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OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

 

 

 PC Code: 101701 

 DP Barcode: D410292 

 Date: September 15, 2015 

MEMORANDUM 

SUBJECT: Preliminary Ecological Risk Assessment for the Registration Review of the 

Herbicide Propyzamide and Proposed New Use on Leaf Lettuce 

TO: Wilhelmena Livingston, Chemical Review Manager

 Kevin Costello, Branch Chief 

 Risk Management and Implementation Branch IV

 Pesticide Re-evaluation Division, 7508P 

 Mindy Ondish, Risk Manager 

Reuben Baris, Product Manager 25 

Daniel Kenny, Branch Chief 

Herbicide Branch 

Registration Division (7505P) 

 

FROM: Karen Milians, Ph.D., Chemist 

Andrew Sayer, Ph.D., Biologist 

 Environmental Risk Branch IV 

 Environmental Fate and Effects Division (7507P)

REVIEWED Catherine Aubee, Senior Scientist

BY: Jim Carleton, Ph.D., Senior Scientist 

Environmental Risk Branch IV 

 Environmental Fate and Effects Division (7507P) 

APPROVED 

BY: Jean Holmes, DVM, MPH, Branch Chief 

 Environmental Risk Branch IV 

 Environmental Fate and Effects Division (7507P)

The Environmental Fate and Effects Division (EFED) has completed a review of the herbicide 

propyzamide (also known as pronamide; PC Code 101701) and its current uses on artichoke, 

blackberry, raspberry, boysenberry, blueberry, alfalfa, clover, birdsfoot, trefoil, head lettuce, 
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radicchio, endive, apple, apricot, winter peas, cherry, nectarines, plum pear, grape, ornamentals, 

Christmas tree, rhubarb, and other agricultural and non-agricultural areas. In addition, a proposed 

use on leaf lettuce is addressed in this assessment. Propyzamide is a systemic, restricted–use, 

organochlorine herbicide that is formulated as a wettable powder in water soluble pouches and as 

a suspension concentrate that can be applied pre-plant, pre-emergence, or post-emergence by 

chemigation, ground or aerial spray equipment. 

This evaluation is limited to the effects and exposure associated with propyzamide specifically, 

and where data are sufficient to permit such analyses, also to its degradates of concern (degradates 

containing the 3,5-dichlorobenzoyl moiety). 

Based on estimated environmental concentrations (EECs) and the most sensitive ecotoxicity data 

across multiple taxa, propyzamide exposure at the maximum proposed application rates may result 

in risk to federally listed threatened and endangered (hereafter referred to as “listed”) and nonlisted species of terrestrial and semi-aquatic monocotyledonous (monocot) and dicotyledonous 

(dicot) plants. There are chronic risk concerns for avian taxa and acute and subacute risk quotients 

(RQs) exceed the listed and non-listed level of concern (LOC) for avian taxa and therefore for 

reptiles and terrestrial-phase amphibians exposed through the terrestrial diet. Use of propyzamide 

on artichoke and apples, alfalfa, blueberries, and head/leaf lettuce, and turf may result in chronic 

risk to listed and non-listed small (15 g), medium (35 g), and large (1000 g) size classes of 

mammals. No acute mammalian exceedances were seen, nor exceedances to honey bees via 

contact exposure. There were no exceedances to listed and non-listed freshwater and 

estuarine/marine fish and invertebrates, or listed and non-listed vascular and non-vascular plants. 

Label Recommendations 

Current propyzamide labels fail to state maximum application rates for certain crops in annual 

terms. Application rates for these crops are instead given on per season (e.g., for turf, leaf lettuce) 

or per crop basis (e.g., head lettuce, endive, escarole, and radicchio greens), or else are not given 

in terms of any particular time frame (e.g., alfalfa seed). For these crops, conservative assumptions 

were employed in this assessment, to estimate plausible maximum annual application rates. 
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Preliminary Ecological Risk Assessment for the Registration Review 

of the Herbicide Propyzamide 

Propyzamide (CAS 23950-58-5) 

PC Code 101701

15 September 2015 

 

Prepared by

Karen Milians, Ph.D., Chemist

Andrew Sayer, Ph.D., Biologist

U.S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division (EFED)

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460 

Reviewed by

Catherine Aubee, Senior Scientist

Jim Carleton, Ph.D., Senior Fate Scientist

Thomas Steeger, Ph.D., Senior Science Advisor

Jean Holmes, D.V.M., M.P.H., Branch Chief

Cl

Cl

N

H

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Table of Contents 

1. Executive Summary ........................................................................................................................................... 6

2. Problem Formulation ........................................................................................................................................ 8

2.1. Nature of Chemical Stressor ..................................................................................................................... 8

2.1. Stressor Source and Distribution .............................................................................................................. 8

2.2. Receptors..................................................................................................................................................... 9

2.3. Assessment Endpoints ................................................................................................................................ 9

2.4. Conceptual Model ...................................................................................................................................... 9

2.4.1. Risk Hypothesis ................................................................................................................................. 9

2.4.2. Conceptual Model Pathways and Effects ...................................................................................... 10

2.5. Analysis Plan ............................................................................................................................................ 11

2.5.1. Conclusions from Previous Risk Assessments .............................................................................. 11

2.5.2. Propyzamide Ecological Risk Assessments ................................................................................... 11

2.5.3. Drinking Water Assessment ........................................................................................................... 12

2.5.4. Identification of Data Gaps and Uncertainties ............................................................................. 13

2.5.5. Measures of Exposure ..................................................................................................................... 14

2.5.6. Measures of Effect ........................................................................................................................... 15

2.5.7. Integration of Exposure and Effects .............................................................................................. 16

3. Analysis ............................................................................................................................................................. 16

3.1. Use Characterization ............................................................................................................................... 16

3.2. Exposure Characterization ...................................................................................................................... 17

3.2.1. Environmental Fate and Transport ............................................................................................... 17

3.2.2. Aquatic Exposure ............................................................................................................................ 19

3.2.3. Terrestrial Exposure ....................................................................................................................... 24

3.3. Ecological Effects Characterization ........................................................................................................ 27

3.3.1. Ecotoxicity Data ............................................................................................................................... 27

3.3.1. Terrestrial Organism and Mammalian Chronic Endpoints ........................................................ 35

3.3.2. Terrestrial Plants ............................................................................................................................. 37

3.3.3. Incident Reports .............................................................................................................................. 38

4. Risk Characterization ...................................................................................................................................... 38

4.1. Risk Estimation ........................................................................................................................................ 38

4.1.1. Aquatic Organisms .......................................................................................................................... 39

4.1.2. Terrestrial Organisms ..................................................................................................................... 40

4.2. Risk Description and Conclusions .......................................................................................................... 42

4.2.1. Aquatic Organisms .......................................................................................................................... 42

4.2.2. Terrestrial Organisms ..................................................................................................................... 43

4.2.3. Conclusions ...................................................................................................................................... 47

4.2.4. Endangered Species Act .................................................................................................................. 48

4.2.5. Endocrine Disruptor Screening Program ..................................................................................... 49

5. Uncertainties ..................................................................................................................................................... 49

6. References ......................................................................................................................................................... 52

List of Tables 

Table 1. List of the various models and the related taxa for which the models will be used to assess risk. ...... 10

Table 2. Maximum Use Patterns for Propyzamide Uses. ....................................................................................... 16

Table 3. General Chemical Properties and Environmental Fate Parameters of Propyzamide. ......................... 18

Table 4. SWCC Input Parameters for Propyzamide (TR). Source Data are in Table 3. .................................... 20

Table 5. SWCC Application-Specific Input Parameters for Propyzamide .......................................................... 21

Table 6. PRZM-GW Input Parameters ................................................................................................................... 21

Table 7. Tier II Total Residue of Concern Estimated Environmental Concentrations in Surface Water (Pond).

 ..................................................................................................................................................................................... 22

Table 8. PRZM-GW (100 year simulation) in Groundwater Resulting from the Use of Propyzamide. ............ 23

Table 9. Terrestrial EECs as food residues for animals exposed to propyzamide as a result of the proposed 

pre-emergent use. ....................................................................................................................................................... 25

Table 10. Contact exposure estimates for honey bees exposed to propyzamide uses ........................................... 26
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Table 11. EECs for non-target terrestrial and semi-aquatic plants based on registered uses and proposed new 

leaf lettuce use of propyzamide (TerrPlant). .......................................................................................................... 26

Table 12. Acute toxicity endpoints used in risk estimation and characterization for freshwater organisms 

exposed to propyzamide. ........................................................................................................................................... 29

Table 13. Acute toxicity endpoints used in risk estimation and characterization for estuarine/marine 

organisms exposed to propyzamide. ......................................................................................................................... 29

Table 14. Sediment toxicity testing with freshwater organisms exposed to propyzamide. ................................. 30

Table 15. Toxicity endpoints used in risk estimation and characterization for aquatic plants and algae 

exposed to propyzamide. ........................................................................................................................................... 30

Table 16. Chronic toxicity endpoints used in risk estimation and characterization for fish and aquatic 

invertebrates exposed to propyzamide. ................................................................................................................... 32

Table 17. Acute toxicity endpoints used in risk estimation and characterization for birds and mammals 

exposed to propyzamide. ........................................................................................................................................... 34

Table 18. Acute toxicity endpoints used in risk estimation and characterization for terrestrial invertebrates 

exposed to propyzamide. ........................................................................................................................................... 34

Table 19. Chronic toxicity endpoints used in risk estimation and characterization for terrestrial animals 

exposed to propyzamide. ........................................................................................................................................... 36

Table 20. Toxicity endpoints used in risk estimation and characterization for terrestrial and semi-aquatic 

plants exposed to propyzamide. ................................................................................................................................ 37

Table 21. Acute and Chronic RQs for Freshwater Fish, Aquatic-Phase Amphibians, and Invertebrates 

Exposed to Propyzamide ........................................................................................................................................... 39

Table 22. Acute and Chronic RQs for Estuarine/Marine Fish, Aquatic-Phase Amphibians, and Invertebrates 

Exposed to Propyzamide ........................................................................................................................................... 39

Table 23. RQ values for listed and non-listed vascular and nonvascular aquatic plants exposed to 

propyzamide in surface water as a result of spray drift. ........................................................................................ 40

Table 24. Acute Mammalian Dose-Based RQ Values for Proposed Uses of Propyzamide1,2 .............................. 41

Table 25. Chronic Mammalian Dose-Based RQ Values for Uses of Propyzamide1 ............................................ 41

Table 26. Contact RQ values for honey bees exposed to propyzamide uses ......................................................... 42

Table 27. Acute a,b Dose-based Avian (20 g) and Dietary-based RQ Values for Propyzamide Based on the 

Canary ........................................................................................................................................................................ 44

Table 28. Acute a,b Dose-based Avian (20 g) and Dietary-based RQ Values for Propyzamide Based on 

Japanese quail ............................................................................................................................................................ 45

Table 29. Chronica Avian Dietary-based RQ Values for Propyzamide ................................................................ 45

Table 30. Propyzamide RQ values for non-listed species1 of non-target terrestrial and semi-aquatic plants 

(TerrPlant). ................................................................................................................................................................ 46

Table 31. Propyzamide RQ values for listed species1 of non-target terrestrial and semi-aquatic plants 

(TerrPlant). ................................................................................................................................................................ 46

Table 32. Seedling Emergence RQ values for listed and non-listed species1 of non-target plants based on 

propyzamide using groundwater-derived irrigation water.................................................................................... 47

Table 33. Vegetative vigor RQ values for listed and non-listed species1 of non-target plants based on 

propyzamide using groundwater-derived irrigation water.................................................................................... 47

Appendices 

Appendix A. Propyzamide Uses .............................................................................................................................. 62

Appendix B. Propyzamide and its Environmental Transformation Products ..................................................... 67

Appendix C. SWCC Results ..................................................................................................................................... 70

Appendix D. Ecotoxicity data gaps and uncertainties ............................................................................................ 72

Appendix E. Example T-REX (v. 1.5.2) input and output data ............................................................................ 77

Appendix F. Example TerrPlant (v. 1.2.2) input and output data ........................................................................ 78

Appendix G. Output from OPP Aggregate Incident Database for Propyzamide ................................................ 79

Appendix H. Example STIR (v. 1.0) input and output data ................................................................................. 80

Appendix I. SIP Results ........................................................................................................................................... 81

Appendix J. Accepted ECOTOX Data Table (sorted by effect; double click) .................................................... 82

Appendix K. Complete List of Propyzamide Studies ............................................................................................ 83
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1. Executive Summary 

Propyzamide (also known as pronamide) is a selective, systemic, restricted–use, organochlorine 

herbicide that is formulated as a wettable powder in water soluble pouches and a suspension 

concentrate that may be applied pre-plant, pre-emergence, or post-emergence by chemigation, 

ground or aerial spray equipment, depending on the use. Wetting-in of applications is 

recommended with rainfall or irrigation so that the compound is available for uptake into plant 

root systems. Most application timing occurs in the fall or early winter prior to freezing. 

Propyzamide is currently registered for use on a variety of outdoor crops, orchards, turf, Christmas 

trees and ornamentals. 

Propyzamide has relatively low volatility and is soluble in water. Therefore, potential transport 

mechanisms considered in this assessment include leaching, spray drift and runoff, but not 

volatilization and atmospheric transport as these are not expected to be important. The compound 

is stable to hydrolysis, from moderately mobile to slightly mobile (FAO, 2000), and has been 

detected in both surface and ground water, in monitoring studies. The major routes of degradation 

appear to be aerobic metabolism in soil and photolysis in water. In anaerobic environments, 

propyzamide may be moderately persistent. 

Toxicity data are not available for degradates of propyzamide; however, all identified degradates 

other than carbon dioxide retain the 3,5-dichlorobenzoyl moiety and in the absence of data to the 

contrary are considered residues of concern for all taxa.. Therefore, a total residues of concern 

(TRC) approach was used to evaluate the potential exposure to the residues of risk concern, which 

include propyzamide and all identified degradates other than carbon dioxide, for drinking water 

and aquatic organisms. In this assessment, the proposed new use on leaf lettuce is considered. 

Propyzamide is classified as slightly-to-moderately toxic to freshwater and estuarine/marine fish 

(and to aquatic-phase amphibians for which freshwater fish serve as surrogates) as well as to 

freshwater and estuarine/marine invertebrates on an acute exposure basis. Propyzamide is 

practically non-toxic to birds (and to terrestrial-phase amphibians and reptiles for which birds serve 

as surrogates) on an acute oral and subacute dietary exposure basis. The compound is classified 

as practically non-toxic to mammals on an acute oral exposure basis and is practically non-toxic 

to young adult honey bees (Apis mellifera) on an acute contact basis. 

Chronic studies demonstrated; 1) impaired reproduction in birds, freshwater fish and invertebrates; 

and 2) adverse growth effects in mammals. 

Toxicity to aquatic to aquatic and terrestrial plants was observed upon exposure to propyzamide. 
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Propyzamide exposure at the labeled application rates may result in risk to federally listed 

threatened and endangered (hereafter referred to as “listed”) species of terrestrial and semi-aquatic 

monocotyledonous (monocot) and dicotyledonous (dicot) plants. Listed terrestrial plants exposed 

to residues of propyzamide in irrigation water are at risk as well. Risk estimates do not exceed the 

levels of concern (LOC) for listed and non-listed freshwater and estuarine/marine fish and 

amphibians, or listed and non-listed vascular and non-vascular aquatic plants. Chronic risk LOC’s 

are exceeded for mammals. Although propyzamide is classified as practically non-toxic to avian 

taxa (and therefore reptiles and amphibians exposed through terrestrial diet), acute and dietary risk 

exceed the LOC. There are also chronic risk concerns for avian taxa. Uses of propyzamide on 

artichoke and apples, alfalfa, blueberries, and head/leaf lettuce, and turf may result in chronic risk 

to small (15 g), medium (35 g), and large (1000 g) size classes of mammals. No acute mammalian 

exceedances were seen, nor exceedances to honey bees via contact exposure. 

Data Gaps/Uncertainties 

Environmental Fate 

There are no environmental fate data gaps for propyzamide. 

Ecological Effects 

No data have been submitted for chronic toxicity to estuarine/marine fish and invertebrates. 

Therefore, a mysid chronic toxicity test (OCSPP 850.1350) and estuarine/marine fish early-life 

stage test (OCSPP 850.1400) are classified as data gaps. An acute-to chronic ratio (ACR) based 

on freshwater invertebrate toxicity values has been calculated to estimate estuarine/marine 

invertebrate toxicity values. An ACR cannot be calculated for estuarine/marine fish because a 

different species of freshwater fish was used in the acute and chronic freshwater fish toxicity tests. 

Additional estuarine marine fish and invertebrate data are not needed because there is minimal 

risks to aquatic organisms from propyzamide use. 

The avian reproduction study (OCSPP 850.2300) with the Mallard (MRID 48931803) was 

classified as supplemental. The reported NOAEC was a non-definitive “less than” (<) the lowest 

concentration tested. Although the avian reproduction study did not establish a lower bound for 

effects on avian reproduction, exceedances were observed at the lowest test concentration used 

311 mg a.i./kg diet. Additional data is needed to characterize the lower bounds of chronic toxicity 

to avian taxa. 

Although data indicate propyzamide is practically non-toxic to young adult bees on an acute 

contact exposure basis, the toxicity endpoint is non-definitive, and there is uncertainty regarding 

potential risk from acute oral exposure when considered in the context of estimated exposures (i.e., 

EECs) from registered uses of propyzamide. There is also uncertainty regarding the potential acute 

and chronic effects of the compound on honey bee larval development and survival as well as 

potential chronic effects in adult bees. Therefore, additional data on pollinators is needed to fully 

characterize the risk associated with propyzamide use to all developmental stages of honey bees, 

as sensitivity may vary according to life-stage and length of exposure (adult vs. larval and acute 
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vs. chronic, respectively). As described in the guidance for assessing risks to bees1,2, depending 

on the outcome of the screening-level risk assessment, additional studies of bees at the colony 

level under semi- and full-field conditions may also be recommended. 

The Tier II vegetative vigor plant toxicity study showed IC25 values that were less than the NOAEC 

values. Extrapolated IC25 values fell outside the range of test concentrations resulting in 

uncertainty regarding the actual IC25 value. As a result, IC25 values have a non-definitive “less 

than” (<) value. The NOAEC value for the seedling emergency monocot study is also described 

as a non-definitive “less than” value. Furthermore, both the seedling emergence and vegetative 

vigor studies were conducted with TGAI as opposed to TEP. TEP formulations may enhance the 

toxicity and persistence of the chemical. Therefore, additional seedling emergence and vegetative 

vigor studies are needed with TEP to characterize the effects of propyzamide on terrestrial plants. 

2. Problem Formulation 

2.1. Nature of Chemical Stressor 

Propyzamide is a systemic restricted–use, organochlorine herbicide that is formulated as a wettable 

powder in water soluble pouches and can be applied pre-plant, pre-emergence, or post-emergence 

by chemigation, ground or aerial spray equipment, depending on the use. Propyzamide is currently 

registered for use on a variety of outdoor crops, orchards, and other agricultural and nonagricultural 

areas. There are eight active registrations which include: two technical grades (EPA Reg. 

Num./percent of active ingredient 62719-394/94.6%; 87285-1/97.5%); two suspension 

concentrates (62719-578/35.6% SC and 87290-22/35.6% SC), three water soluble packets (87290-

3/50%; 87290-9/50% and 62719-397/50%) and manufacturing use product (62719-391/51%). 

The chemical is used on alfalfa, apples, globe artichokes (CA), birdsfoot trefoil, 

blackberry/boysenberry/raspberries, blueberries, cherries, clover, crown vetch, endive, escarole, 

grapes, fallow land, head lettuce, nectarines, peaches, pears, plums, prune, radicchio greens, 

raspberries, rhubarb, sainfoin, winter peas, woody ornamentals, nursery stock of ornamentals, and 

Christmas trees. 

2.1. Stressor Source and Distribution 

The compound is absorbed by plants via the root system and distributed throughout the plant. The 

mode of action of propyzamide is unknown although it has been shown to inhibit cell division by 

preventing the formation of spindle fibers during mitosis via binding to proteins associated with 

microtubule assembly (Griffen 2003). The details regarding the active site of the chemical are not 

known. 

 

1

USEPA. 2014. Guidance for Assessing Pesticide Risks to Bees. Office of Pesticide Programs. United States Environmental Protection Agency. 

Available at 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/terrestrial_biology_tech_team/GuidanceAssessingPesticideRisk2Bees.

pdf 2

http://www2.epa.gov/sites/production/files/2014-06/documents/pollinator_risk_assessment_guidance_06_19_14.pdf 
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2.2. Receptors 

A receptor is a biological entity that is exposed to a stressor (USEPA 1998A). For this assessment, 

the receptors include terrestrial and aquatic plants and animals inhabiting fields where 

propyzamide is applied, and those inhabiting non-target areas to which propyzamide may be 

transported (e.g., via spray drift and runoff). Consistent with the process described in the Overview 

Document (USEPA 2004), the risk assessment uses a surrogate species approach in its evaluation 

of propyzamide. Toxicological data generated from surrogate test species, which are intended to 

be representative of broad taxonomic groups, are used to extrapolate to 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 are used to evaluate potential direct effects of propyzamide to aquatic and 

terrestrial receptors. The open literature studies are located through EPA’s database ECOTOX 

(http://cfpub.epa.gov/ecotox/), which provides a source for locating single chemical toxicity data 

for aquatic life, terrestrial plants, and wildlife. 

 

2.3. Assessment Endpoints 

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

an ecological entity (e.g., species, community) and its attributes (USEPA 1998A). For 

propyzamide, the ecological entities include birds, mammals, freshwater fish and invertebrates, 

estuarine/marine fish and invertebrates, terrestrial plants, insects, and aquatic plants and algae. 

The attributes evaluated for each of these entities may include growth, reproduction, and survival. 

2.4. 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. 

A conceptual model provides a description of the predicted relationships between propyzamide, 

the potential routes of exposure, and the predicted effects for each assessment endpoint. 

2.4.1. Risk Hypothesis 

For propyzamide, the following ecological risk hypothesis is employed for this risk assessment: 

Propyzamide, when used in accordance with current labels, can result in off-site movement 

of the compound via runoff, erosion of sediment-bound residues and spray drift leading to 

exposure of non-target terrestrial and aquatic plants and animals. Applications to foliar 

surfaces may serve as a major source of propyzamide exposure to wildlife. This potential 

exposure pathway may result in adverse effects upon the survival, growth, and 
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reproduction of non-target terrestrial and aquatic organisms. These nontarget organisms 

include Federally-listed threatened and endangered species.

2.4.2. Conceptual Model Pathways and Effects 

 

The environmental fate properties of propyzamide indicate that for ground spray applications, 

spray drift, and runoff are potential transport mechanisms to aquatic habitats where non-target 

organisms may be exposed. It is expected that non-target terrestrial organisms can be exposed to 

propyzamide following pre-emergent application, through consumption of exposed plants and 

invertebrates on the treated field. The plant uptake of the chemical may be a pathway of exposure 

to non-target terrestrial organisms upon consumption. Additionally, propyzamide may reach 

terrestrial environments off treated fields via spray drift, and groundwater containing residues of 

propyzamide. A summary of the transport pathways and the models used to generate estimated 

environmental concentrations (EECs) for those pathways in the assessment is provided in Table 

1. 

 

The transport pathways may result in exposure to various aquatic and terrestrial organisms. With 

exposure, the following attribute changes have the potential to occur: 

 Effects to individual organisms, 

 Effects to food webs (reduction in prey and food,), and 

 Effects to habitat integrity (reduction in primary productivity, reduced cover, community 

change, habitat modification). 

Table 1. List of the various models and the related taxa for which the models will be used 

to assess risk. 

Environment Taxa of 

Concern 

Exposure 

Media 

Exposure 

Pathway 

Model(s) or 

Pathway 

Aquatic 

Vertebrates/ 

Invertebrates 

Surface water/ 

sediment 

Runoff and spray 

drift to water and 

sediment 

SWCC 

Aquatic Plants 

(vascular and 

nonvascular) 

Riparian plants See terrestrial exposure pathways 

Terrestrial Vertebrate 

Dietary items 

Ingestion of 

residues in/on 

dietary items, 

including treated 

seeds as a result 

of direct 

application 

T-REX 

Consumption of 

aquatic organisms 

Residues taken 

up by aquatic 

organisms 

Not a major 

transport 

pathway 

Plants Spray drift/runoff Runoff and spray 

drift to plants 

TERRPLANT 

AgDRIFT 
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Environment Taxa of 

Concern 

Exposure 

Media 

Exposure 

Pathway 

Model(s) or 

Pathway 

Surface water Residues in 

groundwater 

irrigation water 

SWCC 

Groundwater PRZM-GW 

Bees and other 

terrestrial 

invertebrates1 

Contact 

Spray contact 

and ingestion of 

residues in/on 

dietary items as 

a result of direct 

application. 

Uptake of 

pollen/nectar 

from plants. 

T-REX (contact 

only)

All 

Environments All 

Movement through 

air to aquatic and 

terrestrial media 

Spray drift AgDRIFT (Spray 

drift) 

Atmospheric 

transport 

Not a major 

transport 

pathway 

Text in italics represent transport pathways that are not of concern. 1 See pollinator SAP white paper for full list of modeling approaches for evaluating exposure used in this assessment 

(USEPA 2012). 

2.5. Analysis Plan 

The analysis plan is the final step in the Problem Formulation (Docket ID# EPA-HQ-OPP-2009-

0326). During this step, an assessment design is developed, the scope of the assessment is outlined, 

the methods for conducting the assessment are determined, measurements of effects and exposure 

to evaluate the risk hypothesis are delineated, and initial data gaps and assumptions required to 

address them are identified. 

2.5.1. Conclusions from Previous Risk Assessments 

Propyzamide was first registered under the name pronamide in 1972 for use on broadleaf weeds 

and grasses. The Agency conducted multiple subsequent assessments through the preparation of 

the 1994 Re-registration Eligibility Decision (RED), including an emergency exemption 

assessment in 1988 (DP barcode unspecified) for use on marigolds in California. That assessment 

concluded that impacts to non-target organisms were not expected, but that the compound’s 

potential for leaching could not be assessed due to the lack of data. Ecological drinking water 

exposure assessments and the problem formulation on propyzamide conducted in support of the 

registration review and those in the interim are briefly discussed below. The aforementioned 

documents serve as a basis for this preliminary risk assessment. 

2.5.2. Propyzamide Ecological Risk Assessments 

Ecological risk assessments completed for propyzamide include two emergency exemption 

(FIFRA Section 18) assessments conducted in 1994 for use on grass grown for seed in Oregon 
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(DP Barcode unspecified) and in 1998 for use on cranberries in Massachusetts (DP Barcode 

242640). The FIFRA Section 18 assessment for use on grass grown for seed identified potential 

risk to terrestrial and wetland plants, including the listed plant Bradshaw's Lomatium (Lomatium 

bradshawii), and identified significant data gaps for aquatic plants and other taxa. The FIFRA 

Section 18 assessment for use on cranberries in Massachusetts found no potential risk to listed or 

non-listed organisms. 

A Re-registration Eligibility Decision (RED) document was prepared for propyzamide in 1994 

(USEPA 1994). The RED assessed use on food crops (artichoke, blackberry, blueberry, 

boysenberry, cherry, endive, escarole, lettuce, nectarine, peach, pear, plum, prune, raspberry, 

rhubarb), food and feed crops (fallow land, apple, grapes, peas, sugar beet), feed crops (alfalfa 

clover, sainfoin, trefoil, vetch) and non-food crops (Christmas tree farms, golf courses and 

recreational turf, ornamentals), concluding that all products were eligible for re-registration, except 

for broadcast application on residential turf and late season uses on artichokes (USEPA 1994). 

The RED identified no risk to terrestrial animals, aquatic animals, or aquatic plants. Studies of 

toxicity to aquatic invertebrates (chronic), aquatic plants, and terrestrial dicots were requested to 

eliminate data gaps. Risk to terrestrial monocots was identified from all registered uses. 

An ecological risk assessment of proposed uses on chicory, Belgian endive, dandelion, and berries 

was completed in 2007 (USEPA 2007a; DP Barcode 329358). This assessment identified potential 

chronic risk to mammals and potential risk to terrestrial and semi-aquatic plants. Potential risk of 

direct effects was identified to listed mammals, birds, estuarine invertebrates, and terrestrial and 

semi-aquatic plants. Potential risk of indirect effects was identified for most taxa due to potential 

risk to plants. An addendum to the ecological risk assessment (USEPA 2007b) indicated that risk 

to listed estuarine invertebrates was below levels of concern. 

An endangered species assessment was conducted, of risks from propyzamide use to the federally 

threatened California red-legged frog (CRLF; Rana aurora draytonii) (USEPA 2008). The 

Agency made a Likely to Adversely Affect determination for the CRLF from the use of 

propyzamide and determined that there is potential for modification of CRLF designated critical 

habitat as well. The use of propyzamide was found likely to adversely affect terrestrial-phase 

CRLF through chronic effects. Additionally, propyzamide was found likely to adversely affect 

the terrestrial-phase CRLF through reductions in terrestrial plants that serve as cover. The decrease 

in terrestrial plants along riparian zones was also found likely to adversely affect the aquatic-phase 

CRLF through indirect effects on water quality. The use of propyzamide was also found likely to 

modify the primary constituent elements (PCEs) of designated critical habitat for both aquatic- and 

terrestrial-phase CRLF. 

A registration review problem formulation was conducted in 2009 (USEPA 2009; DP Barcode 

363909). In this problem formulation multiple data gaps were identified. These deficiencies 

included freshwater and saltwater fish acute toxicity, saltwater invertebrate acute toxicity, 

freshwater and saltwater fish early life stage toxicity, estuarine/marine invertebrate life cycle 

toxicity, avian oral toxicity (passerine species), and avian reproduction. Since 2009, many of the 

studies have been submitted and reviewed by the Agency and are included in this assessment. 

2.5.3. Drinking Water Assessment 
-Page 13 of 86- 

A drinking water exposure assessment was conducted recently in support of human health risk 

assessment for leaf lettuce use (USEPA, 2015). The estimated drinking water concentrations 

(EDWCs) for the Health Effects Division’s (HED) dietary assessment was 102 ppb for the acute 

dietary assessment and 47.0 ppb for the chronic and cancer dietary assessments. For assessment 

purposes, EFED assumed two leaf lettuce growing seasons may occur per year, resulting in a 

maximum annual rate of 4.0 lbs a.i./acre. In this assessment however, leaf lettuce was modeled 

with only one application a year. 

2.5.4. Identification of Data Gaps and Uncertainties 

In terms of environmental fate studies required to support the registration of propyzamide, the 

environmental chemistry method and the independent laboratory validation in soil studies are 

needed. 

With respect to data requirements to support the assessment of ecological effects, no data have 

been submitted for chronic effects to estuarine/marine fish and invertebrates. An estuarine/marine 

invertebrate life-cycle test (OCSPP 850.1350) and an estuarine/marine fish early-life stage test 

(OCSPP 850.1400) are listed as uncertainties due to an absence of data. An acute-to chronic ratio 

(ACR) based on freshwater invertebrate toxicity value has been calculated to permit estimation of 

estuarine/marine invertebrate toxicity values. An ACR cannot be calculated for estuarine/marine 

fish because different species of freshwater fish were used in the acute and chronic freshwater fish 

toxicity tests. Minimal risks to estuarine/marine fish and invertebrates is expected from 

propyzamide use on a chronic exposure basis, therefore, no additional data is needed. In order for 

chronic exceedances to occur, the NOAEC would need to be 34.4 and 29.3 μg a.i./L for the 

estuarine/marine fish and invertebrate, respectively. Currently, the most sensitive acute 

estuarine/marine fish and invertebrate LC50 is >7,690 and 3,500 μg a.i./L, respectively, for the 

Sheepshead minnow and Eastern oyster (MRIDs 48599212 and 43608401). The most sensitive 

chronic freshwater fish and invertebrate NOAEC is 224 and 600 μg a.i./L, respectively, for the 

Fathead minnow and Water flea (MRIDs 48931801 and 43673301). 

The avian reproduction study (OCSPP 850.2300) with the Mallard was classified as supplemental 

because the reported NOAEC was a non-definitive “less than” (<) the lowest concentration tested. 

Although the avian reproduction study did not establish a lower bound for effects on avian 

reproduction, exceedances were observed at 311 mg a.i./kg diet. Additional data is needed to 

characterize the lower bounds of chronic toxicity to avian taxa. 

Although data indicate propyzamide is practically non-toxic to young adult bees on an acute 

contact exposure basis, the toxicity endpoint is non-definitive, and there is uncertainty regarding 

potential risk from acute oral exposure when considered in the context of estimated exposures (i.e., 

EECs) from registered uses of propyzamide. There is also uncertainty regarding the potential acute 

and chronic effects of the compound on honey bee larval development and survival as well as 

potential chronic effects in adult bees. Therefore, additional data on pollinators is needed to fully 

characterize the risk associated with propyzamide use to all developmental stages of honey bees, 

as sensitivity may vary according to life-stage and length of exposure (adult vs. larval and acute 
-Page 14 of 86- 

vs. chronic, respectively). As described in the guidance for assessing risks to bees3,4, depending 

on the outcome of the screening-level risk assessment, additional studies of bees at the colony 

level under semi- and full-field conditions may also be recommended. 

The Tier II vegetative vigor plant toxicity study showed IC25 values that were less than the NOAEC 

values. Extrapolated IC25 values fell outside the range of test concentrations resulting in 

uncertainty regarding the actual IC25 value. As a result, IC25 values have a non-definitive “less 

than” (<) value. The NOAEC value for the seedling emergency monocot study is also described 

as a non-definitive “less than” value. Furthermore, both the seedling emergence and vegetative 

vigor studies were conducted with TGAI as opposed to TEP. TEP formulations may enhance the 

toxicity and persistence of the chemical. Therefore, additional seedling emergence and vegetative 

vigor studies are needed with TEP to characterize the effects of propyzamide on terrestrial plants. 

2.5.5. Measures of Exposure 

Screening-level assessments are intended to be protective of wildlife on a national level, as 

opposed to being regionally or locally specific. Therefore, this assessment is not intended to 

represent a spatially- or temporally-specific analysis. Maximum application rates are used to 

model EECs. Measures of exposure are based on aquatic and terrestrial models (Table 1) that 

calculate EECs using maximum proposed application rates and methods. Groundwater is also 

assessed due to the leaching potential of propyzamide and the potential to use groundwater as 

irrigation water on crops. Exposure models are parameterized using relevant use (proposed label 

rates) and environmental fate data according to current EFED model input parameter guidance.5 

The Surface Water Concentration Calculator (SWCC, v 1.106, May, 2014) is used to generate 

EECs representing concentrations that may occur in surface water. The SWCC simulates pesticide 

transformation on and runoff from an agricultural field (in addition to loadings from spray drift), 

following applications to crops. The model then simulates resulting concentrations in an adjacent 

surface water body (i.e., the standard pond). 

Groundwater concentrations are estimated using the PRZM-GW model (Pesticide Root Zone 

Model for Groundwater, version 1.07), with the GW-GUI (Graphical User Interface, version 1.0, 

August 31, 2012). PRZM-GW is a one-dimensional leaching model that estimates potential 

concentrations of pesticides in vulnerable groundwater. It accounts for pesticide fate in the crop 

root zone by simulating pesticide transport and degradation through the soil profile after a pesticide 

is applied to an agricultural field. PRZM-GW permits the assessment of multiple years of 

sequential pesticide application (up to 100 years) on a single site. Six standard scenarios, each 

representing a different region known to be vulnerable to leaching and groundwater contamination, 

are currently available for use with PRZM-GW for risk assessment purposes. 

 

3

USEPA. 2014. Guidance for Assessing Pesticide Risks to Bees. Office of Pesticide Programs. United States Environmental Protection Agency. 

Available at 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/terrestrial_biology_tech_team/GuidanceAssessingPesticideRisk2Bees.

pdf 4

http://www2.epa.gov/sites/production/files/2014-06/documents/pollinator_risk_assessment_guidance_06_19_14.pdf 5 http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm
-Page 15 of 86- 

The Terrestrial Residue Exposure Model (T-REX, version 1.5.2, 6/20/2013) is used to derive 

terrestrial EECs on food items for terrestrial vertebrates. Upper-bound Kenega nomogram values 

used in T-REX are based on Hoerger and Kenega (1972) as modified by Fletcher et al. (1994), and 

are used to derive EECs for terrestrial mammals and birds based on dietary- and dose-based 

exposures from pre-emergent applications. A one-year time period is simulated. Consideration is 

given to different types of feeding strategies for mammals and birds, including herbivores, 

insectivores and granivores. For dose-based exposures, three weight classes of mammals (15, 35, 

and 1000 g) and birds (20, 100, and 1000 g) are considered. 

The TerrPlant model (v. 1.2.2, 12/26/2006) is used to derive runoff and spray drift EECs for 

estimating exposures to terrestrial plants inhabiting dry and semi-aquatic areas. Exposure 

estimates using the Screening Tool for Inhalation Risk (STIR, v. 1.0, 11/23/2010) indicated that 

inhalation was not expected to be a significant route of exposure for wildlife (Appendix H). 

Drinking water pathways were screened using the SIP (Screening Imbibition Program, v. 1.0). SIP 

results showed that acute and chronic exposure to propyzamide through drinking water does not 

represent a potential concern for mammals and birds (LOC exceedances not expected; Appendix 

I). SIP is described in detail at: http://www.epa.gov/oppefed1/models/terrestrial/index.htm. 

To characterize potential non-target plant exposure from spray drift alone, Tier 1 modules in 

AgDRIFT (v. 2.1.1, December 2011) were used to estimate how far off-site spray drift exposure 

might occur at a level known to cause adverse effects in terrestrial plant toxicity studies. For 

ground applications, EFED used the American Society of Agricultural and Biological Engineers 

(ASABE, formerly ASAE) Coarse-to-Very Coarse droplet size category in its modeling. This size 

category is an assumption for herbicides that require root uptake. The volume median diameter 

(Dv50) for the Coarse-to-Very Coarse droplet size distribution is 440 microns. 

The Kow-based Aquatic BioAccumulation Model (KABAM)6 v. 1.0 is used to estimate potential 

bioaccumulation of hydrophobic organic pesticides in freshwater aquatic food webs and 

subsequent risks to mammals and birds via consumption of contaminated aquatic prey. Due to 

low measured fish bioconcentration factors (range of 21-77) and low/middle range octanol/water 

partition coefficient (log Kow=3.0-3.3), propyzamide is not expected to bioconcentrate in aquatic 

environments (MRID 43196701). Therefore, KABAM modeling is not triggered by 

propyzamide’s physicochemical characteristics and was not used in this assessment. 

2.5.6. Measures of Effect 

Measures of effect are obtained from a suite of registrant-submitted guideline studies which are 

conducted with a limited number of surrogate species. The test species are not intended to 

necessarily be representative of the most sensitive species but rather are selected based on their 

ability to thrive under laboratory conditions. For example, toxicity testing reported in this risk 

assessment utilizes surrogate species to represent all freshwater fish (>2000 species) and birds 

(>680 species) identified in the U.S. 

 

The acute measures of effect used in this screening-level assessment include the median lethal 

dose (LD50), median lethal concentration (LC50), and the median effect concentration (EC50). 

 

6 http://www.epa.gov/oppefed1/models/water/kabam/kabam_user_guide.html
-Page 16 of 86- 

These are measures of acute toxicity which result in 50% of the respective effect in tested 

organisms. The endpoints for chronic measures of effect are the No Observed Adverse Effects 

Concentration (NOAEC) and the No Observed Adverse Effects Level (NOAEL). Toxicity studies 

are submitted for freshwater fish and invertebrates, estuarine/marine fish and invertebrates, aquatic 

and terrestrial plants, birds, mammals and honey bees. The measurement endpoints used for risk 

characterization are derived from studies which underwent review and are classified as 

“acceptable” (conducted under guideline conditions and considered to be scientifically sound) or 

“supplemental” (conditions deviated from guidelines but the results are scientifically sound). 

The ECOTOXicology database (ECOTOX), was searched in August 2013 to identify whether 

additional, more sensitive ecological effects data were available for propyzamide; however, no 

additional useful data were identified (Appendix J).

2.5.7. Integration of Exposure and Effects 

The exposure and effects data are integrated to evaluate the risks of adverse ecological effects on 

non-target species. For the screening-level assessment of propyzamide, the deterministic, risk 

quotient (RQ) method is used to compare estimated exposure and measured toxicity values. The 

RQ method involves dividing EECs by the most sensitive acute and chronic toxicity values for 

specific taxa. The resulting RQs are then compared to the Agency’s levels of concern (LOCs) 

(USEPA 2004) for acute and chronic risk. These criteria are used to indicate whether applications 

of propyzamide, as directed on the proposed label, have the potential to cause adverse effects to 

non-target organisms. 

Although risk is often described in terms of the likelihood and magnitude of adverse effects, the 

risk quotient-based approach does not provide a quantitative estimate of likelihood or magnitude 

of an adverse effect, but rather provides a “yes” or “no” answer depending upon whether or not 

LOCs are exceeded. 

3. Analysis 

3.1. Use Characterization 

Propyzamide is a systemic, organochlorine herbicide that can be used as pre-emergence and early 

post-emergence control of winter annual and perennial grasses and chickweed. The maximum 

annual application rate is 4.5 lbs a.i./A for the use on turf with a single application rate of 1.5 lbs 

a.i./A. The label failed to specify the number of applications as a result three applications were 

assumed in the spring, summer, and fall with a re-treatment interval of 91 days. Propyzamide can 

be applied to turf by ground (Table 2). 

Table 2. Maximum Use Patterns for Propyzamide Uses. 

Use 

Pattern

Max. 

Single 

App. Rate 

(lbs a.i./A)

Number 

of Apps 

per 

Year.

Annual 

App. Rate 

(lbs a.i./A)

Minimum 

Retreatment 

Interval (days)

Applic

ation 

Metho

d

Comments 

Artichoke 4 1 4 Not applicable Aerial/ In CA only 
-Page 17 of 86- 

ground 

Alfalfa 2 na 2 Not applicable Ground 

Apples 4 1 4 Not applicable Ground 

Blueberries 2 1 2 Not applicable Ground 

Head/leaf 

lettuce1 2 1 2 Not applicable Aerial/

ground 

2

A split 

application can be 

performed at a 

max of 1.0 lbs 

a.i./A and 10 day 

MRI 

Turf3 1.5 3 4.5 91 Ground 

1

 Head lettuce was modeled but this is also representative of leaf lettuce. However, if more application are 

performed for these crops (more than one crop cycles), the EECs may not be conservative. 

2

For Head lettuce only 

3

Assumed 3 days interval and 3 applications/year 

na= not applicable 

3.2. Exposure Characterization 

3.2.1. Environmental Fate and Transport 

Monitoring data on propyzamide have revealed concentrations in the environment (water) 

consistent with the peak (3.7-10.3 μg/L) and annual mean (0.53-4.45 μg/L, USEPA 2009). 

Monitoring data are not available on any degradates of propyzamide. 

Propyzamide is an organochlorine herbicide (pre-emergence and early postemergence control of 

winter annual and perennial grasses and chickweed) that is typically applied aerially or by ground 

equipment, and wetted in, during the fall or winter months. The major routes of degradation of 

parent appear to be aerobic microbial degradation in soil (44.6 d) and photolysis in water (217 d). 

Four major degradates of propyzamide have been identified (RH-24644, RH-24655, RH-24580 

and RH-26059, with maximum applied radioactivity of 31.9%, aerobic soil metabolism; 27.3%, 

aerobic aquatic metabolism; 32.2%, anaerobic soil metabolism and 15.0%, aqueous photolysis 

respectively). The Health Effects Division (HED) found all degradates of propyzamide that contain 

the 3,5-dichlorobenzoyl moiety to be of human risk concern, assuming that their toxicity is similar 

to that of propyzamide parent (USEPA, 2002; 2007). A total residue (TR) approach was therefore 

used to generate EECs (environmental exposure concentrations) that reflect residues, in the pond, 

of the parent compound plus all such degradates of concern. 

Propyzamide has relatively low vapor pressure (8.5 x 10-5 torr; 25°C) and is soluble in water up to 

15 mg/L (25°C). The compound is stable to hydrolysis, relatively resistant to soil photolysis (t1/2

= 249 d), and moderately susceptible to aquatic photolysis (t1/2 = 42 d). Propyzamide degrades 

relatively readily in aerobic soil environments (t1/2 = 20-44.6 d), but is more persistent in anaerobic 

environments (t1/2 = 127-450 d) and aquatic environments (aerobic aquatic and anaerobic aquatic 

half-lives of 119 d and 450 d, respectively). Sorption to soils is a function of both organic carbon 

and cation exchange capacity. Nonetheless the compound is classified as moderately mobile to 

slightly mobile in soil (KFOC range = 700 – 5383), and thus presents a potential groundwater 

concern in some areas, e.g., those with sandy soils and high water tables. Propyzamide has indeed 

been detected in both surface water and groundwater. 
-Page 18 of 86- 

Table 3 summarizes known physical/chemical properties of propyzamide based upon submitted 

environmental fate studies on the pesticide. A complete listing of environmental fate data can be 

found in Appendix K. 

Table 3. General Chemical Properties and Environmental Fate Parameters of 

Propyzamide. 

Chemical/Fate Value Source 

Chemical name 

3,5-dichloro-N-(1,1-

dimethylprop-2-

ynyl)benzamide 

USEPA, 1994 

Molecular mass 256.13 g/mol USEPA, 1994 

Vapor pressure (25C) 8.5 x 10-5 torr USEPA, 1994 

Solubility (25C) 15 mg/L USEPA, 1994 

Octanol-water partition 

coefficient (KOW) 1000-2000 MRID 46413408 

Freundlich organic carbon 

partitioning coefficient (KFOC) 

in L/kgOC

700 

1026 

1150 

1317 

1586 

2283 

2287 

5383 

MRID 49126805 

Hydrolysis half-life at pH 4.7, 

7.4 and 8.8 (20C) No significant degradation MRID 00107980 

Aqueous photolysis half-life for 

parent; 

Total residues method half-life 

41.7 d; 217 d MRID 40420301, MRID 

40320601 

Soil photolysis half-life for 

parent; 

Total residues method half-life 

249 d; No significant 

degradation MRID 41913504 

Aerobic soil metabolism halflife for parent; 

Total residues method half-life 

(soil texture) 

20.1 d; 64.9 d (sandy loam) 

21.5 d; 96.6 d (silty clay loam) 

44.6 d; 166 d (loamy sand) 

MRID 46413407 

Anaerobic soil metabolism halflife for parent; 

Total residues method half-life 

(soil texture) 

450 d; No significant 

degradation (sandy loam) MRID 41913505 

Aerobic aquatic metabolism 

half-life for parent; 

Total residues method half-life 

(sediment texture) 

69.0 d; 899 d (silt loam) 

119 d; 782 d (sand) MRID 46427901 

Anaerobic aqueous metabolism 

half-life for parent; 

Total residues method half-life 

(soil texture) 

127 d; 402 d (loamy sand) MRID 46413408 

Terrestrial field dissipation 18-24 d (sandy loam) MRID 44078601 
-Page 19 of 86- 

Chemical/Fate Value Source 

half-life 

(soil texture) 

34-53 d (loam) 

Propyzamide is a soluble chemical (15 mg/L in water at 25C; USEPA, 1994) that is not expected 

to volatilize significantly due to the compound’s relatively low vapor pressure of 8.5 x 10-5 torr 

(25C; USEPA, 1994). Propyzamide is slightly to moderately mobile, with Freundlich soil-water 

partitioning coefficients (KF) that ranged (in 8 soils) from 18.3 (1/n=0.96) to 47.2 (1/n=0.96). 

Additionally, organic carbon partitioning coefficients (KFOC) ranged from 700 to 5383 L/kgOC. 

These values range in classification from moderately mobile to slightly mobile (FAO 2000). 

Mobility is partially explained by affinity to organic carbon, as the coefficient of variation (CV) 

across six soils for KFOC (40%) is less than that for KF (47%). The compound may also have 

greater mobility in sandy, clay-poor soils, as KF values for propyzamide correlate with cation 

exchange capacity (R2 = 0.9214).

Propyzamide is stable to hydrolysis at pH 5, 7, and 9, relatively persistent with respect to photolysis 

on soil (t1⁄2 = 249 d), but moderately susceptible to degradation by aquatic photolysis (t1⁄2 = 41.7 d). 

Two major photodegradates were identified: RH-26059 and RH-24580. 

Parent propyzamide is slightly persistent (Goring scale, 1975) in aerobic soils (t1⁄2 = 20.1-44.6 d) 

and moderately persistent in aerobic aquatic systems (t1⁄2 = 69.0-119 d). Propyzamide is also 

moderately persistent in anaerobic aquatic systems (t1⁄2 = 127 d), and persistent in anaerobic soils 

(t1⁄2 = 450 d). 

Major degradates of propyzamide (>10% of the applied radioactivity) include RH-24644, RH24580, RH-26059, and carbon dioxide. Six minor degradates have also been identified: RH24655, RH-20839, RH-26521, RH-25891, RH-26702, 3,5-dichlorobenzamide (See the structures 

of degradates in Appendix B). A batch equilibrium study on RH-24644 and RH-24580 indicates 

that RH-24644 has similar to lower mobility compared to propyzamide (KF range = 2.34 

(1/n=0.98) to 55.1 (1/n=0.86); KFOC range = 993-3910 L/kgOC), whereas RH-24580 is 

unambiguously more mobile than propyzamide (KF range = 0.283 (1/n=0.83) to 2.36 (1/n=0.87); 

KFOC range = 96.3-210 L/kgOC. 

The two major degradates observed in metabolism studies were RH-24580 at up to 32.2% of the 

applied, and RH-24644 at up to 31.9% of the applied. Carbon dioxide was also formed, at up to 

50.4% of the applied. Both RH-24580 and RH-24644 appear to degrade no more quickly than the 

parent based on biotic studies. 

3.2.2. Aquatic Exposure 

3.2.2.1 Model Inputs 

Estimated Environmental Concentrations (EECs) for surface water were generated using the 

Surface Water Concentration Calculator (SWCC v. 1.106). Table 4 list the input parameters used 

in aquatic exposure modeling for propyzamide. 
-Page 20 of 86- 

Chemical property model input values were chosen in accordance with EFED’s current input 

parameter guidance7

. Based on analysis of total toxic residues, the upper 90% confidence limit on 

the mean half-life was selected as the model input value for aerobic soil and aerobic aquatic 

metabolism pathways (165 d and 1,020 d TR half-lives respectively). For the anaerobic aquatic 

metabolism pathway (used to represent decay within the benthic zone of the receiving water body), 

the single available half-life was multiplied by 3 (producing a value of 1,210 d) to account for 

uncertainty associated with limited data. 

Table 4. SWCC Input Parameters for Propyzamide (TR). Source Data are in Table 3. 

Input Parameter Value Justification Source 

Molecular Mass (g/mol) 256.13 Product chemistry data USEPA, 1994 

Vapor Pressure at 25°C 

(torr) 

8.5 x 10-5 Study value USEPA, 1994 

Solubility in Water at 

25o

C (mg/L) 

15.0 Product chemistry data USEPA, 1994 

Organic Carbon Partition 

Coefficient (KOC) 

(L/kgOC) 

1966 Represents the mean KFOC for 

propyzamide parent as an 

estimate of the partition 

coefficient for the total 

residues. 

MRID 40211103 

Aerobic Soil Metabolism 

Half-life (days) 

165 Represents the 90 percent 

upper confidence limit on the 

mean (three soils) total residue 

half-life. 

MRID 46413407 

Aerobic Aquatic 

Metabolism Half-life 

(days) 

1020 Represents the 90 percent 

upper confidence limit on the 

mean total residue half-life. 

MRID 46427901 

Anaerobic Aquatic 

Metabolism Half-life 

(days) 

1210 Represents 3 times the single 

available total residue half-life. 

MRID 46413408 

Hydrolysis Half-lives at 

pH 5, 7 and 9 (days) 

Stable No measureable degradation in 

study. 

MRID 00107980 

Aqueous Photolysis 

Half-life (days) 

217 Represents the single 

environmental 

phototransformation total 

residue half-life. 

MRID 40420301 

1EFED input parameter guidance is located at: http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

3.2.2.2 Selection of Crops and Scenarios 

 

Eleven standard scenarios were used in surface water modeling to represent the range of existing 

uses of propyzamide: TX alfalfa OP, NC alfalfa OP, CA alfalfa OP, CA row crop RLF, PA apples, 

CA lettuce, MS corn, NC apple, OR berries, FL turf, and PA turf (Table 5). Aerial and ground 

application were both assumed for modeled scenarios as described on the labels as were maximum 

application rates and minimum retreatment intervals. The retreatment interval is the amount of 

time between sequential pesticide applications. For uses wherein the retreatment interval is not 

specified (turf), a three day interval was assumed as its conservative. The application dates for the 

 

7

 US EPA, 2009. 
-Page 21 of 86- 

scenarios were chosen according to their crop profiles, crop lifecycle and/or time when heavy pest 

pressure is believed likely to occur8

. 

The CA row crop RLF (Red Legged Frog) scenario was used as a proxy in modeling for the globe 

artichoke use, because globe artichokes are grown almost exclusively in California. There is no 

standard scenario for use on artichokes, berries or alfalfa; the CA row crop OP (organophosphate), 

the OR berries OP, and the alfalfa OP scenarios respectively, were used because they provide the 

closest approximations to these crops from among the available scenarios. The highest application 

rates for propyzamide were assessed for turf. 

Table 5. SWCC Application-Specific Input Parameters for Propyzamide 

Uses PRZM Scenario Max App rate 

in lbs a.i./A (kg 

a.i./ha)

# 

Apps/year 

Retreatment 

Interval 

(days)

% Drift/ 

Efficiency

Date of 1st of 

application 

Artichoke1 CA row crop RLF 4 (4.48) 1 not applicable 0.125/0.95 Feb 1

Alfalfa1

CA alfalfa OP 2 (2.24) 1 not applicable 0.062/0.99 Jan 7

MN alfalfa OP 2 (2.24) 1 not applicable 0.062/0.99 Jan 7

NC alfalfa

OP 2 (2.24) 1 not applicable 0.062/0.99 Jan 7

TX alfalfa OP 2 (2.24) 1 not applicable 0.062/0.99 Jan 7

Apples

PA apples 4 (4.48) 1 not applicable 0.062/0.99 Sep 15

NC apples 4 (4.48) 1 not applicable 0.062/0.99 Sep 15

Blueberries OR berries 2 (2.24) 1 not applicable 0.062/0.99 May 15

Head/leaf 

lettuce CA Lettuce 1 (2.24) 1 not applicable 0.125/0.95 Feb 1

Turf

PA Turf 1.5 (1.68) 3 3 0.062/0.99 March 15

FL turf 1.5 (1.68) 3 91 0.062/0.99 March 15

1

There is not a standard scenario available for this crop and therefore, a non-standard scenario (OPs or RLFs) was used because it 

provided the closest representation of agricultural practices for the crop from among available EFED-approved scenarios. 

Table 6 (below) shows the input parameters used in modeling ground water. Hydrolysis was 

modeled as stable, the aerobic soil metabolism half-live employed was 165 d, and the organic 

carbon-normalized soil partition coefficient (Koc) was the mean observed value: 1,966 mL/goc. 

The maximum application rate on turf was used as it is the maximum annual application rate of 

all the uses (4.5 lbs a.i./A per year). 

Table 6. PRZM-GW Input Parameters 

Parameter (units) Input Value Data Source 

Application Rate (lbs a.i./A) 4.5 Labels (EPA #s: 62719-397; 

Number of Applications/yr 3 62719-578; 87290-3; 87290-22) 

 

8 USDA Crop Profiles. Available online at: http://www.ipmcenters.org/cropprofiles/CP_form.cfm
-Page 22 of 86- 

Application Dates

(month/day) March 15, 18 and 21 IPM center* 

Hydrolysis Half-life (days) Stable (0) MRID 00107980 

Soil Metabolism Half-life (days) 165 (upper 90 percent 

confidence limit on the mean) MRID 46413407 

Koc (mL/goc) 1,966 (average) MRID 40211103 

*http://www.ipmcenters.org/cropprofiles/CP_form.cfm

3.2.2.3 Surface and Ground Water Modeling Results 

The propyzamide surface water EECs for representative use sites are listed in Table 7. The highest 

EECs were generated by the NC apples scenario, with an acute value of 45.4 μg/L (parts per 

billion; ppb) and chronic values slightly lower than this. 

Table 7. Tier II Total Residue of Concern Estimated Environmental Concentrations in 

Surface Water (Pond). 

Drinking Water 

Source (Model, Use, 

Modeled rate) 

Scenario 

(application aerial, 

A; or ground, G) 

EECs (ppb) 

Peak 96-hour 21-day 60-day 

Pond (SWCC, 

Artichokes, 

4 lb a.i./A x 1 applic.; 

total of 4 lb/A/yr) 

CA row crop RLF (A) 

37.1 34.5 28.7 22.9 

Pond (SWCC, Alfalfa, 

2 lb a.i./A x 1 applic.; 

total of 2 lb/A/yr) 

CA alfalfa OP (G) 11.6 11.0 9.82 8.51 

MN alfalfa OP(G) 10.8 10.2 8.52 7.03 

NC alfalfa OP (G) 20.5 19.3 16.5 14.0 

TX alfalfa OP (G) 21.3 20.4 17.6 14.3 

Pond (SWCC, Apple, 

4 lb a.i./A x 1 applic.; 

total of 4 lb/A/yr) 

PA apples (G) 38.2 36.0 31.2 26.1 

NC apples (G) 45.4 42.3 34.4 29.3 

Pond (SWCC, 

Blueberries, 

2 lb a.i./A x 1 applic.; 

total of 2 lb/A/yr) 

OR berries OP (G) 

11.5 10.8 9.00 7.33 

Pond (SWCC, Head/leaf 

lettuce1

, 2 lb a.i./A x 1 

applic.; total of 2 

lb/A/yr) 

CA lettuce (A) 38.2 36.3 30.0 25.8 

Pond (SWCC, Turf, 

1.5 lb a.i./A x 3 applic. 

(91 days); total of 4.5 

lb/A/yr) 

PA turf (G) 22.4 20.7 17.8 14.7 

FL turf (G) 18.4 17.1 14.5 11.7 

Bolded values represent the highest EECs from all the values. 

For ground water (Table 8) the maximum concentrations, which were somewhat lower than those 

for surface water, were generated by the WI corn scenario, which produced a maximum singleday concentration of 23.9 μg/L. The ground water concentrations were modeled using the 
-Page 23 of 86- 

maximum application rate of 4.5 lbs a.i./A year which represents the use on turf. However, the 

data indicate that ground water is not likely the route of concern when compared with surface 

water. 

Table 8. PRZM-GW (100 year simulation) in Groundwater Resulting from the Use of 

Propyzamide. 

Crop/Scenario Highest Daily value (μg/L) Post Breakthrough 

Average (μg/L) 

Average Simulation 

Breakthrough Time (days) 

FL potato 3.42 x 10-5 Incomplete Incomplete 

FL citrus 22.7 22.2 2.04 x 104

Delmarva 3.19 2.81 2.47 x 104

NC cotton 0.953 0.897 2.05 x 104

GA coastal 0.504 0.475 3.37 x 104

WI corn 23.9 21.1 2.87 x 104

Bolded values represent the highest values from all the scenarios modeled. 

3.2.2.4 Monitoring Data 

A cursory review of both ground and surface water monitoring data on propyzamide was 

conducted as part of the 2002 Tolerance Reassessment Eligibility Decision (TRED; USEPA, 

2002a). The current assessment contains additional review of currently available monitoring data. 

The United States Geological Survey National Water Quality Assessment (USGS NAWQA) 

database contains environmental monitoring data on pesticides through 2005 (USGS, 2006). In 

surface water, propyzamide (parent only) was detected above the level of quantitation in 2.2% of 

samples (459 of 20,720 samples). The maximum measured surface water concentration was 1.12 

μg/L in Shelby County, Tennessee in January, 2003. In groundwater, propyzamide was detected 

above the level of quantitation in 0.05% of samples (5 of 9624 samples). The maximum 

concentration measured in groundwater was 0.820 μg/L in Benton County, Arkansas, in April 

1994. 

The USGS National Stream Quality Accounting Network (NASQAN) database contains 

monitoring data of pesticides by regional basin from 1996 to 2000 (USGS, 2006a). The maximum 

concentration of propyzamide detected in this program was 0.125 μg/L in the Colorado Basin in 

June, 1997. Concentrations of propyzamide were also detected above the reporting limit in the 

Columbia, Colorado, Rio Grande, and Mississippi River basins; however, detections of this 

chemical only occurred in the Northwest and Southwest. 

The California Department of Pesticide Regulation (DPR) Surface Water Database contains 

monitoring data on pesticides in California from 1990 to 2005 (CDPR, 2006). Propyzamide was 

detected in 8% of 1678 samples collected in the state, with the majority of detections occurring in 

water bodies within the Sacramento Valley. The maximum concentration of propyzamide reported 

in this database was 0.25 μg/L, detected in Yolo County in February, 1994. 

Propyzamide was detected in one Oklahoma reservoir out of twelve which were monitored in the 

Pilot Reservoir Monitoring Program due to their particular vulnerability to pesticide contamination 

(USEPA, 2002a). The compound was detected at up to 0.044 ppb in 83% of 41 raw water samples 

and up to 0.012 ppb in 42% of 19 finished drinking water samples. 
-Page 24 of 86- 

Propyzamide was not detected in 432 ground water wells nationwide from 1984 to 1990, according 

to the EPA Pesticides in Ground Water Database (USEPA, 1992). Propyzamide is not a regulated 

chemical under the Safe Water Drinking Act (SWDA) or related statutes. Therefore, it is not listed 

in the EPA Safe Drinking Water Information System database (SDWIS/FED; USEPA, 2007c) nor 

is it found in the EPA Unregulated Contaminants Monitoring Rules (UCMR) chemical monitoring 

database (USEPA, 2006b). 

Recently, an article published by Smalling, K.L. et al. (2013) mentioned that propyzamide was 

detected 100% frequency throughout the year in water samples (N=19) collected from the upper 

and lower estuary sites and Orcutt Creek. 

Monitoring data are not available on the degradates of propyzamide. Therefore, exposure estimates 

of total residues cannot be directly compared against monitoring data. 

Recently, water and sediment (both bed and suspended) were collected from January 2008 through 

October 2009 from 12 sites in 3 of the largest watersheds along California’s Central Coast (Pajaro, 

Salinas, and Santa Maria Rivers) and analyzed for a suite of pesticides by the U.S. Geological 

Survey in cooperation with the California State Water Resources Control Board. Propyzamide was 

detected in more than 50% of the water samples in the Salinas and Pajaro Rivers and greater than 

95% of the samples in Santa Maria River. The maximum concentrations of propyzamide ranged 

from 30.4 to 14,000 ng/L (14 ppb) during summer dry season and 47.8 to 1,390 ng/L (1.3 ppb) in 

storm events in Pajaro and Santa Maria Estuaries, respectively (USGS, 2011). Propyzamide was 

one of the pesticides detected most frequently and with the maximum concentrations in the 

samples obtained in the monitoring study. 

3.2.3. Terrestrial Exposure 

The application of propyzamide to crops and turf has the potential to cause propyzamide residues 

of concern to reach non-target terrestrial organisms via spray drift and/or runoff (in the case of 

plants). Propyzamide may settle on plants and/or be taken up by plants as a result of systemic 

uptake and distribution. For terrestrial animals, T-REX (version 1.5.2) is used to calculate dietaryand dose-based EECs of propyzamide for mammals and birds feeding on the site of application. 

Input values for T-REX include the maximum single application rates, number of applications, 

and minimum retreatment interval for a given use and are located in Table 2. In this assessment, 

EFED uses a default foliar dissipation half-life of 35 days as an input for terrestrial exposure 

modeling in T-REX. Dietary- and dose-based exposure estimates from application of propyzamide 

are presented in Table 9; output from T-REX is presented in Appendix E. 
-Page 25 of 86- 

Table 9. Terrestrial EECs as food residues for animals exposed to propyzamide as a result of the proposed pre-emergent use. 

Food Type

Dietary Based 

(mg/kg diet) 

(mammals and 

birds) 

Dose Based (mg/kg bw) 

(birds)

Dose (mg/

(mam

All Size Classes Small (20 g) Medium (100 g) Large (1000 g) Small (15 g) Me

(3

Artichoke and apples; 4.0 lbs a.i./A; 1 application 

Short grass 960.0 1093.3 623.5 279.1 915.3 63Tall grass 440.0 501.1 285.8 127.9 419.5 28Broadleaf plants/small insects 540.0 615.0 350.7 157.0 514.8 35Fruits/pods/large insects/seeds (dietary only) 60.0 68.3 39.0 17.4 57.2 3Arthropods 376.0 428.2 244.2 109.3 358.5 24Seeds (granivore) NA 1093.3 623.5 279.1 915.3 63

Alfalfa, blueberries, and head/leaf lettuce; 2.0 lbs a.i./A; 1 application 

Short grass 480 546.7 311.7 139.6 457.6 31Tall grass 220 250.6 142.9 64.0 209.8 14Broadleaf plants/small insects 270 307.5 175.4 78.5 257.4 17Fruits/pods/large insects/seeds (dietary only) 30 34.2 19.5 8.7 28.6 1Arthropods 188 214.1 122.1 54.7 179.2 12Seeds (granivore) NA 546.7 311.7 139.6 457.6 31

Turf; 1.5 lbs a.i./A; 3 applications; 91-d app interval 

Short grass 429.2 488.8 278.7 124.8 409.2 28Tall grass 196.7 224.0 127.7 57.2 187.5 12Broadleaf plants/small insects 241.4 274.9 156.8 70.2 230.2 15Fruits/pods/large insects/seeds (dietary only) 26.8 30.5 17.4 7.8 25.6 1Arthropods 168.1 191.4 109.2 48.9 160.3 11Seeds (granivore) NA 6.8 3.9 1.7 5.7 3

N/ANot applicable. 
-Page 26 of 86- 

Honey bee EEC values were calculated based on the USEPA Guidance for Assessing Risks to Bees

document (USEPA 2014). EEC’s are calculated for individual adult survival through contact 

exposure (Table 10). 

Table 10. Contact exposure estimates for honey bees exposed to propyzamide uses 

Use 

(app. Rate) 

Measurement 

Endpoint 

Exposure 

Route Equation9 EEC 

Artichoke and 

Apples 

4.0 lbs a.i./A 

Individual Survival 

(Adults) Contact AREnglish*(2.7 μg a.i./bee) 10.8 

Alfalfa, 

blueberries, 

and head/leaf 

lettuce 

2.0 lbs a.i./A 

Individual Survival 

(Adults) Contact AREnglish*(2.7 μg a.i./bee) 5.4 

Turf 

1.5 lbs a.i./A 

Individual Survival 

(Adults) Contact AREnglish*(2.7 μg a.i./bee) 4.1 

AREnglish = application rate in lbs a.i./A. 

TerrPlant is used to calculate EECs for non-target plants that inhabit dry and semi-aquatic areas. 

In this assessment, EECs for non-target plants are calculated based on the potential runoff and 

spray drift of pre-emergent applications of propyzamide (Table 11). TerrPlant does not account 

for particulate drift (Appendix F). AgDrift is discussed in more detail in Section 4.1.2. 

Table 11. EECs for non-target terrestrial and semi-aquatic plants based on registered uses and proposed new 

leaf lettuce use of propyzamide (TerrPlant). 

Use 

Application 

rate 

(lbs a.i./A) 

Application 

method 

Drift 

Value 

(%) 

Spray drift 

EEC 

(lbs a.i./A) 

Dry area 

EEC 

(lbs a.i./A) 

Semi-aquatic 

area EEC 

(lbs a.i./A) 

Artichoke, apples 4 Foliar - ground 1% 0.04 0.12 0.84 

Artichoke 4 Foliar - aerial 5% 0.08 0.28 1.0 

Alfalfa, blueberries, 

head/leaf lettuce

2 Foliar - ground 1% 0.02 0.06 0.42 

Head/leaf lettuce 2 Foliar - aerial 5% 0.1 0.14 0.5 

Turf 1.5 Foliar - ground 1% 0.015 0.045 0.315 

To estimate exposure to plants when groundwater contaminated by propyzamide is applied to 

crops, the following method was used. Assume a field is irrigated with one inch of water 

containing 23.9 μg propyzamide/L water. One acre has 6,272,640 cubic inches of water on the 

field. The one acre field with one inch of water has 3,630 cubic ft of water (6,272,640 x 0.00058 

cubic ft/cubic inch). The field has 27,156 gallons of water (3,630 cubic ft x 7.481 gallons/cubic 

ft). Therefore, one inch of water on the one acre field weighs 226,625 lbs (27,156 gallons x 8.3453 

lbs/gallon of water). 

226,625 lb of water/acre x 23.9 μg/L = EEC = 0.005 lbs a.i./A 

1,000,000,000 

 

9

 AR English is the application rate in pounds A.I./acre 
-Page 27 of 86- 

Residues in groundwater-derived irrigation water range between 4-168 times lower than those 

EECs estimated using TerrPlant for spray drift, runoff, and semi-aquatic areas. 

3.3. Ecological Effects Characterization 

3.3.1. Ecotoxicity Data 

Toxicity endpoints used in risk estimation and characterization for propyzamide are shown in 

Table 12 through Table 19. In the current risk assessment, the most sensitive endpoints available 

from registrant-submitted toxicity studies classified as acceptable or supplemental are the 

endpoints selected for quantitative use in risk estimation. A complete listing of ecotoxicity data 

can be found in Appendix K. 

A search of the ECOTOXicology database in August 2013, yielded no new data from suitable 

studies with more sensitive toxicity endpoints than the registrant-submitted guideline studies 

described below. The endpoints from the ECOTOX-catalogued open literature studies are 

provided in Appendix J, for reference.

3.3.1.1. Aquatic Organisms 

Acute toxicity data for fish and aquatic invertebrates are summarized in Table 12 and Table 13. 

Based on the available data, propyzamide technical grade active ingredient (TGAI) is classified as 

slightly toxic to freshwater rainbow trout (Oncorhynchus mykiss) and bluegill sunfish (Lepomis 

macrochirus). Reported sub-lethal effects reported in the bluegill study included fish lying on test 

chamber bottom, loss of equilibrium, and surfacing. A propyzamide formulation, Rh-315-75WP 

(containing 75% a.i. propyzamide) was also classified as slightly toxic to rainbow trout 

(Oncorhynchus mykiss). Regarding estuarine/marine fish, propyzamide was classified as no more 

than moderately toxic to the sheepshead minnow (Cyprinodon variegatus) on an acute exposure 

basis. Sub-lethal effects in this study included fish lying on the bottom of the test chamber, loss 

of equilibrium, and surfacing. Excluding the rainbow trout, for all of the freshwater and 

estuarine/marine fish tested (as well as aquatic-phase amphibians for which freshwater fish serve 

as surrogates), the acute 96-hr LC50 value exceeded the highest concentration tested, i.e, the acute 

toxicity estimates were non-definitive values at or close to the aqueous solubility limit 15 mg a.i./L. 

The solubility limit of propyzamide (15 mg/L at 25 °C) may be an important consideration in 

determining the toxicity classifications for non-definitive endpoints. 

Propyzamide is no more than moderately toxic to the freshwater invertebrate water flea (Daphnia 

magna) and yielded a non-definitive endpoint (EC50>5.6 mg a.i./L). The compound is also 

moderately toxic to estuarine/marine mysid shrimp (Americamysis bahia) and the Eastern oyster 

(Crassostrea virginica) on an acute exposure basis. 

An acute whole sediment toxicity test was carried out with propyzamide on midge larvae 

(Chironomus dilutus; 10-day test). Endpoints assessed in the study included midge survival and 

growth (Table 14). In the study, the LC50 was determined to be greater than the highest treatment 

level i.e., >97.5 mg total radioactive residues (TRR)/kg sediment. At the highest test 

concentration, growth (based on ash-free dry weight) was significantly different than controls 
-Page 28 of 86- 

resulting in a NOAEC/LOAEC of 47.1/97.5 mg a.i./kg dry sediment. In terms of sediment pore 

water, the NOAEC for survival and growth are 8.80 and 8.49 mg TRR/L, respectively. Assuming 

that all of the residues were in the form of the parent propyzamide, the NOAEC for this study is 

8.49 mg a.i./L, based on pore water concentration and impaired growth. No abnormal behavioral 

or sub-lethal effects were reported for surviving midges in controls or treatment groups during the 

exposure period. No additional sediment toxicity studies have been submitted to the Agency. 

Toxicity endpoints for aquatic plants and algae exposed to TGAI propyzamide are shown in Table 

15. The freshwater vascular plant duckweed (Lemna gibba) was exposed to propyzamide (MRID 

43738301) over a 14-day period; the mean-measured IC50 was determined to be 1.18 mg a.i./L 

based on inhibition of yield and frond density. The NOAEC in this study was statistically 

determined to be 0.56 mg a.i./L. 

The effects of propyzamide on the growth of the freshwater green alga (nonvascular plant), 

Pseudokirchneriella subcapitata, were tested (MRID 42176802); the 5-day mean-measured IC50

and NOAEC were determined to be 0.76 and 0.26 mg a.i./L, respectively, based on cell density. 

Exposure of blue-green alga (Anabaena flos-aquae; MRID 47842093) to propyzamide resulted in 

a mean-measured IC50 and NOAEC of >4.0 and 0.39 mg a.i./L, respectively, based on inhibition 

of growth (MRID 43738304; 5-day test). 

The effects of propyzamide on the toxicity to the freshwater diatom (Navicula pelliculosa; MRID 

43738302) were tested; the 5-day mean-measured IC50 and empirical NOAEC were determined to 

be >4.0 and 4.0 mg a.i./L, respectively, based on a lack of effects. The effects of propyzamide on 

the toxicity to the marine diatom (Skeletonema costatum); MRID 43738303) were tested; similarly 

to the freshwater diatom, the 5-day mean-measured IC50 and empirical NOAEC were determined 

to be >3.4 and 3.4 mg a.i./L, respectively, based on a lack of effects. 
-Page 29 of 86- 

Table 12. Acute toxicity endpoints used in risk estimation and characterization for freshwater organisms exposed to propyzami

Study Type Species Test Material 

Endpoints 

(mg a.i./L) 

(Study Duration) 

Tox

(St

Acute toxicity to 

freshwater vertebrates 

Rainbow trout 

(Oncorhynchus mykiss) TGAI (96.2% a.i.) LC50=10.6 mg a.i./L (96 hour test) 

Rainbow trout 

(Oncorhynchus mykiss) RH-315-75WP (75% a.i.) LC50=72 mg a.i./L (96 hour test) 

Bluegill sunfish 

(Lepomis macrochirus) TGAI (96.2% a.i.) 

LC50>14.0 mg a.i./L 

EC50=14.0 mg a.i./L (sub-lethal 

effects) 

 (96 hour test) 

No m

Endpo

on tes

of e

Acute toxicity to 

freshwater invertebrates 

Water flea 

(Daphnia magna) TGAI (93.8% a.i.) EC50 >5.6 mg a.i./L (48-hour test) No mo

Table 13. Acute toxicity endpoints used in risk estimation and characterization for estuarine/marine organisms exposed to prop

Study Type Species Test Material 

Endpoints1

(mg a.i./L) 

(Study Duration) 

Tox

(St

Acute toxicity to 

estuarine/marine fish 

Sheepshead minnow 

(Cyprinodon variegatus) TGAI (96.2% a.i.) LC50 > 7.69 mg a.i./L (96 hour test) No mo

Acute toxicity to 

estuarine/marine 

invertebrates 

Mysid shrimp 

(Americamysis bahia) TGAI (96.2% a.i.) LC50 =6.43 mg a.i./L (96-hour test) 

Acute toxicity to 

estuarine/marine 

invertebrates 

Mysid shrimp 

(Americamysis bahia) TGAI (95.7% a.i.) LC50>3.9 mg/L (96-hour test) 

Toxicity to 

estuarine/marine mollusks 

– shell deposition 

Eastern oyster 

(Crassostrea virginica) TGAI (95.7% a.i.) IC50=3.5 mg a.i./L (96-hour test) No mo

1 Bolded values are the most sensitive endpoint(s) for a given taxonomic group and will be used in risk estimation. 
-Page 30 of 86- 

Table 14. Sediment toxicity testing with freshwater organisms exposed to propyzamide. 

Study Type Species Test Material 

Endpoints1

(mg a.i./L) 

(Study Duration) 

Tox

(St

Whole sediment acute 

toxicity to freshwater 

invertebrates 

Midge larvae 

(Chironomus dilutus) TGAI (96.2% a.i.) 

LC50>97.5 mg a.i./kg 

NOAEC=47.1 mg a.i./kg 

LOAEC=97.5 mg a.i./kg 

(based on dry sediment) 

 (10-day test) 

G

1 Bolded values are the most sensitive endpoint(s) for a given taxonomic group and will be used in risk estimation. Table 15. Toxicity endpoints used in risk estimation and characterization for aquatic plants and algae exposed to propyzamide. 

Study Type Species Test Material Endpoints1 (mg a.i./L) 

(St

Toxicity to vascular 

aquatic plants 

Duckweed 

(Lemna gibba) TGAI (95.7% a.i.) 

IC50 = 1.18 mg a.i./L 

NOAEC = 0.56 mg a.i./L 

LOAEC = 1.10 mg a.i./L 

(14-day static test) 

Inhi

Toxicity to nonvascular 

aquatic plants 

Green algae 

(Pseudokirchneriella 

subcapitata) 

TGAI (96.8% a.i.) 

IC50=0.76 mg a.i./L 

NOAEC=0.26 mg a.i./L 

LOAEC=0.49 mg a.i./L 

(5-day test) 

Most 

Toxicity to blue-green 

alga 

Blue-green alga (Anabaena 

flos-aquae) TGAI (95.7% a.i.) 

IC50>4.0 mg a.i./L 

NOAEC=0.39 mg a.i./L 

LOAEC=0.74 mg a.i./L 

(5-day test) 

In

Toxicity to the freshwater 

diatom 

Freshwater diatom (Navicula 

pelliculosa) TGAI (95.7% a.i.) 

IC50>4.0 mg a.i./L 

NOAEC=4.0 mg a.i./L 

LOAEC>4.0 mg a.i./L 

(5-day test) 

Toxicity to the marine 

diatom 

Marine diatom (Skeletonema 

costatum) TGAI (95.7% a.i.) 

IC50>3.4 mg a.i./L 

NOAEC=3.4 mg a.i./L 

LOAEC>3.4 mg a.i./L 

(5-day test) 

1 Bolded values are the most sensitive endpoint(s) for a given taxonomic group and will be used in risk estimation.
-Page 31 of 86- 

Freshwater Fish and Invertebrates: Chronic 

Chronic toxicity data for freshwater fish and aquatic invertebrates exposed to propyzamide are 

summarized in Table 16. In a 25-week freshwater fish full life-cycle toxicity test with fathead 

minnows exposed to TGAI propyzamide (MRID 48931801), there was a significant reduction 

(p<0.05) in the mean number of spawns and day 56 post-hatch survival resulting in a 

NOAEC/LOAEC of 0.224/0.441 mg a.i./L, respectively. In a 21-day chronic freshwater life-cycle 

study with D. magna (MRID 43673301), the NOAEC/LOAEC was 0.60/1.20 mg a.i./L, 

respectively. The affected endpoints were growth (length and weight) and larvae survival. It 

should be noted that because there is no acute toxicity for the fathead minnow, there is uncertainty 

regarding if this species is more/less sensitive compared to rainbow trout or bluegill sunfish. 

Estuarine/Marine Fish and Invertebrates: Chronic 

No chronic data have been submitted to the Agency for estuarine/marine invertebrates. Using 

available information and assuming the non-definitive endpoints in the acute freshwater 

invertebrate study is definitive, an acute-to-chronic (ACR) ratio was calculated. Although it is 

mollusk and not a crustacean, the best available estuarine/marine information comes from the 

Eastern oyster toxicity value. Based on the acute value of 5.6 mg a.i./L and chronic NOAEC of 

0.60 for the water flea (D. magna), the ACR is 9.3. Applying this ratio to the estuarine/marine 

invertebrate acute value of 3.5 mg a.i./L (using the Eastern oyster Crassostrea virginica value of 

3.5 mg a.i./L) results in an estimated estuarine/marine invertebrate NOAEC of >0.38 mg a.i./L. 

No chronic data have been submitted to the Agency for estuarine/marine fish. An ACR cannot be 

calculated for estuarine/marine fish because different species of freshwater fish were used in the 

acute and chronic freshwater fish toxicity tests. 

 
-Page 32 of 86- 

Table 16. Chronic toxicity endpoints used in risk estimation and characterization for fish and aquatic invertebrates exposed to 

Study Type Species Test Material Endpoints1 (mg a.i./L) 

(St

Freshwater fish full lifecycle test Fathead minnow (Pimephales promelas) TGAI (96.2% a.i.) NOAEC=0.224 mg a.i./L LOAEC=0.441mg a.i./L (25-week test) F0 day 56 

n

Freshwater invertebrate 

life-cycle test 

Water flea 

(Daphnia magna) TGAI (95.7% a.i.) 

NOAEC=0.60 mg a.i./L 

LOAEC =1.20 mg a.i./L 

(21-day test) 

Growth (

surv

Estuarine/marine chronic 

invertebrate toxicity 

Eastern oyster 

(Crassostrea virginica) -- 

NOAEC>0.38 mg a.i./L2

LOAEC >0.75 mg a.i./L Es

1 Bolded values are the most sensitive endpoint(s) for a given taxonomic group and will be used in risk estimation 2 Estimated using an acute-to-chronic (ACR) ratio 
-Page 33 of 86- 

3.3.1.2. Terrestrial Organisms 

Birds and Mammals: Acute and Dietary 

Acute toxicity data for birds and mammals exposed to propyzamide are summarized in Table 17. 

Based on the available data, propyzamide is classified as practically non-toxic to the birds Japanese 

quail, Coturnex japonica; Mallard duck, Anas platyrhynchos; and canary, Serinus canaria; on an 

acute oral exposure basis, and practically non-toxic to bobwhite quail and mallard duck on a 

subacute dietary exposure basis. The acute study with Japanese quail was classified as 

supplemental because formulated product was used and less than ten birds per treatment level were 

used. In the Mallard study, birds were observed regurgitating if given one large dose of the 

chemical. In the acute toxicity study with the canary, sub-lethal effects included ruffled 

appearance, wing droop, and loss of coordination. In the dietary studies, there was no reduction 

in weight gain or food consumption in treated groups. Since birds serve as a surrogate for 

terrestrial-phase amphibians and reptiles, propyzamide is classified as practically non-toxic on an 

acute oral and dietary exposure basis for these taxa. Propyzamide is classified as practically nontoxic to mammals on an acute oral exposure basis (96-hr LD50 >5000 mg/kg bw).

Terrestrial Invertebrates 

Acute toxicity data for adult honey bees are summarized in Table 18. Propyzamide is practically 

non-toxic on a contact basis to adult honey bees (formulated product, % a.i. unknown). No data 

are available for evaluating the effects on adult bees from acute oral and chronic exposure, nor are 

data available to evaluate acute or chronic effects on honey bee larvae. 
-Page 34 of 86- 

Table 17. Acute toxicity endpoints used in risk estimation and characterization for birds and mammals exposed to propyzamide

Study Type Species Test Material Endpoints1 

To

(S

Acute oral toxicity to birds 

Japanese quail

(Coturnex japonica) 

Mallard duck 

(Anas platyrhynchos) 

RH-315 (75% a.i.) 

LD50 = 8870 mg a.i./kg bw 

24-hr test 

LD50 = > 14,000 mg a.i./kg bw 

24-hr test 

P

Bobwhite quail

(Colinus virginianus) TGAI (96.2% a.i.) LD50 > 2165 mg a.i./kg bw 14-day test P

Canary 

(Serinus canaria) TGAI (96.2% a.i.) 

LD50 > 1924 mg a.i./kg bw 

NOAEL = 1154 mg a.i./kg bw 

14-day test 

P

Subacute dietary toxicity to 

birds 

Bobwhite quail

(Colinus virginianus) TGAI (94.9% a.i.) LC50 > 10,000 mg a.i./kg die.t 8-day test P

Mallard duck 

(Anas platyrhynchos) TGAI (94.9% a.i.) LC50 > 10,000mg a.i./kg diet 8-day test P

Acute oral toxicity to mammals Laboratory rat (Rattus norvegicus) RH-315 (% a.i. unknown) 8350 (males) mg/kg bw 5620 (females) mg/kg bw 96-hr LD50 P

1 Bolded values are the most sensitive endpoint(s) for a given taxonomic group and will be used in risk estimation. 

Table 18. Acute toxicity endpoints used in risk estimation and characterization for terrestrial invertebrates exposed to propyza

Study Type Species Test Material Endpoints

T

(S

Acute contact toxicity to honey 

bees 

Honey bee 

(Apis mellifera) 

Formulated product 

(% a.i. unknown) 

LD50 >181 μg a.i./bee 

 (48-hour test) 
-Page 35 of 86- 

3.3.1. Terrestrial Organism and Mammalian Chronic Endpoints 

Birds and Mammals: Chronic 

Chronic laboratory toxicity data for birds and mammals exposed to propyzamide are summarized 

in Table 19. In a 20-week avian reproduction study with bobwhite quail exposed to propyzamide 

in the diet, no effects were reported (NOAEC/LOAEC 615/>615 mg a,i./kg diet; MRID 

48931802). The study was, however, classified as supplemental because according to test 

guideline 850.2300, at least one test concentration should indicate a reproductive effect capturing 

the LOAEC or be greater than 5000 mg/kg diet. The highest dose used in the study was 615 mg 

a.i./kg diet. 

In a 20-week avian reproduction study with the mallard exposed to propyzamide in the diet (MRID 

48931803), there were no treatment-related effects on adult male body weight or food consumption 

at any dietary level; female body weight gain was significantly reduced (5%) from control (p<0.05) 

at the 2454 mg a.i./kg diet level. At the 2454 mg a.i./kg diet level, there was also a significant 

(p<0.05) reduction (29%) in the number of eggs laid. There was a significant (p<0.05) reduction 

in the number of viable embryos to eggs set and the number of live 3-week embryos to eggs set at 

the 624 and 2454 mg a.i./kg levels, respectively, relative to the control. The ratios of hatchlings 

to egg set, 14-day survivors to eggs set, and number of hatchlings to live 3-week embryos were 

also significantly (p<0.05) reduced 15-28% from control at all treated levels. Based on these more 

sensitive effects, the reviewer concluded that a NOAEC could not be determined for this study 

(i.e., NOAEC<311 mg a.i./kg diet). Because the study resulted in a non-definitive NOAEC less 

than the lowest concentration tested, it was classified as supplemental. 

In a rat 2-generation study evaluated by the Health Effects Division (HED) (MRID 41540301) 

multiple effects were observed. These included decreases in body weight in females and feed 

consumption in both sexes, increased incidences of histopathology of the anterior pituitary gland 

(cellular hypertrophy) in males in both generations, increased incidences of uterine gross 

pathology (black foci/serosal surface) in P2 females, decreases in combined male/female pups 

weigh/litter, and increased incidences of histopathology of the liver (centrilobular hepatocytes 

hypertrophy), adrenal gland (zona glomerulosa cellular hypertrophy), and thyroid gland (zona 

glomerulosa cellular hypertrophy) in both sexes and generations. The parental systemic and 

offspring toxicity NOAEL/LOAEL was 200/1500 ppm (15.4/114.0 mg/kg/day for males). 
-Page 36 of 86- 

Table 19. Chronic toxicity endpoints used in risk estimation and characterization for terrestrial animals exposed to propyzamid

Study Type Species Test Material Endpoints1 

Effects 

(MRID) 

(Study Classific

Avian reproduction

Bobwhite quail

(Colinus 

virginianus)

TGAI (93.9 a.i.%)

NOAEC = 615 mg a.i./kg diet

LOAEL > 615 mg a.i./kg diet

20-week test

No effects

(48931802

(Supplement

Mallard duck 

(Anas 

platyrhynchos) 

TGAI (96.8 a.i.%)

NOAEC < 311 mg a.i./kg diet 

LOAEL = 311 mg a.i./kg diet

20-week test

Viable embryos 

set, live 3-week e

to egg set, hatchl

live 3-week emb

hatchlings to eg

and 14-day survi

egg set

(48931803

(Supplement

Chronic toxicity to 

mammals – twogeneration 

reproduction 

Crl:CD BR Rats TGAI (93.1 a.i.%) 

NOAEL = 15 mg/kg/day 

(200 ppm) 

LOAEL = 114 mg/kg/day 

(1500 ppm)

Decreases in b

weight in femal

feed consumpti

both sexes, decre

combined male/

pups weigh/li

(41540301

(Acceptable

1 Bolded values are the most sensitive endpoint(s) for a given taxonomic group and will be used in risk estimation. 
-Page 37 of 86- 

3.3.2. Terrestrial Plants 

Terrestrial Plant Seedling Emergence and Vegetative Vigour 

Toxicity data, used to assess the effects on seedling emergence and vegetative vigor in listed and 

non-listed terrestrial plants, from exposure to propyzamide (TGAI 96.8% a.i.) are shown in Table 

20. 

The effects of propyzamide on terrestrial monocotyledonous and dicotyledonous plants were tested 

in Tier II seedling emergence and vegetative vigor tests (MRIDs 42176801and 44029001). Results 

of the Tier II seedling emergence study identify ryegrass as the most sensitive monocot tested, 

with an IC25 of 0.019 lb a.i./A and a NOAEC of <0.015 lb a.i./A, based on a decrease in percent 

emergence. The most sensitive dicot, based on a decrease in shoot length, is cucumber with an 

IC25 and IC05 of 0.015 and 0.004 lb a.i./A, respectively (the IC05 was used as a surrogate in this 

study because the NOAEC was roughly equal to the IC25). 

Results of the Tier II vegetative vigor studies identify oat as the most sensitive monocot and tomato 

as the most sensitive dicot, with decreased shoot weight and root weight, respectively, as the most 

sensitive endpoints (MRID 42176801). The IC25 and NOAEC values were <0.2 and <0.2 lbs a.i./A, 

respectively, for oat, and the IC25 and NOAEC values were <0.041 and <0.041 lbs a.i./A, 

respectively, for tomato. The Tier II vegetative vigor plant toxicity DER originally showed IC25

values that were less than the NOAEC values based on an extrapolation of test concentrations. 

The extrapolated IC25 values fell outside the range of test concentrations used in the study resulting 

in an uncertainty regarding the actual IC25 value. As a result, the IC25 values have a non-definitive 

“less than” (<) value. 

Table 20. Toxicity endpoints used in risk estimation and characterization for terrestrial and semi-aquatic 

plants exposed to propyzamide. 

Study Type Test Material Most Sensitive 

Species 

Endpoints 

(lbs ai/A) 

Effects 

(MRID) 

(Study 

Classification) 

Terrestrial 

plant toxicity: 

Tier II 

seedling 

emergence 

TGAI (96.8 

a.i.%)

Monocot: ryegrass 

(Lolium perenne) 

IC25 = 0.019 lbs a.i./A 

NOAEC < 0.015 lbs a.i./A 

Percent emergence 

(42176801) 

(Supplemental) 

Dicot: cucumber 

(Cucumis sativa) 

IC25 = 0.015 lbs a.i./A 

IC05 = 0.004 lbs a.i./A 

Shoot length 

(42176801, 

44029001) 

(Supplemental, 

Acceptable) 

Terrestrial 

plant toxicity: 

Tier II 

vegetative 

vigor 

TGAI (96.8 

a.i.%)

Monocot: oat 

(Avena sativa) 

IC25 = < 0.2 lbs a.i./A 

NOAEC < 0.2 lbs a.i./A 

Shoot weight 

(42176801) 

(Supplemental) 

Dicot: tomato 

(Lycopersicon 

esculentum) 

IC25 < 0.041 lbs a.i./A 

NOAEC < 0.041 lbs a.i./A 

Shoot weight 

(42176801) 

(Supplemental) 
-Page 38 of 86- 

3.3.3. Incident Reports 

The ecological incident information system (EIIS) is a database maintained by the Office of 

Pesticide Programs; the database contains ecological incidents that have been reported to the 

Agency. When available, EIIS includes date and location of an incident, type and magnitude of 

effects observed in various species, use(s) of pesticides known or suspected of contributing to the 

incident, and results of any chemical residue analysis or other analyses conducted during incident 

investigation. EIIS incidents are categorized according to the certainty that the incident resulted 

from pesticide exposure. The Avian Incident Monitoring System (AIMS) is a database 

administered by the American Bird Conservancy that contains publicly available data on reported 

avian incidents involving pesticides. Many of the incidents listed in this database are also in the 

EIIS. Because of uncertainties regarding the extent to which incidents are reported to EPA, an 

absence of incident reports cannot be construed as proof of an absence of incidents. 

Based on the 40 CFR §159.184, information on all known incidents must be submitted to the 

Agency by the registrant(s). EIIS contained three incidents for propyzamide causing plant damage. 

The first incident occurred on 10/11/01 caused lettuce damage in Arizona on 23 acres using Kerb®

50 W. The second incident occurred on 9/30/03 also resulted in lettuce damage in California on 

22 acres via aerial broadcast application of Kerb®. The third incident occurred on 10/2/04 caused 

broccoli damage in Japan on about 1 acre from a wettable powder ground spray application of 

Agromax® WP. 

Aggregate Incident Reports (AIR) are incidents reported as quarterly by the registrant(s). The 

incidents listed in this database may also appear in the EIIS. From the AIR, a total of six minor 

incidences were reported occurring from 1/1/97-6/7/13 (Appendix G). Four of these incidences 

involved human exposure, one of which also caused minor property damage. One incident resulted 

in minor plant damage, and one incident resulted in moderate property damage. Because of 

uncertainties regarding the extent to which incidents are reported to EPA, the absence of incident 

reports cannot be construed as proof of the absence of incidents. 

4. Risk Characterization 

Toxicity data and exposure estimates for propyzamide are used to evaluate the potential for adverse 

ecological effects on non-target species. This screening-level assessment employs a deterministic 

risk estimation method, based on RQ values, to provide a metric of potential risks (Section 4.1). 

The potential for risk is further characterized in the Risk Description (Section 4.2) based on the 

risk estimation results and other relevant information about toxicity and ecosystems potentially at 

risk, and the environmental fate and transport characteristics of propyzamide. 

4.1. Risk Estimation 

Unitless RQ values are compared to the Agency’s LOCs to identify taxonomic groups potentially 

at risk of acute or chronic effects associated with propyzamide registered uses and proposed new 

use on leaf lettuce. 
-Page 39 of 86- 

4.1.1. Aquatic Organisms 

As shown in Table 21 and Table 22, none of the propyzamide uses exceed risk to listed non-listed 

species of freshwater and estuarine/marine fish and invertebrates (LOC>0.05). No listed or nonlisted exceedances for estuarine/marine invertebrates were observed (chronic data not available 

for estuarine/marine fish; chronic LOC≥1). 

Table 21. Acute and Chronic RQs for Freshwater Fish, Aquatic-Phase Amphibians, and Invertebrates 

Exposed to Propyzamide 

Use 

Applica

tion 

Rate 

lbs 

a.i./A 

Application 

Method

EECs 

(μg a.i./L) 

Freshwater Fish and 

Amphibian RQs1

Acute 96h LC50 = 10,600 μg 

a.i./L 

Chronic NOAEC = 224 μg 

a.i./L 

Freshwater 

Invertebrate RQs1 

Acute 48h LC50 = 

5,600 μg a.i./L 

Chronic NOAEC = 

600 μg a.i./L 

Peak 21-day 60-day Acute Chronic Acute Chronic 

Artichokes 4.0 Aerial 37.1 28.7 22.9 <0.01 0.10 0.01 0.04 

Alfalfa 2.0 Ground 21.3 17.6 14.3 <0.01 0.06 <0.01 0.02 

Apple 4.0 Ground 45.4 34.4 29.3 <0.01 0.13 0.01 0.05 

Blueberries 2.0 Ground 11.5 9.0 7.33 <0.01 0.03 <0.01 0.01 

Head/leaf 

Lettuce 2.0 Aerial 38.2 30.0 25.8 <0.01 0.12 0.01 0.04 

Turf 1.52 Ground 14.9 11.8 10.1 <0.01 0.05 <0.01 0.02 

1

 RQ=peak EEC/LC50 (acute) or 21-day (invert) or 60-day (fish) EEC/NOAEC (chronic) 2

 Turf has 3 applications/91 day interval for a total of 4.5 lbs a.i./A a Exceeds the acute risk to listed species LOC (RQ≥0.05) b Exceeds the acute risk to non-listed species LOC (RQ≥0.5) c

 Exceeds the chronic risk LOC (RQ≥1) 

Table 22. Acute and Chronic RQs for Estuarine/Marine Fish, Aquatic-Phase Amphibians, and Invertebrates 

Exposed to Propyzamide 

Use 

Applica

tion 

Rate 

lbs 

a.i./A 

Application 

Method

EECs 

(μg a.i./L) 

Estuarine/Marine 

Fish and Amphibian RQs1

Acute 96h LC50 > 7,690 μg 

a.i./L 

Chronic NOAEC = NA 

Estuarine/Marine 

Invertebrate RQs1

Acute 48h LC50 = 

3,500 μg a.i./L 

Chronic NOAEC3

 = 

420 μg a.i./L 

Peak 21-day 60-day Acute Chronic Acute Chronic 

Artichokes 4.0 Aerial 37.1 28.7 22.9 0.01 NA 0.01 0.05 

Alfalfa 2.0 Ground 21.3 17.6 14.3 <0.01 NA 0.01 0.03 

Apple 4.0 Ground 45.4 34.4 29.3 0.01 NA 0.01 0.07 

Blueberries 2.0 Ground 11.5 9.0 7.33 <0.01 NA <0.01 0.02 

Head/leaf 

Lettuce 2.0 Aerial 38.2 30.0 25.8 0.01 NA 0.01 0.06 

Turf2 1.5 Ground 14.9 11.8 10.1 <0.01 NA <0.01 0.03 

NA Not Applicable 
-Page 40 of 86- 

1

 RQ=peak EEC/LC50 (acute) or 21-day (invert) or 60-day (fish) EEC/NOAEC (chronic) 2

 Turf has 3 applications/91 day interval for a total of 4.5 lbs a.i./A 3

 Estimated using an ACR 

a Exceeds the acute risk to listed species LOC (RQ≥0.05) b Exceeds the acute risk to non-listed species LOC (RQ≥0.5) c

 Exceeds the chronic risk LOC (RQ≥1) 

Table 23 summarizes RQ values for aquatic vascular and nonvascular plants. Further 

characterization of the potential for adverse effects to aquatic organisms, based on the available 

data, is provided as part of the Risk Description in Section 4.2.1. No exceedances were observed 

to listed and non-listed aquatic plants for any propyzamide use. 

Table 23. RQ values for listed and non-listed vascular and nonvascular aquatic plants exposed to 

propyzamide in surface water as a result of spray drift. 

Use 

App 

Rate 

lbs 

a.i./A 

App 

Method 

EECs 

(μg/L)

RQ Values 

Vascular Plants 

IC50=1,180 μg a.i./L 

NOAEC=560 μg a.i./L

Nonvascular Plants 

IC50= 760 μg a.i./L 

NOAEC= 260 μg a.i./L

Peak Listed Non-listed Listed Non-listed 

Artichokes 4.0 Aerial 37.1 0.03 0.07 0.05 0.14 

Alfalfa 2.0 Ground 21.3 0.02 0.04 0.03 0.08 

Apple 4.0 Ground 45.4 0.04 0.08 0.06 0.17 

Blueberries 2.0 Ground 11.5 0.01 0.02 0.02 0.04 

Head/leaf 

Lettuce 2.0 Aerial 38.2 0.03 0.07 0.05 0.15 

Turf 1.51 Ground 14.9 0.01 0.03 0.02 0.06 

Bold values exceed the plant LOC 1.0 

RQ = EEC/IC50 for non-listed species; EEC/NOAEC for listed species 1

Turf has 3 applications/91 day interval for a total of 4.5 lbs a.i./A 

4.1.2. Terrestrial Organisms 

In this assessment, acute oral and chronic RQ values are calculated for mammals (Table 24 and 

Table 25). Acute honey bee RQ values are presented in Table 26. Acute oral, dietary, and chronic 

RQ values for birds are presented in (Table 27-Table 29) in the risk description section because 

of the uncertainty surrounding avian taxa toxicity endpoints, which are non-definitive values. 

The acute dose-based RQ values for mammals are below the Agency’s LOC for acute risk to listed 

(RQ≥0.1) and non-listed (RQ≥0.5) species (Table 24). However, chronic dose-based RQ values 

exceed the chronic risk LOC (RQ >1;Table 25) for small (15 g), medium (35 g), and large (1000 

g) sized mammals that consume all food sources. No chronic risk LOCs are triggered by 

consumption of fruits/pods/seeds by any sized mammals for alfalfa, blueberries, head/leaf lettuce, 

and turf. Chronic risk LOC values are also not exceeded for large mammals (1000 g) for artichoke 

and apples. 
-Page 41 of 86- 

Table 24. Acute Mammalian Dose-Based RQ Values for Proposed Uses of Propyzamide1,2

Application 

Rate lbs a.i./A 

#app/interval 

(d) 

Body 

Weight 

(g) 

RQs for Specified Food Items

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods 

Artichoke and apples 

4.0 

1

15 0.07 0.03 0.04 <0.01 0.03 

35 0.06 0.03 0.04 <0.01 0.02 

1000 0.03 0.02 0.02 <0.01 0.01 

Alfalfa, blueberries, and head/leaf lettuce 

2.0 

1

15 0.04 0.02 0.02 <0.01 0.01 

35 0.03 0.01 0.02 <0.01 0.01 

1000 0.02 0.01 0.01 <0.01 0.01 

Turf 

1.5 

3/91

15 0.03 0.02 0.02 <0.01 0.01 

35 0.03 0.01 0.02 <0.01 0.01 

1000 0.02 0.01 0.01 <0.01 0.01 1 Bolded values exceed the acute risk to listed species LOC for mammals (0.1) 2 Bolded values exceed the acute risk to non-listed species LOC for mammals (0.5) 

Table 25. Chronic Mammalian Dose-Based RQ Values for Uses of Propyzamide1

Application 

Rate lbs a.i./A 

#app/interval 

(d) 

Body 

Weight 

(g) 

RQs for Specified Food Items

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods 

Artichoke and apples 

4.0 

1

15 27.8 12.7 15.6 1.7 10.9 

35 23.7 10.9 13.3 1.5 9.3 

1000 12.7 5.8 7.2 0.8 5.0 

Alfalfa, blueberries, and head/leaf lettuce 

2.0 

1

15 13.9 6.4 7.8 0.9 5.4 

35 11.9 5.4 6.7 0.7 4.6 

1000 6.4 2.9 3.6 0.4 2.5 

Turf 

1.5 

3/91

15 12.41 5.69 6.98 0.78 4.86 

35 10.60 4.86 5.96 0.66 4.15 

1000 5.68 2.60 3.20 0.36 2.23 1Bolded values exceed the chronic LOC for listed and non-listed mammals (1) 
-Page 42 of 86- 

The RQ values for risk to honey bees (Table 26) are compared to an acute risk LOC of 0.4 and a 

chronic risk LOC of 1.0 (USEPA 2014). Propyzamide is practically non-toxic to honey bees on 

an acute contact exposure (LD50>181 μg a.i./bee). No use showed exceedances. 

Table 26. Contact RQ values for honey bees exposed to propyzamide uses 

Use 

(app. Rate) 

Measurement 

Endpoint 

Exposure 

Route EEC Acute Chronic 

Artichoke and 

Apples 

4.0 lbs a.i./A 

Individual Survival 

(Adults) Contact 10.8 0.06 Not calculated 

Alfalfa, 

blueberries, 

and head/leaf 

lettuce 

2.0 lbs a.i./A 

Individual Survival 

(Adults) Contact 5.4 0.03 Not calculated 

Turf 

1.5 lbs a.i./A 

Individual Survival 

(Adults) Contact 4.1 0.02 Not calculated 

AREnglish = application rate in lbs a.i./A. Bold values exceed the LOC for risk to bees (acute LOC=0.4, chronic 

LOC=1) 

Acute toxicity studies with the young adult honey bee demonstrate that propyzamide is practically 

non-toxic to young adult honey bees on an acute contact exposure basis (LD50 >11 μg a.i./bee). 

The potential for risk to non-target terrestrial organisms exposed to propyzamide is discussed 

further in the Risk Description (Section 4.2.2). There is uncertainty regarding the potential acute 

and chronic effects of the compound on honey bee larvae as well as potential for chronic effects 

on adult bees. 

Due to reported non-definitive endpoint uncertainties, terrestrial plants will be assessed in Section 

4.2.2. 

4.2. Risk Description and Conclusions 

This assessment evaluates the potential for ecological risks associated with the proposed use of 

propyzamide as an organochlorine herbicide. Propyzamide is formulated as a wettable powder 

in water soluble pouches that can be applied pre-plant, pre-emergence, or post-emergence by 

ground or aerial spray equipment, depending on the use. 

4.2.1. Aquatic Organisms 

RQ values are calculated for acute and chronic risk to fish and aquatic invertebrates, when 

submitted ecotoxicity and fate data are sufficient to use in risk estimation. Aquatic animal and 

plant toxicity data reported in Section 3.3.1.1 and EECs are both reported in similar units, i.e.,

mg/L. For the uses of propyzamide, no RQ values exceed the LOC for freshwater and 

estuarine/marine fish and invertebrates for listed and non-listed species (acute and chronic). Based 

on available data for the acute freshwater Rainbow trout (Oncorhynchus mykiss) and chronic 

freshwater Fathead minnow (Pimephales promelas) along with the acute estuarine/marine 
-Page 43 of 86- 

Sheepshead minnow (Cyprinodon variegatus), the chronic estuarine/marine NOAEC/LOAEC 

values would be 0.163/0.320 mg a.i./L based on an ACR. 

Sediment toxicity testing with the midge, Chironomus dilutus, resulted in an LC50>97.5 mg a.i./L 

and a NOAEC of 47.1 mg a.i./L. Propyzamide was classified as slight-to-moderately toxic to all 

aquatic organisms tested on an acute exposure basis. Due to low measured fish bioconcentration 

factors (range of 21-77) and low/middle range octanol/water partition coefficient (log Kow=3.0-

3.3), propyzamide is not expected to bioconcentrate in aquatic environments (MRID 43196701). 

According to the benthic pore water peak derived from the SWCC, the EEC is 25.0 ppb. Therefore, 

the benthic RQ is <0.01 and does not exceed the LOC. 

Propyzamide has no LOC exceedances (RQ≥1) for aquatic nonvascular plants or aquatic vascular 

plants for any uses. Based on submitted data, green algae are more sensitive to propyzamide than 

duckweed. Among nonvascular species (green algae, blue-green algae, freshwater diatom, and 

marine diatom), only green algae reported a definitive IC50 value, while the other nonvascular 

plants reported non-definitive “greater than” (>) values. 

4.2.2. Terrestrial Organisms 

The RQ values in Section 4.1 demonstrate use of propyzamide may result in chronic risk to listed 

and non-listed mammals (RQ>1.0). Although propyzamide is classified as practically non-toxic 

to mammals on an acute oral exposure basis, chronic RQ values indicate potential for adverse 

effects. The submitted two-generation reproduction study in rats indicated toxicity at 15 mg/kg 

bw/day resulting in multiple treatment-related effects (i.e., decreases in body weight in females 

and feed consumption in both sexes; increased incidences of histopathology of the liver, adrenal 

gland, and thyroid gland in both sexes and decreases in combined male/female pups weigh/litter). 

Chronic dose-based RQ values exceed the LOC for small, medium, and large-sized mammals that 

consume all dietary categories modeled (artichoke and apples, alfalfa, blueberries and head/leaf 

lettuce, and turf). No chronic risk LOCs are triggered by consumption of fruits/pods/seeds by any 

sized mammals for alfalfa, blueberries, and head/leaf lettuce. Chronic risk LOCs were not 

exceeded for large mammals (1000 g) for artichoke and apples. 

RQ values for listed and non-listed species of monocot and dicot plants exceed the LOC for dry 

and semi-aquatic areas exposed through runoff as well as those exposed from spray drift. Only 

the use on turf did not result in exceedances to listed monocots’ LOCs from spray drift. LOCs 

were not exceeded to listed dicots for propyzamide use on alfalfa, blueberries, head/leaf lettuce 

(ground application only), or turf. Semi-aquatic risks showed the highest RQ values, followed by 

dry area plants, and plants exposed via spray drift. Listed terrestrial plants exposed to residues of 

propyzamide in irrigation water exceed the LOC as well. 

Acute laboratory tests with terrestrial insects (i.e., honey bees) have demonstrated that 

propyzamide is practically non-toxic to adult honey bees on a contact exposure basis, although 

there is uncertainty regarding potential chronic effects on adult bees and acute and chronic effects 

on larvae. The artichoke/apple uses of propyzamide indicate a non-definitive RQ that does not 

exceed the LOC for acute contact risk to adult bees. 
-Page 44 of 86- 

Acute, dietary, and chronic RQ values were not calculated in the risk estimation section (Section 

4.1) for dose-based risk to birds (and reptiles and terrestrial phase amphibians for which birds serve 

as surrogates) because of uncertainties surrounding non-definitive study endpoints. The acute oral 

toxicity study on the Japanese quail (MRID 00107997) was found to have an LD50 = 8870 mg 

a.i./kg bw. The acute oral toxicity study conducted on the canary and was found to have an LC50

>1924 mg a.i./kg bw. While both DER’s were classified as practically non-toxic on an acute 

exposure basis, differences exist when determining RQ exceedances upon consumption of various 

food categories (the Agency’s acute risk LOC is ≥0.1 and ≥0.5 to listed and non-listed species, 

respectively). The canary shows more acute dose-based RQ exceedances and higher RQ values 

for propyzamide compared to the Japanese quail10 for every food category as seen in Table 27 and 

Table 28, respectively. A passerine species such as the canary may be more sensitive upon 

exposure compared to a game bird like the Japanese quail. A weight of 26.2 g was used as the 

input parameter in T-REX for the canary (based on the average weight of the canary in MRID 

48599209). 

The avian reproduction study with the Mallard (MRID 48931803) was classified as supplemental. 

The reported NOAEC was a non-definitive “less than” (<) the lowest concentration tested, which 

indicates all reported RQ values will be “greater than” (>) values. In this study, the most sensitive 

reported endpoints included egg production, female body weight gain, viable embryo’s to egg set, 

live 3-week embryos to egg set, hatchlings to live 3-week embryos, hatchling to egg set, and 14-

day survivors to egg set resulting in a NOAEC/LOAEC of <311/311 mg a.i./kg diet. The number 

of hatchlings to egg set, 14-day survivors to eggs set, and number of hatchlings to live 3-week 

embryos were reduced 15-28% compared to control. If the reported non-definitive value were 

instead definitive, exceedances would exist for all propyzamide uses (Table 29). Another 

reproduction study is needed to better characterize the lower bounds of chronic propyzamide 

toxicity to avian taxa. 

Table 27. Acute a,b Dose-based Avian (20 g) and Dietary-based RQ Values for Propyzamide Based on the 

Canary 

Artichoke and apples; 4.0 lbs a.i./A; 1 application 

Dietary Category Acute RQs Dietary RQs 

Short Grass <0.59 a,b <0.10 b

Tall Grass <0.27 b <0.04 

Broadleaf plants/sm insects <0.33 b <0.05 

Fruits/pods/seeds <0.04 <0.01 

Arthropods <0.23 b <0.04 

Alfalfa, blueberries, and head/leaf lettuce; 2.0 lbs a.i./A; 1 application 

Dietary Category Acute RQs Dietary RQs 

Short Grass <0.30 b <0.05 

Tall Grass <0.14 b <0.02 

Broadleaf plants/sm insects <0.17 b <0.03 

Fruits/pods/seeds <0.02 <0.00 

Arthropods <0.12 b <0.02 

Turf; 1.5 lbs a.i./A; 3 applications; 91-d app interval 

Dietary Category Acute RQs Dietary RQs 

Short Grass <0.26 b <0.04

Tall Grass <0.12 b <0.02 

 

10 The Bobwhite quail was used as a surrogate for the Japanese quail for parameter input in T-REX 
-Page 45 of 86- 

Broadleaf plants/sm insects <0.15 b <0.02 

Fruits/pods/seeds <0.02 <0.01 

Arthropods <0.10 b <0.02 a

Acute and dietary risk LOC exceeded for non-listed species is 0.5 

b

Acute and dietary risk LOC exceeded for listed species is 0.1 

Table 28. Acute a,b Dose-based Avian (20 g) and Dietary-based RQ Values for Propyzamide Based on 

Japanese quail 

Artichoke and apples; 4.0 lbs a.i./A; 1 application 

Dietary Category Acute RQs Dietary RQs 

Short Grass 0.17 b 0.10 b

Tall Grass 0.08 0.04 

Broadleaf plants/sm insects 0.10 b 0.05 

Fruits/pods/seeds 0.01 0.01 

Arthropods 0.07 0.04 

Alfalfa, blueberries, and head/leaf lettuce; 2.0 lbs a.i./A; 1 application 

Dietary Category Acute RQs Dietary RQs 

Short Grass 0.09 0.05 

Tall Grass 0.04 0.02 

Broadleaf plants/sm insects 0.05 0.03 

Fruits/pods/seeds 0.01 0.00 

Arthropods 0.03 0.02 

Turf; 1.5 lbs a.i./A; 3 applications; 91-d app interval 

Dietary Category Acute RQs Dietary RQs 

Short Grass 0.08 0.04

Tall Grass 0.04 0.02 

Broadleaf plants/sm insects 0.04 0.02 

Fruits/pods/seeds <0.01 <0.01 

Arthropods 0.03 0.02 

a

Acute and dietary risk LOC exceeded for non-listed species is 0.5 

b

Acute and dietary risk LOC exceeded for listed species is 0.1 

Table 29. Chronica

 Avian Dietary-based RQ Values for Propyzamide 

Artichoke and apples; 4.0 lbs a.i./A; 1 application 

Dietary Category Chronic RQs 

Short Grass >3.1a

Tall Grass >1.4 a

Broadleaf plants/sm insects >1.7 a

Fruits/pods/seeds >0.2 

Arthropods >1.2 a

Alfalfa, blueberries, and head/leaf lettuce; 2.0 lbs a.i./A; 1 application 

Dietary Category Chronic RQs 

Short Grass >1.5 a

Tall Grass >0.7

Broadleaf plants/sm insects >0.9

Fruits/pods/seeds >0.1 

Arthropods >0.6

Turf; 1.5 lbs a.i./A; 3 applications; 91-d app interval 

Dietary Category Chronic RQs 

Short Grass >1.4 a

Tall Grass >0.6

Broadleaf plants/sm insects >0.8

Fruits/pods/seeds >0.1 

Arthropods >0.5
-Page 46 of 86- 

a

Chronic risk LOC (1.0) exceeded for listed and non-listed species 

For terrestrial plants, RQ values (Table 30 and Table 31) for propyzamide uses are calculated 

based on the most sensitive toxicity endpoints from the submitted seedling emergence/vegetative 

vigor studies (Table 20)

11. The monocot NOAEC for the seedling emergence test and 

IC25/NOAEC for the vegetative vigor test were all non-definitive “less than” (<) values which 

introduces uncertainty regarding the actual RQ value. Because of this uncertainty, RQ values were 

not reported in the risk estimation section (Section 4.1). Although many of the endpoints were 

non-definitive, RQ values for non-listed species appear definitive (Table 30). These values 

represent an uncertainty, however, since TerrPlant selects the most sensitive IC25/NOAEC value 

when calculating RQ values. The non-definitive “less than” (<) values could be less than the 

definitive endpoint selected by TerrPlant. 

RQ values for listed and non-listed monocot and dicot plants all exceed the Agency’s LOC risk to 

dry and semi-aquatic plants from runoff as well as those exposed via spray drift. Exceedances did 

not occur for non-listed monocot plants exposed to spray drift for use on turf, and listed dicot 

plants exposed to spray drive for uses on alfalfa, blueberries, lettuce (ground application only), 

and turf. 

Table 30. Propyzamide RQ values for non-listed species1 of non-target terrestrial and semi-aquatic plants 

(TerrPlant).

Use 

Dry Area 

RQs 

Semi-Aquatic Area 

RQs 

Spray Drift Only 

RQs 

Monocot Dicot Monocot Dicot Monocot Dicot 

Artichoke, Apples 

(ground) 6.3 8.0 44.2 56.0 2.1 3.9 

Artichoke 

(aerial) 14.7 18.7 52.6 66.7 10.5 19.2 

Alfalfa, blueberries, head/leaf lettuce 

(ground) 3.2 4.0 22.1 28.0 1.1 1.9 

Head/leaf lettuce 

(aerial) 7.4 9.3 26.3 33.3 5.3 9.6 

Turf 

(ground) 2.4 3.0 16.6 21.0 0.8 1.4 

Bolded values exceed the Agency’s level of concern (LOC) for risk to listed and non-listed species of terrestrial plants (RQ > 1). 1Seedling emergence IC25 and NOAEC monocot values are 0.019 and <0.015, and IC25 and NOAEC dicot values are 0.015 and 

0.004 (units are lbs a.i./A). Vegetative vigor IC25 and NOAEC monocot values are <0.2 and <0.2, and IC25 and NOAEC dicot 

values are <0.041 and <0.041 (units are lbs a.i./A). 

Table 31. Propyzamide RQ values for listed species1 of non-target terrestrial and semi-aquatic plants 

(TerrPlant).

Use 

Dry Area 

RQs 

Semi-Aquatic Area 

RQs 

Spray Drift Only 

RQs 

Monocot Dicot Monocot Dicot Monocot Dicot 

 

11 TerrPlant v. 1.2.2 User Guide (December 26, 2006). 

http://www.epa.gov/oppefed1/models/terrestrial/terrplant/terrplant_user_guide.html 
-Page 47 of 86- 

Artichoke, Apples 

(ground) >8.0 30.0 >56.0 210.0 >2.7 1.0 

Artichoke 

(aerial) >18.7 70.0 >66.7 250.0 >13.3 4.9 

Alfalfa, blueberries, head/leaf lettuce 

(ground) >4.0 15.0 >28.0 105.0 >1.3 0.5 

Head/leaf lettuce 

(aerial) >9.3 35.0 >33.3 125.0 >6.7 2.4 

Turf 

(ground) >3.0 11.3 >21.0 78.8 >1.0 0.4 

Bolded values exceed the Agency’s level of concern (LOC) for risk to listed and non-listed species of terrestrial plants (RQ > 1). 1Seedling emergence IC25 and NOAEC monocot values are 0.019 and <0.015, and IC25 and NOAEC dicot values are 0.015 and 

0.004 (units are lbs a.i./A). Vegetative vigor IC25 and NOAEC monocot values are <0.2 and <0.2, and IC25 and NOAEC dicot 

values are <0.041 and <0.041 (units are lbs a.i./A). 

Residues of propyzamide in surface or groundwater that is used for irrigation of plants may result 

in potential injury to terrestrial plants (Table 32 and Table 33). Assuming an acre of land is 

irrigated with one inch of contaminated water, the 23.9 μg ai/L peak groundwater EEC is 

equivalent to an application rate of 0.005 lbs ai/A. The most sensitive of the available endpoints, 

the IC05 and IC25 for cucumber from the seedling emergence study is 0.004 and 0.015 lbs ai/A, 

respectively. The resulting IC05/IC25 RQs are 1.25/0.33. The IC05 RQ exceeds the Agency’s LOC 

of 1.0 for terrestrial plants. 

Table 32. Seedling Emergence RQ values for listed and non-listed species1 of non-target plants based on 

propyzamide using groundwater-derived irrigation water.

Monocot: ryegrass (Lolium perenne) Dicot: cucumber (Cucumis sativa) 

IC25 = 0.019 lbs a.i./A NOAEC = <0.015 lbs a.i./A IC25 = 0.015 lbs a.i./A IC05 = 0.004 lbs a.i./A 

0.79 >0.33 0.33 1.25 

Bolded values exceed the Agency’s level of concern (LOC) for risk to listed and non-listed species of terrestrial plants (RQ > 1). 1RQ values are based on the irrigation water EEC of 0.0102 lbs a.i./A / the seedling emergence IC25 (non-listed) or NOAEL 

(listed) value. 

Table 33. Vegetative vigor RQ values for listed and non-listed species1 of non-target plants based on 

propyzamide using groundwater-derived irrigation water.

Monocot: oat (Avena sativa) Dicot: tomato (Lycopersicon esculentum) 

IC25 = <0.2 lbs a.i./A NOAEC = <0.2 lbs a.i./A IC25 = <0.041 lbs a.i./A NOAEC = <0.041 lbs a.i./A 

>0.025 >0.025 >0.122 >0.122 

Bolded values exceed the Agency’s level of concern (LOC) for risk to listed and non-listed species of terrestrial plants (RQ > 1). 1RQ values are based on the irrigation water EEC of 0.0102 lbs a.i./A / the vegetative vigor IC25 (non-listed) or NOAEL (listed) 

value. 

4.2.3. Conclusions 

Based on this screening-level assessment, the physicochemical properties of propyzamide indicate 

that the herbicide has the potential to reach aquatic environments, including surface and ground 
-Page 48 of 86- 

water following application. The available ecotoxicity data demonstrate that propyzamide is 

slightly-to-moderately toxic to fish and aquatic invertebrates and LOCs were not exceeded. 

Therefore, the likelihood of adverse effects to fish, aquatic invertebrates, and aquatic-phase 

amphibians, from exposure to propyzamide use is considered low. Freshwater invertebrates 

exhibit similar sensitivity to estuarine/marine invertebrates on an acute exposure basis. Based on 

chronic toxicity values, RQ values are below the chronic risk LOC for estuarine/marine 

invertebrates. 

Submitted propyzamide data used to determine risk to avian taxa (and terrestrial-phase amphibians 

and reptiles) indicate acute and dietary LOC’s are exceeded regardless of whether the Japanese 

quail or canary are used. There is uncertainty, however, because the canary endpoint was nondefinitive, and the Japanese quail study used a formulation study as opposed to TGAI. Additionally 

the formulation used in the Japanese quail study is not a currently registered formulation. Although 

the avian reproduction study did not establish a lower bound for effects on avian reproduction, 

exceedances were observed at 311 mg a.i./kg diet. At 311 mg a.i./kg diet, the number of hatchlings 

to egg set, 14-day survivors to eggs set, and number of hatchlings to live 3-week embryos were 

also significantly (p<0.05) reduced 15-28% from control at all treated levels. Additional data is 

needed to characterize the lower bounds of chronic toxicity to avian taxa. 

The risk hypothesis and conceptual diagrams articulated in this assessment identified concerns that 

the use of propyzamide may result in chronic risk to small (15 g), medium (35 g), and large (1000 

g) size classes of mammals. 

The artichoke/apple uses of propyzamide indicate a non-definitive RQ that does not exceed the 

LOC for acute contact risk to adult bees. The LD50 for acute toxicity to honey bees is > 181 ug 

a.i./bee. 

Data indicate that monocots are dicots are both susceptible to the toxic effects of propyzamide. 

RQ values for listed and non-listed monocots and dicots in dry and semi-aquatic areas exceed the 

Agency’s LOC for risk to plants from runoff, as well as monocots and dicots exposed via spray 

drift. Listed terrestrial plants exposed to residues of propyzamide in irrigation water are at risk as 

well. 

To characterize potential non-target plant exposure from spray drift alone, Tier 1 modules in 

AgDrift (v. 2.1.1, December 2011) were used to estimate how far off-site spray drift exposure 

might occur at a level known to cause adverse effects in terrestrial plant toxicity studies. For 

ground applications, EFED used the American Society of Agricultural and Biological Engineers 

(ASABE, formerly ASAE) Coarse-to-Very Coarse droplet size category in its modeling. This size 

category is an assumption for herbicides that require root uptake. Due to the non-definitive values 

from the vegetative vigor study, area of adverse effect distances could not be calculated for listed 

and non-listed monocots and dicots. 

4.2.4. Endangered Species Act 

Consistent with EPA’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 
-Page 49 of 86- 

pesticides in accordance with the Joint Interim Approaches developed to implement the 

recommendations of the April 2013 National Academy of Sciences (NAS) report, Assessing Risks 

to Endangered and Threatened Species from Pesticides. The NAS report12 outlines 

recommendations on specific scientific and technical issues related to the development of pesticide 

risk assessments that EPA and the Services must conduct in connection with their obligations 

under the ESA and FIFRA. EPA will address concerns specific to propyzamide in connection 

with the development of its final registration review decision for propyzamide. 

In November 2013, EPA, the U.S. Fish and Wildlife Service, National Marine Fisheries (the 

Services), and USDA released a white paper13 containing a summary of their joint Interim 

Approaches for assessing risks to listed species from pesticides. These Interim Approaches were 

developed jointly by the agencies in response to the NAS recommendations, and reflect a common 

approach to risk assessment shared by the agencies as a way of addressing scientific differences 

between the EPA and the Services. Details of the joint Interim Approaches are contained in the 

November 1, 2013 white paper, Interim Approaches for National-Level Pesticide Endangered 

Species Act Assessments Based on the Recommendations of the National Academy of Sciences 

April 2013 Report.

Given that the agencies are continuing to develop and work toward implementation of the Interim 

Approaches to assess the potential risks of pesticides to listed species and their designated critical 

habitat, this ecological risk assessment supporting the Preliminary Work Plan for propyzamide 

does not describe the specific ESA analysis, including effects determinations for specific listed 

species or designated critical habitat, to be conducted during registration review. While the 

agencies continue to develop a common method for ESA analysis, the planned risk assessment for 

the registration review of propyzamide will describe the level of ESA analysis completed for this 

particular registration review case. This assessment will allow EPA to focus its future evaluations 

on the types of species where the potential for effects exists, once the scientific methods being 

developed by the agencies have been fully vetted. Once the agencies have fully developed and 

implemented the scientific methods necessary to complete risk assessments for listed species and 

their designated critical habitats, these methods will be applied to subsequent analyses of 

propyzamide as part of completing this registration review.

4.2.5. Endocrine Disruptor Screening Program 

Propyzamide was included in the first group of 67 chemicals issued an order to conduct Tier 1 

Endocrine Disrupting Screen Program (EDSP) testing. Tier 1 screening results for List 1 

chemicals are available at http://www2.epa.gov/ingredients-used-pesticide-products/endocrinedisruptor-screening-program-tier-1-assessments. For additional information on the EDSP, visit 

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

 

5. Uncertainties 

 

12 http://www.nap.edu/catalog.php?record_id=18344 

13 http://www.epa.gov/espp/2013/nas.html 
-Page 50 of 86- 

Aquatic Exposure 

This assessment is based upon available environmental fate data. There are no significant data 

gaps in the environmental fate database. Only the Environmental Chemical Methods in soil is 

necessary to fulfill all fate data requirements. 

For ecological effects, no data have been submitted for chronic effects to estuarine/marine fish and 

invertebrates. ACRs were used to estimate chronic toxicity values for estuarine/marine 

invertebrates. However, the endpoint for the acute toxicity to estuarine/marine fish was a nondefinitive “greater than” (>) value, therefore introducing uncertainty upon calculation of the ACR. 

Risks to aquatic organisms is expected to be minimal from propyzamide use, therefore, no 

additional data is needed.

Terrestrial Exposure 

With regard to the acute avian toxicity study with the canary (MRID 48599209), there is 

uncertainty due to the non-definitive “greater than” (>) endpoint. 

The two avian reproduction studies (OCSPP 850.2300) with the Bobwhite quail (MRID 48931802) 

and Mallard (MRID 48931803) were classified as supplemental. The Bobwhite quail study did 

not test up to a concentration to elicit an adverse effect or test up to 5,000 mg/kg diet, and the 

Mallard study reported a non-definitive “less than” (<) NOAEC. Although the Mallard study did 

not establish a lower bound for effects on avian reproduction, exceedances were observed at 311 

mg a.i./kg diet (the lowest test concentration used in the study). Additional data is needed to 

characterize the lower bounds of chronic toxicity to avian taxa. 

The Tier II vegetative vigor plant toxicity study originally showed IC25 values that were less than 

the NOAEC values based on an extrapolation of test concentrations. The extrapolated IC25 values 

fell outside the range of test concentrations resulting in uncertainty regarding the actual IC25 value. 

As a result, the IC25 values have a non-definitive “less than” (<) value. Additionally, a nondefinitive “less than” (<) NOAEC from the seedling emergence study was used for monocots. 

Although these values were still used for risk estimation, the reported RQ values likely 

underestimate the risk to listed and non-listed dicots. Exceedances did not occur for non-listed 

monocot plants exposed to spray drift for use on turf, and listed dicot plants exposed to spray drift 

for uses on alfalfa, blueberries, lettuce (ground application only), or turf. Dry and semi-aquatic 

areas all showed exceedances to propyzamide for every crop use (including turf). An additional 

uncertainty associated with the submitted terrestrial plant studies is that they were conducted with 

TGAI as opposed to TEP. TEP formulations may enhance the toxicity and persistence of the 

chemical. 
-Page 51 of 86- 

Data Gaps 

The environmental chemistry method and its independent laboratory validation in soil (MRIDs 

48599206 and 48599205) were insufficient to satisfy the data requirements for these studies. 

Therefore, this data is still recommended. 

Appendix D lists whether data gaps for ecological effects have been identified. 

No data have been submitted for chronic toxicity to estuarine/marine fish and invertebrates. 

Therefore, estuarine/marine invertebrate life-cycle (OCSPP 850.1350) and estuarine/marine fish 

early-life stage (OCSPP 850.1400) are needed. However, in the absence of these data, an ACR 

has been used to estimate chronic toxicity endpoints for estuarine/marine invertebrates. An ACR 

cannot be calculated for estuarine/marine fish because a different species of freshwater fish was 

used in the acute and chronic freshwater fish toxicity tests. 

The avian reproduction study (OCSPP 850.2300) with the Mallard (MRID 48931803) was 

classified as supplemental. The reported NOAEC was a non-definitive “less than” (<) the lowest 

concentration tested. Although the avian reproduction study did not establish a lower bound for 

effects on avian reproduction, exceedances were observed at 311 mg a.i./kg diet. Additional data 

is needed to characterize the lower bounds of chronic toxicity to avian taxa. 

 

Although data indicate propyzamide is practically non-toxic to young adult bees on an acute 

contact exposure basis, the toxicity endpoint is non-definitive, and there is uncertainty regarding 

potential risk from acute oral exposure when considered in the context of estimated exposures (i.e., 

EECs) from registered uses of propyzamide. There is also uncertainty regarding the potential acute 

and chronic effects of the compound on honey bee larval development and survival as well as 

potential chronic effects in adult bees. Therefore, additional data on pollinators is needed to fully 

characterize the risk associated with propyzamide use to all developmental stages of honey bees, 

as sensitivity may vary according to life-stage and length of exposure (adult vs. larval and acute 

vs. chronic, respectively). As described in the guidance for assessing risks to bees14,15 depending 

on the outcome of the screening-level risk assessment, additional studies of bees at the colony 

level under semi- and full-field conditions may also be recommended. 

The Tier II vegetative vigor plant toxicity study showed IC25 values that were less than the NOAEC 

values. Extrapolated IC25 values fell outside the range of test concentrations resulting in 

uncertainty regarding the actual IC25 value. As a result, IC25 values have a non-definitive “less 

than” (<) value. The NOAEC value for the seedling emergency monocot study is also described 

as a non-definitive “less than” value. Furthermore, both the seedling emergence and vegetative 

vigor studies were conducted with TGAI as opposed to TEP. TEP formulations may enhance the 

toxicity and persistence of the chemical. Therefore, additional seedling emergence and vegetative 

vigor studies are needed with TEP to characterize the effects of propyzamide on terrestrial plants. 

 

14USEPA. 2014. Guidance for Assessing Pesticide Risks to Bees. Office of Pesticide Programs. United States Environmental Protection Agency. 

Available at 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/terrestrial_biology_tech_team/GuidanceAssessingPesticideRisk2Bees.

pdf 15http://www2.epa.gov/sites/production/files/2014-06/documents/pollinator_risk_assessment_guidance_06_19_14.pdf 
-Page 52 of 86- 

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Environmental Fate MRIDs 

161-1 Hydrolysis 

MRID Citation Reference 

107980 

Rohm and Haas Co. (1973) A Study of the Hydrolysis of the Herbicide Kerb in Water: 

Laboratory 23 Technical Report No. 23-73-8. (Un- published study received Apr 27, 1973 

under 707-113; CDL: 120314-A) 

107989 Rohm and Haas Co. (1971) Degradation of C14 Kerb ?3,5-dichloro-N- (1,1-dimethyl-2-

propynyl)-benzamide| in Water: Laboratory 23 Technical Report No. 23-71-24. 

(Unpublished study received May 16, 1972 under 707-98; CDL:120402-I) 

107990 Satterthwaite, S.; Fisher, J. (1972) Photodecomposition Study of Kerb (3,5-dichloro-N-

(1,1-dimethyl-2-propynyl)-benzamide) in Water: Laboratory 11 Metabolism Group 

Memorandum Report No. 7. (Unpublished study received May 16, 1972 under 707-98; 

submitted by Rohm & Haas Co., Philadelphia, PA; CDL:120402-J) 

161-2 Photodegradation-water 

40320601 Nelson, S. (1987) Characterization of Degradates from the Photoly- sis of Pronamide: Rept. 

No. 31C-87-27. Unpublished supplemental report prepared by Rohm and Haas Co. 58 p. 

40420301 Carpenter, M.; Fennessey, M. (1987) Determination of the Photolysis Rate of ?Carbon 14|-

phenyl Pronamide in pH-7 Aqueous Solution: ABC Final Report No. 35172. Unpublished 

study prepared by Rohm and Haas Co. in cooperation with Analytical Bio-Chemistry Laboratories, Inc. 1028 p. 

161-3 Photodegradation-soil 

143746 Burgess, D. (1985) Photolysis of [Carbon-14] Pronomide (Kerb) on Soil Surface Exposed 

to Artificial Sun Light: Revised Draft Report: Project No. 84-E-216SP. Unpublished study 

prepared by Biospherics Incorporated. 27 p. 

41913504 Carpenter, M. (1987) Soil Photolysis of 14-C-Phenyl Pronamide: Lab Project Number: 

35238. Unpublished study prepared by Rohm and Haas Company. 683 p. 
-Page 54 of 86- 

162-1 Aerobic soil metabolism 

41568901 Olson, G.; Lawrence, L. (1990) Aerobic Metabolism of (Carbon 14) Pronamide in 

Sandy Loam Soil: Lab Project Number: 1250: 309. Unpublished study prepared by 

Pharmacology and Toxicology Research Laboratory. 67 p. 

41913502 Nelson, S. (1991) Aerobic Soil Metabolism of 14C-Pronamide in Sandy Loam Soil: 

Response to EPA Review (Shaughnessy No. 101701): Lab Project Number: 34-91-39. 

Unpublished study prepared by Rohm and Haas Company. 7 p. 

46413407 Volkl, S. (2001) Degradation Rate of (Carbon 14)-Propyzamide (Kerb) in Three Soils 

Incubated Under Aerobic Conditions. Project Number: 773897, 34/00/108. 

Unpublished study prepared by RCC Umweltchemie Ag. 134 p. 

162-2 Anaerobic soil metabolism 

MRID Citation Reference 

161097 Stahovec, W. (1986) Pronamide (Kerb) Anaerobic Soil Metabolism: Revised Final 

Report: Biospherics Project No. 85E-105ANA. Un- published study prepared by Rohm 

and Haas Co. 178 p. 

162749 Yih, R.; Swithenbank, C.; McRae, D. (1970) Transformations of the herbicide N-(1,1-

dimethylpropynyl)-3,5-dichlorobenzamide in Soil. Weed Science 18(5):604-607. 

40244401 Nelson, S. (1987) Response to EPA Review of Kerb Herbicide Anaero- bic Soil 

Metabolism: Supplement to W. L. Stahovec--Pronamid (Kerb) Anaerobic Soil 

Metabolism...: Lab. Memorandum No. 31C-87- 142. Unpublished study prepared by 

Rohm and Haas Co. 5 p. 

41913505 Olson, G.; Lawrence, L. (1989) Anaerobic Metabolism of (Carbon 14) Propamide in 

Sandy Loam Soil: Lab Project Number: 1175: 271. Unpublished study prepared by 

Pharmacology and Toxicology Research Laboratory. 54 p. 

162-3 Anaerobic aquatic metab. 

107989 

Rohm and Haas Co. (1971) Degradation of C14 Kerb ?3,5-dichloro-N- (1,1-dimethyl-2-

propynyl)-benzamide| in Water: Laboratory 23 Technical Report No. 23-71-24. 

(Unpublished study received May 16, 1972 under 707-98; CDL:120402-I) 

163-1 Leach/adsorp/desorption 

107970 

Fisher, J. (1973) Soil Leaching Study with Kerb Degradation Prod- ucts RH-24,580 and 

RH-24,644: Technical Report 3923-73-4. (Un- published study received Aug 20, 1973 

under 3F1317; submitted by Rohm & Haas Co., Philadelphia, PA; CDL:094306-A) 

107971 Rohm & Haas Co. (1971) Soil Adsorption Studies with C14 Kerb: Technical Report 23-

71-12. (Unpublished study received Aug 20, 1973 under 3F1317; CDL:094306-B) 

107982 Rohm & Haas Co. (1971) Soil Absorption Studies with Kerb ?3,5-di- chloro-N-(1,1-

dimethyl-2-propynyl)-benzamide|: Laboratory 23 Technical Report No. 23-71-12. 

(Unpublished study received May 16, 1972 under 707-98; CDL:120402-B) 
-Page 55 of 86- 

107983 Fisher, J.; Satterthwaite, S. (1971) Leaching and Metabolism Studies of C14 Kerb ?3,5-

dichloro-N-(1,1-dimethyl-2-propynyl)- benzamide| in Soils: Laboratory 11 Research 

Report No. 11-228. (Unpublished study received May 16, 1972 under 707-98; submitted 

by Rohm & Haas Co., Philadelphia, PA; CDL:120402-C) 

40211103 

Vincent, P. (1987) Soil Adsorption/Desorption of [Carbon 14]-Prona- mide: ADC 

Project #1002. Unpublished study prepared by Analy- tical Development Corp. 230 p. 

40211104 

Nelson, S. (1987) Adsorption/Desorption of [Carbon 14] RH-24,580 and [Carbon 14] 

RH-24,644: Rohm and Haas Technical Report No. 31C-87-15. Unpublished study 

prepared by Rohm and Haas Co. 350 p. 

41913501 

Nelson, S. (1987) Mobility Studies Related to Pronamide: Response to EPA review 

(Shaughnessy No. 101701): Lab Project Number: 34- 91-40. Unpublished study 

prepared by Rohm amd Haas Company. 8 p. 

164-1 Terrestrial field dissipation 

107957 Rohm & Haas Co. (1971) Results of Tests on the Amount of Residue Remaining in or 

on Lettuce and Related Crops and Soil Including a Description of the Analytical Method: 

(Kerb). (Compilation; unpublished study received Mar 11, 1971 under 1F1139; CDL: 

090917-A; 090916) 

107986 Rohm & Haas Co. (1972) Leaching, Runoff and Persistence of Kerb ?3,5-dichloro-N-

(1,1-dimethyl-2-Propynyl)-benzamide| in Soil under Field Trial Conditions during 1970-

1971: AFTG Research Report No. XXXXVI. (Unpublished study received May 16, 

1972 under 707-98; CDL:120402-F) 

138403 Rohm & Haas Co. (1974) Kerb--Long Term Soil Residues (A Part of the fate in 

Environment Studies on Kerb Herbicide). (Compilation; unpublished study received 

May 8, 1974 under 707-98; CDL: 120407-A) 

40925401 Nelson, S.; Zogorski, W. (1988) Kerb Herbicide Terrestrial Field Dissipation: Two Sites: 

Project ID. 34C-88-54. Unpublished stu- dy prepared by Rohm and Haas Co. in 

cooperation wtih Craven Laboratories and Pan-Agricultural Associates. 1609 p. 

41913503 

Nelson, S. (1991) Kerb Herbicide Terrestrial Field Dissipation: Response to EPA 

Review (Shaughnessy No. 101701): Lab Project Number: 34-91-41. Unpublished study 

prepared by Rohm and Haas Company. 5 p. 

44078601 

Choo, D. (1996) Terrestrial Field Dissipation of Kerb Herbicide at California and 

Wisconsin: Lab Project Number: 34-96-100: TR-34-96-100: TR 34-95-34. Unpublished 

study prepared by ABC Labs., California; Centre Analytical Labs., Inc.; and QC, Inc. 

753 p. 

165-1 Confined rotational crop 

41913506 Nelson, S. (1991) Pronamide Confined Rotational Crop Study: Respon- se to EPA 

Review (Shaughnessy No. 101701): Lab Project Number: 34-91-42. Unpublished study 

prepared by Rohm and Haas Company. 9 p. 

165-2 Field rotational crop 
-Page 56 of 86- 

44661501 Smith, S. (1998) Field Rotation Crop Study of Kerb Herbicide in California-Bare 

Ground, Rotated with Small Grains, Root Crops, and Leafy Vegetables: Lab Project 

Number: 34P-95-13: 34P-95-14: 34P-95-13A. Unpublished study prepared by Rohm and 

Haas Company, and ABC Laboratories California. 944 p. 

165-4 Bioaccumulation in fish 

43196701 Liu, P. (1994) (Carbon 14)-Pronamide: Flow-Through Bluegill Bioconcentration Study: 

Lab Project Number: XBL 93105: RPT00162: 34-94-27. Unpublished study prepared by 

ABC Labs., Inc. and XenoBiotic Labs., Inc. 144 p. 

Ecological Effects MRIDs 

101701 Pronamide Eco Effects Bibliography Revised 05/23/12 

71-1 Avian Single Dose Oral Toxicity 

MRID Citation Reference 

107997 Robinson, D.; Shillam, K. (1969) Toxicity of RH-315 to the Japanese Quail and the 

Mallard Duck: 2839/69/265. (Unpublished study re- ceived Jun 22, 1970 under 707-EX63; prepared by Huntingdon Research Centre, Eng., submitted by Rohm & Haas Co., 

Phila- delphia, PA; CDL:123888-B) 

48471001 Hubbard, P. (2011) Propyzamide: An Acute Oral Toxicity Study with the Zebra Finch 

(Poephila guttata). Project Number: 379/256, 379/022311A/ZF/LD/SUB379. 

Unpublished study prepared by Wildlife International, Ltd. 15 p 

48599208 Hubbard, P.M., and Beavers, J.B. 20 l l.Propyzamide: An Acute Oral Toxicity Study with 

the Northern Bobwhite. Unpublished study performed by Wildlife International, LTD. 

Project Number: 379-254. Study sponsored by Dow AgroSciences, LLC, Midland, Ml. 

Study initiated 30 March 2011 and submitted 12May 2011. 

48599209 Hubbard, P.M., and Beavers, J.B. 2011. Propyzamide: An Acute Oral Toxicity Study with 

the Canary (Serinus canaria). Unpublished study performed by Wildlife lntemational, 

LTD. Project Number: 379-256. Study sponsored by Dow AgroSciences, LLC, Midland, 

MI. Study initiated 25 July 20 II and submitted 2 September 2011. 

71-2 Avian Dietary Toxicity 

MRID Citation Reference 

107993 Shellenberger, T. (1971) Subacute Toxicity Evaluation of Kerb ?3,5- dichloro-N-(1,1-

dimethyl-2-propynyl)-benzamide| with Young Adult Bobwhite Quail (A Seven Day 

Range Finding Study): GSRI Project No. NC-501. (Unpublished study received May 16, 

1972 under 707- 98; prepared by Gulf South Research Institute, submitted by Rohm & 

Haas Co., Philadelphia, PA; CDL:120402-N) 
-Page 57 of 86- 

107994 Shellenberger, T. (1971) A Subacute Toxicity and Tissue Residue Study of Kerb ?3,5-

dichloro-N-(1,1-dimethyl-2-propynyl)-ben- zamide| Herbicide in Young Adult Bobwhite 

Quail: GSRI Project No. NC-501. Final rept. (Unpublished study received May 16, 1972 

under 707-98; prepared by Gulf South Research Institute, submitted by Rohm & Haas 

Co., Philadelphia, PA; CDL:120402-O) 

108002 Fink, R. (1975) Eight-day Dietary LC50--Mallard Duck: Technical Kerb: Project No. 129-

107. Final rept. (Unpublished study re- ceived Feb 25, 1977 under 707-98; prepared by 

Truslow Farms Inc., submitted by Rohm & Haas Co., Philadelphia, PA; CDL: 233723-A) 

108003 Fink, R. (1975) Eight-day Dietary LC50--Bobwhite Quail: Technical Kerb: Project No. 

129-106. Final rept. (Unpublished study received Feb 25, 1977 under 707-98; prepared by 

Truslow Farms Inc., submitted by Rohm & Haas Co., Philadelphia, PA; CDL: 233723-B)

71-4 Avian Reproduction 

MRID Citation Reference 

48931802 Frey, L.; Martin, K.; Beavers, J. et al. (2000) Kerb Technical Herbicide: A Reproduction 

Study with the Northern Bobwhite Quail. Project Number: 99RC/0235, 129/175. 

Unpublished study prepared by Wildlife International, Ltd. 168p. 

48931803 Frey, L.; Martin, K.; Beavers, J. et al. (2012) Propyzamide: A Reproduction Study with 

the Mallard: Final Report. Project Number: 379/257, 110231. Unpublished study prepared 

by ABC Laboratories, Inc. 240p. 

72-1 Acute Toxicity to Freshwater Fish 

MRID Citation Reference 

107196 McCann, J. (1971) ?Kerb 50-W: Bluegill|: Test No. 325. (U.S. Agricultural Research 

Service, Pesticides Regulation Div., Animal Biology Laboratory; unpublished study; 

CDL:130346-A) 

107996 Binns, R.; Clark, G. (1969) The Acute Toxicity to Fish of An Exper- imental Herbicide 

RH-315-75WP: 2932/69/358. (Unpublished study received Jun 22, 1970 under 707-EX63; prepared by Huntingdon Research Centre, Eng., submitted by Rohm & Haas Co., 

Phila- delphia, PA; CDL:123888-A) 

48599210 Gerke, Amanda. 2011. Pronamide Technical: Acute Toxicity to the Bluegill Sunfish, 

Lepomismacrochirus, Determined Under Static-Renewal Conditions. Unpublished study 

performed by ABC Laboratories,Inc. Project Number 66996. Study sponsored by the Dow 

Chemical Company, Midland, MI. Study completed 31 

August 2011. 

48599211 Dinehart, Simon. 2011. Pronamide Technical: Acute Toxicity to the Rainbow Trout, 

Oncorhynchusmykiss, Determined Under Static-Renewal Conditions. Unpublished study 

performed by ABC Laboratories, Inc.Project Number 66993. Study sponsored by the Dow 

Chemical Company, Midland, Ml. Study completed 31 

August 2011. 

72-2 Acute Toxicity to Freshwater Invertebrates 
-Page 58 of 86- 

MRID Citation Reference 

98313 Vilkas, A.G.; Browne, A.M. (1980) The Acute Toxicity of Kerb Tech- nical (No Clay) 

to the Water Flea~Daphnia magna~Straus: UCCES Project No. 11506-33-43. 

(Unpublished study received Apr 1, 1982 under 707-159; prepared by Union Carbide 

Corp., submitted by Rohm & Haas Co., Philadelphia, Pa.; CDL:247155-A) 

72-3 Acute Toxicity to Estuarine/Marine Organisms 

MRID Citation Reference 

43608401 Drottar, K.; Swigert, J. (1995) Kerb Technical: A 96-Hour Shell Deposition Test With 

the Eastern Oyster (Crassostrea virginica): Final Report: Lab Project Number: 

129A/123: 94RC-0192. Unpublished study prepared by Wildlife International, Ltd. 104 

p. 

43608402 Drottar, K.; Swigert, J. (1995) Kerb Technical: A 96-Hour Flow-Through Acute 

Toxicity Test With the Saltwater Mysid (Mysidopsis bahia): Final Report: Lab Project 

Number: 129A-122C: 94RC-0193. Unpublished study prepared by Wildlife 

International Ltd. 93 p. 

48599212 Dinehart, Simon. 2011. Pronamide Technical: Acute Toxicity to the Sheepshead 

Minnow, Cyprinodonvariegates, Determined Under Static-Renewal Conditions. 

Unpublished study performed by ABC Laboratories, Inc. 

Project Number 67070. Study sponsored by the Dow Chemical Company, Midland, MI. 

Study completed 31 August 2011. 

123-1 Seed germination/seedling emergence and vegetative vigor 

MRID Citation Reference 

42176801 Hoberg, J. (1992) Kerb Technical--Determination of Effects on Seed Germination, 

Seedling Emergence and Vegetative Vigor of Ten Plant Species: Final Report: Lab 

Project Number: 91-10-3974: 86.0591.6138.610: RH 91RC-0069. Unpublished study 

prepared by Springborn Labs, Inc. 218 p. 

43448101 Hoberg, J. (1994) KERB Technical--Determination of the Effects on Seed Germination, 

Seedling Emergence and Vegetative Vigor of Ten Plant Species: Supplement: Lab 

Project Numbers: 91-10-3974: 91RC-0069A. Unpublished study prepared by Springborn 

Labs, Inc. 160 p. 

44029001 Teixeira, D. (1996) Kerb Technical--Determination of Effects on Seedling Emergence 

of Two Plant Species: Supplement to: "Kerb Technical--Determination of Effects on 

Seed Germination, Seedling Emergence and Vegetative Vigor of Ten Plant Species: 

MRID 43448101:" Final Report: Lab Project Number: 96-2-6389: 86.0995.6193.610: 

95RC-0190. Unpublished study prepared by Springborn Labs, Inc. 89 p. 

123-2 Aquatic plant growth 
-Page 59 of 86- 

MRID Citation Reference 

42176802 Hoberg, J. (1991) Kerb Technical--Toxicity to the Freshwater Green Alga, Selenastrum 

capricornutum: Lab Project Number: 91-11-4005: 91RC-0070: 86. 0591. 6137. 430. 

Unpublished study prepared by Springborn Labs, Inc. 65 p. 

43738301 Thompson, S.; Swigert, J. (1995) Kerb Technical: A 14-Day Toxicity Test with 

Duckweed (Lemna gibba G3): Final Report: Lab Project Number: 129A-119: 94RC-0191. 

Unpublished study prepared by Wildlife International Ltd. 98 p. 

43738302 Thompson, S.; Swigert, J. (1995) Kerb Technical: A 5-Day Toxicity Test with the 

Freshwater Diatom (Navicula pelliculosa): Final Report: Lab Project Number: 129A-117: 

94RC-0196. Unpublished study prepared by Wildlife International Ltd. 104 p. 

43738303 Thompson, S.; Swigert, J. (1995) Kerb Technical: A 5-Day Toxicity Test with the Marine 

Diatom (Skeletonema costatum): Final Report: Lab Project Number: 129A-118: 94RC0195. Unpublished study prepared by Wildlife International Ltd. 103 p. 

43738304 Thompson, S.; Swigert, J. (1995) Kerb Technical: A 5-Day Toxicity Test with the 

Freshwater Alga (Anabaena flos-aquae): Final Report: Lab Project Number: 129A-120: 

94RC-0190. Unpublished study prepared by Wildlife International Ltd. 106 p. 

142-3 Simulated or Actual Field Testing 

MRID Citation Reference 

107951 Rohm & Haas Co. (1970) Effect of Herbicide and Insecticide Treat- ments on China 

Lettuce to Honey Bees and Leafcutter Bees. (Un- published study received 

43176701 Kuhner, C. (1993) Assessment of Side Effects of Kerb 50 W on the Predatory Mite, 

Typhlodromus pyri SCHEUTEN (Acari, Phytoseiidae) in the Laboratory: Lab Project 

Number: 93009/01/ TP: 93RC/1078. Unpublished study prepared by 

Arbeitsgemeinschaft, GAB Biotechnologie GmbH und IFU Umweltanalytik GmbH. 24 

p. 

43177001 Kuhner, C. (1993) Assessment of Side Effects of Kerb 50 W on the Lady Bird Beetle, 

Coccinella septempunctata L. (Coleoptera, Coccinellidae) in the Laboratory: Pronamide: 

Lab Project Number: 93009/01-Cs: 93RC-1079. Unpublished study prepared by 

Arbeitsgemeinschaft, GAB Biotechnologie GmbH und IFU Umweltanalytik GmbH. 20 

p. 

850.1075 Fish acute toxicity test, freshwater and marine 

MRID Citation Reference 

48599210 Gerke, A. (2011) Pronamide Technical: Acute Toxicity to the Bluegill Sunfish, Lepomis 

macrochirus, Determined Under Static-Renewal Test Conditions. Project Number: 

66996, 110036. Unpublished study prepared by ABC Laboratories, Inc. 59p. 
-Page 60 of 86- 

48599211 Dinehart, S. (2011) Pronamide Technical: Acute Toxicity to the Rainbow Trout, 

Oncorhynchus mykiss, Determined Under Static-Renewal Test Conditions. Project 

Number: 66993, 110033. Unpublished study prepared by ABC Laboratories, Inc. 54p. 

48599212 Dinehart, S. (2011) Pronamide Technical: Acute Toxicity to the Sheepshead Minnow, 

Cyprinodon variegatus, Determined Under Static-Renewal Conditions. Project Number: 

67070, 110363. Unpublished study prepared by ABC Laboratories, Inc. 54p. 

850.1500 Fish life cycle toxicity 

MRID Citation Reference 

48931801 Dinehart, S. (2012) Pronamide Technical: Life-Cycle Toxicity Test with the Fathead 

Minnow, Pimephales promelas, Under Flow-Through Conditions. Project Number: 

67560, 110364. Unpublished study prepared by ABC Laboratories, Inc. 150p. 

850.2100 Avian acute oral toxicity test 

MRID Citation Reference 

48471001 Hubbard, P. (2011) Propyzamide: An Acute Oral Toxicity Study with the Zebra Finch 

(Poephila guttata). Project Number: 379/256, 379/022311A/ZF/LD/SUB379. 

Unpublished study prepared by Wildlife International, Ltd. 15 p. 

48599208 Hubbard, P.; Beavers, J. (2011) Propyzamide: An Acute Oral Toxicity Study with the 

Northern Bobwhite. Project Number: 379/254, 110228. Unpublished study prepared by 

Wildlife International, Ltd. 35p. 

48599209 Hubbard, P.; Beavers, J. (2011) Propyzamide: An Acute Oral Toxicity Study with the 

Canary (Serinus canaria). Project Number: 379/256, 110230. Unpublished study 

prepared by Wildlife International, Ltd. 60p. 

850.2300 Plant 

MRID Citation Reference 

49300801 Gemrot, F. (2013) Propyzamide - Independent Laboratory Validation of an Analytical 

Method for the Determination of Residues of Propyzamide and its Relevant 

Metabolites in Soil by Liquid Chromatography with Tandem Mass Spectrometry. 

Project Number: 130751, S13/03290. Unpublished study prepared by Eurofins 

Agroscience Services Chem. 96p. 

48931803 : Frey, L.T., et al. 2012. Propyzamide: A Reproduction Study with the Mallard. 

Unpublished study performed by Wildlife International Ltd., Easton, MD. 

Laboratory Project No. 379-257. Study sponsored by The Dow Chemical Company, 

Midland, MI for Dow AgroSciences, LLC, Indianapolis, IN. Study initiated 

December 13, 2011 and completed August 7, 2012 
-Page 61 of 86- 

850.6100 Environmental Chemistry Methods and Associated Independent Laboratory Validation 

MRID Citation Reference 

49300801 Gemrot, F. (2013) Propyzamide - Independent Laboratory Validation of an Analytical 

Method for the Determination of Residues of Propyzamide and its Relevant 

Metabolites in Soil by Liquid Chromatography with Tandem Mass Spectrometry. 

Project Number: 130751, S13/03290. Unpublished study prepared by Eurofins 

Agroscience Services Chem. 96p. 

FRESHWATER SEDIMENT Chironomus dilutus EMERGENCE TEST 

MRID Citation Reference 

48599214 Pronamide Technical: Whole Sediment 10 Day Acute Toxicity 

Test with Midge Larvae (Chironomus dilutus)
-Page 62 of 86- 

Appendix A. Propyzamide Uses 

Products for registration containing propyzamide. 

Use Formula

tion 

Application 

Type 

Max 

Single 

App 

Rate 

(lb 

a.i./A) 

Max 

#Apps

/CC1

Max app 

rate/CC 

(lb a.i. / 

A/CC) 

Max # 

CC per 

Year 

Max 

#Apps/ 

Year 

Max App 

rate/Year 

(lb a.i. / 

A/Yr) 

MRI 

(days) 

Artichoke (globe) 

WSP, SC Ground, 

broadcast; Ground, banded; Aerial 

4 1 4 (established 

plants); 

2 (newly 

planted) 

1 1 4 

(established 

plants); 

2 (newly 

planted) 

na 

blackberry / boysenberry / raspberry 

WSP, SC ground, 

broadcast; Ground, banded 

3 1 3 1 na 3 na 

Blueberry WSP, SC ground, 

broadcast; Ground, banded 

2 1 2 1 1 2 na 

alfalfa, 

WSP, SC ground, broadcast 2 na na na na 2 na 

 clover, birdsfoot trefoil, crown vetch, sainfoin alfalfa (dodder control) 

WSP, SC ground, 

broadcast 

2 na na na na 2 na 
-Page 63 of 86- 

alfalfa (cheatgrass control) 

WSP, SC ground, 

broadcast 

1 na na na na na Should 

be 2 

na 

head lettuce, endive, escarole, radicchio greens, leaf lettuce (proposed) 

WSP, SC ground: 

banded, bedtopped, or broadcast; 

2 

2 at 

rate of 

1 lb 

a.i. for 

split 

apps 

2 na na 2 10 

head lettuce, 

WSP, SC aerial 

leaf lettuce 

(proposed) 

WSP, SC ground: 

banded, bedtopped, or broadcast; 2 1 2 

na na na na 

aerial 

na na na na 

head lettuce 

WSP, SC chemigation 1 1 1 na na na na 

endive, escarole, radicchio greens,  leaf lettuce (proposed) WSP, SC chemigation 1 1 1 na na na na 
-Page 64 of 86- 

Rhubarb WSP, SC ground, 

broadcast 

2 1 2 na 1 2 na 

Apple, apricot, cherry, nectarine, peach, pear, plum, prune and grape plantings 

WSP, SC ground, 

broadcast 

4 1 4 na 1 4 na 

Winter peas 

WSP, SC ground, 

broadcast 

1.5 1 1.5 na 1 1.5 na 

Woody ornamentals, nursery stock of ornamentals, Christmas trees 

WSP, SC ground, 

broadcast 

2 1 2 1 1 2 na 
-Page 65 of 86- 

Turf grown for sod, nonresidential incl. golf course, industrial and office building sites, stadium fields or professional athletic fields. 

WSP, SC ground, 

broadcast 

1.5 1 1.5 3 3 4.5 na 

nonresidential woody ornamentals, nursery stock of ornamentals, and Christmas trees 

WSP, SC ground, 

broadcast 

2 1 2 3 1 2 na 

SLNs Fall, CarbonSeeded Grasses Grown for Seed (Oregon) 

SC ground, 

banded 

0.25 na na na na na 

Established Orchardgrass Grown for Seed (Oregon) 

SC ground 0.375 1 0.375 1 1 0.375 
-Page 66 of 86- 

Christmas Tree Plantations (Oregon) 

SC aerial 2 na na na na na 

Sugarbeets Grown for Seed (Oregon) 

SC ground 1 na na na na na 

Rhubarb (Michigan) 

SC ground 

broadcast 

2 1 2 1 1 2 

Direct Seeded Head Lettuce 

SC ground 6 1 6 1 1 6 

1 CC=crop cycle 
-Page 67 of 86- 

Appendix B. Propyzamide and its Environmental Transformation Products 

Chemical Name Structure Propyzamide (Pronamide, RH-23315) IUPAC name: 3,5-dichloro-N-(1,1-dimethylprop-2-ynyl)benzamide CAS name: 3,5-dichloro-N-(1,1-dimethyl-2-propynyl)benzamide RH-24644 (M1) 2-(3,5-dichlorophenyl)-4,4-dimethyl-5-methylene-2-oxazoline RH-24655 (M2) 3,5-dichloro-N-(1,1-dimethyl-2-propenyl)benzamide RH-20839 (M3) 3,5-dichlorobenzoic acid 

Cl

Cl

NH

O

Cl

Cl

N

O

Cl

Cl

NH

O

Cl

Cl

OH

O
-Page 68 of 86- 

Chemical Name Structure RH-24580 (M4)N-(1,1-dimethylacetonyl)-3,5-dichlorobenzamide RH-26521 (M9) N-(1,1-dimethyl-2,3-dihydroxypropyl)-3,5-dichlorobenzamide RH-26059 β-(3,5-dichlorobenzamino-β-methyl-butyric acid RH-25891 2-(3,5-dichlorophenyl)-4,4-dimethyl-Shydroxymethyloxazoline 

Cl

Cl

NH

O

O

Cl

Cl

NH

O

OH

OH

Cl

Cl

NH

O

HO

O

Cl

Cl

N

O

OH
-Page 69 of 86- 

Chemical Name Structure RH-26702 N-(1,1-dimethyl-3-hydroxacetonyl)-3,5-dichlorobenzamide 3,5-Dichlorobenzamide MDCBmethyl 3,5-dichlorobenzoateCarbon dioxide

Cl

Cl

NH

O

O

OH

Cl

Cl

NH2

O

Cl

Cl

O

O

O O
-Page 70 of 86- 

Appendix C. SWCC Results Variable Volume Water Model, SWCC Compatible Version  ******************************************* Performed on: 5/29/2015 at 14:22 Peak 1-in-10 = 45.4 ppb Chronic 1-in-10 = 19.6 ppb Simulation Avg = 13.6 ppb 4-day avg 1-in-10 = 42.3 ppb 21-day avg 1-in-10 = 34.4 ppb 60-day avg 1-in-10 = 29.3 ppb 90-day avg 1-in-10 = 28.2 ppb Benthic Pore Water Peak 1-in-10 = 25.0 ppb Benthic Pore Water 21-day avg 1-in-10 = 25.1 ppb Benthic Conversion Factor = 79.0 -Pore water (ug/L) to (total mass, ug)/(dry sed mass,kg) Benthic Mass Fraction in Pore Water = 0.469E-02 YEAR Peak 4-day 21-day 60-day 90-day Yearly Avg Benthic Pk Benthic 21-day  1 2.35E+01 2.15E+01 1.80E+01 1.32E+01 1.14E+01 3.17E+00 8.04E+00 8.02E+00  2 2.12E+01 1.98E+01 1.75E+01 1.61E+01 1.52E+01 9.01E+00 1.28E+01 1.27E+01  3 2.15E+01 2.02E+01 1.65E+01 1.46E+01 1.40E+01 1.05E+01 1.24E+01 1.25E+01  4 2.57E+01 2.41E+01 2.03E+01 1.72E+01 1.62E+01 1.14E+01 1.42E+01 1.41E+01  5 2.39E+01 2.26E+01 1.91E+01 1.71E+01 1.58E+01 1.15E+01 1.36E+01 1.38E+01  6 2.55E+01 2.45E+01 2.07E+01 1.75E+01 1.69E+01 1.26E+01 1.51E+01 1.51E+01  7 2.54E+01 2.42E+01 2.21E+01 2.03E+01 1.90E+01 1.34E+01 1.64E+01 1.63E+01  8 3.34E+01 3.14E+01 2.84E+01 2.31E+01 2.13E+01 1.43E+01 1.81E+01 1.81E+01  9 2.39E+01 2.25E+01 1.92E+01 1.75E+01 1.96E+01 1.34E+01 1.74E+01 1.76E+01  10 2.27E+01 2.14E+01 1.89E+01 1.60E+01 1.53E+01 1.22E+01 1.46E+01 1.45E+01  11 5.13E+01 4.72E+01 3.71E+01 2.95E+01 2.69E+01 1.48E+01 2.16E+01 2.16E+01  12 2.81E+01 2.74E+01 2.39E+01 2.15E+01 2.38E+01 1.67E+01 2.08E+01 2.11E+01  13 5.65E+01 5.25E+01 4.31E+01 3.49E+01 3.26E+01 1.93E+01 2.67E+01 2.67E+01  14 3.08E+01 2.95E+01 2.58E+01 2.78E+01 2.84E+01 2.11E+01 2.59E+01 2.63E+01  15 4.29E+01 4.01E+01 3.32E+01 2.91E+01 2.81E+01 2.01E+01 2.46E+01 2.46E+01  16 3.16E+01 3.03E+01 2.66E+01 2.64E+01 2.61E+01 1.88E+01 2.42E+01 2.44E+01  17 2.63E+01 2.48E+01 2.09E+01 1.85E+01 2.00E+01 1.53E+01 1.88E+01 1.91E+01  18 2.44E+01 2.31E+01 1.96E+01 1.80E+01 1.74E+01 1.42E+01 1.56E+01 1.56E+01  19 2.33E+01 2.21E+01 1.97E+01 1.79E+01 1.73E+01 1.32E+01 1.55E+01 1.55E+01  20 2.37E+01 2.23E+01 1.86E+01 1.64E+01 1.65E+01 1.31E+01 1.55E+01 1.55E+01  21 2.30E+01 2.18E+01 1.81E+01 1.50E+01 1.47E+01 1.21E+01 1.40E+01 1.41E+01  22 2.19E+01 2.08E+01 1.78E+01 1.69E+01 1.63E+01 1.16E+01 1.48E+01 1.47E+01  23 2.30E+01 2.17E+01 1.79E+01 1.62E+01 1.61E+01 1.22E+01 1.48E+01 1.48E+01  24 2.48E+01 2.36E+01 1.96E+01 1.74E+01 1.61E+01 1.17E+01 1.38E+01 1.38E+01 
-Page 71 of 86- 

 25 3.59E+01 3.44E+01 2.99E+01 2.38E+01 2.18E+01 1.32E+01 1.78E+01 1.78E+01  26 3.70E+01 3.47E+01 3.25E+01 2.60E+01 2.36E+01 1.59E+01 2.08E+01 2.07E+01 ****************************************************************************************************  Effective compartment halflives averaged over simulation duration:  zero washout 0  water col metab halflife (days) = 2137.70354017518  zero hydrolysis 0  photolysis halflife (days) = 21157.0863297993  volatile halflife (days) = 129.466394372249  total water col halflife (days) = 121.372931876219  zero burial 0  benthic metab halflife (days) = 2535.90321922743  zero benthic hydrolysis 0  total benthic halflife (days) = 2535.90321922743 ***********************************************************************  Fractional Contribution of Transport Processes to Waterbody & Total Mass (kg):  Due to Runoff = 0.5890 10.68  Due to Erosion = 0.0126 0.2293  Due to Drift = 0.3983 7.222 ***********************************************************************  Flow in/out Characteristics of Waterbody:  Average Daily Runoff Into Waterbody (m3/s) = 5.401811262854584E-004  Baseflow Into Waterbody (m3/s) = 0.000000000000000E+000  Average Daily Flow Out of Waterbody (m3/s) = 5.401811262854674E-004 ***********************************************************************  Inputs:  1966. = oc partitioning coefficient  1020. = water column half Life  25.00 = reference temp for water column degradation  1210. = benthic Half Life  25.00 = Reference temp for benthic degradation  2.000 = Q ten value  217.0 = photolysis half life  40.00 = reference latitude for photolysis study  0.000 = hydrolysis half life  256.1 = molecular wt 

 0.8500E-04 = vapor pressure  15.00 = solubility  0.1000E+06 = field area  0.1000E+05 = water body area  2.000 = initial depth  2.000 = maximum depth  2 1=vvwm, 2=usepa pond, 3 = usepa reservoir, 4 const vol w/flow  F T = burial, else no burial  0.1000E-07 = mass transfer coefficient  0.5000 = PRBEN  0.5000E-01 = benthic compartment depth  0.5000 = benthic porosity  1.350 = benthic bulk density  0.4000E-01 = OC frcation in benthic sediment  5.000 = DOC in benthic compartment  0.6000E-02 = benthic biomass  1.190 = DFAC  30.00 = SS  0.5000E-02 = chlorophyll  0.4000E-01 = OC frcation in water column SS  5.000 = DOC in water column  0.4000 = biomass in water column  FRACTION AREA CROPPED = 1.0000000000000
-Page 72 of 86- 

Appendix D. Ecotoxicity data gaps and uncertainties Table D1. Aquatic ecotoxicity data gaps and uncertainties. 

Guideline Data Requirement Test Substance MRID EPA Study Classification 

Are 

Additional 

Data 

Needed? 

En

850.1350 

Estuarine/marine 

invertebrate lifecycle Propyzamide (TGAI) NA NA No1 

850.1400 

Estuarine/marine 

fish early-life 

stage 

Propyzamide 

(TGAI) -- -- No2 

N/A = Data are not available 1 ACR values have been calculated in absence of data 2 Minimal risks to estuarine/marine invertebrates are expected from propyzamide use on a chronic exposure basis, therefore, no additional data is needed. In order for ch

estuarine/marine invertebrates, the NOAEC would need to be less than 29.3 μg a.i./L. There is no data to suggest propyzamide is highly or very highly toxic to aquatic f
-Page 73 of 86- 

Table D2. Terrestrial ecotoxicity data gaps and uncertainties. 

Guideline Data Requirement Test Substance MRID EPA Study Classification Are Additional Data Needed? E

850.2300 

Avian 

reproduction 

test 

Mallard duck 

(Anas 

platyrhynchos) 

Propyzamide 

(TGAI) 48931803 Supplemental 

Yes; The reported 

NOAEC was a nondefinitive “less than” 

(<) the lowest 

concentration tested. 

Exceedances would 

have occurred at the 

lowest test 

concentration used 

311 mg a.i./kg diet. 

Therefore, additional 

data is needed to 

characterize the lower 

bounds of chronic 

toxicity to avian taxa. 

NO

mg 

(20

Non-guideline 

Adult honey 

bee acute oral 

toxicity 

Propyzamide 

(TGAI)1 -- -- 

Yes 

This test is needed to 

evaluate the acute oral 

toxicity of 

propyzamide to adult 

honey bees as outlined 

in 40 CFR 158 

Subpart G16

16 CFR. 2013. Title 40 (Protection of the Environment), Chapter 1 (Environmental Protection Agency), Subchapter E (Pesticide Programs), Part 158 (D

Pesticides), Subpart G (Ecological Effects) http://www.ecfr.gov/cgi-bin/textidx?c=ecfr&SID=ff5c7fef3645e7cd5abceca0b597bccb&rgn=div6&view=text&node=40:25.0.1.1.9.7&idno=40
-Page 74 of 86- 

Guideline Data Requirement Test Substance MRID EPA Study Classification Are Additional Data Needed? E

NonGuideline Acute larval toxicity Propyzamide (TGAI) 

-- -- 

Yes; Although data indicate propyzamide is practically non-toxic to young adult honey bees on an acute contact exposure basis, no data are available on the acute and chronic toxicity for honey bee larvae. Therefore, data are needed on acute and chronic toxicity of TGAI to honey bee larvae1. In the absence 

of data, EFED will be unable to complete a risk assessment for terrestrial invertebrates (specifically, insect pollinators). 

NonGuideline Chronic larval toxicity Propyzamide (TGAI) 

Non-guideline Adult chronic oral (10-day) 

toxicity 

Propyzamide 

(TGAI) -- -- 

Yes; This test is needed to evaluate the chronic toxicity of propyzamide to adult honey bees1. In the 

absence of data, EFED will be unable to complete a risk assessment for terrestrial invertebrates (specifically, insect pollinators). 
-Page 75 of 86- 

Guideline Data Requirement Test Substance MRID EPA Study Classification Are Additional Data Needed? E

Special study 

Semi-field 

Testing 

Tunnel or 

Colonyfeeding Test 

(Tier II) 17

Propyzamide 

(TEP) -- -- 

Yes

May be triggered based on results of lower tier honey bee toxicity studies. 

Special study 

Field trial of 

residues in 

pollen and 

nectar with 

TEP 

(Tier II)18

17 Semi-field testing for pollinators with TEP may be needed based on the evaluation of the lower tier studies and the submitted field te

studies. 

18 Field trial of residues of residues in pollen and nectar with TEP would be needed based on the evaluation of the lower tier studies and 

testing for pollinators studies. 
-Page 76 of 86- 

Guideline Data Requirement Test Substance MRID EPA Study Classification Are Additional Data Needed? E

850.3040 Field testing for pollinators Propyzamide -- -- 

Yes2 

May be triggered based on results of lower tier honey bee toxicity studies. 

850.4225 

Terrestrial 

plant toxicity: 

Tier II seedling 

emergence 

Propyzamide 

(96.8 a.i.%) 

42176801, 

44029001

Supplemental, 

Acceptable Yes3

Perc

Mon

(Lo

S

Dic

(C

850.4150 

Terrestrial 

plant toxicity: 

Tier II 

vegetative 

vigor 

Propyzamide 

(96.8 a.i.%) 42176801 Supplemental Yes3

S

Mono

S

D

(L

e

1 Data on TEP is required if the formulation may enhance the toxicity of the chemical. 2 Data requirement is dependent on a re-review of the submitted field studies with propyzamide. 3 Studies should be conducted with TEP. 

TGAI=Technical Grade Active Ingredient; TEP=typical End-Use Product
-Page 77 of 86- 

Appendix E. Example T-REX (v. 1.5.2) input and output data 

 
-Page 78 of 86- 

Appendix F. Example TerrPlant (v. 1.2.2) input and output data 

   

TerrPlant v. 1.2.2

Green values signify user inputs (Tables 1, 2 and 4). 

Input and output guidance is in popups indicated by red arrows.

Parameter

Chemical Name

PC code

Use

Application Method

Application Form

Solubility in Water (ppm)

Input Parameter Symbol Value (user inputs) Units

Application Rate A 4 lbs ai/A

Incorporation I 1 none

Runoff Fraction R 0.02 none

Drift Fraction D 0.05 none

Equation EEC

(A/I)*R 0.08

(A/I)*R*10 0.8

A*D 0.2

((A/I)*R)+(A*D) 0.28

((A/I)*R*10)+(A*D) 1

Plant type EC25 NOAEC EC25 NOAEC 

Monocot 0.019 0.015 0.2 0.2

Dicot 0.015 0.004 0.041 0.041

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed 14.74 52.63 10.53

Monocot listed 18.67 66.67 13.33

Dicot non-listed 18.67 66.67 13.33

Dicot listed 70.00 250.00 50.00

Total for semi-aquatic areas

liquid

15

101701

User Inputs

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.

Seedling Emergence Vegetative Vigor

Table 5. RQ values for plants in dry and semi-aquatic areas exposed to Propyzamide through runoff and/or 

spray drift.*

Table 4. Plant survival and growth data used for RQ derivation. Units are in lbs ai/A. All values are user 

inputs

Description

Table 3. EECs for Propyzamide. Units in lbs ai/A.

Runoff to dry areas

Runoff to semi-aquatic areas

Spray drift

Total for dry areas

Table 1. Chemical Identity.

Propyzamide

Artichoke

Table 2. Input parameters used to derive EECs.

Foliar - aerial
-Page 79 of 86- 

Appendix G. Output from OPP Aggregate Incident Database for Propyzamide 
-Page 80 of 86- 

Appendix H. Example STIR (v. 1.0) input and output data 

Welcome to the EFED 

Screening Tool for Inhalation Risk

This tool is designed to provide the risk assessor with a rapid method for determining the potential

significance of the inhalation exposure route to birds and mammals in a risk assessment.

Input

Application and Chemical Information

Enter Chemical Name Propyzamide

Enter Chemical Use Multiple Food Uses

Is the Application a Spray? (enter y or n) y

If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 256.13

Enter Chemical Vapor Pressure (mmHg) 8.50E-05

Enter Application Rate (lb a.i./acre) 4

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 2165

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 5620

Enter Lowest Rat Inhalation LC50 (mg/L) 2.1

Duration of Rat Inhalation Study (hrs) 96

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 1.17E+00

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 1.47E-01

Adjusted Inhalation LD50 1.08E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 1.36E-03 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 4.23E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 3.90E-03 Exposure not Likely Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 1.17E+00

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 1.85E-01

Adjusted Inhalation LD50 3.00E+03

Ratio of Vapor Dose to Adjusted Inhalation LD50 6.17E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 5.31E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 1.77E-04 Exposure not Likely Significant

**NOTE**: When entering values, press

order to update linked cells.
-Page 81 of 86- 

Appendix I. SIP Results 

Table 1. Inputs

Parameter Value

Chemical name Propyzamide

Solubility (in water at 25o

C; mg/L) 15

Mammalian LD50 (mg/kg-bw) 5620

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 15

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 2165

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 311

Bobwhite quail NOAEC (mg/kg-diet) 615

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

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 2.5800 2.5800

Adjusted toxicity value (mg/kg-bw) 4322.6824 11.5374

Ratio of exposure to toxicity 0.0006 0.2236

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) 12.1500 12.1500

Adjusted toxicity value (mg/kg-bw) 1559.7299 15.4295

Ratio of exposure to acute toxicity 0.0078 0.7875

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.
-Page 82 of 86- 

Appendix J. Accepted ECOTOX Data Table (sorted by effect; double click) 

 

Propyzamide 

ECOTOX bibliography 

Propyzamide 

Refresh Aug. 2013
-Page 83 of 86- 

Appendix K. Complete List of Propyzamide Studies 

Table 1. Available environmental fate data for propyzamide and remaining data gaps.

158 

Guideline 

(OPPTS) 

Description Reference (MRID) Classification 

835.2120 Hydrolysis 107980 Acceptable 

835.2240 Photodegradation in water 107956 

107990 

40320601, 40420301

Unacceptable 

Unacceptable 

Acceptable 

835.2410 Photodegradation on soil 107990 

143746 

41913504 

Unacceptable 

Unacceptable 

Supplemental 

835.4100 Aerobic soil metabolism Hance, 1979 

Walker and 

Thompson, 1977 

Walker, 1976 

Walker, 1978 

Yih, 19?? 

107968 

107984 

107953 

41568901 

41913502 

46413407 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Upgradeable 

Acceptable 

(in review) 

835.4200 Anaerobic soil metabolism Acc No. 263649 

161097 

40244401 

41913505 

Unacceptable 

Unacceptable 

Unacceptable 

Acceptable 

835.4300 Aerobic Aquatic 

Metabolism 

107989 

46427901 

Unacceptable 

 (in review) 

835.4400 Anaerobic Aquatic 

Metabolism 

46413408 (in review) 

835.1230 

835.1240 

 Leaching and adsorption/ 

desorption 

Walker and 

Thompson, 1978 

107983 

107971, 107982 

107970 

40211103 

40211104 

41913501 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Acceptable 

Acceptable 

Acceptable 
-Page 84 of 86- 

158 

Guideline 

(OPPTS) 

Description Reference (MRID) Classification 

835.6100 Terrestrial Field 

Dissipation 

Walker, 1976 

Walker, 1978 

Yih, 19?? 

Zandvoort et al., 1979

Rohm and Hass Co., 

19?? 

Hance et al., 1978 

Hance et al., 1978 (2)

40925401 

107953 

44078601 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Unacceptable 

Upgradeable 

850.1730 Bioaccumulation in Fish 43196701 Acceptable 

835.6100 Environmental Chemistry 

Method in Soil 

48599205 Invalid 

835.6100 Independent Laboratory 

Validation in Soil 

48599206 Invalid 

835.6100 Environmental Chemistry 

Method in Water 

48599207 Supplemental 

835.6100 Independent Laboratory 

Validation in Water 

48690302 Supplemental 

835.6100 Environmental Chemistry 

Method in Soil 

49800801 Supplemental 

835.6100 Independent Laboratory 

Validation in Soil 

49800802 Supplemental 

Table 2. Available ecological effects data for terrestrial animals exposed to technical propyzamide and 

remaining data gaps 

158 

Guideline 

(OPPTS) 

Description MRID/ 

Accession Classification 

71-1 

(850.2100) Avian oral toxicity 

001079-97 

485992-08

485992-09 

Supplemental 

Acceptable 

Acceptable 

71-2 

(850.2200) 

Avian dietary 

toxicity 

001079-93 

001079-94 

001080-03 

001080-02 

Supplemental 

Acceptable 

71-4 

(850.2300) Avian reproduction 489318-02 

489318-03 Supplemental 

141-1 

(850.3020) 

Honeybee acute 

contact toxicity 00028772 Acceptable 

NA=Not Available 

Table 3. Available ecological effects data for aquatic animals exposed to technical propyzamide and 

remaining data gaps 
-Page 85 of 86- 

Guideline Description MRID/ 

Accession Classification 

72-1 

(850.1075) 

Freshwater fish – 

Acute toxicity 

001071-96 

485992-11 

485992-10 

Supplemental 

Acceptable 

Acceptable 

72-3 

(850.1075) 

Saltwater fish – 

Acute toxicity 485992-12 Acceptable 

72-2 

(850.1010) 

Freshwater 

invertebrates – 

Acute toxicity 

00098313 Acceptable 

72-3 

(850.1025) 

(850.1035) 

Saltwater 

invertebrates – 

Acute toxicity 

Mysid shrimp 

Eastern yster 

485992-13 

436084-02 

436084-01 

Acceptable 

Supplemental 

Acceptable 

(850.1735) 

Whole sediment 

acute toxicity to 

freshwater 

invertebrates 

485992-14 Acceptable 

72-4 

(850.1300) 

Freshwater 

invertebrate – 

life cycle test 

436733-01 Acceptable 

72-4 

(850.1350) 

Saltwater 

invertebrates – 

life cycle test 

NA NA 

72-4 

(850.1400) 

Freshwater fish – 

early life stage test NA NA 

72-4 

(850.1400) 

Saltwater fish – 

early life stage test NA NA 

72-5 

(850.1500) 

Fish – 

life cycle test 489318-01 Acceptable 

NA=Not Available 
-Page 86 of 86- 

Table 4. Available ecological effects data for plants exposed to propyzamide and remaining data gaps 

Guideline Description MRID Classificati

on 

122-1 

(850.4100) 

Terrestrial Plant 

toxicity: Tier I seedling 

emergence 

NA NA 

123-1 

(850.4225) 

Terrestrial Plant 

toxicity: Tier 2 

seedling emergence 

421768-01 

440290-01 

Supplement

al 

Acceptable 

122-1 

(850.4150) 

Terrestrial Plant 

toxicity: Tier I 

vegetative vigor 

NA NA 

123-1 

(850.4150) 

Terrestrial Plant 

toxicity: Tier 2 

vegetative vigor 

421768-01 Supplement

al 

123-2 

(850.4400) 

Aquatic Plant Growth: 

algae 

437383-04 

437383-02 

437383-03 

Acceptable 

Acceptable 

Acceptable 

123-2 

(850.4400) 

Aquatic Plant Growth: 

vascular plants 437383-01 Acceptable 

NA=Not Available