusion efficiency across the avian lung membrane compared to the mammalian lung 

membrane.

STIR relies on the application rate, application method, defined droplet spectra (if applicable), 

molecular weight, vapor pressure and the temperature associated with the vapor pressure of a 

specific chemical to obtain an estimate of the droplet and vapor concentration in the air. These 

concentrations are compared with an estimated inhalation LD50 of a specific chemical as a ratio 
45

that is then compared with a threshold of 0.1. If the ratio of the exposure to the toxicity exceeds 

0.1, then the screening tool indicates that a reviewer is to "Proceed to Refinements", at which 

point the reviewer can request specific studies that will help to address uncertainty related to 

inhalation risk. The user's guide contains information for the specific studies that may be 

requested. However, if the screening tool indicates "Exposure not Likely Significant", then the 

reviewer can assume that the inhalation pathway is not expected to be a significant source of 

risk. 

Notes

* The saturated air concentration is the theoretical maximum pure product air concentration at 

25oC and 1 atm of pressure.

* The height of the direct spray column is 3.3 m for aerial applications and 1 m for ground 

applications.

* The duration of vapor inhalation is assumed to be 1 hour and the duration of direct spray 

inhalation is assumed to be 1.5 minutes for aerial and 30 seconds for ground applications.

* The fraction of direct spray that can be inhaled is assumed to be 90%, unless a droplet spectra 

is specified on the label. Please see the user's guide for more information.

* This model accounts for the difference in both avian and mammalian field active inhalation 

rate compared to the resting rate by multiplying the resting inhalation rate by 3 according to 

USEPA, 1993.

* Both of the mammalian and avian inhalation LD50's are adjusted for body weight using 

allometric equations based on work by Mineau et al. 1996. The avian allometric equation uses 

the Mineau scaling factor to modify the equation based on chemical specific data. If chemicalspecific data are available the user can specify the avian scaling factor (see Mineau, et al.,1996). 

Otherwise, enter the EFED default value of 1.15. STIR will not run unless a Mineau scaling 

factor is entered. However, 1 can be entered if the assessor believes that body weight does not

influence the toxicity of the chemical being assessed. 

* The inhalation of droplets and the inhalation of vapor phase pesticide are accounted for in this 

model as two separate routes of exposure. The corresponding dose estimations should not be 

combined to obtain a composite exposure value. 
46

Input

Application and Chemical Information

Enter Chemical Name hydramethylnon

Enter Chemical Use granular

Is the Application a Spray? (enter y or n) n

If Spray What Type (enter ground or air)

Enter Chemical Molecular Weight (g/mole) 494.5

Enter Chemical Vapor Pressure (mmHg) 2.00E-08

Enter Application Rate (lb a.i./acre) 0.0219

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 1828

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 817

Enter Lowest Rat Inhalation LC50 (mg/L) 2.9

Duration of Rat Inhalation Study (hrs) 8

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 5.32E-04

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 6.69E-05

Adjusted Inhalation LD50 7.24E+01

Ratio of Vapor Dose to Adjusted Inhalation LD50 9.25E-07 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 not applicable not applicable

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 5.32E-04

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 8.41E-05

Adjusted Inhalation LD50 3.45E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.44E-07 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 not applicable not applicable
47

APPENDIX C. Physical and Chemical Properties of Hydramethylnon Major Degradates

1,5-bis(alpha, alpha, alpha-trifluoro-p-tolyl)-1,4-pentadien-3-one

Chemical CL98,724 MRID 42473301

Chemical Name 1,5-bis(alpha, alpha, alphatrifluoro-p-tolyl)-1,4-

pentadien-3-one

MRID 42473301

Empirical Formula C19H12F6O1 EPI V4.10

SMILES O=C(C=Cc2ccc(C(F)(F)F)c

c2)C=Cc3ccc(C(F)(F)F)cc3

EPI V4.10

Structure MRID 42473301 Degradate found in

Aqueous Photolysis

Anaerobic Soil Meta.

Field Dissipation

Molecular Mass 370.3 MRID 42473301

Water solubility 38.9 ppb EPI V4.10

4H-pyrimido [2,1-c) as-triazio-4-one 1, 6, 7, 8-tetrahydro-7,7-dimethyl-3-[p-(trifloromethyl)-styryl]

Chemical CL247,176 MRID 42473301

Chemical Name 4H-pyrimido [2,1-c) astriazio-4-one 1, 6, 7, 8-

tetrahydro-7,7-dimethyl-3-

[p-(trifloromethyl)-styryl]

MRID 42473301

Empirical Formula C17H7F3N4O1 EPI V4.10

SMILES C1(=O)C(C=Cc2ccc(C(F)(F)F)

cc2)=NNC2=NCC(C)(C)CN12

EPI V4.10

Structure MRID 42473301 Degradate found in

Aqueous Photolysis 

Field Dissipation

Molecular mass 350.35 MRID 42473301

Water solubility 11,670 ppb EPI V4.10
48

APPENDIX D. Toxicity Data of ECOSAR estimation (EPI V4.10) 

Hydramethylnon

SMILES : N1CC(C)(C)CNC1=NN=C(C=Cc2ccc(C(F)(F)F)cc2)C=Cc3ccc(C(F)(F)F)cc3

CHEM : Hydramethylnon

CAS Num: 067485-29-4

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C25 H24 F6 N4 

MOL WT : 494.49

Log Kow: 8.51 (KowWin estimate)

Melt Pt: 

Wat Sol: 0.006 mg/L (experimental database)

ECOSAR v1.00 Class(es) Found

------------------------------

Aliphatic Amines

Hydrazines

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Aliphatic Amines : Fish 96-hr LC50 0.011 *

Aliphatic Amines : Daphnid 48-hr LC50 0.004

Aliphatic Amines : Green Algae 96-hr EC50 0.014 *

Aliphatic Amines : Fish ChV 0.000314

Aliphatic Amines : Daphnid ChV 0.014 *

Aliphatic Amines : Green Algae ChV 0.00102

Aliphatic Amines : Fish (SW) 96-hr LC50 0.012 *

Aliphatic Amines : Mysid Shrimp (SW) 96-hr LC50 0.003

Aliphatic Amines : Green Algae (SW) 96-hr EC50 0.014 *

Aliphatic Amines : Fish (SW) ChV 0.000314

Aliphatic Amines : Mysid Shrimp (SW) ChV 0.014 *

Aliphatic Amines : Green Algae (SW) ChV 0.00118

Hydrazines : Fish 96-hr LC50 0.003

Hydrazines : Daphnid 48-hr LC50 2.854 *

Hydrazines : Green Algae 72-hr EC50 9.27e-005

Hydrazines : Fish ChV 0.000151 !

Hydrazines : Daphnid ChV 0.000604 !

Hydrazines : Green Algae ChV 2.31e-005 !

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 0.00118

(Baseline Toxicity) : Daphnid 48-hr LC50 0.00149

 : Green Algae 96-hr EC50 0.009 *

 : Fish ChV 9.67e-005

 : Daphnid ChV 0.000436

 : Green Algae ChV 0.011 *
49

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Aliphatic Amines:

----------------

 For Fish 96-hr LC50: For aliphatic amines with log Kow greater than 7.0,

a test duration of greater than 96 hrs may be required for proper

expression of toxicity. Also, if the toxicity value obtained by the use

of this equation exceeds the water solubility (measured or estimated),

mortalities greater than 50% would not be expected in a saturated

solution during an exposure period of 96 hrs.

 For Daphnid 48-hr LC50: For aliphatic amines with log Kow greater than

5.0, a test duration of greater than 48 hrs may be required for proper

expression of toxicity. Also, if the toxicity value obtained by the use

of this equation exceeds the water solubility (measured or estimated),

significant mortalities would not be expected in a saturated solution 

during an exposure period of 48 hrs.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 7, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For Mysid Shrimp Acute Toxicity Values: If the log Kow of the chemical is

greater than 6, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For Fish and Daphnid Chronic Toxicity Values: If the log Kow of the chemical

is greater than 8.0, or if the compound is solid and the ChV exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For Green Algae Chronic Toxicity Values: If the log Kow of the chemical

is greater than 7.0, or if the compound is solid and the ChV exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 6.0 (Fish, Mysid LC50)

Maximum LogKow: 5.0 (Daphnid LC50)

Maximum LogKow: 7.0 (Green Algae EC50)

Maximum LogKow: 8.0 (Fish, Daphnid ChV)

Maximum LogKow: 7.0 (Green Algae ChV)

Maximum Mol Wt: 1000
50

Hydrazines:

----------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

------------------------------------------------------------------------------

Degradate CL247,176

SMILES : O=C1C(C=Cc3ccc(C(F)(F)F)cc3)=NNC2=NCC(C)(C)CN12

CHEM : 4H-pyrimido [2,1-c) as-triazio-4-one 1, 6, 7, 8-tetrahydro-7,7-dimeth

 yl-3-[p-(trifloromethyl)-styryl] 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C17 H17 F3 N4 O1 

MOL WT : 350.35

Log Kow: 3.19 (KowWin estimate)

Melt Pt: 

Wat Sol: 11.67 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Amides 
51

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Amides : Fish 96-hr LC50 5.182

Amides : Daphnid 48-hr LC50 4.400

Amides : Green Algae 96-hr EC50 0.359

Amides : Fish ChV 0.031

Amides : Daphnid ChV 0.058 !

Amides : Green Algae ChV 0.585

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 26.648 *

(Baseline Toxicity) : Daphnid 48-hr LC50 17.752 *

 : Green Algae 96-hr EC50 12.462 *

 : Fish ChV 2.464

 : Daphnid ChV 2.023

 : Green Algae ChV 5.603

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

------------------------------------------------------------------------------
52

Degradate CL98,724

SMILES : O=C(C=Cc2ccc(C(F)(F)F)cc2)C=Cc3ccc(C(F)(F)F)cc3

CHEM : 1,5-bis(alpha, alpha, alpha-trifluoro-p-tolyl)-1,4-pentadien-3-one 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C19 H12 F6 O1 

MOL WT : 370.30

Log Kow: 5.95 (KowWin estimate)

Melt Pt: 

Wat Sol: 0.03888 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Vinyl/Allyl Ketones

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Vinyl/Allyl Ketones : Fish 96-hr LC50 0.446 *

Vinyl/Allyl Ketones : Daphnid 48-hr LC50 0.108 *

Vinyl/Allyl Ketones : Green Algae 96-hr EC50 0.286 *

Vinyl/Allyl Ketones : Fish ChV 0.019

Vinyl/Allyl Ketones : Daphnid ChV 0.030 !

Vinyl/Allyl Ketones : Green Algae ChV 0.246 *!

Vinyl/Allyl Ketones : Fish (SW) 96-hr LC50 0.045 *

Vinyl/Allyl Ketones : Mysid Shrimp (SW) 96-hr LC50 0.012

Vinyl/Allyl Ketones : Fish (SW) ChV 0.055 *

Vinyl/Allyl Ketones : Mysid Shrimp (SW) ChV 0.00015 !

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 0.130 *

(Baseline Toxicity) : Daphnid 48-hr LC50 0.121 *

 : Green Algae 96-hr EC50 0.264 *

 : Fish ChV 0.011

 : Daphnid ChV 0.022

 : Green Algae ChV 0.196 *

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Vinyl/Allyl Ketones:

-------------------

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the
53

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50; Mysid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

------------------------------------------------------------------------------