1

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

February 18, 2016

 PC Code: 009801

MEMORANDUM DP Barcode: 428597

SUBJECT: Bensulide: Preliminary Ecological Risk Assessment for Registration Review

FROM: Ryan Mroz, Biologist

He Zhong, Ph.D., Biologist

Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

THRU: Sujatha Sankula, Ph.D., Branch Chief

Greg Orrick, Risk Assessment Process Leader

Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

TO: Meg Hathaway, Chemical Review Manager

Cathryn Britton, Team Leader

Kevin Costello, Branch Chief

Risk Management and Implementation Branch II

Pesticide Re-evaluation Division (7508P)

This memorandum transmits the preliminary ecological risk assessment for the registration 

review of bensulide, a systemic organophosphate herbicide. Based on currently registered uses 

and labeled rates, this preliminary assessment identifies potential risks to non-target organisms. 

This assessment is focused on species that are not federally listed as threatened or endangered 

(referred to as “listed”); however, some general discussion of taxa of listed species for which “no 

effect” determinations are expected is included in this assessment. For taxa where risk concerns 

have been identified, specific determinations for listed species are considered uncertain at this 

time. The Agency has used the conservative assumptions due to the lack of fate and effects data, 

which may be reconsidered upon the review of new data submissions. Currently labeled rates of 

bensulide pose a potential for adverse effects, i.e., risk, in some way to all aquatic/terrestrial 

animals and plants. In addition, Section 2 addresses ambiguous label language that could be 

revised to reduce conservative assumptions used in assessing potential risks. In this assessment 

dietary risks to pollinators could not be assessed due to a lack of honeybee data (only an adult 

contact study is available).
2

Preliminary Environmental Fate and Ecological Risk 

Assessment in Support of Registration Review for

Bensulide

CAS Number 741-58-2

PC Code: 009801

Prepared by:

Ryan Mroz, Biologist

He Zhong, Ph.D., Biologist

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch I

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

Sujatha Sankula, Ph.D. Branch Chief

Greg Orrick, Risk Assessment Process Leader

Michael Lowit, Ph.D., Ecologist

Faruque Khan, Ph.D., Senior Scientist 

OFFICE OF CHEMICAL 

SAFETY

AND POLLUTION 

PREVENTION
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Contents

1. Executive Summary.................................................................................................................... 5

2. Problem Formulation .................................................................................................................. 6

2.1 Previous Assessments ...................................................................................................... 6

2.2 Data Gaps/Uncertainties Identified in the Problem Formulation..................................... 7

2.3 Updated Information Since the 2008 Problem Formulation. ........................................... 8

2.3.1 Bensulide Oxon........................................................................................................ 8

2.3.2 Uncertainties/information gaps identified for this assessment........................... 8

2.3.3 Updated Requirements since the Problem Formulation..................................... 9

3. Use Characterization and Methods of Application ................................................................... 10

4. Environmental Fate ................................................................................................................... 13

4.1 Bensulide and Degradates.............................................................................................. 13

4.2 Residues of Concern....................................................................................................... 15

4.3 Aquatic Exposures.......................................................................................................... 16

4.3 Monitoring Data ............................................................................................................. 21

4.4 Terrestrial Habitats......................................................................................................... 21

4.4.1 Birds and Mammals.............................................................................................. 21

4.4.2 Terrestrial Invertebrates...................................................................................... 25

4.4.3 Terrestrial Plants.................................................................................................. 25

5. Summary of Ecological Effects ................................................................................................ 27

5.1 Evaluation of mixtures................................................................................................... 27

5.2 Aquatic Organisms......................................................................................................... 28

5.3 Terrestrial Organisms..................................................................................................... 30

5.4 Incident Information....................................................................................................... 32

6. Risk Estimation......................................................................................................................... 32

6.1 Aquatic Organisms......................................................................................................... 33

6.2 Birds and Mammals ....................................................................................................... 35

6.3 Drinking Water and Inhalation....................................................................................... 40

6.4 Terrestrial Invertebrates ................................................................................................. 41

6.5 Terrestrial and Semi-Aquatic Plants .............................................................................. 41

7. Risk Characterization and Conclusions .................................................................................... 43

7.1 Aquatic Organisms......................................................................................................... 43

7.1.1 Aquatic fish and invertebrates............................................................................. 43

7.1.2 Aquatic plants........................................................................................................ 44

7.2 Terrestrial Organisms..................................................................................................... 44

7.2.1 Birds and Mammals.............................................................................................. 44

7.2.2 Drinking Water ..................................................................................................... 45

7.2.3 Non-Target Terrestrial Invertebrates................................................................. 45

7.2.4 Terrestrial Plants.................................................................................................. 46

8. Risk to Listed Species............................................................................................................... 47

9. Endocrine Disruptor Screening Program .................................................................................. 48

10. References............................................................................................................................... 49

11. Appendices.............................................................................................................................. 52

Appendix A. Submitted MRID Bibliography........................................................................... 52
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Appendix B. Bensulide Screening Level Usage Estimates ...................................................... 57

Appendix C: Results of ECOSAR Modeling............................................................................ 58

Appendix D. SWCC Representative Results............................................................................ 59

Appendix E: Representative T-REX Input and Output (Turf).................................................. 63

Appendix F: TerrPlant Input and Output (Turf) ....................................................................... 69

Appendix G. Review of Open Literature Toxicity Data Available for Bensulide.................... 70

Appendix H Summary of Bensulide Toxicity .......................................................................... 70

Appendix I. Aggregate Incident Report for Bensulide:............................................................ 77

Appendix J: Aquatic animal and plant risk quotients uses of bensulide................................... 78

Appendix K: STIR and SIP Inputs and Outputs....................................................................... 82
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1. Executive Summary

Bensulide is a pre-emergence systemic organophosphate (OP) herbicide used to control grasses 

and broadleaf weeds in a variety of agricultural (e.g. lettuce, cantaloupes, broccoli) and nonagricultural (e.g. golf courses, turf farms, residential lawns) settings. Bensulide inhibits 

meristematic root tissues (inhibits cell division in root tips) and inhibits seedling growth by 

conjugation of acetyl co-enzyme A, specific site unknown (Ware, 1978; Martin, 2000). It is 

usually applied to bare ground before crops are planted. The primary mode of action of OP 

pesticides, including bensulide, on organisms with nervous systems (e.g., mammals), is inhibition of 

acetylcholinesterase and accumulation of acetylcholine at the nerve synapses, resulting in classic 

symptoms of organophosphate poisoning (e.g. nausea, dizziness, confusion).

Environmental fate data indicate bensulide and its oxon degradate are persistent. While the 

parent bensulide is slightly mobile in soil, its degradates bensulide oxon and 

benzenesulfonamide, range from mobile to moderately mobile. In general, bensulide is highly 

toxic to freshwater and estuarine/marine fish on an acute basis. It is also highly toxic to 

freshwater invertebrates, and very highly toxic to estuarine/marine invertebrates. Chronic effects 

were observed for all aquatic taxa. Bensulide is slightly toxic to birds on an acute oral basis, 

practically non-toxic to birds on a subacute dietary basis, moderately toxic to mammals on an 

acute oral basis, and at most practically non-toxic to honey bees on an acute contact basis.

Chronic effects observed in avian studies included a decrease in eggshell thickness, increase in 

the number of cracked eggs, decrease in the percent of eggs hatched, and decrease in the percent 

survival of 3-week embryos and 14-day chicks. Chronic effects that were observed in 

mammalian studies included decreased pup survival and reduction in plasma cholinesterase 

activity. Phytotoxic effects (stunting, leaf blotch, and leaf rolling) were observed in terrestrial 

plant studies at rates that were much lower than maximum labeled application rates.

This assessment considers the most up to date toxicology and fate data, uses current exposure

models including those exploring pathways not quantitatively assessed in past risk assessments 

(e.g., drinking water and inhalation exposure), and considers the most recent labels, incident 

information, and monitoring data. Based on the latest information, conclusions of this 

assessment are substantially similar to those of the IRED. An acute and chronic risk concern is 

expected for both listed and non-listed species of birds, mammals, fish, and aquatic 

invertebrates. Terrestrial invertebrate risk cannot be fully assessed due to lack of data (dietary), 

or non-definitive (contact) data, and remains an uncertainty. Risk concerns are also identified for 

both terrestrial (listed monocots) and aquatic plants. In conclusion, consistent with past 

assessments there is a risk concern (summary in Table 1.1) for aquatic organisms and terrestrial 

wildlife including listed species for the labeled uses of bensulide.

Table 1.1 Summary of direct and indirect effects associated with registered uses of 

bensulide*

Taxon Risk Concern for

Direct Effects?

Risk Concern for 

Indirect Effects to 
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Non-Listed Listed Non-Listed and 

Listed Species2

Birds, reptiles, and terrestrial-phase amphibians Y (A,C,DW) Y (A,C) Y

Mammals Y (A,C) Y (A,C) Y

Terrestrial invertebrates (honeybees1) ? ? Y

Terrestrial (upland and semi-aquatic) plants – monocots N Y Y

Terrestrial (upland and semi-aquatic) plants – dicots N N Y

Freshwater fish and aquatic-phase amphibians Y (C) Y (A,C) Y

Marine/estuarine fish Y (A,C) Y (A,C) Y

Freshwater invertebrates Y (A,C) Y (A,C) Y

Aquatic vascular plants Y Y Y

Aquatic non-vascular plants N N3 N

* At this current stage of the Registration Review process, it is premature to make effects determinations until 

further refinements are conducted.

A = Acute, C = Chronic, DW = Drinking water 1 Only adult contact data is available. Risks from other exposure routes or life stages could not be assessed due to 

lack of data. The systemic nature of the chemical and persistence make risk concerns possible from a dietary 

standpoint. Concerns could also exist for potential exposure through concentrations in drinking water for bees. 2 Indirect effects are possible for all animals and plants that rely on plants and other primary food chain animals for 

food, habitat, or other environmental resources. 3 No currently listed non-vascular plants

2. Problem Formulation

The purpose of problem formulation is to provide the foundation for the environmental fate and 

ecological risk assessment being conducted for the representative labeled uses of bensulide. A 

Registration Review Problem Formulation document was completed for bensulide in June of 

2008 (USEPA 2008, D347544). The problem formulation identifies the characteristics of the 

potential ecosystems at risk, the assessment endpoints, and outlines a conceptual model which 

leads to a risk hypothesis evaluated in this assessment. The risk hypothesis written in the 2008 

Registration Review Problem Formulation is summarized as follows: Bensulide is expected to be 

persistent in both aquatic and terrestrial environments. The potential for bensulide to be 

transported to aquatic habitats is likely via suspended sediments, while in terrestrial habitats it 

has the potential to persist in soils. Consequently, terrestrial and aquatic organisms will be 

acutely and chronically exposed to bensulide via interactions with soils or other substrates 

contaminated with bensulide residues.

2.1 Previous Assessments

Bensulide was first registered in 1964. The four most recent comprehensively reviews of 

bensulide were the 2000 Interim Reregistration Eligibility Decision (IRED) (USEPA, 2000), the 

2000 Addendum to the Bensulide RED: Revised Risk Assessment and Risk Characterization for 

Risk to Aquatic Organisms from Use on Turf (USEPA, 2000), the 2007 Pesticide Effects 

Determination for Risks of Bensulide to the Federally Listed California Red-legged Frog (Rana 

aurora draytonii) (USEPA, 2007), and a 2012 effects determination (completed after the 2008 

problem formulation) for several Federally threatened and endangered species in California 

(USEPA 2012a). The 2000 IRED indicated the potential for risk to birds and mammals on an 

acute and chronic basis, freshwater and estuarine/marine fish and invertebrates on an acute and 

chronic basis, and aquatic plants.
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The IRED indicated the turf use of bensulide poses greater risk concerns to aquatic, terrestrial 

and avian species than the agricultural uses. Chronic risk to birds was of particular concern for 

the turf uses because birds tend to be attracted to large turf areas (e.g., golf course fairways) and 

may nest, feed or forage near or on these areas. Based on the IRED, the following mitigation was 

implemented:

• Prohibiting use on large non-golf course turf sites (e.g., parks and recreational areas), 

restriction of the golf course fairway use to a single grass type (i.e., bentgrass), and to certain 

states where bensulide serves a limited, but important purpose, restriction of the number of 

fairway applications to one.

• Limiting fairway application during fall season, to minimize exposure to birds during the 

breeding season, thereby mitigating the risk of reproductive impairment. 

The IRED was followed up by a cumulative organophosphate assessment RED in 2006. The 

IRED noted the environmental risks from bensulide use to non-target organisms result from the 

high use rates, the persistence of the chemical and multiple applications (up to two times a year). 

The conclusions for the effects determinations for listed species in California USEPA 2007 and 

USEPA 2012a were generally in line with those of the IRED, with additional LOC exceedances 

for terrestrial invertebrates, avian/mammalian acute dosed-based and chronic diet-based LOCs 

and terrestrial plants. The risk conclusions from these documents are summarized in Table 2.1

below.

Table 2.1. Summary of previously identified risks resulting from bensulide use 

Mammals Birds Terr. 

Inverts2

FW 

Fish

E/M 

Fish

FW 

inverts

E/M 

Inverts

Terr. Plants4 Aquatic 

Plants4

Acute Y1 Y1 Not 

Assessed

Y1 Y1 Y1 Y1 Listed Y3 Y

Chronic Y1 Y1 Not 

Assessed

Y1 Y1 Y1 Y1 NonlistedN Y

1 Listed and non-listed species 2 The only study available shows bensulide is practically non-toxic to the honeybee on an acute contact basis with a 

non-definitive endpoint; LD50 > 24.17 μg/bee 3

Listed monocot species only 4 Risk from acute and chronic exposure not assessed; listed and non-listed risks are identified

FW – Freshwater; E/M – Estuarine/Marine

2.2 Data Gaps/Uncertainties Identified in the Problem Formulation

The fate and ecotoxicity data gaps identified in the problem formulation are listed below. All 

studies requested from the resulting DCI were received. The mysid chronic toxicity test was 

given a supplemental classification based on a solvent effect for 14 day endpoints to which the 

registrant submitted a status rebuttal (USEPA 2012b, D403396). EFED concluded the 28 day 

endpoints were acceptable for use in risk assessment and a reasonable risk management decision 

would be to not request a new acceptable study. The registrant also submitted a waiver, which 

was denied, for the fish life-cycle studies (USEPA 2010, D381471). The submitted

estuarine/marine and freshwater fish life-cycle studies were deemed supplemental; however the 

registrant resubmitted additional data for both studies. After evaluation of the additional data

(USEPA 2014a, D420181 and USEPA 2014b, D420826), the estuarine/marine fish study was 

upgraded to acceptable while the freshwater fish study remained supplemental. The endpoints 
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from all these ecotoxicity studies submitted as a result of the DCI are used quantitatively in this

risk assessment. 

Ecotoxicity Data Gaps:

850.1300 – Daphnid Chronic Toxicity Test: MRID 49110401 – Acceptable

850.1350 – Mysid Chronic Toxicity Test: MRID 48424501 - Supplemental

850.1500 – Freshwater Fish Life-Cycle Test: MRID 49001601/49378102 – Supplemental

850.1500 – Estuarine/marine Fish Life-Cycle Test: MRID 49362301/49059101 – Acceptable

2.3 Updated Information Since the 2008 Problem Formulation.

2.3.1 Bensulide Oxon

The bensulide oxon, a major degradate, was not considered in the problem formulation or any 

assessment prior to the 2012 SF-Bay Effects determination. There are no toxicity data available 

for the bensulide oxon. For aquatic exposures, a total toxic residue approach was used to 

consider both bensulide and its major degradate (bensulide oxon) as potential stressors. 

ECOSAR estimates of toxicity suggest comparable toxicity. Available data also show detectable 

residues of parent and oxon for Brassica leafy vegetables at 33 days but no detectable levels in 

vegetables at more protracted intervals. Therefore, it is believed that the use of a 35-day 

dissipation half-life (for terrestrial exposures) is a conservative way to account for the role of 

both parent (as an endogenous source of oxon when consumed) and oxon produced in the 

environment.

Additionally, in a response to a Registrants waiver request (USEPA 2010; D381471) for a full 

fish life-cycle toxicity test after the problem formulation was completed, EFED suggested 

bensulide oxon data (none received) be requested. In addition to the EFED studies suggested in

this waiver response a full toxicity profile for HED was also recommended for the oxon. The 

relevant EFED studies mentioned for the oxon are listed below:

• 850.1010 – Acute toxicity freshwater invertebrate 

• 850.1075 – Acute toxicity freshwater fish - Rainbow trout, and bluegill sunfish, 

• 850.2100 – Avian Acute oral toxicity - Northern bobwhite quail, or mallard duck, and a 

passerine species

2.3.2 Uncertainties/information gaps identified for this assessment

The following section describes uncertainties and/or studies which were not identified in the 

problem formulation but which could reduce uncertainty (regarding studies) in the risk 

assessment.

Fate Data

• 835.4100 – Aerobic soil metabolism study for bensulide and bensulide oxon (has one soil

type and three more soils are needed)

• 835.4300 – Aerobic aquatic metabolism study for bensulide and bensulide oxon (a full 

study is needed)
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Terrestrial plant toxicity 

• The submitted vegetative vigor and seedling emergence study (MRID 44746301 -

Acceptable) was performed at rate (6 lb ai/A) much lower than the maximum labeled 

rate. While the EC25 values were non-definitive (greater than) for both dicots and 

monocots, statistically significant phytotoxic endpoints (based on phytotoxicity) for some 

species which were lower than the fresh weight endpoints. Phytotoxicity is not a normal 

regulatory endpoint. It is uncertain if phytotoxic effects would alter the viability of a 

plant species, but the effect is noted. Conservatively assuming the EC25 to be the 

application rate tested still did not have LOC exceedances for non-listed terrestrial plants.

Label Uncertainties

• The current labels do not fully specify the application rates, number of applications, and 

minimum retreatment intervals. In this document, the Agency assessed what is believed 

to be the intended application rates, number of applications, and minimum retreatment 

intervals as indicated in Table 2.1. If the final application rates and number of 

applications are higher than in Table 2.1, and/or minimum retreatment intervals are 

shorter, then risk may be under-estimated in this document.

Additional Uncertainties

• The aerobic soil metabolism study for bensulide evaluated only one soil, with a half-life 

of 363 days. The TTR half-life was 749 days with the inclusion of bensulide oxon. 

Because the registrant only submitted data for one soil type, model inputs were 

conservatively multiplied by three to account for potential variability across soils, 

following EFED guidance (USEPA, 2009c).

• The modeled aerobic aquatic metabolism half-life was calculated by multiplying the 

aerobic soil metabolism half-life by 2 (t1/2 = 2,247 × 2 = 4,494 days) due to the absence of 

data, following EFED guidance (USEPA, 2009c).

2.3.3 Updated Requirements since the Problem Formulation

• Based on the new Pollinator Risk Assessment Framework1 (USEPA 2014c) there are 

uncertainties with respect to the toxicity of bensulide to honeybees. The available acute 

contact study classifies bensulide as practically non-toxic to the honeybee (LD50 > 24.17

μg/bee (1.6% mortality at the limit test)). Bees could potentially be exposed through 

direct contact with treated surfaces, through pollen and nectar (due to the systemic nature 

of chemical), and drinking water (e.g. after a rain event or watering in of granules). The 

studies listed below would significantly reduce uncertainty in an attempt to adequately

assess the risks to pollinators. Additional studies (higher tiered semi-field/field) may be 

required for refinements if results of the studies below indicate significant risks to bees.

• Non-guideline (OECD 213) - Acute oral toxicity to adult honeybees

• Non-guideline (OECD 237) - Acute oral toxicity to larval honeybees

• Chronic oral toxicity to adult honeybees 

• Chronic oral toxicity to larval honeybees

 1

http://www2.epa.gov/sites/production/files/201406/documents/pollinator_risk_assessment_guidance_06_19_14.pdf
10

• Residues of pollen and nectar

• The new CFR requires an oral toxicity study with a passerine species. Passerine species 

have higher metabolic rates due to their smaller sizes than either waterfowl or upland 

game bird species and because they may utilize different metabolic pathways, they may 

be more or less sensitive to bensulide. An acute oral study with a passerine species would 

clarify any uncertainty surrounding the sensitivity of this group of birds; however, data 

are likely to be confirmatory and unlikely to significantly alter risk conclusions.

• 850.2100 – Avian acute toxicity with a passerine species

• Sediment toxicity testing is triggered if a chemical demonstrates moderate to high 

moderate to high sorption potential (i.e. Kd is ≥ 50 L/kg-solid, KOC is ≥1000 L/kg-OC, 

log KOW is ≥ 3). Bensulide’s fate properties (log Kow = 4.2, Koc = 2884 ml/g), toxicity to 

aquatic water column invertebrates, and use patterns indicate sediment testing2 is

required. While there is uncertainty in the risks bensulide poses to benthic invertebrates, 

it is unlikely risk conclusions for aquatic invertebrates given the pore water 

concentrations relative to the surface water concentrations, toxicity to water column 

invertebrates, mode of action, etc would change with these studies. Whole sediment 

chronic invertebrate freshwater and marine testing for the freshwater amphipod, Hyalella 

azteca, freshwater midge, Chironomus dilutus, and marine amphipod Leptocheirus 

plumulosus would confirm sensitivities to these benthic organisms; however, obtaining 

these data are also unlikely to significantly change any risk conclusions for aquatic 

invertebrates in general. The following guidelines are available from USEPA Office of 

Research and Development (ORD) for chronic testing.

• EPA 600/R-99/064 - Whole sediment chronic invertebrate freshwater

• EPA 600/R-01/020 - Whole sediment chronic invertebrate marine

3. Use Characterization and Methods of Application

Bensulide controls weeds by inhibiting meristematic root tissues and seedling growth. 

Bensulide is used for pre-emergence control of broadleaf weeds and grasses in numerous 

agricultural crops, including fruiting vegetables, leafy vegetables (mostly head lettuce), dry bulb 

vegetables (onions), cucurbits (mostly melons), and cole crops (cauliflower, cabbage, broccolini 

and broccoflower). Use data (full table in Appendix B) from 2004-2013 provided by BEAD 

(USEPA 2015) indicates the highest use rates of bensulide are for lettuce, cantaloupe, and 

broccoli with annual national averages of 300,000, 80,000 and 60,000 lb ai applied respectively. 

It is also registered for use on residential grass lawns, golf courses, turf farms, rights-of-way, 

and in landscaping applications. There are currently 2 technical registrations for bensulide and 9 

formulated products.

As an emulsifiable concentrate or granular application, bensulide single application rates are up 

to 16 lb ai/A for turf uses and 5 – 9 lb ai/A for agricultural uses. It is usually applied to bare 

 2

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/aquatic_biology_tech_team/ToxTesting_

EcoRiskAssessmentForBenthicInvertebrates.pdf
11

ground before crops are planted. Depending on the use, bensulide is applied by tractor drawn or 

push-type spreaders, ground boom or low pressure/high volume turf gun, low pressure hand 

wand for spot treatments, sprinklers, ground sprayer or chemigated through an overhead 

sprinkler system.

While the product labels list a maximum number of applications per year and a retreatment 

interval for turf uses, they do not clearly state a maximum number of applications allowed per 

crop cycle or applications per year for agricultural uses. The bensulide risk assessment is based 

on the information shown in Table 3.1. The information on maximum application rates and use 

patterns should be reflected on all bensulide labels (information not currently on labels indicated 

as bolded values in Table 3.1). If for any reason the final labels contain higher application rates, 

higher numbers of applications, and/or shorter minimum retreatment intervals, the actual risks 

posed by those products may exceed the risk estimated in this assessment.

Table 3.1. Maximum application rates, number of applications, and minimum retreatment 

intervals for specific bensulide uses.

Use Application 

Method1

Maximum 

Single 

Application 

Rate

(lb ai/A)

Maximum

Number of 

Applications 

per Year2

Maximum 

Yearly 

Application 

Rate

(lb ai/A)

Application 

Interval

(days)

Golf course turf

EPA9198-176

Broadcast –

granular 16 2 32 1203

Golf course turf, turf 

Ornamental lawns 

EPA10163-196

EPA10163-198

EPA10163-199

EPA10163-204

EPA2217-778

EPA9198-172

EPA 2217-696

Broadcast –

granular 

Broadcast spray 

–

Emulsifiable 

Concentrate

12.5 2 25 120

Ornamental lawns and turf

Residential lawns

EPA10163-205

Handy spray

Disposable 

container (16oz) 

8.65 2 or more NS2 120

Ornamental lawns and turf

Residential lawns

EPA 2217-838

Broadcast -

Granular 7.5-12.5 2 15-25 120
12

Use Application 

Method1

Maximum 

Single 

Application 

Rate

(lb ai/A)

Maximum

Number of 

Applications 

per Year2

Maximum 

Yearly 

Application 

Rate

(lb ai/A)

Application 

Interval

(days)

Artichokes, beans, beet, 

bell pepper, Brassica (head 

and stem) vegetables, 

broccoli, broccoli raab, 

Brussels sprouts, cabbage, 

cardoon, carrot, 

cauliflower, celery, 

celtuce, chervil, 

chicory/radicchio, 

chrysanthemum (garland), 

cole crops, collards, corn 

salad, cress (garden, 

upland), dandelion, dock 

(sorrel), eggplant, endive, 

fennel, garlic, greens, 

groundcherry (strawberry 

tomato/tomatillo), kale, 

kohlrabi, leafy vegetables, 

lettuce (head, leaf), 

mustard, mustard cabbage, 

okra, onion (dry bulb and 

green), orach (mountain 

spinach), parsley, peas, 

pepper, pepper (chili), 

pimento, radish, roquette 

(arugula), shallot, spinach, 

Swiss chard

EPA10163-200

AZ-080003

Broadcast spray 

–

Emulsifiable 

Concentrate

5 (for carrot

only)

6

1, 2, or 3 6, 12, or 18 120

Cantaloupe, chayote, 

cucumber, cucurbit 

vegetables, cucuzzi, 

gherkin, gourds, gourd 

(wax), melons (bitter, 

honeydew, citron, mango, 

musk, water, winter 

melons), pepino, pumpkin, 

squash (butternut, summer, 

zucchini squash)

AZ120003

CA960003

NJ070001

Broadcast spray 

–

Emulsifiable 

Concentrate

8.94 1 or 2 9 or 18 120

1

When there are several application methods (because of different types of formulation), the listed application

method would either result in the highest environmental exposure or was labeled for a higher maximum rate 

than other application methods.

2

The maximum yearly rate is not specified. Scenarios were modeled for multiple seasons at the 120 day 

application interval.

NS – not specified. A maximum annual rate at 18 lb ai/A is assumed. The information should be clarified. 3

The minimum application intervals from the labels are used with an assumption of the crop rotation (or 

replantation). 
13

4. Environmental Fate

4.1 Bensulide and Degradates

Information from acceptable and supplemental laboratory studies indicates bensulide is 

persistent. Abiotic hydrolysis or aquatic photolysis appears to be a major degradation pathway 

(Table 4.1). Aerobic soil metabolism transforms the parent bensulide into a major toxic 

degradate, bensulide oxon. Under aerobic soil conditions, bensulide oxon reached a maximum 

concentration of 13.8% of the applied at 270 days and 10.1% at 360 days, and carbon dioxide (up 

to 21% of the applied) (MRID 40460301). A minor degradate benzenesulfonamide reached a 

maximum level of 0.52% at 360 days. However, the aerobic soil metabolism study was classified 

as supplemental as only one soil type was used. Under anaerobic soil conditions in the 

laboratory, bensulide is considered stable (MRID 40460302). No aerobic aquatic metabolism 

study available for this assessment. 

The degradate bensulide oxon is more soluble in water (461 mg/L, EPISuite v. 4.10) than 

bensulide (5.6 mg/L, MRID 41532001). Bensulide is slightly mobile according to FAO, 2000

classification in the four soils tested (Koc values ranged from 1,433 to 4,326 mL/g) based on an 

acceptable study (MRID 42826701); however, its major degradate bensulide oxon (average Koc = 

557, MRID 43180701) and the minor degradate benzenesulfonamide (average Koc = 17.72, 

MRID 43180702) ranged from moderately mobile to mobile in the same four test soils. 

Bensulide is not expected to leach to groundwater, but bensulide oxon may leach to groundwater 

due to its higher solubility and mobility.

There are eight submitted field dissipation studies classified as supplemental. Three were 

conducted in California with reported half-lives ranging from 15-34 days (MRID 40534902, 

40534904 and 40534905), which all have the limited values because of the poor material 

balances recovered. Three were conducted in Mississippi with half-lives ranging from 30-210 

days (MRID 40534901, 40534903 and 40534906). The half-life (30 days) for one of the 

Mississippi studies (MRID 40534906) was considered as the limited value as it was only 

calculated from the top 3 inches and the residues in the 3-6 and 6-12 inches were not analyzed. 

Another two studies were conducted in North Carolina with half-life ranging from 76-107 days 

with 10-24% bensulide oxon formed (MRID 44297001 and 45550301). The field dissipation 

data confirmed the laboratory findings that bensulide is a persistent herbicide. Bensulide and 

bensulide oxon were detected in the 6-12 inches deep in soil. 

Bensulide may bioconcentrate in fish based on log Kow 4.2 with a whole body bioconcentration 

factor (BCF) of 550. However, it was reported that 98% of the compound is eliminated after 14 

days depuration, once residues are removed from the water (MRID 41931001). Consequently, 

the residue inter-trophic transfers are not evident with the rapid depuration.

The physical, chemical, and environmental fate properties of bensulide and bensulide oxon are 

summarized in Table 4.1. 
14

Table 4.1 Physical, Chemical, and Environmental Fate Properties of Bensulide and 

Bensulide Oxon. 

Parameter Bensulide (Parent) Bensulide Oxon (Major Degradate)

Value Reference Value Reference

Chemical Name O,O-Diisopropyl-S-2-

phenylsulfonylaminoe

thyl 

phosphorodithioate

MRID 45761801 O,O-diisopropyl-S-2-

phenylsulfonylaminoethyl

phosphorothioate

MRID 

45761801

CAS Number 741-58-2 MRID 45761801 20243-81-6 MRID 

476604-03

Empirical Formula C14 H24 NO4 PS3 MRID 45761801 C14 H24 NO5 PS2 EPI Suite (v 

4.10)

Molecular Weight 

(g/mole)

397.54 MRID 45761801 381.44 EPI Suite (v 

4.10)

Chemical Structure EPI Suite (v 4.10) EPI Suite (v 

4.10)

SMILES Code CC(C)OP(=S)(OC(C)

C)SCCNS(=O)(=O)c1

ccccc1

EPI Suite v4.10 CC(C)OP(=O)(OC(C)C)S

CCNS(=O)(=O)c1ccccc1

EPI Suite (v 

4.10)

Melting Point (oC) 36 MRID 41532001 89.97 EPI Suite (v 

4.10)

Boiling Point (oC) 424.96 EPI Suite (v 4.10) 476.9 EPI Suite (v

4.10)

Vapor pressure (mm 

Hg @ 25oC)

8.2 x 10-7 MRID 41532001 2.48 10-8 EPI Suite (v 

4.10)

Henry’s Constant 

(atm m3 mole-1)

7.7 x 10-8 MRID 41532001 7.10 x 10-12 EPI Suite (v 

4.10)

Solubility (mg/L @ 

25oC)

5.6 MRID 41532001 461.24 EPI Suite (v 

4.10)

Log Kow 4.20 EPI Suite (v 4.10) 2.35 EPI Suite (v 

4.10)

Kd (mL/g) 10.9 Sand 

30.5 Sandy Loam Soil

34.0 Clay Loam Soil 1

96.8 Clay Loam Soil 2

MRID 42826701 1.96 Sand 

4.23 Sandy Loam Soil

6.05 Clay Loam Soil 1

26.5 Clay Loam Soil 2

MRID 

43180701

Koc (mL/g)

3479.93 Sand 

1348.26 Sandy Loam 

Soil

4379.47 Clay Loam 

Soil 1

2327.52 Clay Loam 

Soil 2

MRID 42826701 

(2884 mL/g ) 

(average of 4 

values, EFED 

Guideline)

625.75 Sand 

186.99 Sandy Loam Soil

778.70 Clay Loam Soil 1

636.70 Clay Loam Soil 2

MRID 

43180701 

(557 mL/g) 

(average of 4 

values, EFED 

Guideline)
15

Parameter Bensulide (Parent) Bensulide Oxon (Major Degradate)

Value Reference Value Reference

Hydrolysis t1/2(day) 

@ 25 0C

230 (pH 5)

220 (pH 7 & 9)

MRID 00160074 NA1 NA1

Aerobic soil met. 

t1/2(day)

Bensulide Oxon 

13.8%@270 days

Benzenesulfonamide 

<0.5%

363 MRID 40460301 749

(Bensulide + Oxon)

MRID 

40460301

Aquatic photolysis 

t1/2 (day)

Bensulide Oxon 

4.8%@41 days

132

MRID 40513401

173

(Bensulide + Oxon)

MRID 

40513401

Anaerobic Soil met. Stable MRID 40460302 NA NA

Field Dissipation,

California

34 days

30 days

15 days

MRID 40534902

MRID 40534904

MRID 40534905

NA NA

Field Dissipation,

Mississippi

30-210 days MRID 40534901

MRID 40534903

MRID 40534906

NA NA

Field Dissipation

North Carolina

107 days (10% max 

oxon at 90 days)

76 days (24% max 

oxon at 28 days)

MRID 44297001

MRID 45550301

94 days

(Bensulide + Oxon)

MRID 

44297001 

MRID 

45550301

Bioconcentration 

factor (BCF)

550 MRID 41931001 NA NA

1

NA = Data or studies are not available

4.2 Residues of Concern

Both bensulide and bensulide oxon (up to 13.8% in aerobic soil) are considered as the residues of 

concerns for aquatic organisms in this risk assessment. Because the inherent toxicity of bensulide 

oxon is unknown, the ecological relevance of oxon residues potentially present in the aquatic 

environment cannot be ignored. The toxicity of oxon is estimated by ECOSAR and compared to 

the toxicity of the parent (known values). ECOSAR results suggest the parent bensulide and its 

oxon degradate have similar toxicity against aquatic non-vascular plant (chronic) and fish 

(chronic). In the meantime, ECOSAR also estimates the toxicity of the oxon degradate about 20 

to 30 times less toward aquatic fish (acute) and aquatic invertebrates (acute and chronic) 

comparing to the parent bensulide (Appendix C). These estimates are all within 1 order of 

magnitude of each other (except for freshwater invertebrates (EC50 parent = 0.58; EC50 oxon 

estimate = 16.4; oxon ~30X less toxic). Because of the similarity of the toxicity estimates, it is 

conservatively assumed that the toxicity of the oxon is equivalent to that of parent bensulide in 

the absence of the oxon toxicity data. For terrestrial organisms, only parent bensulide is 

considered as the residue of concern. 
16

4.3 Aquatic Exposures

Exposure Estimates 

The Surface Water Concentration Calculator (SWCC v 1.106) model3 was used to generate 

estimated environmental concentrations (EECs) for all uses. The SWCC is a graphical user 

interface that runs the Pesticide Root Zone Model (PRZM, v 5, November 15, 2006) and the 

Variable Volume Water Body Model (VVWM, 3/6/2014) (USEPA, 2006b). Simulations are run 

for multiple (usually 30) years and the EECs represent peak values that are expected once every 

ten years based on the thirty years of daily values generated during the simulation. The SWCC 

model was parameterized using relevant use and environmental fate data for bensulide and 

bensulide oxon according to the EFED input parameter guidance for water modeling (USEPA, 

2009). A representative output is presented in Appendix D.

Ground spray applications may potentially result in transport and loading of bensulide to offfield soil, and foliage, and water bodies via spray drift. Granular ground application methods are 

expected to result in negligible spray drift; however on-field bensulide soil residues from ground 

spray and granular application methods have the potential to be transported both dissolved in 

water and on suspended soil in runoff to off-field terrestrial areas and to adjacent surface waters. 

Once in the aquatic system, bensulide is expected to partition primarily to sediment where it will 

be relatively stable.

A total residues method (USEPA, 2008a) to include both bensulide and bensulide oxon as the 

residues of concern was used in the exposure assessment. The bensulide aerobic soil half-life 

was recalculated to include bensulide oxon degradation (t1/2 = 749 days). Because only one soil 

type was submitted (MRID 40460301), the half-life was timed a factor of 3 (t1/2 = 749 days × 3 = 

2,247 days). Due to the lack of aerobic aquatic data, the half-life was estimated by another factor 

of 2 (t1/2 = 2247 × 2 = 4,494) based on the EFED guidance (USEPA 2009c). This method was 

used to estimate the 1-in-10 year exposure concentrations for total residues representing the 

combined exposure to the residues of concern (bensulide and bensulide oxon). Input parameters 

of SWCC are provided in Table 4.2.

Table 4.2 Summary of Environmental Fate Data Used for Aquatic Exposure Estimation for 

Bensulide and Bensulide Oxon (Total Toxic Residues)

Input variable (Units) Input value and 

calculations

Source

Crop name

See Table 1 Product labels

Application method

Application rate (lb ai./acre)

Application interval (days)

Application efficiency

Ground spray

0.99

 3 http://www.epa.gov/oppefed1/models/water /index.htm
17

Input variable (Units) Input value and 

calculations

Source

Spray drift fraction

Ground spray

0.062

EFED input parameters guideline 

(12/20/2013) (USEPA 2013)

Application efficiency

Granular broadcast

1

Spray drift fraction

Granular broadcast

0

Molecular Weight (g/mole) 397.5 MRID 45761801 (Value for parent)

Henry's Law Constant

(atm.m3

/mole)

7.10 x 10-12 EPI Suite (v 4.10)

Vapor pressure @ 25oC (mm Hg) 2.48 10-8 EPI Suite (v 4.10)

Solubility in Water (mg/L) 461 (Maximum value for bensulide oxon)

Aquatic photolysis t1/2 (day) 173 Based on parent and oxon the data from 

MRID# 40513401 and recalculated half-life 

using R program

Aerobic soil met. t1/2(day) 2,247 749 (Re-calculated for parent and oxon from 

original data) x 3 (EFED guideline)

Hydrolysis t1/2(day) @ 25 0C 230 (pH 5)

220 (pH 7 & 9)

MRID 00160074 (Value for parent - bensulide 

oxon not formed)

Aerobic aquatic met. t1/2(day) 4,494 No data; (soil aerobic met. half-life x 2; EFED 

guideline)

Anaerobic soil met. t1/2(day) 0 Stable (no ending point)

Koc ml/g (mean) 557 (Average of 4 values, EFED Guideline) for 

bensulide oxon)

Application rate, date, frequency, 

intervals, chemical application 

method (CAM), efficiency and 

spray drift

Same values used for the pesticide from the label and as per the parameters 

guidance document

The EECs based on TTRs as bensulide oxon equivalent for representative usage scenarios and 

application rates are provided in Table 4.3. However, there are some uncertainties associated 

with modeling for the EECs due to the lack of aerobic aquatic metabolism study and inadequate 

aerobic soil metabolism study. Based on EFED policy, the aerobic soil and aerobic aquatic halflives were recalculated, which may result in the conservative estimation of the EECs. To 

estimate the contribution of bensulide to the estimated surface water concentrations, the numbers 

of applications starting with the highest to the lowest were modeled for the same scenarios. For 

ground spray applications, the spray drift (%) entering pond were also listed in the Table 4.3. 
18

Table 4.3 Estimated Environmental Concentrations (EECs) for Bensulide Oxon Using TTR Approach

Use/Scenario

Granular (G) 

or Ground 

Spray (GS)1

Max. Single

App. Rate

(lb ae/A)

Max. 

Number 

of App.

Max. App. Rate 

Per Year

(lb ai/A)

Min. App. 

Interval 

(Days)

Surface Water (μg/L) Pore Water (μg/L)

% Spray Drift 

Contribution2

to Total 

Pesticide and 

Degradates 

Peak 21-day 60-day Peak 21-day Entering Pond 

Golf course turf, Turf, and Ornamental lawns,

FL Turf

(W12834.dvf) G / (4/1) 16 2 32 120 254 228 197 166 166 -

PA Turf

(W12834.dvf) G / (4/1) 16 2 32 120 440 397 350 290 290 -

TurfBSS

(W13958.dvf) G / (4/1) 16 2 32 120 304 280 259 211 211 -

CA TurfRLF

(W23234.dvf) G / (4/1) 16 2 32 120 322 308 277 243 243 -

FL Turf

(W12834.dvf) GS / (4/1) 12.5 2 25 120 154 141 131 117 117 75

PA Turf

(W12834.dvf) GS / (4/1) 12.5 2 25 120 193 178 161 143 143 68

TurfBSS

(W13958.dvf) GS / (4/1) 12.5 2 25 120 174 161 147 132 132 69

CA TurfRLF

(W23234.dvf) GS / (4/1) 12.5 2 25 120 162 154 143 131 131 68

FL Turf

(W12834.dvf) G / (4/1) 12.5 2 25 120 199 178 154 130 130 -

PA Turf

(W12834.dvf) G / (4/1) 12.5 2 25 120 343 310 273 230 230 -

TurfBSS

(W13958.dvf) G / (4/1) 12.5 2 25 120 237 219 202 165 165 -

CA TurfRLF

(W23234.dvf) G / (4/1) 12.5 2 25 120 259 241 216 190 190 -

FL Turf

(W12834.dvf) G / (4/1) 7.5 2 15 120 119 107 93 78 78 -

PA Turf

(W12834.dvf) G / (4/1) 7.5 2 15 120 206 186 164 140 140 -

TurfBSS

(W13958.dvf) G / (4/1) 7.5 2 15 120 142 131 121 99 99 -
19

Use/Scenario

Granular (G) 

or Ground 

Spray (GS)1

Max. Single

App. Rate

(lb ae/A)

Max. 

Number 

of App.

Max. App. Rate 

Per Year

(lb ai/A)

Min. App. 

Interval 

(Days)

Surface Water (μg/L) Pore Water (μg/L)

% Spray Drift 

Contribution2

to Total 

Pesticide and 

Degradates 

Peak 21-day 60-day Peak 21-day Entering Pond 

CA TurfRLF

(W23234.dvf) G / (4/1) 7.5 2 15 120 156 145 130 114 114 -

Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, Brussels sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, 

chervil, chicory/radicchio, chrysanthemum (garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, endive, fennel, garlic, 

greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy vegetables, lettuce (head, leaf), mustard, mustard cabbage, okra, onion (dry bulb and green), 

orach (mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, roquette (arugula), shallot, spinach, Swiss chard

FL Peppers

(W12844.dvf) GS / (2/1) 6 3 18 120 566 549 516 490 490 15

FL Cabbage

(W12842.dvf) GS / (2/1) 6 3 18 120 389 365 344 315 315 20

CA Lettuce 

(W23273.dvf) GS / (2/1) 6 3 18 120 547 505 444 388 388 19

CA Avocado 

(W23188.dvf) GS / (2/1) 6 3 18 120 113 108 102 96 96 73

FL Peppers

(W12844.dvf) GS / (4/1) 6 2 12 120 411 382 352 323 323 15

FL Cabbage

(W12842.dvf) GS / (4/1) 6 2 12 120 338 320 301 273 272 17

CA Lettuce 

(W23273.dvf) GS / (4/1) 6 2 12 120 387 364 334 280 280 19

CA Avocado 

(W23188.dvf) GS / (4/1) 6 2 12 120 79 74 69 60 59 73

FL Peppers

(W12844.dvf) GS / (4/1) 6 1 6 NA 199 187 176 146 146 17

FL Cabbage

(W12842.dvf) GS / (4/1) 6 1 6 NA 171 158 149 148 148 19

CA Lettuce 

(W23273.dvf) GS / (4/1) 6 1 6 NA 232 217 200 171 171 18

CA Avocado 

(W23188.dvf) GS / (4/1) 6 1 6 NA 52 48 43 35 35 71

Carrot (Texas Only)
20

Use/Scenario

Granular (G) 

or Ground 

Spray (GS)1

Max. Single

App. Rate

(lb ae/A)

Max. 

Number 

of App.

Max. App. Rate 

Per Year

(lb ai/A)

Min. App. 

Interval 

(Days)

Surface Water (μg/L) Pore Water (μg/L)

% Spray Drift 

Contribution2

to Total 

Pesticide and 

Degradates 

Peak 21-day 60-day Peak 21-day Entering Pond 

TXCorn

(W13958.dvf) GS / (4/1) 5 1 5 NA 168 149 130 112 112 19

Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons (bitter, honeydew, citron, mango, musk, water, winter melons), pepino, 

pumpkin, squash (butternut, summer, zucchini squash). AZ120003, CA960003, NJ070001

CA Melons_RLF

(W93193.dvf) GS / (4/1) 9 2 18 120 180 169 153 141 141 47

NJ Melons_Std

(W13781.dvf) GS / (4/1) 9 2 18 120 260 239 220 193 193 36

CA Melons_RLF

(W93193.dvf) GS / (4/1) 9 1 9 NA 111 99 88 67 67 58

NJ Melons_Std

(W13781.dvf) GS / (4/1) 9 1 9 NA 135 122 112 92 92 43

1The application dates for the SWCC modeling were simplified as following: for two applications, the application dates were April 1 and August 1; and for three applications, the 

dates were February 1, June 1 and October 1 respectively.

2The % spray drift contributions to total pesticide and degradates entering pond were captured in the SWCC model output. This information will be useful for the consideration of 

using the spray buffer as the potential mitigation for the reduction of the total toxic residues in a water body.
Page 21 of 85

4.3 Monitoring Data

No monitoring data were found for bensulide and bensulide oxon in the U.S. Geological 

Survey (USGS) National Water Quality Assessment (NAWQA) surface and groundwater 

databases. However, California Department of Pesticide Regulation reported that bensulide 

had a detection frequency of 45% out of 348 samples (2004-2014) in surface water with the 

highest value at 45.5 ppb with the top ten values ranged from 8.6 to 45.5 ppb and the 

detection limit at 0.04 ppb. (http://www.cdpr.ca.gov/docs/emon/surfwtr/surfdata.htm). 

4.4 Terrestrial Habitats

4.4.1 Birds and Mammals

Terrestrial wildlife exposure is estimated with EFED’s T-REX v1.5.2 model (June 6, 2013) 

for birds and mammals emphasizing a dietary exposure route for the consumption of 

pesticide residues on vegetative matter and insects. Birds are considered surrogates for 

terrestrial-phase amphibians and reptiles. Therefore, conclusions related to risks to birds also 

apply to risks to terrestrial-phase amphibians and reptiles. The estimated environmental 

concentrations (EECs) on food items may be compared directly with sub-acute dietary 

toxicity data or converted to an ingested whole-body dose (single oral dose). Risk was 

assessed based on toxicity of the TGAI. Foliar application exposures (residues on food) are 

estimated for birds in Table 4.5 and mammals in Table 4.6. For terrestrial uses applications 

are expressed per crop cycle on the label, EECs were modeled for 1 or 2 crop-cycles per 

year. A third application was not modeled due to concerns identified at 2 applications. 

For granular applications (LD50 method for direction consumption of granules), exposure is 

estimated by an LD50 ft-2 value (assuming 0% incorporation to the soil). Terrestrial EECs 

are calculated based on an estimated loading of pesticides per unit area. This approach 

compares the available mass of pesticide per square foot to the acute oral dose for toxicity 

(LD50) to get LD50 ft-2 values. The LD50 ft-2 is the amount of a pesticide estimated to kill 

50% of exposed animals in each square foot of applied. The LD50 ft-2 value (Table 4.4) is 

calculated using the following equation: 

LD50 ft2 = EEC (mg ai ft-2) / (Adj LD50 ÷ bw (kg) of assessed animal)

A sample of T-REX input and output is provided in Appendix E. Exposure estimates 

account for both the parent bensulide and the degradate bensulide oxon. Determination of 

residue dissipation over time on food items following single and multiple applications are 

predicted using a first-order residue degradation half-life with T-REX. The risk assessment 

uses a default foliar dissipation half-life estimate of 35 days. This default value is used

because available data show detectable residues of parent and oxon for Brassica leafy 

vegetables at 33 days but no detectable levels in vegetables at more protracted intervals. It is 

believed that the use of a 35-day dissipation half-life is a conservative way to account for the 

role of both parent (as an endogenous source of oxon when consumed) and oxon produced in

the plant. In addition to foliar half-life, inputs into T-REX include the application rate, 
Page 22 of 85

interval, and number of applications. The application scenarios for all crops are grouped by 

application rate and interval.

Table 4.4. LD50/sq ft Analysis from Broadcast Application with 0% Incorporation

Proposed 

Application 

Methods

EEC (mg ai/ft2)

(Mammals and Birds)

LD50/sq ft

(birds)

LD50/sq ft

(mammals)

All Size Classes Small

(20 g)

Medium

(100 g)

Large

(1000 g)

Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Golf course turf

1 application @16.0 

lb ai/A

166.61 8.34 1.31 0.09 18.72 9.91 0.80

Ornamental lawns 

and turf, 

residential lawns

1 application @ 

12.5 lbs ai/A

130.16 6.52 1.02 0.07 14.62 7.75 0.63

Table 4.5. T-REX Derived Avian EECs for Bensulide Uses

Food Items

Dose-based1 EECs (mg/kg-bw) Dietary-based

EECs (mg/kg-food item)

Small

20 g

Medium

100 g

Large

1000 g

Kenaga Values

(Maximum)

Golf course turf, turf, ornamental lawns

120-d application interval, 2 applications / year: 12.5 lbs ai/A each

Short Grass 3734.02 2129.30 953.32 3278.62

Tall Grass 1711.43 975.93 436.94 1502.70

Broadleaf plants 2100.39 1197.73 536.24 1844.23

Fruits/pods 233.38 133.08 59.58 204.91

Arthropods 1462.49 833.98 373.38 1284.13

Seeds 51.86 29.57 13.24 204.91

Ornamental lawns, turf, residential lawns

120-d application interval, 2 applications / year; 8.65 lbs ai/A each

Short Grass 2583.94 1473.47 659.69 2268.81

Tall Grass 1184.31 675.34 302.36 1039.87

Broadleaf plants 1453.47 828.83 371.08 1276.20

Fruits/pods 161.50 92.09 41.23 141.80

Arthropods 1012.05 577.11 258.38 888.62

Seeds 35.89 20.46 9.16 141.80

Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, Brussels 

sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, 
Page 23 of 85

endive, fennel, garlic, greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy 

vegetables, lettuce (head, leaf), mustard, mustard cabbage, okra, onion (dry bulb and green), orach 

(mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, roquette (arugula), shallot, 

spinach, Swiss chard -

1 application / year; 6.0 lbs ai/A

Short Grass 1640.02 935.21 418.70 1440.00

Tall Grass 751.67 428.64 191.91 660.00

Broadleaf plants 922.51 526.05 235.52 810.00

Fruits/pods 102.50 58.45 26.17 90.00

Arthropods 642.34 366.29 163.99 564.00

Seeds 22.78 12.99 5.82 90.00

Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, Brussels 

sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, 

endive, fennel, garlic, greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy 

vegetables, lettuce (head, leaf), mustard, mustard cabbage, okra, onion (dry bulb and green), orach 

(mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, roquette (arugula), shallot, 

spinach, Swiss chard -

120 -d application interval, 2 applications / year; 6.0 lbs ai/A each

Short Grass 1792.33 1022.06 457.59 1573.74

Tall Grass 821.49 468.45 209.73 721.30

Broadleaf plants 1008.19 574.91 257.40 885.23

Fruits/pods 112.02 63.88 28.60 98.36

Arthropods 702.00 400.31 179.22 616.38

Seeds 24.89 14.20 6.36 98.36

Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, 

summer, zucchini squash

1 applications / year; 8.94 lbs ai/A

Short Grass 2432.69 1387.22 621.08 2136.00

Tall Grass 1114.98 635.81 284.66 979.00

Broadleaf plants 1368.39 780.31 349.36 1201.50

Fruits/pods 152.04 86.70 38.82 133.50

Arthropods 952.80 543.33 243.26 836.60

Seeds 33.79 19.27 8.63 133.50

Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, 

summer, zucchini squash

120 -d application interval, 2 applications / year; 8.94 lbs ai/A each

Short Grass 2658.63 1516.06 678.76 2334.38

Tall Grass 1218.54 694.86 311.10 1069.92

Broadleaf plants 1495.48 852.78 381.80 1313.09

Fruits/pods 166.16 94.75 42.42 145.90

Arthropods 1041.29 593.79 265.85 914.30

Seeds 36.93 21.06 9.43 145.90
Page 24 of 85

Table 4.6. T-REX Derived Mammalian EECs for Bensulide Uses

Food Items

Dose-based1 EECs (mg/kg-bw) Dietary-based1

EECs (mg/kg-food item)

Small

15 g

Medium

35 g

Large

1000 g

Kenaga Values

Golf course turf, turn, ornamental lawns

120-d application interval, 2 applications / year: 12.5 lbs ai/A each

Short Grass 3125.92 2160.43 500.90 3278.62

Tall Grass 1432.71 990.20 229.58 1502.70

Broadleaf plants 1758.33 1215.24 281.76 1844.23

Fruits/pods 195.37 135.03 31.31 204.91

Arthropods 1224.32 846.17 196.19 1284.13

Seeds 43.42 30.01 6.96 204.91

Ornamental lawns, turf, residential lawns

120-d application interval, 2 applications / year; 8.65 lbs ai/A each

Short Grass 2163.13 1495.02 346.62 2268.81

Tall Grass 991.44 685.22 158.87 1039.87

Broadleaf plants 1216.76 840.95 194.98 1276.20

Fruits/pods 135.20 93.44 21.66 141.80

Arthropods 847.23 585.55 135.76 888.62

Seeds 30.04 20.76 4.81 141.80

Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, Brussels 

sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, 

endive, fennel, garlic, greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy 

vegetables, lettuce (head, leaf), mustard, mustard cabbage, okra, onion (dry bulb and green), orach 

(mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, roquette (arugula), shallot, 

spinach, Swiss chard -

1 application / year; 6.0 lbs ai/A

Short Grass 1372.93 948.88 220.00 1573.74

Tall Grass 629.26 434.90 100.83 721.30

Broadleaf plants 772.27 533.74 123.75 885.23

Fruits/pods 85.81 59.30 13.75 98.36

Arthropods 537.73 371.64 86.17 616.38

Seeds 19.07 13.18 3.06 98.36

Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, Brussels 

sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, 

endive, fennel, garlic, greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy 

vegetables, lettuce (head, leaf), mustard, mustard cabbage, okra, onion (dry bulb and green), orach 

(mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, roquette (arugula), shallot, 

spinach, Swiss chard -

120 -d application interval, 2 applications / year; 6.0 lbs ai/A each

Short Grass 1500.44 1037.00 240.43 1573.74

Tall Grass 687.70 475.29 110.20 721.30
Page 25 of 85

Broadleaf plants 844.00 583.32 135.24 885.23

Fruits/pods 93.78 64.81 15.03 98.36

Arthropods 587.67 406.16 94.17 616.38

Seeds 20.84 14.40 3.34 98.36

Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, 

summer, zucchini squash

1 application / year; 8.94 lbs ai/A

Short Grass 2432.69 1387.22 621.08 2136.00

Tall Grass 1114.98 635.81 284.66 979.00

Broadleaf plants 1368.39 780.31 349.36 1201.50

Fruits/pods 152.04 86.70 38.82 133.50

Arthropods 952.80 543.33 243.26 836.60

Seeds 33.79 19.27 8.63 133.50

Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, 

summer, zucchini squash

120 -d application interval, 2 applications / year; 8.94 lbs ai/A each

Short Grass 2225.65 1538.22 356.64 2334.38

Tall Grass 1020.09 705.02 163.46 1069.92

Broadleaf plants 1251.93 865.25 200.61 1313.09

Fruits/pods 139.10 96.14 22.29 145.90

Arthropods 871.71 602.47 139.69 914.30

Seeds 30.91 21.36 4.95 145.90

4.4.2 Terrestrial Invertebrates

The latest EFED guidance for assessing pesticide risks to bees (USEPA 2014c) was used to 

estimate the EECs for honeybee exposure. Only adult honeybee acute contact toxicity data 

are available to the Agency. The acute contact EECs are presented in Table 4.7 below and 

calculated using the following formula: Application Rate x 2.7 μg ai/bee. Only spray 

treatment EECs are calculated, due to only contact data being available. Granular 

applications are not modeled for contact exposure because it is generally assumed that exposure 

of honey bees from direct contact with the pesticide is minimal. Due to a lack of dietary data,

there are no EECs calculated for spray applications. All EECs are based on a single 

application.

Table 4.7. Honeybee Contact EECs Based on Spray Uses

Use Application Rate (lb ai/A) EEC (μg ai/bee)

Golf course turf, turf, ornamental lawns 12.5 33.8

Ornamental lawns, turf, residential lawns 8.65 23.4

Agricultural uses - lower rate 6 16.2

Agricultural uses - higher rate 8.94 24.1

4.4.3 Terrestrial Plants
Page 26 of 85

TerrPlant (v 1.2.2) was used to calculate EECs for characterizing exposure to terrestrial and 

semi-aquatic plants through spray drift and runoff of bensulide. The EECs were derived for 

dry and semi-aquatic areas adjacent to the treatment site. The input value for spray drift 

fraction is 0 for granular applications, and 0.01 for ground spray, while runoff fraction is 0.01 

based on the bensulide water solubility (5.6 mg/L). The input for incorporation depth is 1 

inch for all applications. Representative inputs and outputs for TerrPlant are in Appendix F.

The most sensitive endpoints in the seedling emergence and vegetative vigor terrestrial plant 

studies were plant fresh weight. The most sensitive monocot was corn in the vegetative vigor 

study, and onion in the seedling emergence study. The most sensitive dicot was lettuce in the 

vegetative vigor study while the most sensitive dicot could not be determined due to lack of 

toxicity at the highest rate tested in the seedling emergence study. These endpoints are based 

on fresh weight. Phytotoxic effects evaluated based on visual injury scores were found to be 

the most sensitive parameter for dicots in the vegetative vigor study. While phytotoxicity is 

not a normal regulatory endpoint, it was a statistically significant effect in both studies. The 

risk characterization has further discussion; however phytotoxicity was not considered 

quantitatively any further in this assessment. Table 4.8 lists the plant EECs for bensulide 

uses.

Table 4.8. TerrPlant Derived Plant EECs for Bensulide Uses

Description Equation* EECs

(Granular)

EECs

(Ground spray)

Golf course turf – Granular broadcast

Golf course turf, turf, ornamental lawns – Broadcast spray

1 application at 16 lbs ai/A – Granular

1 application at 12.5 lb ai/A – Spray

Runoff to dry areas (A/I)*R 0.16 0.125

Runoff to semi-aquatic areas (A/I)*R*10 1.6 1.25

Spray drift A*D 0 0.125

Total for dry areas ((A/I)*R)+(A*D) 0.16 0.25

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 1.6 1.375

Ornamental lawns, turn, residential lawns – Granular broadcast

Ornamental lawns, turn, residential lawns – Broadcast spray

1 application at 12.5 lb ai/A – Granular

1 application at 8.65 lb ai/A – Spray

Runoff to dry areas (A/I)*R 0.125 0.0865

Runoff to semi-aquatic areas (A/I)*R*10 1.25 0.865

Spray drift A*D 0 0.0865

Total for dry areas ((A/I)*R)+(A*D) 0.125 0.173

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 1.25 0.9515

Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, 

Brussels sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, 

chrysanthemum (garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock 

(sorrel), eggplant, endive, fennel, garlic, greens, groundcherry (strawberry tomato/tomatillo), kale, 

kohlrabi, leafy vegetables, lettuce (head, leaf), mustard, mustard cabbage, okra, onion (dry bulb and 

green), orach (mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, roquette 

(arugula), shallot, spinach, Swiss chard - Broadcast spray
Page 27 of 85

1 application at 6.0 lb ai/A – Spray

Runoff to dry areas (A/I)*R N/A 0.06

Runoff to semi-aquatic areas (A/I)*R*10 N/A 0.6

Spray drift A*D N/A 0.06

Total for dry areas ((A/I)*R)+(A*D) N/A 0.12

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) N/A 0.66

Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, 

summer, zucchini squash- Broadcast spray

1 application at 8.94 lb ai/A – Spray

Runoff to dry areas (A/I)*R N/A 0.0894

Runoff to semi-aquatic areas (A/I)*R*10 N/A 0.894

Spray drift A*D N/A 0.0894

Total for dry areas ((A/I)*R)+(A*D) N/A 0.1788

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) N/A 0.9834

*Equation abbreviation: A – Application Rate; I – Incorporation; R – Runoff; and D – Drift Fraction 

N/A = Not applicable

5. Summary of Ecological Effects

Bensulide is slightly toxic to very highly toxic to aquatic and practically non-toxic to highly 

toxic to terrestrial animals based on available toxicity studies. For plants, bensulide shows 

greater toxicity to monocotyledons (monocot) than to dicotyledons (dicot). Registrant 

submitted toxicity studies are not available for degradation products. A review of ECOTOX 

data was conducted in 2007 as part of the CRLF Effects Determination (USEPA 2007) and 

conclusions found there are mirrored here. A search performed for studies since that 

assessment in the open literature (EOCTOX data) contains several studies on bensulide

toxicity to non-target organisms; however, none are considered in this assessment due to 

none showing greater toxicity than available studies. Additional information is included in 

Appendix G. Toxicity endpoints (from registrant studies) used to calculate risk quotients 

(RQs) are reported in Tables 5.1 and 5.2. All available studies including additional details 

are provided in Appendix H.

5.1 Evaluation of mixtures

The Agency does not routinely include, in its risk assessments, an evaluation of mixtures of 

active ingredients, either those mixtures of multiple active ingredients in product 

formulations or those in the applicator’s tank. In the case of the product formulations of 

active ingredients (that is, a registered product containing more than one active ingredient), 

each active ingredient is subject to an individual risk assessment for regulatory decision 

regarding the active ingredient on a particular use site. If effects data are available for a 

formulated product containing more than one active ingredient, they may be used 

qualitatively or quantitatively in accordance with the Agency’s Overview Document and the 

Services’ Evaluation Memorandum (USEPA, 2004; USFWS/NMFS/NOAA, 2004). 
Page 28 of 85

There are two registered products that contain bensulide and another registered active 

ingredient, oxadiazon. Analysis of the available acute oral mammalian LD50 data for multiple 

active ingredient products relative to the single active ingredient is provided in in the 2012 

effects determination Appendix A. This data set is limited, and a qualitative analysis does not 

support any broad conclusions about the interactive nature of bensulide in combination with 

other pesticides. Given that the active and inert ingredients would not be expected to have 

similar mechanisms of action, metabolites or toxicokinetic behavior, it is reasonable to 

conclude that an assumption of dose-addition would be inappropriate. Consequently, the

focus of this assessment is based on the toxicity of the single active ingredient of bensulide 

(including its major degradate).

5.2 Aquatic Organisms

A summary of aquatic toxicity studies are listed in Table 5.1. The full suite of available 

toxicity studies for bensulide is available in Appendix H. Bensulide is moderately toxic to 

highly toxic to freshwater and estuarine/marine fish, highly toxic to freshwater invertebrates, 

and very highly toxic to estuarine/marine invertebrates, on an acute basis. The most sensitive 

aquatic plant was the marine diatom Skeletonema costatum with observed density effects. 

Chronic effects were observed for most aquatic taxa and included effects on length and 

viable eggs for freshwater fish, length for estuarine/marine fish, surviving young, length and 

growth for freshwater invertebrates. There were no effects observed for the estuarine/marine 

invertebrate study with the mysid after 28 days.

Table 5.1. Bensulide Toxicity Endpoints for Aquatic Organisms Used in RQ Calculations

Taxonomic 

Group

Study 

Type

(% ai)

Surrogate 

Species Toxicity Value

Acute 

Toxicity 

Category 

Source

and

Classification

Freshwater fish

Acute

(92.9)

Rainbow trout

(Oncorhynchus 

mykiss)

LC50 = 1.1 mg 

ai/L

Moderately 

toxic

157315

Acceptable

Chronic

Life –

cycle

(97.7)

Fathead minnow

(Pimephales 

promelas)

NOAEC= 0.169 

mg ai/L 

LOAEC = 0.369 

mg ai/L(based on 

reproductive 

endpoints)

Most sensitive 

endpoint(s):

F0 viable eggs 

per female per 

day

--

49001601

(amended under 

49378102)

Supplemental

Freshwater 

invertebrates

Acute

(92.8)

Waterflea 

(Daphnia magna)

LC50 = 0.58 mg 

ai/L Highly toxic 159322

Supplemental
Page 29 of 85

Chronic

(97.7)

Waterflea 

(Daphnia magna)

NOAEC = 0.011 

mg ai/L

LOAEC = 0.016 

mg ai/L

Most sensitive 

endpoint(s):

Reproduction 

(mean number of 

young per 

surviving adult) 

and growth 

(length)

-- 49110401

Acceptable

Estuarine/marine 

fish

Acute

(92.0)

Sheepshead 

minnow 

(Cyprinodon 

variegatus)

LC50 = 0.56 mg 

ai/L Highly toxic 42750201

Acceptable

Chronic

Life –

cycle 

(97.7)

Sheepshead 

minnow 

(Cyprinodon 

variegatus)

NOAEC: 0.036 

mg ai/L (based 

on post-hatch 

length) 

LOAEC: 0.074 

mg ai/L

Endpoint(s) 

Affected:

F0 4-week 

length, F0 8-

week length, F0

17-week 

survival, F0 17-

week length, F0

17-week female 

length, F0 17-

week wet weight, 

F0 17-week 

female weight, 

F1 4-week length

Most Sensitive 

Endpoint(s):

F0 4-week length

--

49059101

(amended under 

49362301)

Acceptable

Estuarine/marine 

invertebrates Acute

(92.0)

Mysid shrimp

(Mysidopsis 

bahia)

LC50 = 0.0624 

mg ai /L Very highly 

toxic

42750203

Acceptable
Page 30 of 85

Chronic

(94.1)

Mysid shrimp

(Mysidopsis 

bahia)

LC50 > 0.0485 

mg ai/L

NOAEC = 

0.0485 mg ai/L

LOAEC > 

0.0485 mg ai/L

No effects were 

observed. 14 day 

endpoints should 

not be used due 

to potential 

solvent effects 

observed. 28 day 

endpoints are 

acceptable.

-- 48424501

Supplemental

Aquatic plants 

and algae

Vascular

Duckweed

(Lemna gibba)

EC50 = 0.140 mg 

ai/L

NOAEC <0.042 

mg ai/L

LOAEC = 0.042 

mg ai/L

Based on density

-- 44720406

Supplemental

Nonvascular

(93.4)

Marine diatom

(Skeletonema 

costatum)

EC50 = 0.78 mg 

ai/L 

NOAEC = 0.635 

mg ai/L 

Based on density

-- 44720405

Acceptable

1 Fish represent surrogates for aquatic-phase amphibians.

5.3 Terrestrial Organisms

The terrestrial toxicity studies are presented in Table 5.2. Bensulide is slightly toxic to birds 

on an acute oral basis, practically non-toxic to birds on a subacute dietary basis, moderately 

toxic to mammals on an acute oral basis, and practically non-toxic to honey bees on an acute 

contact basis. Data are not available for a passerine species or for oral toxicity (both acute 

and chronic) to adult honeybee or their larvae. All terrestrial studies are classified as 

acceptable for use in risk assessment. The avian toxicity studies showed that bensulide can 

impair avian reproduction at relatively low dietary concentrations and the most sensitive 

endpoint appears to be a reduction of eggshell thickness.

The most sensitive endpoints in the terrestrial plant studies were analyzed based on fresh

weight. Phytotoxicity (stunting, leaf blotch, leaf rolling), not normally a regulatory endpoint, 

was evaluated in both the vegetative vigor and seedling emergence studies and NOAEC’s 

based on phytotoxicity were more sensitive than the endpoints for fresh weight. Only fresh 

weight was quantitatively considered in this assessment. Uncertainties also exist for toxicity 

to honeybees, as the acute contact endpoint was non-definitive and no data (beside contact)

using other OPs are available.
Page 31 of 85

Table 5.2. Bensulide Toxicity Endpoints for Terrestrial Organisms

Taxonomic 

Group

Study Type

(% ai)

Surrogate 

Species Toxicity Value

Acute 

Toxicity 

Category

Source

&

Classification

Birds

Acute oral

(92.9)

Bobwhite quail

(Colinus 

virginianus)

LD50 = 1386 mg 

ai/kg-bw

Sublethal effects: 

decreased body 

weight, loss of 

coordination, and 

lethargy.

Slightly toxic 158455

Acceptable

Sub-acute 

dietary

(92.9)

Bobwhite quail

(Colinus 

virginianus)

LC50 > 5620 mg 

ai/kg-diet

No mortality or 

overt signs of 

toxicity at the 

highest test 

concentration of 

5620 ppm

Practically 

non-toxic

158456

Acceptable

Chronic

(92.3)

Mallard duck

(Anas 

platyrhynchos)

NOAEC = 2.5 mg 

ai/kg-diet

LOAEC = 25 mg 

ai/kg-diet

Endpoints affected: 

Eggshell thickness

N/A 44860901

Acceptable

Mammals

Acute oral

(92.5)

Laboratory rat 

(Rattus 

norvegicus)

LD50 = 270 mg/kgbw 

Sublethal effects: 

Convulsions, 

ataxia, 

exophthalmus, 

diarrhea, yellow 

stains in ano-genital 

region, red stains 

about face, and 

depression

Moderately 

toxic

92005011

Acceptable

Chronic

(92.4)

Laboratory rat 

(Rattus 

norvegicus)

NOAEC = 150 

mg/kg-diet

LOAEC = 900 

mg/kg-diet

Endpoint affected: 

F2 pup survival

ACH inhibition at 

as low as 23 

mg/kg/day

N/A 43948701 

Acceptable

Terrestrial 

invertebrates2

Acute 

contact

Honeybee

(Apis mellifera 

L.)

LD50 > 24.17

μg/bee

Practically 

non- toxic

00036935

Acceptable
Page 32 of 85

Terrestrial 

plants

Vegetative 

Vigor

(45.9)

Monocot –

Corn

(Zea mays)

EC25 > 6.0 lb/A

NOAEC = 0.75 

lb/A

Endpoint: shoot 

fresh weight

-- 44746301

Acceptable

Dicot – Lettuce

(Lactuca sativa)

EC25 > 6.0 lb/A

NOAEC = 1.5 lb/A

Endpoint: shoot 

fresh weight

-- 44746301

Acceptable

Seedling 

Emergence

(45.9)

Monocot –

Onion

(Allium cepa)

EC25 = 3.1 lb/A

NOAEC = 0.75 

lb/A

Endpoint: shoot 

fresh weight

-- 44746301

Acceptable

Dicot – Could 

not determine 

most sensitive

species

EC25 > 6.0 lb/A

NOAEC = 6.0 lb/A

Endpoint: shoot 

fresh weight 

-- 44746301

Acceptable

1 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 2 Bensulide is practically non-toxic to honeybees on an acute contact basis resulting in an LD50 >24.17 μg ai /bee (MRID 

00036935 - Acceptable). However, there are uncertainties based on a lack of other honeybee studies. No adult oral toxicity 

data, larval acute data, chronic data for adult and larvae are available for this risk assessment.

5.4 Incident Information

No incident information was found in the Ecological Incident Information System (EIIS, 

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

September 1, 2015). A review of the Avian Monitoring Information System (AIMS), which 

is maintained by the American Bird Conservancy, was also conducted on September 1, 2015.

No incidents associated with bensulide were identified.

Although no incidents were recorded in EIIS or AIMS, some incidents have been reported to 

the Agency in aggregated incident reports. Pesticide registrants report certain types of 

incidents to the Agency as aggregate counts of incidents occurring per product per quarter.

Ecological incidents reported in aggregate reports include those categorized as ‘minor fish 

and wildlife’ (W-B), ‘minor plant’ (P-B), and ‘other non-target’ (ONT) incidents. ‘Other 

non-target’ incidents include reports of adverse effects to insects and other terrestrial 

invertebrates. An incident report was run in 2012 for the Threatened/Endangered effects 

determination and found 57 minor plant incidents (Appendix I). No new ecologically 

relevant incidents have been reported since that assessment. Although incident reporting is 

required under FIFRA Section 6(a) (2), the absence of reports in EIIS does not indicate that 

the chemical has no effects on wildlife; rather, it is possible that incidents are unnoticed and

unreported.

6. Risk Estimation

This preliminary assessment of bensulide was used to provide a metric of potential risks 

based on the RQ method, which is a comparison of exposure estimates to toxicity endpoints 

(i.e., RQ = EEC/toxicity endpoint). The resulting RQs are compared to the Agency’s risk 
Page 33 of 85

levels of concern (LOC) criteria, which are the Agency’s interpretive policy such that when 

acute or chronic risk LOCs are exceeded, the need for regulatory action may be considered.

The acute LOC (0.5) is for non-listed terrestrial birds, mammals and aquatic animals, and the 

acute LOC (0.4) is for non-listed terrestrial invertebrates. The acute LOC (0.1) is for listed 

terrestrial birds and mammals, and LOC (0.05) is for listed aquatic animals and terrestrial 

invertebrates. The chronic LOC (1) is the same for all listed and non-listed terrestrial birds, 

mammals and invertebrates, and aquatic animals. For terrestrial and aquatic plants, the LOC 

(1) is same for both non-listed species (based on the estimation of EEC/EC25) and listed 

species (based on estimation of EEC/EC05 or NOAEL). 

6.1 Aquatic Organisms

Risk quotients are presented below in Table 6.1 for aquatic animal taxa. The range of values 

brackets all the scenarios modeled (e.g. turf use scenarios: FL Turf, PA Turf, TurfBSS, CA 

TurfRLF). Risk concerns are identified for most taxa and use patterns of bensulide. The risk 

quotients are presented in a range regardless of crop scenario. For example the range from 

the granular application 2 apps @16 lb ai/A is the range of 4 different turf scenarios modeled 

A, B, C, and D, and the min/max RQs for freshwater fish could result from scenarios A/LC50

and B/LC50 while the max min RQs for estuarine/marine invertebrates could result from 

scenarios B/LC50 and C/LC50. The acute listed species LOC (0.05) is exceeded for all taxa 

and scenarios. For non-listed species all scenarios and application rates RQs exceed the acute 

LOC (0.5) for estuarine/marine invertebrates, while for freshwater fish the non-listed LOC is 

not exceeded but for 1 scenario/application rate (artichokes, ground spray 3 apps @ 6 lb ai).

There are acute exceedances for estuarine/marine fish and freshwater invertebrates depending 

on the scenario; however, the RQs tend to dip below the agency non-listed LOC as rate 

decreases and number of applications decreases to 1. There are chronic LOC (1) exceedances 

for all taxa in all application scenarios with the exception of freshwater fish for which RQs 

are below the LOC for some uses. A full output of RQs for all application scenarios can be 

found in Appendix J.

No data are available for benthic sediment dwelling organisms. Based on comparing the 

pore water EECs to water column invertebrate toxicity endpoints, RQ exceedances would be 

generally be the same. Consequently, the RQs presented below for water column 

invertebrates are expected to be protective of benthic invertebrates. 

Table 6.1. Aquatic RQs for Fish and Invertebrates from Bensulide Uses

Application 

Rate

FWF –

A1*

FWF-C E/MF - A E/MF-C FWI-A FWI-C E/MI-A E/MI-C

EEC/

LC50 = 

1100 μg 

ai/L

EEC/

NOAEC 

= 169 μg 

ai/L

EEC/

LC50 = 

560 μg 

ai/L

EEC/

NOAEC 

= 6 μg 

ai/L

EEC/

LC50 = 

580 μg 

ai/L

EEC/

NOAEC 

= 11 μg 

ai/L

EEC/

LC50 = 

62.4 μg 

ai/L

EEC/

NOAEC 

= 48.5 μg 

ai/L

Golf course turf, Turf, and Ornamental lawns

Granular - 2 

apps@ 16 lb ai/A

0.23 - 0.40 1.17 -

2.07***

0.45 -

0.79**

5.47 -

9.72***

0.44 -

0.76**

20.73 -

36.09***

4.07 -

7.05**

4.7 -

8.19***

Ground spray - 2 

apps@ 12.5 lb 

0.14 - 0.18 0.78 - 0.95 0.28 -

0.34*

3.64 -

4.47***

0.27 -

0.33*

12.82 -

16.18***

2.47 -

3.09**

2.91 -

3.67***
Page 34 of 85

ai/A

Granular - 2 

apps@ 12.5 lb 

ai/A

0.18 - 0.31 0.91 -

1.62***

0.36 -

0.61**

4.28 -

7.58***

0.34 -

0.59**

16.18 -

28.18***

3.19 -

5.5**

3.67 -

6.39***

Granular - 2 

apps@ 7.5 lb 

ai/A

0.11 - 0.19 0.55 - 0.97 0.21 -

0.37*

2.58 -

4.56***

0.21 -

0.36*

9.73 -

16.91

1.91 -

3.3**

2.21 -

3.84***

Artichokes etc.2

Ground spray - 3 

apps@ 6 lb ai/A

0.1 - 0.51 0.6 -

3.05***

0.2 -

1.01**

2.83 -

14.33***

0.19 -

0.98**

9.82 -

49.91

1.81 -

9.07**

2.23 -

11.32***

Ground spray - 2 

apps@ 6 lb ai/A

0.07 - 0.37 0.41 -

2.08***

0.14 -

0.73**

1.92 -

9.78***

0.14 -

0.71**

6.73 -

34.73

1.27 -

6.59**

1.53 -

7.88***

Ground spray - 1 

app@ 6 lb ai/A

0.05 - 0.21 0.25 -

1.18***

0.09 -

0.41*

1.19 -

5.56***

0.09 -

0.4*

4.36 -

19.73

0.83 -

3.72**

0.99 -

4.47***

Carrot

Ground spray - 1 

app@ 6 lb ai/A

0.15 - 0.15 0.77 - 0.77 0.3 - 0.3* 3.61 -

3.61***

0.29 -

0.29*

13.55 -

13.55

2.69 -

2.69**

3.07 -

3.07***

Cantaloupe etc.3

Ground spray - 2 

apps@ 9 lb ai/A

0.16 - 0.24 0.91 -

1.3***

0.32 -

0.46*

4.25 -

6.11***

0.31 -

0.45*

15.36 -

21.73

2.88 -

4.17**

3.48 -

4.93***

Ground spray - 1 

app@ 9 lb ai/A

0.1 - 0.12 0.52 - 0.66 0.2 - 0.24* 2.44 -

3.11***

0.19 -

0.23*

9 - 11.09 1.78 -

2.16**

2.04 -

2.52***

* At least one scenario exceeds the listed species LOC (0.05) for the specified application rate

**At least one scenario exceeds the listed and non-listed species LOC (0.5) for the specified application rate

*** Exceeds the chronic LOC of 1for listed and non-listed species.

NC = Not calculated

1 All uses exceed the listed species LOC for FWF Acute 2Artichokes etc. = Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, 

Brussels sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, endive, fennel, garlic, 

greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy vegetables, lettuce (head, leaf), mustard, mustard 

cabbage, okra, onion (dry bulb and green), orach (mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, 

roquette (arugula), shallot, spinach, Swiss chard - 3 Cantaloupe etc. = Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, summer, zucchini 

squash)

FWF = Freshwater fish; E/MF = Estuarine/marine fish; FWI = Freshwater invertebrates, E/MI = Estuarine/marine 

invertebrates. X–A = Acute RQ; X-C = Chronic RQ

Risk quotients are presented below in Table 6.2 for aquatic plants. The range of values 

brackets all the scenarios modeled (e.g. turf use scenarios: FL Turf, PA Turf, TurfBSS, CA 

TurfRLF). For vascular plants RQs could not be calculated for listed species due to not 

having an NOAEC value from an acceptable study. The LOC is exceeded for non-listed 

species for at least some scenarios at all application rates, except, the cantaloupe et al. group 

(CA or NJ melon scenario) using 1 application. No LOCs are exceeded for listed or nonlisted non-vascular plants. A list of all RQs is presented in Appendix J.
Page 35 of 85

Table 6.2. Aquatic RQs for Aquatic Plants from Bensulide Uses

Application Rate

Vascular Plants

non-listed species

Vascular 

Plants listed

Non-Vascular 

Plants non-listed

Non-Vascular Plants 

listed

EEC/

EC50 = 140 μg 

ai/L

EEC/

NOAEC = <

42 μg ai/L

EEC/

EC50 = 780 μg ai/L

EEC/

NOAEC = 635 μg 

ai/L

Golf course turf, Turf, and Ornamental lawns

Granular - 2 

apps@ 16 lb ai/A 1.81 - 3.14*** N/C 0.33 - 0.56 0.4 - 0.69

Ground spray - 2 

apps@ 12.5 lb 

ai/A

1.1 - 1.38*** N/C 0.2 - 0.25 0.24 - 0.3

Granular - 2 

apps@ 12.5 lb 

ai/A

1.42 - 2.45*** N/C 0.26 - 0.44 0.31 - 0.54

Granular - 2 

apps@ 7.5 lb ai/A 0.85 - 1.47*** N/C 0.15 - 0.26 0.19 - 0.32

Artichokes etc.1

Ground spray - 3 

apps@ 6 lb ai/A 0.81 - 4.04*** N/C 0.14 - 0.73 0.18 - 0.89

Ground spray - 2 

apps@ 6 lb ai/A 0.56 - 2.94*** N/C 0.1 - 0.53 0.12 - 0.65

Ground spray - 1 

app@ 6 lb ai/A 0.37 - 1.66*** N/C 0.07 - 0.3 0.08 - 0.37

Carrot

Ground spray - 1 

app@ 6 lb ai/A 1.2 - 1.2*** N/C 0.22 - 0.22 0.26 - 0.26

Cantaloupe etc.

2

Ground spray - 2 

apps@ 9 lb ai/A 1.29 - 1.86*** N/C 0.23 - 0.33 0.28 - 0.41

Ground spray - 1 

app@ 9 lb ai/A 0.79 - 0.96 N/C 0.14 - 0.17 0.17 - 0.21

1 Artichokes etc. = Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, 

Brussels sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, endive, fennel, garlic, 

greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy vegetables, lettuce (head, leaf), mustard, mustard 

cabbage, okra, onion (dry bulb and green), orach (mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, 

roquette (arugula), shallot, spinach, Swiss chard - 2 Cantaloupe etc. = Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, summer, zucchini 

squash)

*** Exceeds the plant LOC of 1 for non-listed species.

NC = Not calculated

6.2 Birds and Mammals

Risk quotients exceeded the LOC for many uses and size classes for both birds and 

mammals. Table 6.3 is a summary of acute LOC exceedances from spray applications for 

both birds and mammals based on diet item and size class with comments for additional 

clarification. No comments in the table indicate all size classes listed in that field exceeded 

the LOC. No LOC exceedances were observed for birds or mammals that feed on seeds; 

therefore, that category was omitted from Table 6.3. For all uses, acute dose based LOCs 
Page 36 of 85

were generally exceeded for most size classes and dietary items for birds and mammals. 

Acute dietary RQs were not calculated for birds because endpoints were non-definitive 

(LC50>5620 mg ai/kg-diet). An EEC of > 2580 would be required to exceed the non- listed 

bird species LOC. Uses that would result in LOC exceedance are those with 2 applications 

per year (specifically turf, ornamentals, and cantaloupe et al.) for birds eating short grass. All 

chronic dietary RQs were also above the Agency’s LOC for birds. All chronic dietary RQs 

were also above the agency LOC for mammals except for those feeding fruits/pods, and 

seeds. Table 6.4 and Table 6.5 list the avian and mammalian RQs, respectively for all spray 

application of bensulide.

For granular applications, based on the estimated available ai per square foot (Table 4.4), an 

analysis was done to see how many granules would need to be consumed and the minimum 

foraging area required to achieve the LD50, LOC of 0.5 (1/2 of LD50) and 0.1 (1/10 of LD50). 

This was done for small bird and mammals because they had the highest LD50 ft-2 values. 

Table 6.6 shows small birds and mammals would have to consume about 36 and 15 granules 

respectively (for both uses) to reach the listed LOC of 0.1 and forage areas ranging from 0.01 

to 0.15 square feet (depending on use) to reach the listed LOC of 0.1. Sufficient ai would be 

present in one square foot of treated area to produce toxicity for small birds and mammals 

and that a small bird or mammal may be affected by as little as 15 granules, and that acute 

toxicity would be expected if about 350 granules were consumed by a small bird or about 

150 were consumed for a small mammal.

Table 6.3. Summary of Avian and Mammalian RQ Exceedances from Acute Exposure 

to Spray Applications of Bensulide 

Food item1

Use/Rate LOC Compared

Short and Tall 

Grasses,

Broadleaf Plants, 

Arthropods

Fruit, Pods Comment

Turf – 2 apps/yr 

@12.5 lb ai/A

Listed 

exceedance

B S, M, L S, M

M S, M, L S, M, L

Non-listed 

exceedance

B S, M ,L None L = Short grass only exceedance

M S, M, L None

Ornamentals, 2 

apps/yr @ 8.65 lb 

ai/A

Listed 

exceedance

B S, M, L S

M S, M, L S, M, L

Non-listed 

exceedance

B S, M None Arthropods exceeded in S only

M S, M, L None

Artichokes etc.2

1 app / year; 6.0 lbs 

ai/A

Listed 

exceedance

B S, M, L S Arthropods not exceeded in L

M S, M, L S, M L exceedances only in Short grass 

and broadleaf plants

Non-listed 

exceedance

B S, M None Short grass is only exceedance for 

M

M S, M, L None

Artichokes etc.2

2 apps / year; 6.0 lbs 

ai/A each

Listed 

exceedance

B S, M, L S

M S, M, L S, M

Non-listed 

exceedance

B S, M None Short grass is only exceedance for 

M

M S, M, L None L has no exceedances for 
Page 37 of 85

arthropods

Cantaloupe etc3

1 app / year; 8.94 lbs 

ai/A

Listed 

exceedance

B S, M, L S

M S, M, L S, M, L

Non-listed 

exceedance

B S, M None Short grass/broad leaf plants are 

only M exceedances

M S, M, L None

Cantaloupe etc.3

2 apps / year; 8.94 

lbs ai/A each

Listed 

exceedance

B S, M, L S

M S, M, L S, M, L

Non-listed 

exceedance

B S, M None Arthropods not exceeded in M

M S, M, L None

1 There were no exceedances for seed consumption, thus no data are reported in the table. 2 Artichokes etc. = Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, 

Brussels sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, endive, fennel, garlic, 

greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy vegetables, lettuce (head, leaf), mustard, mustard 

cabbage, okra, onion (dry bulb and green), orach (mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, 

roquette (arugula), shallot, spinach, Swiss chard – 3 Cantaloupe etc. = Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, summer, zucchini 

squash)

B = bird; S=Small (20g); M= Medium (100g); L= Large (1000g) 

M = Mammal S=Small (15g); M= Medium (35g); L= Large (1000g) 

Table 6.4. Avian RQs for Bensulide Spray Applications

Uses Food Items

Avian Oral Dose-based1

Acute RQs

Avian Dietary-based1

RQs

20 g 100 g 1000 g Acute Chronic***

Golf course turf, turn, 

ornamental lawns

120-d application 

interval, 2 

applications / year: 

12.5 lbs ai/A each

Short Grass 3.74** 1.68** 0.53** N/C4 1311.45

Tall Grass 1.71** 0.77** 0.24* N/C4 601.08

Broadleaf plants 2.1** 0.94** 0.3* N/C4 737.69

Fruits/pods 0.23* 0.1* 0.03 N/C4 81.97

Arthropods 1.46** 0.66** 0.21* N/C4 513.65

Seeds 0.05 0.020 0.01 N/C4 81.97

Ornamental lawns, 

turf, residential lawns

120-d application 

interval, 2 

applications / year; 

8.65 lbs ai/A each

Short Grass 2.59** 1.16** 0.37* N/C4 907.52

Tall Grass 1.19** 0.53** 0.17* N/C4 415.95

Broadleaf plants 1.46** 0.65** 0.21* N/C4 510.48

Fruits/pods 0.16** 0.070 0.02 N/C4 56.72

Arthropods 1.01** 0.45* 0.14* N/C4 355.45

Seeds 0.04 0.020 0.01 N/C4 56.72

Artichokes, 

etc.2

, 

1 app / 

year; 

6.0 lbs 

ai/A

Short Grass 1.64** 0.74** 0.23* N/C4 576.00

Tall Grass 0.75** 0.34* 0.11* N/C4 264.00

Broadleaf plants 0.92** 0.41* 0.13* N/C4 324.00

Fruits/pods 0.1** 0.050 0.01 N/C4 36.00

Arthropods 0.64** 0.29* 0.09 N/C4 225.60

Seeds 0.02 0.010 <0.01 N/C4 36.00

120 -d 

app 

interval, 

2 apps / 

Short Grass 1.79** 0.8** 0.25* N/C4 629.50

Tall Grass 0.82** 0.37* 0.12* N/C4 288.52

Broadleaf plants 1.01** 0.45* 0.14* N/C4 354.09

Fruits/pods 0.11** 0.050 0.02 N/C4 39.34
Page 38 of 85

year; 

6.0 lbs 

ai/A 

each

Arthropods 0.7** 0.31* 0.1* N/C4 246.55

Seeds 0.02 0.010 0 N/C4 39.34

Cantaloupe 

etc.3

1 app / 

year; 

8.94 lbs 

ai/A

Short Grass 2.44** 1.09** 0.35* N/C4 854.40

Tall Grass 1.12** 0.5** 0.16* N/C4 391.60

Broadleaf plants 1.37** 0.61** 0.19* N/C4 480.60

Fruits/pods 0.15* 0.070 0.02 N/C4 53.40

Arthropods 0.95* 0.43* 0.14* N/C4 334.64

Seeds 0.03 0.020 0 N/C4 854.40

120 -d 

app 

interval, 

2 apps / 

year; 

8.94 lbs 

ai/A 

each

Short Grass 2.66** 1.19** 0.38* N/C4 933.75

Tall Grass 1.22** 0.55** 0.17* N/C4 427.97

Broadleaf plants 1.5** 0.67** 0.21* N/C4 525.24

Fruits/pods 0.17* 0.070 0.02 N/C4 58.36

Arthropods 1.04** 0.47** 0.15* N/C4 365.72

Seeds 0.04 0.040 0.01 N/C4 58.36

1The below notation will be used to denote values that exceed the Levels of Concern (LOC)

*exceeds acute listed species LOC (0.1) 

**exceeds acute non-listed species LOC (0.5)

*** All uses exceed the chronic listed and non-listed species LOC (1) 2 Artichokes etc. = Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, 

Brussels sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, endive, fennel, garlic, 

greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy vegetables, lettuce (head, leaf), mustard, mustard 

cabbage, okra, onion (dry bulb and green), orach (mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, 

roquette (arugula), shallot, spinach, Swiss chard - 3 Cantaloupe etc. = Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, summer, zucchini 

squash)

4 N/C – Not calculated due to non-definitive sub-acute dietary endpoint.

Table 6.5. Mammalian RQs for Bensulide Uses

Uses Food 

Items

Small mammal1

15 g

Medium mammal1

35 g

Large mammal1

1000 g

Dietarybased 

RQs

Acute Chronic Acute Chronic

***

Acute Chronic Chronic

Golf course turf, turn, 

ornamental lawns

120-d application 

interval, 2 applications / 

year: 12.5 lbs ai/A each

Short 

Grass 5.27** 189.64*** 4.5** 161.99*** 2.41** 86.83*** 21.86***

Tall Grass

2.41** 86.92*** 2.06** 74.24*** 1.11** 39.8*** 10.02***

Broadleaf 

plants 2.96** 106.67*** 2.53** 91.12*** 1.36** 48.84*** 12.29***

Fruits/pods 0.33* 11.85*** 0.28* 10.12*** 0.15* 5.43*** 1.37***

Arthropods 2.06** 74.27*** 1.76** 63.44*** 0.94** 34.01*** 8.56***

Seeds 0.07 2.63*** 0.06 2.25*** 0.03 1.21*** 1.37***

Ornamental lawns, turf, 

residential lawns

120-d application 

Short 

Grass 3.65** 131.23*** 3.11** 112.09*** 1.67** 60.09*** 15.13***

Tall Grass 1.67** 60.15*** 1.43** 51.38*** 0.76** 27.54*** 6.93***

Broadleaf 2.05** 73.82*** 1.75** 63.05*** 0.94** 33.8*** 8.51***
Page 39 of 85

Uses Food 

Items

Small mammal1

15 g

Medium mammal1

35 g

Large mammal1

1000 g

Dietarybased 

RQs

Acute Chronic Acute Chronic

***

Acute Chronic Chronic

interval, 2 applications / 

year; 8.65 lbs ai/A each

plants

Fruits/pods 0.23* 8.2*** 0.19* 7.01*** 0.1* 3.76*** 0.95

Arthropods 1.43** 51.4*** 1.22** 43.9*** 0.65** 23.53*** 5.92***

Seeds 0.05 1.82*** 0.04 1.56*** 0.02 0.83 0.95

Artichokes 

etc.2, 

1 app/ year; 

6.0 lbs ai/A

Short 

Grass 2.31** 83.29*** 1.98** 71.15*** 1.06** 38.14*** 9.6***

Tall Grass 1.06** 38.17*** 0.91** 32.61*** 0.49* 17.48*** 4.4***

Broadleaf 

plants 1.3** 46.85*** 1.11** 40.02*** 0.6* 21.45*** 5.4***

Fruits/pods 0.14 5.21*** 0.12* 4.45*** 0.07* 2.38*** 0.6

Arthropods 0.91** 32.62*** 0.77** 27.87*** 0.41* 14.94*** 3.76***

Seeds 0.03 1.16*** 0.03 0.99 0.01 0.53 0.6

120 -d 

application 

interval, 2 

applications 

/ year; 6.0 

lbs ai/A 

each

Short 

Grass 2.53** 91.03*** 2.16** 77.75*** 1.16** 41.68*** 10.49***

Tall Grass 1.16** 41.72*** 0.99** 35.64*** 0.53** 19.1*** 4.81***

Broadleaf 

plants 1.42** 51.2*** 1.21** 43.74*** 0.65** 23.44*** 5.9***

Fruits/pods 0.16 5.69*** 0.13 4.86*** 0.07 2.6*** 0.66

Arthropods 0.99** 35.65*** 0.85** 30.45*** 0.45* 16.32*** 4.11***

Seeds 0.04 1.26*** 0.03 1.08*** 0.02 0.58 0.66

Cantaloupe 

etc.

3

1 app / 

year; 8.94 

lbs ai/A 

Short 

Grass 3.43** 123.55*** 2.93** 105.53*** 1.57* 56.57*** 14.24***

Tall Grass 1.57** 56.63*** 1.34** 48.37*** 0.72* 25.93*** 6.53***

Broadleaf 

plants 1.93** 69.5*** 1.65** 59.36*** 0.88* 31.82*** 8.01***

Fruits/pods 0.21 7.72*** 0.18* 6.6*** 0.1* 3.54*** 0.89

Arthropods 1.34** 48.39*** 1.15** 41.33*** 0.62** 22.16*** 5.58***

Seeds 0.05 1.72*** 0.04 1.47*** 0.02 0.79 0.89

120 -d 

application 

interval, 2 

applications 

/ year; 8.94 

lbs ai/A 

each

Short 

Grass 3.75** 135.02*** 3.2** 115.33*** 1.72** 61.82*** 15.56***

Tall Grass 1.72** 61.88*** 1.47** 52.86*** 0.79** 28.34*** 7.13***

Broadleaf 

plants 2.11** 75.95*** 1.8** 64.88*** 0.97** 34.78*** 8.75***

Fruits/pods 0.23* 8.44*** 0.2* 7.21*** 0.11* 3.86*** 0.97

Arthropods 1.47** 52.88*** 1.25** 45.17*** 0.67** 24.21*** 6.1***

Seeds 0.05 1.88*** 0.04 1.6*** 0.02 0.86 0.97 1The below notation will be used to denote values that exceed the Levels of Concern (LOC)

*exceeds acute listed species LOC (0.1) 

**exceeds acute listed and non-listed species LOC (0.5)

*** exceeds chronic listed and non-listed species LOC (1)
Page 40 of 85

2 Artichokes etc. = Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, 

Brussels sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, endive, fennel, garlic, 

greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy vegetables, lettuce (head, leaf), mustard, mustard 

cabbage, okra, onion (dry bulb and green), orach (mountain spinach), parsley, peas, pepper, pepper (chili), pimento, radish, 

roquette (arugula), shallot, spinach, Swiss chard - 3 Cantaloupe etc. = Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons 

(bitter, honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, summer, zucchini 

squash)

For granular applications, based on the estimated available ai per square foot (Table 4.4), an 

analysis was done to see how many granules would need to be consumed and the minimum 

foraging area required to achieve the LD50, LOC of 0.5 (1/2 of LD50) and 0.1 (1/10 of LD50). 

This was done for small bird and mammals because they had the highest LD50 ft-2 values. 

Table 6.6 shows small birds and mammals would have to consume about 36 and 15 granules 

respectively (for both uses) to reach the listed LOC of 0.1 and forage areas ranging from 0.01 

to 0.15 square feet (depending on use) to reach the listed LOC of 0.1. The analysis also 

indicates, sufficient ai would be present in one square foot of treated area to produce toxicity 

for small birds/mammals and a small bird or mammal may be affected by as little as 15 

granules. Acute toxicity (reach the LD50) would be expected if about, 350 granules were 

consumed by a small bird or about 150 were consumed for a small mammal.

Table 6.6. Required Number of Granules Consumed for Various LOC Exceedances

Use 

Description Consumed Granules1 Birds (20 g) Mammals (15g)

Golf course 

turf

1 application 

@16.0 lb ai/A

Ornamental 

lawns and 

turf, 

residential 

lawns

1 application 

@ 12.5 lbs 

ai/A

No. of granules needed to achieve 

LD50 

353 157

No. of granules needed to achieve the 

LOC of 0.5 (1/2 LD50) 176 79

No. of granules needed to achieve the 

LOC of 0.1 (1/10 LD50) 36 16

Foraging Area Golf 

Course

Ornamental 

Lawns

Golf 

Course

Ornamental 

Lawns

Foraging area (square feet) needed to 

achieve LOC of 0.1 exceedance 

assuming 100% feeding efficiency

0.01 0.02 0.01 0.01

Foraging area (square feet) needed to 

achieve LOC of 0.1 exceedance 

assuming 50% feeding efficiency

0.02 0.03 0.01 0.01

Foraging area (square feet) needed to 

achieve LOC of 0.1 exceedance 

assuming 10% feeding efficiency

0.12 0.15 0.05 0.07

1 Consumed Granules is the same for both uses within each taxa (birds, mammals)

6.3 Drinking Water and Inhalation

Inhalation and drinking water exposure pathways were screened using the STIR (Screening 

Tool for Inhalation Risk) and SIP (Screening Imbibition Program) and screening methods. 

Model inputs and outputs are presented in Appendix K. Description of these models and 

their assumptions are available at: http://www.epa.gov/oppefed1/models/terrestrial/index.htm
Page 41 of 85

Inhalation

The Screening Tool for Inhalation Risk (STIR v1.0) 4 provides an upper bound estimate of 

bird and mammal exposure to bensulide through vapor inhalation. The screening analysis 

suggests that bensulide uses do not have the potential for significant vapor inhalation risk 

(the ratio of vapor concentration in the air to the inhalation LD50 does not exceed the 

screening threshold of 0.1).

Drinking Water

The Screening Imbibition Program (SIP v.1.0) provides an upper bound estimate of bird and 

mammal exposure to bensulide in drinking water (bensulide concentration in drinking water 

assumed to be at solubility limit in water at 25oC). The screening by the SIP model indicates 

potential chronic exposure concerns to birds through the consumption of bensulidecontaminated drinking water while chronic exposures were not of concern for mammals. 

Acute exposure through drinking water alone was not found to be a potential concern for 

birds or mammals in the screen. 

6.4 Terrestrial Invertebrates

Only one terrestrial invertebrate study was submitted indicating bensulide is practically nontoxic to honeybees on an acute contact basis. This study had a non-definitive (> 24.17 μg 

ai/bee) endpoint, thus RQs could not be calculated for spray applications. RQs for granular 

applications were also not calculated due to lack of dietary toxicity data. The non-definitive 

contact endpoint, and insufficient data for other life stages (larval) or exposure routes (oral, 

drinking water), leave uncertainties as to the actual risks posed to pollinators or other 

terrestrial invertebrates. The risk to insect pollinators is discussed in greater detail in the Risk 

Characterization section (7.2.3) 

6.5 Terrestrial and Semi-Aquatic Plants

Risk quotients for terrestrial and semi-aquatic non-listed species inhabiting dry and semiaquatic areas are derived by dividing the EEC by the EC25 from seedling emergence and 

vegetative vigor toxicity tests. Risk quotients for listed terrestrial plant species are calculated 

by dividing the EEC by the NOAEC value. The input values for runoff fraction is 1% based 

on the bensulide solubility (5.6) and drift fraction is 0 for granular applications and 1% for 

ground spray. A summary of the RQs for terrestrial plants is provided in Table 6.7. The table 

lists the RQs calculated using endpoints based on fresh weight. Where RQs are listed as ND,

they could not be calculated based on non-definitive endpoints.

The RQs are below the Agency LOCs for all plant types (excluding non-listed dicots based 

on non-definitive endpoints for which RQs were not calculated) receiving residues through 

spray drift or to terrestrial plants in dry areas (Table 6.7). Listed LOCs are exceeded for

monocots in semi-aquatic habitats for turf spray/granular uses and one agricultural spray use 

(8.94 lb ai/A). The EC50 values for dicots were based on fresh weight and were nondefinitive (greater than); therefore so RQs for non-listed dicots could not be calculated. 

 4 http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/models-and-databases-used-pesticiderisk-assessment#models
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Table 6.7. RQ Values for Plants in Dry and Semi-aquatic Areas Exposed to Bensulide

through Runoff and/or Spray Drift.*

Plant 

Type

Listed 

Status

Dry1 Semi-Aquatic2 Spray Drift

Granular Spray Granular Spray Granular Spray

Golf course turf – Granular broadcast

Golf course turf, turf, ornamental lawns – Broadcast spray

1 application at 16 lbs ai/A – Granular

1 application at 12.5 lb ai/A – Spray

Monocot non-listed <0.1 <0.1 0.52 0.44 N/A <0.1

Monocot listed 0.21 0.33 2.13 1.83 N/A 0.17

Dicot non-listed ND ND ND ND

N/A

ND

Dicot listed <0.1 <0.1 0.27 0.23

N/A

<0.1

Ornamental lawns, turn, residential lawns – Granular broadcast

Ornamental lawns, turn, residential lawns – Broadcast spray

1 application at 12.5 lb ai/A – Granular

1 application at 8.65 lb ai/A – Spray

Monocot non-listed <0.1 <0.1 0.40 0.31 N/A <0.1

Monocot listed 0.17 0.23 1.67 1.27 N/A 0.12

Dicot non-listed ND ND ND ND N/A ND

Dicot listed <0.1 <0.1 0.21 0.16 N/A <0.1

Artichokes, beans, beet, bell pepper, Brassica (head and stem) vegetables, broccoli, broccoli raab, Brussels 

sprouts, cabbage, cardoon, carrot, cauliflower, celery, celtuce, chervil, chicory/radicchio, chrysanthemum 

(garland), cole crops, collards, corn salad, cress (garden, upland), dandelion, dock (sorrel), eggplant, 

endive, fennel, garlic, greens, groundcherry (strawberry tomato/tomatillo), kale, kohlrabi, leafy vegetables, 

lettuce (head, leaf), mustard, mustard cabbage, okra, onion (dry bulb and green), orach (mountain 

spinach), parsley, peas, pepper, pepper (chili), pimento, radish, roquette (arugula), shallot, spinach, Swiss 

chard - Broadcast spray

1 application at 6.0 lb ai/A – Spray

Monocot non-listed N/A <0.1 N/A 0.21 N/A <0.1

Monocot listed N/A 0.16 N/A 0.88 N/A <0.1

Dicot non-listed N/A ND N/A ND N/A ND

Dicot listed N/A <0.1 N/A 0.11 N/A <0.1

Cantaloupe, chayote, cucumber, cucurbit vegetables, cucuzzi, gherkin, gourds, gourd (wax), melons (bitter, 

honeydew, citron, mango, musk, water, winter melons), pepino, pumpkin, squash (butternut, summer, 

zucchini squash- Broadcast spray

1 application at 8.94 lb ai/A – Spray

Monocot non-listed N/A <0.1 N/A 0.32 N/A <0.1

Monocot listed N/A 0.32 N/A 1.31 N/A 0.12

Dicot non-listed N/A ND N/A ND N/A ND

Dicot listed N/A <0.1 N/A 0.16 N/A <0.1

ND = Value is not determined because of non-definitive endpoints

N/A = Not applicable, spray application only * Bold Values: If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group
Page 43 of 85

7. Risk Characterization and Conclusions

This preliminary risk assessment for bensulide was used to provide a metric of potential risks 

based on the RQ method, which is a comparison of exposure estimates to toxicity endpoints 

(i.e., RQ = EEC/toxicity endpoint). The resulting RQs are compared to the Agency’s risk 

levels of concern (LOC) criteria (Table 7.1), which are the Agency’s interpretive policy such 

that when acute or chronic risk LOCs are exceeded, the need for regulatory action may be 

considered. These criteria are used to indicate when the use of a pesticide, as directed on the 

label, has the potential to cause adverse effects to non-target organisms. Finally, possible 

mitigations are discussed for each taxa.

Table 7.1. The Agency’s Levels of Concern (LOC) Criteria

Risk Presumption

Terrestrial Birds 

and Mammals 

(LOC)

Aquatic 

Animals (LOC)

Terrestrial and 

Aquatic Plants (LOC)

Terrestrial 

Invertebrates

Acute 0.5 0.5 1 0.4

Acute Endangered 

Species 0.1 0.05 1 0.4

Chronic 1 1 N/A 1

7.1 Aquatic Organisms

7.1.1 Aquatic fish and invertebrates

The standard modeling approach based on exposure of aquatic organisms to total toxic 

residues of bensulide and bensulide oxon indicates an acute and chronic risk concern for fish 

and aquatic invertebrates from all uses bensulide (Table 6.1). TTR was used to calculate 

EECs because the bensulide oxon is assumed to be similarly in toxicity to the parent based 

on the lack of data (fate and ecotoxicity) to rule out this assumption. The lack of fate data

(e.g. aerobic soil metabolism and aerobic aquatic metabolism) for both the parent and its 

oxon degradate, may increase the uncertainty in the EEC estimates. There are no reported 

incidents on aquatic organisms from bensulide usage: however, this does not necessarily 

indicate a lack of incidents or reduced risk. Monitoring data (See section 4.3) produced a 

peak value of 45.5 ppb of bensulide which is significant enough to produce LOC 

exceedances for aquatic taxa. 

In general, estuarine/marine organisms are more sensitive to bensulide on an acute exposure 

basis than freshwater counterparts. The agricultural uses, contribute less to the risk picture 

than high multi-application turf use sites (see Appendix J for full list of RQs and scenarios). 

In general, for agricultural uses, acute LOC exceedances for non-listed species of all aquatic 

animal taxa only occur after a second application (listed species LOCs are almost always 

exceeded). The exception is for estuarine/marine fish which exceed listed and non-listed 

LOCs in all application scenarios.

Depending on the application scenario, the number of freshwater fish chronic exceedances go 
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down when only one application is used. Calculating chronic freshwater fish RQs at the 

LOAEC (0.369 mg ai/L) would only exceed agency LOCs for a few scenarios at multiple 

applications. For estuarine/marine fish, NOAEC values for reproductive effects seen in the 

chronic study and ranged across all concentrations tested, and had chronic LOC exceedances

in all scenarios modeled. The NOAEC would have to be at least one order of magnitude less 

sensitive to eliminate chronic risk concerns for estuarine/marine fish. For aquatic 

invertebrates the chronic LOC is almost always exceeded regardless of application scenario.

There is some uncertainty as to the potential for reproductive effects to estuarine/marine

invertebrates since the mysid life-cycle study produced no effects at the highest concentration 

tested. As with their estuarine/marine fish counterparts, NOAEC would have to be at least 

one order of magnitude less sensitive to eliminate chronic risk concerns for estuarine/marine 

invertebrates. The persistence of bensulide may also add uncertainty to this characterization 

as there could be a yearly build up increasing exposure. Additionally, No data are available 

for benthic sediment dwelling organisms. The risk conclusions for aquatic invertebrates 

would not change with additional data; however, the estimation of risk to benthic dwelling 

organisms is an additional uncertainty.

7.1.2 Aquatic plants

Vascular aquatic plants appear more sensitive to bensulide than non-vascular plants. The 

available vascular plant study was determined to be supplemental as a NOAEC was not 

established (less than the highest test concentration). Because there was risk based on the less 

sensitive EC50 to all non-listed vascular plants, risks would be also expected for this group. 

Although there are not currently any listed aquatic vascular plant species, risks to this group 

would be expected if such a determination were necessary. Based on available evidence, 

there is a risk concern for aquatic vascular plants while there is not a risk concern for aquatic 

non-vascular plants. The LOC (1.0) is not exceeded for listed or non-listed aquatic nonvascular plants (RQs ≤ 0.89) from any labeled use.

7.2 Terrestrial Organisms

7.2.1 Birds and Mammals

Exposure concerns combined with the toxicity of bensulide suggest acute and chronic risk 

concern for birds (acute RQ range 0.01-5.27; chronic RQ range 36-1311.45) and mammals 

(acute RQ range <0.01-3.74; chronic RQ range 0.53-189.64) from the labeled uses. There are 

several potential sources of bensulide exposure to birds and mammals. Granules may be 

ingested directly by birds foraging for seed and grit at or below the soil surface on treated 

areas. For avian species, the similarity of the granule to natural forage or grit has been 

suggested as an important characteristic which may influence ingestion of granules. Birds 

and mammals may also ingest granules adhered to the surface of invertebrate prey items such 

as earthworms and grubs or accidentally ingest granules, when foraging for seeds and insects.

Bensulide product labels state watering in of the granule soon after application for 10-15 

minutes. This practice may greatly reduce the number of exposed granules, but does not 

eliminate potential exposure. Even assuming watering leaves 1% of granules applied 
Page 45 of 85

available, 1.67 mg of ai would be available per square foot and a little over 5 square feet of 

foraged area would exceed the acute listed LOCs for small mammals (assuming 10% 

foraging efficiency). The effectiveness of the watering in process is uncertain, and if highly 

effective could greatly reduce exposure. Additionally, while granular availability may be 

reduced by this practice, exposure of prey items to residues as a result of excess pooled water 

may increase, and/or the potential for runoff may also increase.

Terrestrial animals may also ingest prey items or forage on plants with bensulide residues. 

Acute and chronic LOC exceedances occur for most uses for both birds and mammals. 

Chronic RQs which are based on the NOAEC values (2.5 mg ai/kg-diet; birds and 150 mg 

ai/kg-diet; mammals) would also still exceed the LOC for most uses if calculated using the 

LOAEC (25 mg ai/kg-diet; birds and 900 mg ai/kg-diet; mammals) indicating chronic risk 

reproductive concerns for these taxa. Where bensulide is applied to bare ground, lack of 

attractive food items may reduce exposure to potential plant food items on the field; 

however, exposure is still possible for other attractive food items (weeds, seeds, insects etc)

off the field. The amount or exposure birds or mammals would be subject to when bensulide 

is applied to bare ground is uncertain as a) attractive food items may or may not be in the 

(bare) field and b) it is uncertain the extent to which an animal would enter the field to find 

forage.

Other routes of exposure include ingestion of contaminated drinking water, and dermal 

exposure through contact with treated soil or directly through spray drift. While there is no 

concern from inhalation exposure, contaminated drinking water exposure is still a possibility 

for foraging birds and mammals. As mentioned in the RED, application in the fall for turf 

areas (golf courses) would reduce risks for these organisms as the sensitive chronic endpoints 

are reproductive-based and potential exposure could be outside the breeding season. This 

restriction may not eliminate risk concerns given that the chemical is persistent and systemic 

as the model only considers risk from exposure on the plant surface instead of within the 

foliage or other edible plant parts.

7.2.2 Drinking Water

The SIP model indicates a potential chronic risk concerns to birds through consumption of 

bensulide contaminated drinking water. This screening is qualitative, is based on drinking 

water exposure alone, and is based on several conservative assumptions which add 

considerable uncertainty to this risk conclusion (see Appendix K). Nonetheless, bensulide 

exposure through drinking water may contribute to a total aggregated exposure that has 

potential effects on non-target animals.

7.2.3 Non-Target Terrestrial Invertebrates

Bensulide is practically non-toxic to the adult honeybee (48 hr LD50 > 24.2 μg ai /bee with 

1.6% mortality at limit dose) through contact exposure. Exposure to direct spray or residues 

in plants are the most likely exposure route. Although exposure through drinking water is 

possible, the importance of exposure through consumption of drinking water, relative to the 

dietary and contact routes of exposure is under investigation (USEPA 2014c). The contact 
Page 46 of 85

EECs for all uses range from 33.75 to 16.2 μg ai/bee. The highest ratio of the EEC to the 

highest level tested in the contact toxicity assay (33.8 μg ai /bee to 24.2 μg ai /bee) is greater 

than the honeybee LOC (0.4). This endpoint would have to be about 85 μg ai /bee to 

eliminate risk concerns from the spray application uses on a contact basis. Given only 1.6% 

mortality occurred at the highest dose tested, the actual endpoint is higher than 24.2 μg ai 

/bee; however, the lack of any additional data makes it uncertain how much higher the LC50

for contact exposure actually is.

Bensulide is a systemic pesticide, which can be translocated into plant tissues after soil 

applications. Dietary exposure of honeybees to systemic pesticides via soil application is 

expected to result primarily from translocation of the pesticide to plant tissues (pollen, nectar, 

exudates, and honeydew) and assumed obtained through diet (USEPA, 2014). Exposure may 

occur from visiting plants on or off the treatment field. Plants attractive to pollinators off the 

treated field may obtain residues from spray drift and run-off, while plants on the treated 

field could expose visiting pollinators due to the systemic nature of bensulide. Based on 

limited data contact risk to honeybees is considered low. However, dietary risk could not be 

assessed because acute and chronic oral toxicity (adult or larval) data are not available for 

bensulide. Although dietary risk cannot be quantified, it is reasonable to expect risk could 

occur to honeybees given mode of action, and systemic nature of the chemical. The toxicity 

to other life stages and via other exposure routes (i.e., oral, larval or chronic) is also uncertain

due to the lack of data. There are significant data gaps for honeybees which serve as the 

invertebrate surrogate, the LOC values for other non-target terrestrial invertebrates cannot be 

estimated. The potential risk to terrestrial invertebrates cannot be assessed due to these

uncertainties.

7.2.4 Terrestrial Plants

No LOCs were exceeded for terrestrial plants in dry areas, or due to exposure from only 

spray drift. Risk quotients were not calculated for non-listed dicots based on non-definitive 

(greater than) endpoints. LOCs to listed monocots and dicots in dry areas or from sprat drift 

are not exceeded. Because the listed risk quotient is based on the more conservative NOAEC, 

any definitive EC25 would be higher than the established NOAEC resulting in a lower risk 

quotient. The non-definitive EC25 values are also lower than the highest labeled application 

rate. A calculation was done in TerrPlant conservatively using the EC25 as 6 lb ai/A at the 

highest labeled spray application rate of 12.5 lb ai/A, and RQs for the same groups would 

still be below the agency LOCs. Consequently risks to these species are not expected.

The RQs for granular/spray turf applications, and agricultural spray applications at 8.94 lb 

ai/A exceeded the agency listed monocot LOCs for semi-aquatic plants. RQs suggest that

only listed monocots in semi-aquatic areas are at risk from proposed bensulide uses. While 

risks to non-listed dicots were not calculated based on a non-definitive endpoint, because 

there are no risks expected to listed species based on a more sensitive endpoint (NOAEC), 

risk are also not expected for non-listed dicots. 

Phytotoxicity is not a normal regulatory endpoint; however, as mentioned previously there 

were statistically significant phytotoxic endpoints for some species which were lower than 
Page 47 of 85

the fresh weight endpoints (MRID 44746301). These phytotoxic effects were seen in the 

monocots in the seeding emergence study and dicots in the vegetative vigor study. In the 

seedling emergence study the most sensitive monocot based on phytotoxicity was ryegrass 

with an EC25 of 1.9 lb ai/A and NOAEC of 0.38 lb ai/A, and in the vegetative vigor study the 

most sensitive dicot based on phytotoxicity was cucumber with an EC25 of 1.3 lb ai/A and 

NOAEC of 0.38 lb ai/A. As an herbicide targeting grasses, plants are expected to be affected. 

It is uncertain the degree to which phytotoxic effects to non-target plants would affect their 

viability but the effect is noted. The lack of major incident data from usage at potentially 

higher rates than those tested, or additional studies with lower endpoints suggest the risks to 

terrestrial plants are reasonably covered in this assessment.

8. Risk to Listed Species

Potential direct effects to listed birds (surrogates for terrestrial-phase amphibians and 

reptiles), mammals, and terrestrial and aquatic plants from the use of bensulide may be 

associated with modification of primary constituent elements (PCEs) of designated critical 

habitat, where such designations have been made. However, at the current stage of the 

Registration Review process, it is premature to make effects determinations for listed species 

until further scientific analysis and refinements are conducted, based on recommendations 

received from the National Academy of Sciences’ (NAS) National Research Council (NRC) 

April 2013 report, available at http://www.nap.edu/catalog.php?record_id=18344. The NAS 

report outlines recommendations on specific scientific and technical issues related to the 

development of pesticide risk assessments that are compliant with the Endangered Species 

Act (ESA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).

The EPA along with the U.S. Fish & Wildlife Service (USFWS), the National Marine 

Fisheries Service (NMFS) (collectively, the Services), and the U.S. Department of 

Agriculture (USDA), released a summary of their implementation plan for assessing risks of 

pesticides to listed species ahead of the stakeholder workshop held on November 15, 2013. 

This plan was developed in response to the NAS’ recommendations, including a common 

approach to risk assessment as a way of addressing scientific differences between EPA and 

the Services. During the workshop, the agencies received feedback from the public on the 

interim scientific approaches that were developed as part of the initial implementation of the 

NAS recommendations. These approaches will be jointly implemented and vetted as part of a 

phased iterative process. Once fully vetted, EPA will further refine the listed species effects 

determination portion of this risk assessment.

To make effects determinations for individual listed species, useful refinements may include, 

but are not limited to, analyses of: 1) more detailed, species-specific ecological and 

biological data; 2) more detailed and accurate information on bensulide use patterns; and 3) 

sub-county level spatial proximity data for the co-occurrence of potential effects areas and 

listed species and any designated critical habitat. Examples of such refinements are described 

below.

EFED is currently developing tools that are expected to further refine the assessment and are 

designed to support effects determinations for individual federally listed species and their 
Page 48 of 85

designated critical habitats (where applicable). Scientific information obtained from the 

Services, and other reliable sources is being collated by EFED to address all currently listed 

species. This information is being stored in an Office of Pesticide Programs (OPP) Pesticide 

Registration Information SysteM (PRISM) listed species knowledgebase. The listed species 

knowledgebase consists of an information repository that houses biological and behavioral 

information relevant to individual species (e.g., habitat, diet, and life history, including 

specific temporal and spatial associations) and a document repository that contains 

supporting documents (e.g., USFWS recovery plans) and electronic information (e.g., GIS 

data files). For terrestrial taxa, biological information relevant to the assessment (e.g., diet 

and body weight) will be used to parameterize exposure estimates using a method consistent 

with currently used methods in the T-REX and T-HERPS models.

Refinements will also include more detailed analyses of the registered uses and specific use 

patterns that result in either “Likely to Adversely Affect” (LAA) or “Not Likely to Adversely 

Affect” (NLAA) determinations for federally listed species. The analyses may include more 

information on where, when, and how bensulide is used on all use sites. Actual usage data 

(when available) and national land-cover datasets that indicate potential use sites [e.g., 

National Land Cover Dataset (NLCD), Cropland Data Layer (CDL)] may be used to support 

a more refined analysis of where bensulide is reasonably expected to be used. Similarly, 

refinements on the timing of applications and a more in-depth exploration of agronomic 

practices for bensulide may be included as part of the refinement.

The refinements based on individual species data; additional, detailed usage information, 

when available; and recommendations from the NRC report are expected to help to more 

accurately identify potential areas of effect and to better inform effects and habitat 

determinations for listed species and any designated critical habitats.

9. Endocrine Disruptor Screening Program

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

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

subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, 

developmental, reproductive, and general or systemic toxicity. These studies include 

endpoints which may be susceptible to endocrine influence, including effects on endocrine 

target organ histopathology, organ weights, estrus cyclicity, sexual maturation, fertility, 

pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard 

assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental 

and reproductive effects in different taxonomic groups. As part of registration review for 

bensulide, EPA reviewed these data and selected the most sensitive endpoints for relevant 

risk assessment scenarios from the existing hazard database. However, as required by 

FFDCA section 408(p), bensulide is not subject to the endocrine screening part of the 

Endocrine Disruptor Screening Program (EDSP). 

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

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

produced by a “naturally occurring estrogen, or other such endocrine effects as the 
Page 49 of 85

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

statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to 

identify the potential of a chemical substance to interact with the estrogen, androgen, or 

thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are 

found to have the potential to interact with E, A, or T hormonal systems will proceed to the 

next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are 

necessary based on the available data. Tier 2 testing is designed to identify any adverse 

endocrine-related effects caused by the substance, and establish a dose-response relationship 

between the dose and the E, A, or T effect. 

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

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

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

second list of chemicals identified for EDSP screening was published on June 14, 2013[1] and 

includes some pesticides scheduled for registration review and chemicals found in water. 

Neither of these lists should be construed as a list of known or likely endocrine disruptors.

Bensulide is not on the first or second list chemicals for which EPA intends to issue test 

orders/data call-ins in the near future. For further information on the status of the EDSP, the 

policies and procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 

screening battery, please visit the website, http://www.epa.gov/endo/.

10. References

USEPA. 2000. Interim Reregistration Eligibility Decision (IRED) for Bensulide June 2000). 

Office of Pesticide Programs, United States Environmental Protection Agency. 

Available at: 

http://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/ired_PC009801_1-Jun-00.pdf#_ga=1.256960648.2069058676.1438265748

USEPA. 2006 Reregistration Eligibility Decision (RED) for Bensulide (July 2006), Office of 

Pesticide Programs, United States Environmental Protection Agency. Docket: EPAHQ-OPP-2006-0618

USEPA. 2007a. Risks of Bensulide Use to the Federally Listed California Red Legged Frog 

(Rana aurora draytonii), October 2007. Available at: 

http://www.epa.gov/espp/litstatus/effects/redleg-frog/bensulide/determination.pdf

USEPA. 2008. Registration Review Preliminary Problem Formulation for the Ecological 

Risk Assessment of Bensulide. U.S. Environmental Protection Agency, Office of 

Pesticide Programs, Environmental Fate and Effects Division. June 11,2008. 23 pp.

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

list of chemicals.
Page 50 of 85

USEPA. 2009a. ECOTOXicology Database. Office of Research and Development National

Health and Environmental Effects Research Laboratory’s (NHEERL’s) MidContinent Ecology Division (MED). http://cfpub.epa.gov/ecotox/

USEPA. 2009b. Ecological Incident Information System.

http://www.epa.gov/oppefed1/general/databasesdescription.htm#eiis

USEPA. 2009c. Guidance for Selecting Input Parameters in Modeling the Environmental 

Fate and Transport of Pesticides. Version 2.1. U.S. Environmental Protection Agency, 

Office of Pesticide Programs, Environmental Fate and Effects Division. Oct. 22, 2009

USEPA. 2010. Bensulide: Response to Data Waiver Requests for Fish Full Life Cycle 

Toxicity Tests. Office of Pesticide Programs, United States Environmental Protection 

Agency. DP Barcode 381471

USEPA. 2012a. Risks of Bensulide Use to the Federally Threatened Bay Checkerspot 

Butterfly (Euphydryas editha bayensis), Delta Smelt (Hypomesus transpacificus), 

California Tiger Salamander (Ambystoma californiense) Central California Distinct 

Population Segment, and Valley Elderberry Longhorn Beetle (Desmocerus 

californicus dimorphus), And the Federally Endangered California Clapper Rail 

(Rallus longirostris obsoletus), California Freshwater Shrimp (Syncaris pacifica), 

California Tiger Salamander (Ambystoma californiense) Sonoma County Distinct 

Population Segment and Santa Barbara County Distinct Population Segment, San 

Francisco Garter Snake (Thamnophis sirtalis tetrataenia), and Tidewater Goby 

(Eucyclogobius newberryi), June 2012. Available at: 

http://www3.epa.gov/pesticides/endanger/litstatus/effects/redlegfrog/2012/bensulide/analysis.pdf#_ga=1.64532012.2069058676.1438265748

USEPA. 2012b. Response to Gowan Company's Rebuttal of the Status of the Mysid Shrimp 

Chronic Toxicity Study. Office of Pesticide Programs, United States Environmental 

Protection Agency. DP Barcode 403396 

USEPA. 2014a. EFED Response to the Registrant's Rebuttal on the Data Evaluation Record 

for Bensulide Full Life-Cycle Toxicity Study with Sheepshead Minnow (Cyprinodon 

variegatus) in Support of Registration Review Office of Pesticide Programs, United 

States Environmental Protection Agency. DP Barcode 420181

USEPA. 2014b. EFED Response to the Registrant's Rebuttal on the Data Evaluation Record 

for Bensulide Full Life-Cycle Toxicity Study with Fathead Minnow (Pimephales 

promelas) in Support of Registration Review. Office of Pesticide Programs, United 

States Environmental Protection Agency. DP Barcode 420826

USEPA. 2014c. Guidance for Assessing Pesticide Risks to Bees. U.S. Environmental 

Protection Agency, Office of Pesticide Programs; Health Canada Pest Management 

Regulatory Agency; and California Department of Pesticide Regulation. Jun. 23, 

2014. Available at: http://www2.epa.gov/pollinator-protection/pollinator-risk-
Page 51 of 85

assessment-guidance. 

USEPA. 2015. Bensulide Screening Level Usage Analysis. Biological and Economic 

Analysis Division, Office of Pesticide Programs, United States Environmental 

Protection Agency.

U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS).

1998. Endangered Species Consultation Handbook: Procedures for Conducting 

Consultation and Conference Activities Under Section 7 of the Endangered Species 

Act. Final Draft. March 1998.
Page 52 of 85

11. Appendices

Appendix A. Submitted MRID Bibliography 

Toxicity Studies

MRID Citation Reference

157315

McAllister, W.; Swigert, J.; Bowman, J. (1986) Acute Toxicity of Betasan Technical to Rainbow Trout 

(Salmo gairdneri): Static Acute Toxicity Report #34028: T-12395. Unpublished study pre- pared by 

Analytical Bio-Chemistry Laboratories, Inc. 51 p. 

157316

McAllister, W.; Swigert, J.; Bowman, J. (1986) Acute Toxicity of Betasan Technical to Bluegill Sunfish 

(Lepomis macrochirus): Static Acute Toxicity Report #34027: T-12394. Unpublished study prepared by 

Analytical Bio-Chemistry Laboratories, Inc. 47 p. 

159322

Forbis, A.; Burgess, D.; Frazier, S. (1986) Acute Toxicity of Beta- san Technical to Daphnia magna: 

Static Acute Toxicity Report #34029. Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 36 p. 

42750201

Morrow, J.; Ward, G. (1993) Bensulide Technical: Acute Toxicity to the Sheepshead Minnow, 

Cyprinodon variegatus, Under Flow-Through Test Conditions: Lab Project Number: F9209003D. 

Unpublished study prepared by Toxikon Environmental Sciences. 24 p. 

42750202

Morrow, J.; Ward, G. (1993) Bensulide Technical: Acute Toxicity to the Eastern Oyster, Crassostrea 

virginica, Under Flow-Through Test Conditions: Lab Project Number: J9209003E. Unpublished study 

prepared by Toxikon Environmental Sciences. 27 p. 

42750203

Ward, G. (1993) Bensulide Technical: Acute Toxicity to the Mysid, Mysidopsis bahia, Under FlowThrough Test Conditions: Lab Project Number: J9209003C. Unpublished study prepared by Toxikon 

Environmental Sciences. 25 p. 

43616001

Beavers, J.; Haberlein, D.; Mitchell, L. et al. (1995) Betasan (Bensulide) Technical: A Reproduction 

Study with the Northern Bobwhite: Lab Project Number: 334/103: CHR23. Unpublished study prepared 

by Wildlife International Ltd. 178 p. 

43616002

Beavers, J.; Haberlein, D.; Mitchell, L. et al. (1995) Betasan (Bensulide) Technical: A Reproduction 

Study with the Mallard: Lab Project Number: 334/104: CHR23. Unpublished study prepared by Wildlife 

International Ltd. 182 p. 

44720407

Kranzfelder, J.; Stuerman, L.; Malorin, D. (1998) Life Cycle Toxicity Test of Daphnia magna Under 

Flow-Through Conditions (Bensulide Technical): Lab Project Number: 44606. Unpublished study 

prepared by ABC Laboratories, Inc. 42 p. 

44720408

Kranzfelder, J.; Stuerman, L.; Malorin, D. (1998) Early Life-Stage Toxicity Test of Fathead Minnow, 

Pimephales Promelas Under Flow-Through Conditions (Bensulide Technical): Lab Project Number: 

44607. Unpublished study prepared by ABC Laboratories, Inc. 42 p. 

44724007

Stuerman, L.; Kranzfelder, J.; Malorin, D. (1998) Life-Cycle Toxicity Test of Daphnia magna Under 

Flow-Through Conditions: Lab Project Number: 44606. Unpublished study prepared by ABC Labs., 

Inc. 42 p. 

44724008

Stuerman, L.; Kranzfelder, J.; Malorin, D. (1998) Early Life-Stage Toxicity Test of Fathead Minnow, 

Pimephales promelas, Under Flow-Through Conditions: Lab Project Number: 44607. Unpublished 

study prepared by ABC Labs., Inc. 42 p. 

44746301

Schwab, D. (1998) Evaluating the Effects of Bensulide on the Seedling Emergence and Vegetative 

Vigor of Non-Target Terrestrial Plants: Lab Project Number: 44608. Unpublished study prepared by 

ABC Laboratories, Inc. 174 p. {OPPTS 850.4225, 850.4250} 

45063401

Kranzfelder, J.; Stuerman, L.; Malorin, D. (1998) Life-Cycle Toxicity Test of Daphnia magna Under 

Flow-Through Conditions: (Bensulide): Lab Project Number: 44606. Unpublished study prepared by 

ABC Labs., Inc. 86 p. 

48424501

Gerke, A. (2011) Bensulide: Life-Cycle Toxicity Test of the Saltwater Mysid, Americamysis bahia, 

Conducted Under Flow-Through Conditions. Project Number: 66433. Unpublished study prepared by 

ABC Laboratories, Inc. 88 p.

48504301 Rebstock, M. (2011) Bensulide: Chronic Toxicity Test with the Water Flea, Daphnia magna, Conducted 

Under Flow-Through Conditions. Project Number: 66432. Unpublished study prepared by ABC 
Page 53 of 85

Laboratories, Inc. 59 p.

49059101

Lee, M. (2013) Bensulide - Full Life-Cycle Toxicity Test with Sheepshead Minnow (Cyprinodon 

variegatus) Under Flow-Through Conditions. Project Number: 092111/OPPTS/FLC/SHM, 12791/6168. 

Unpublished study prepared by Smithers Viscient Laboratories. 170p.

49110401

Rebstock, M. (2013) Bensulide: Chronic Toxicity Test with the Cladoceran, Daphnia magna, Exposed

Under Static-Renewal Conditions. Project Number: 69125. Unpublished study prepared by ABC 

Laboratories, Inc. 68p.

49378102

Leak, T. (2014) Bensulide: Life-Cycle Toxicity Test with the Fathead Minnow, Pimephales promelas, 

Under Flow-Through Conditions. Project Number: 67498. Unpublished study prepared by ABC 

Laboratories, Inc. 131p.

27401

Christensen, C.; Rogers, W.; Colbert, F.; et al. (1976) Sward^(TM)I 50W for Preemergence Control of 

Annual Grasses and Some Broad- leaf Weeds in Mature Turfgrasses. (Unpublished study received Aug 

12, 1976 under 1471-106; prepared in cooperation with Univ. of Florida, submitted by Elanco Products 

Co., Div. of Eli Lilly and Co., Indianapolis, Ind.; CDL:224918-A) 

36066

Hill, R. (1963) Fish Bio-Assay, Technical Report: Lab. No. 2H7459. (Unpublished study received Dec 

16, 1971 under 1F1084; prepared by Diablo Laboratories, Inc., submitted by Stauffer Chemical Co., 

Richmond, Calif.; CDL:093396-I)

36067 Meyding, G.D. (1963) R-4461 4-E: Fish Toxicity Assay: Report No. 366. (Unpublished study received 

Dec 16, 1971 under 1F1084; submitted by Stauffer Chemical Co., Richmond, Calif.; CDL: 093396-J)

101187

Shellenberger, T.; Newell, G. (1965) Toxicological evaluations of agricultural chemicals with Japanese 

quail (Coturnix coturnix japonica). Laboratory Animal Care 15(2):119-130. (Also In unpublished 

submission received on unknown date under unknown admin. no.; submitted by Shell Chemical Co., 

Washington, DC; CDL:120482-S) 

40098001

Mayer, F.; Ellersieck, M. (1986) Manual of Acute Toxicity: Inter- pretation and Data Base for 410 

Chemicals and 66 Species of Freshwater Animals. US Fish & Wildlife Service, Resource Pub- lication 

160. 579 p.

40098001

Mayer, F.; Ellersieck, M. (1986) Manual of Acute Toxicity: Interpretation and Data Base for 410 

Chemicals and 66 Species of Freshwater Animals. US Fish & Wildlife Service, Resource Pub- lication 

160. 579 p.

44720402

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Green Alga, Selenastrum capricornutum (Bensulide Technical): Lab Project Number: 44601. 

Unpublished study prepared by ABC Laboratories, Inc. 30 p. 

44720402

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Green Alga, Selenastrum capricornutum (Bensulide Technical): Lab Project Number: 44601. 

Unpublished study prepared by ABC Laboratories, Inc. 30 p. 

44720403

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Blue-Green Alga, Anabaena flos-aquae (Bensulide Technical): Lab Project Number: 44602. 

Unpublished study prepared by ABC Laboratories, Inc. 29 p. 

44720403

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Blue-Green Alga, Anabaena flos-aquae (Bensulide Technical): Lab Project Number: 44602. 

Unpublished study prepared by ABC Laboratories, Inc. 29 p. 

44720404

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Freshwater Diatom, Navicula pelliculosa: (Bensulide Technical): Lab Project Number: 44603. 

Unpublished study prepared by ABC Laboratories, Inc. 30 p. 

44720405

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Saltwater Diatom, Skeletonema costatum: (Bensulide Technical): Lab Project Number: 44604. 

Unpublished study prepared by ABC Laboratories, Inc. 30 p. 

44720405

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Saltwater Diatom, Skeletonema costatum: (Bensulide Technical): Lab Project Number: 44604. 

Unpublished study prepared by ABC Laboratories, Inc. 30 p. 

44720406

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to Duckweed, Lemna gibba G3 (Bensulide Technical): Lab Project Number: 44605. Unpublished study 

prepared by ABC Laboratories, Inc. 29 p. 

44720406

Kranzfelder, J.; Stuerman, L. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to Duckweed, Lemna gibba G3 (Bensulide Technical): Lab Project Number: 44605. Unpublished study 

prepared by ABC Laboratories, Inc. 29 p. 
Page 54 of 85

44724002

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Green Alga, Selenastrum capricornutum: Lab Project Number: 44601. Unpublished study 

prepared by ABC Labs., Inc. 30 p. 

44724002

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Blue-Green Alga, Anabaena flos-aquae: Lab Project Number: 44602. Unpublished study 

prepared by ABC Labs., Inc. 29 p. 

44724003

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Blue-Green Alga, Anabaena flos-aquae: Lab Project Number: 44602. Unpublished study prepared 

by ABC Labs., Inc. 29 p. 

44724003

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Freshwater Diatom, Navicula pelliculosa: Lab Project Number: 44603. Unpublished study 

prepared by ABC Labs., Inc. 30 p. 

44724004

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Freshwater Diatom, Navicula pelliculosa: Lab Project Number: 44603. Unpublished study 

prepared by ABC Labs., Inc. 30 p. 

44724004

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Saltwater Diatom, Skeletonema costatum: Lab Project Number: 44604. Unpublished study 

prepared by ABC Labs., Inc. 30 p. 

44724005

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to the Saltwater Diatom, Skeletonema costatum: Lab Project Number: 44604. Unpublished study 

prepared by ABC Labs., Inc. 30 p. 

44724005

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to Duckweed, Lemna gibba: Lab Project Number: 44605. Unpublished study prepared by ABC Labs., 

Inc. 29 p. 

44724006

Stuerman, L.; Kranzfelder, J. (1998) Static Toxicity Test for Determining the Effects of Test Substances 

to Duckweed, Lemna gibba: Lab Project Number: 44605. Unpublished study prepared by ABC Labs., 

Inc. 29 p. 

45334101

Madsen, T.; Goble, M. (2001) Toxicity of Bensulide Technical to Duckweed, Lemna gibba G3, 

Determined Under Static Test Conditions: Lab Project Number: 46422. Unpublished study prepared by 

ABC Laboratories, Inc. 50 p. 

45334101

Madsen, T.; Goble, M. (2001) Toxicity of Bensulide Technical to Duckweed, Lemna gibba G3, 

Determined Under Static Test Conditions: Lab Project Number: 46422. Unpublished study prepared by 

ABC Laboratories, Inc. 50 p. 

48150301

McNutt, J. (2010) Waiver Justification for Fish Life Cycle Toxicity Test, 850.1500 for Generic Data 

Call-In of Bensulide. Project Number: GC/JJM/1004/1. Unpublished study prepared by Gowan 

Company. 12 p.

49378101

Leak, T. (2014) Response to Data Evaluation Record for MRID 49001601 (Bensulide: Life-Cycle 

Toxicity Test with the Fathead Minnow, Pimephales promelas, Under Flow-Through Conditions). 

Unpublished study prepared by ABC Laboratories. 8p.

Fate Studies

MRID Citation Reference

00160074 Chang, L.; Lee, K. (1986) Hydrolysis Studies of Bensulide: Report No. RRC 86-50. 

Unpublished study prepared by Stauffer Chemical Co. 36 p. 

92005023 Lee, K. (1990) ICI Americas Inc. Phase 3 Summary of MRID 00160074. Hydrolysis Studies 

of Bensulide: Laboratory Study ID No. RR 90-123B. Prepared by ICI Americas Inc. 9 p. 

40513401 Riggs, R. (1988) Bensulide--Aqueous Photolysis Study: Laboratory Project ID: RRC 88-08. 

Unpublished study prepared by ICI Americas, Inc. 55 p. 

92005024 Lee, K. (1990) Ici Americas Inc. Phase 3 Summary of MRID 40513401. Bensulide - Aqueous 

Photolysis Study: Laboratory Study ID No. RR 90-124B. Prepared by ICI Americas Inc. 12 p. 
Page 55 of 85

40460301 Subba-Rao, R. (1987) Aerobic Metabolism of Bensulide in Soil: Docu- ment No. PMS-219. 

Unpublished study prepared by ICI Americas, Inc. Western Research Center. 71 p. 

92005025 Subba-Rao, R. (1990) Ici Americas Inc. Phase 3 Summary of MRID 40460301. Aerobic 

Metabolism of Bensulide in Soil: PMS 219: Summary ID # RR 90-223B. Prepared by ICI 

Americas, Inc. 13 p. 

40460302 Subba-Rao, R. (1987) Anaerobic Metabolism of Bensulide in Soil: Document No. PMS-220. 

Unpublished study prepared by ICI Americas, Inc. Western Research Center. 65 p. 

92005026 Subba-Rao, R. (1990) Ici Americas Inc. Phase 3 Summary of MRID 40460302. Anaerobic 

Metabolism of Bensulide in Soil: PMS 220: Summary ID # RR 90-224B. Prepared by ICI 

Americas Inc. 13 p. 

42826701 McCowan, C.; Mackie, J.; Hall, B. (1982) The Adsorption and Desorption of (carbon 14)--

Bensulide in Soil: Lab Project Number: 382398: 9607. Unpublished study prepared by 

Inveresk Research International. 80 p. 

43180701 Mackie, J.; Hall, B. (1993) The Adsorption and Desorption of (carbon 14) Bensulide Oxon in 

Soil: Lab Project Number: 382927: 9703. Unpublished study prepared by Inveresk Research 

International. 78 p. 

43180702 Mackie, J.; Hall, B. (1993) The Adsorption and Desorption of (carbon 14) 

Benzenesulphonamide in Soil: Lab Project Number: 382911: 9776. Unpublished study 

prepared by Inveresk Research International. 77 p. 

40534901 McKay, J. (1987) Betasan (Bensulide) 4-E Field Dissipation Study: Mississippi, 1986: 

Laboratory Project ID: 87-115. Unpublished study prepared by Stauffer Chemical Co. 69 p. 

40534902 McKay, J. (1987) Betasan (Bensulide) 4-E Field Dissipation Study: California, 1986: 

Laboratory Project ID: 87-109. Unpublished study prepared by Stauffer Chemical Co. 44 p. 

40534903 McKay, J. (1987) Betasan (Bensulide) 12.5-G Field Dissipation Study: Mississippi, 1986: 

Laboratory Project ID: 87-107. Unpub- lished study prepared by Stauffer Chemical Co. 72 p. 

40534904 McKay, J. (1987) Betasan (Bensulide) 12.5-G Field Dissipation Study: California, 1986: 

Laboratory Project ID: 87-108. Unpub- lished study prepared by Stauffer Chemical Co. 48 p. 

40534905 McKay, J. (1987) Prefar (Bensulide) 4-E Field Dissipation Study: California, 1986: 

Laboratory Project ID: 87-112. Unpublished study prepared by Stauffer Chemical Co. 45 p. 

40534906 McKay, J. (1987) Prefar (Bensulide) 4-E Field Dissipation Study: Mississippi, 1986: 

Laboratory Project ID: 87-116. Unpublished study prepared by Stauffer Chemical Co. 57 p. 

41694201 Iwata, Y. (1990) Betasan: Field Dissipation Study for Terrestrial Uses: Lab Project Number: 

RR 89-044B: BETA-88-SD-02. Unpublish- ed study prepared by ICI Americas, Inc. 108 p. 

41694202 Iwata, Y. (1990) Betasan: Field Dissipation Study for Terrestrial Uses: Lab Project Number: 

RR 89-008B: BETA-88-SD-01. Unpublished study prepared by ICI Americas, Inc. 117 p. 

44297001 Kemman, R. (1997) Prefar 4-E (Bensulide) Herbicide Field Soil Dissipation Study Following 

Pre-plant Treatment to Cabbage: (Final Report): Lab Project Number: GOWN-9319: BENS91-SD-03. Unpublished study prepared by Compliance Services International. 201 p. 

44733401 Mickelson, K. (1998) Field Soil Dissipation of Bensulide in Bare Ground North Carolina: 

Lab Project Number: AA980603: 98-0014: ASW1217R. Unpublished study prepared by ENCAS Analytical Laboratories and American Agricultural Services, Inc. 323 p. 

44908801 Mickelson, K. (1999) Field Soil Dissipation of Bensulide in Bare Ground in North Carolina: 

Final Report: Lab Project Number: AA980603: 98-0014: CSI-013-02. Unpublished study 

prepared by American Agricultural Services, Inc. 339 p. 
Page 56 of 85

45550301 Willard, T. (2001) Field Soil Dissipation of Bensulide in Bare Ground in North Carolina: 

Amended Final Report: Lab Project Number: AA980603. Unpublished study prepared by 

EN-CAS Analytical Laboratories. 411 p. 

46418401 Jacobson, S. (2004) Determination of the Frozen Stability of Bensulide and Bensulide Oxon 

in Soil. Project Number: 95037. Unpublished study prepared by Compliance Services 

International. 86 p.

92005028 Iwata, Y. (1990) Ici Americas Inc. Phase 3 Summary of MRID 40534903 and Related 

MRIDs 40534901, 40534902, 40534904, 40534905, 40534906. Betasan/ Prefar Field 

Dissipation Study for Terrestrial Uses: ICIA Reports RR 89-008B and RR 89-044B; 

Laboratory Summary ID No. RR 90-187B. Prepared by ICI Americas Inc. 34 p. 

41931001 Akhaven, M. (1991) The Bioaccumulation of 14C-Bensulide in Bluegill Sunfish: Lab Project 

Number: PMS355: RR 91-032B. Unpublished study prepared by ICI Americas Inc. and 

Analytical Biochemistry Laboratories, Inc. 91 p. 
Page 57 of 85

Appendix B. Bensulide Screening Level Usage Estimates

Date: July 06, 2015 

Screening Level Estimates of Agricultural Uses of Bensulide (009801)

Sorted Alphabetically

Reporting Years: 2004-2013

Annual Average Percent Crop Treated

Crop Lbs. A.I. Applied Average Maximum

1 Broccoli 60,000 15 25

2 Brussels Sprouts* <500 <2.5 5

3 Cabbage 20,000 5 20

4 Cantaloupes 80,000 20 40

5 Cauliflower 10,000 5 20

6 Celery 2,000 <2.5 5

7 Chicory* <500 <2.5 10

8 Cucumbers 9,000 <2.5 5

9 Honeydews 4,000 15 30

10 Lettuce 300,000 25 40

11 Onions 40,000 10 20

12 Peppers 10,000 5 10

13 Pumpkins 7,000 <2.5 10

14 Spinach 4,000 5 10

15 Squash 10,000 5 15

16 Watermelons 30,000 5 10

All numbers are rounded.

<500: less than 500 pounds of active ingredients.

 <2.5: less than 2.5 percent of crop is treated.

<1: less than 1 percent of crop is treated.

* Based on CA DPR data only (80% or more of U.S. acres grown are in California).

SLUA data sources include: 

USDA-NASS (United States Department of Agriculture's National Agricultural Statistics Service) 

Private Pesticide Market Research

California DPR (Department of Pesticide Regulation)

These results reflect amalgamated data developed by the Agency and are releasable to the public.
Page 58 of 85

Appendix C: Results of ECOSAR Modeling

ECOSAR is a screening-level tool based on chemical structures developed by the USEPA’s 

Office of Chemical Safety and Pollution Prevention for rapid screening of chemicals for 

ecotoxicity hazards The modeling results suggest bensulide oxon is are less toxic for 

freshwater fish and freshwater invertebrates (acute and chronic) and slightly more toxic 

(although within one order of magnitude) than the parent bensulide. This comparison is based 

on the amide class of chemicals. The estimated toxicity values by the ECOSAR for bensulide

are similar to observed toxicity values from the submitted studies. The values are not as close 

for non-vascular plants, although predicted values are still within one order of magnitude of 

each other. EFED proceeded with assuming equal toxicity when performing the risk 

assessment.

Table C.1. ECOSAR (Class Amides) estimates for bensulide and bensulide oxon 

compared to known toxicity endpoints

Assessment Endpoint Toxicity Studies on 

Bensulide (ppm)

ECOSAR Estimate 

Bensulide (ppm)

ECOSAR Estimate 

Bensulide Oxon (ppm)

Acute Freshwater Fish LC50 = 1.1 (MRID 

157315) LC50 = 1.08 LC50 = 25.79

Chronic Freshwater Fish NOAEC = 0.169 

(49001601/49378102) NOAEC = 0.041 NOAEC = 0.152

Acute Freshwater 

Invertebrate EC50 = 0.58 (159322) EC50 = 1.26 EC50 = 16.41

Chronic Freshwater 

Invertebrate

NOAEC = 0.011 

(49110401) NOAEC = 0.017 NOAEC = 0.217

Acute Non-vascular Plant 

Toxicity (Green Algae) EC50 = 1.8 (44720402) EC50 = 0.224 EC50 = 0.668

Chronic Non-vascular Plant 

Toxicity (Green Algae)

NOAEC = 0.93

(44720402) NOAEC = 0.664* NOAEC = 0.637

*Unreliable value give the NOAEC is higher than the EC50
Page 59 of 85

Appendix D. SWCC Representative Results

Summary of Water Modeling of Bensulide and Bensulide Oxon 

and the USEPA Standard Pond

Estimated Environmental Concentrations for Bensulide and Bensulide Oxon are presented in 

Table 1 for the USEPA standard pond with the FLpeppersSTD field scenario. A graphical 

presentation of the year-to-year peaks is presented in Figure 1. These values were generated 

with the Surface Water Concentration Calculator (SWCC Version 1.106). Critical input 

values for the model are summarized in Tables 2 and 3.

This model estimates that about 4.1% of Bensulide and Bensulide Oxon applied to the field 

eventually reaches the water body. The main mechanism of transport from the field to the 

water body is by runoff (84.7% of the total transport), followed by spray drift ( 15%) and 

erosion (0.35%).

In the water body, pesticide dissipates with an effective water column half-life of 207.7 days. 

(This value does not include dissipation by transport to the benthic region; it includes only 

processes that result in removal of pesticide from the complete system.) The main source of 

dissipation in the water column is hydrolysis (effective average half-life = 220.3 days) 

followed by metabolism (4834 days), photolysis (14733.6 days), and volatilization (8322091 

days).

In the benthic region, pesticide dissipation is negligible (13454.8 days). The main source of 

dissipation in the benthic region is hydrolysis (effective average half-life = 13454.8 days). 

The vast majority of the pesticide in the benthic region (98.36%) is sorbed to sediment rather 

than in the pore water.

Table 1. Estimated Environmental Concentrations (ppb) for Bensulide and Bensulide 

Oxon.

Peak (1-in-10 yr) 566.

4-day Avg (1-in-10 yr) 559.

21-day Avg (1-in-10 yr) 549.

60-day Avg (1-in-10 yr) 516.

365-day Avg (1-in-10 yr) 434.

Entire Simulation Mean 326.

Table 2. Summary of Model Inputs for Bensulide and Bensulide Oxon.

Scenario FLpeppersSTD

Cropped Area Fraction 1

Koc (ml/g) 557

Water Half-Life (days) @ 25 °C 4494
Page 60 of 85

Benthic Half-Life (days) @ 25 °C 0

Photolysis Half-Life (days) @ 40 

°Lat

173

Hydrolysis Half-Life (days) 220

Soil Half-Life (days) @ 25 °C 2274

Foliar Half-Life (days)

Molecular Wt 397.5

Vapor Pressure (torr) 2.48e-8

Solubility (mg/l) 461

Table 3. Application Schedule for Bensulide and Bensulide Oxon.

Date (Mon/Day) Type Amount (kg/ha) Eff. Drift

2/1 Foliar 6.72 .99 .062

6/1 Foliar 6.72 .99 .062

10/1 Foliar 6.72 .99 .062

Figure 1. Yearly Peak Concentrations
Page 61 of 85

Summary of Water Modeling of Bensulide and Bensulide Oxon 

and the USEPA Standard Pond

Estimated Environmental Concentrations for Bensulide and Bensulide Oxon are presented in 

Table 1 for the USEPA standard pond with the PAturfSTD field scenario. A graphical 

presentation of the year-to-year peaks is presented in Figure 1. These values were generated 

with the Surface Water Concentration Calculator (SWCC Version 1.106). Critical input 

values for the model are summarized in Tables 2 and 3.

This model estimates that about 0.98% of Bensulide and Bensulide Oxon applied to the field 

eventually reaches the water body. The main mechanism of transport from the field to the 

water body is by runoff (92.3% of the total transport) followed by erosion (7.72%).

In the water body, pesticide dissipates with an effective water column half-life of 213.0 days. 

(This value does not include dissipation by transport to the benthic region; it includes only 

processes that result in removal of pesticide from the complete system.) The main source of 

dissipation in the water column is hydrolysis (effective average half-life = 220.3 days) 

followed by metabolism (9449.1 days), photolysis (20025.6 days), and volatilization 

(1.205298E+07 days).

In the benthic region, pesticide dissipation is negligible (13454.8 days). The main source of 

dissipation in the benthic region is hydrolysis (effective average half-life = 13454.8 days). 

The vast majority of the pesticide in the benthic region (98.36%) is sorbed to sediment rather 

than in the pore water.

Table 1. Estimated Environmental Concentrations (ppb) for Bensulide and Bensulide 

Oxon.

Peak (1-in-10 yr) 440.

4-day Avg (1-in-10 yr) 430.

21-day Avg (1-in-10 yr) 397.

60-day Avg (1-in-10 yr) 350.

365-day Avg (1-in-10 yr) 237.

Entire Simulation Mean 139.

Table 2. Summary of Model Inputs for Bensulide and Bensulide Oxon.

Scenario PAturfSTD

Cropped Area Fraction 1

Koc (ml/g) 557

Water Half-Life (days) @ 25 °C 4494

Benthic Half-Life (days) @ 25 °C 0

Photolysis Half-Life (days) @ 40 

°Lat

173
Page 62 of 85

Hydrolysis Half-Life (days) 220

Soil Half-Life (days) @ 25 °C 2247

Foliar Half-Life (days)

Molecular Wt 397.5

Vapor Pressure (torr) 2.48e-8

Solubility (mg/l) 461

Table 3. Application Schedule for Bensulide and Bensulide Oxon.

Date (Mon/Day) Type Amount (kg/ha) Eff. Drift

4/1 Incorporated to 0 

cm

17.92 1 0

8/1 Incorporated to 0 

cm

17.92 1 0

Figure 1. Yearly Peak Concentrations
Page 63 of 85

Appendix E: Representative T-REX Input and Output (Turf)

Chemical Identity and Application Information

Chemical Name: Bensulide

Seed Treatment? (Check if yes) FALSE

 Use:

Product name and form:

% A.I. (leading zero must be entered for 

formulations <1% a.i.): 100.00%

Application Rate (lb ai/acre) 16

Half-life (days): 35

Application Interval (days): 120

Number of Applications: 2

Are you assessing applications with 

variable rates or intervals? no

Assessed Species Inputs (optional, use defaults for RQs for national 

level assessments)

What body weight range is assessed (grams)? Birds Mammals

Small 20 15

Medium 100 35

Large

1000 1000

Avian

Endpoint Toxicity value

Indicate test 

species below

LD50 (mg/kg-bw)

1386.00 1

LC50 (mg/kg-diet) 2

NOAEL (mg/kg-bw)

1

NOAEC (mg/kg-diet) 2.50 2

Enter the Mineau et al. Scaling Factor 1.15
Page 64 of 85

Mammalian

Acute Study Chronic Study

Size (g) of mammal used in toxicity study

Default rat body weight is 350 grams 350 350

Endpoint Toxicity value

Reference 

(MRID)

LD50 (mg/kg-bw) 270.00

LC50 (mg/kg-diet)

Reported Chronic Endpoint 150.00

2

Is estimated daily dose (mg/kg-bw) reported 

from the available chronic mammal study? 

(yes or no)

no

Upper Bound Kenaga Residues For RQ Calculation

Chemical Name: Bensulide

 Use 0

 Formulation 0

Application Rate 16 lbs a.i./acre

Half-life 35 days 

Application Interval 120 days

Maximum # Apps./Year 2

Length of Simulation 1 year

Variable application rates? no

Endpoints

Avian

Bobwhite quail 

LD50 

(mg/kg-bw) 1386.00

Mallard duck)

LC50 

(mg/kg-diet) 0.00

Bobwhite quail 

NOAEL(mg/k

g-bw) 0.00

Mallard duck 

NOAEC 

(mg/kg-diet) 2.50

Mammals LD50 (mg/kg-bw) 270.00

LC50 (mg/kg-diet) 0.00

NOAEL (mg/kg-bw) 7.50
Page 65 of 85

NOAEC (mg/kg-diet) 150.00

Dietary-based EECs (ppm) Kenaga

Values

Short Grass 4196.64

Tall Grass 1923.46

Broadleaf plants 2360.61

Fruits/pods/seeds 262.29

Arthropods 1643.68

Avian Results

Avian Body 

Ingestio

n (Fdry)

Ingestion 

(Fwet)

% body 

wgt FI

Class Weight (g)

(g 

bw/day) (g/day)

consum

ed

(kgdiet/da

y)

Small 20 5 23 114 2.28E02

Mid 100 13 65 65 6.49E02

Large 1000 58 291 29 2.91E01

20 5 5 25

5.06E03

Granivores 100 13 14 14

1.44E02

1000 58 65 6

6.46E02

Avian Body 

Adjusted 

LD50

Weight (g) (mg/kg-bw)

20 998.52

100 1271.16

1000 1795.56

Dose-based EECs 

(mg/kg-bw) 

Avian Classes and Body Weights (grams)

small mid large

20 100 1000

Short Grass 4779.55 2725.50 1220.24

Tall Grass 2190.63 1249.19 559.28

Broadleaf plants 2688.50 1533.10 686.39

Fruits/pods 298.72 170.34 76.27

Arthropods 1871.99 1067.49 477.93

Seeds 66.38 37.85 16.95

Dose-based RQs 

(Dose-based EEC/adjusted 

LD50)

Avian Acute RQs

Size Class (grams)
Page 66 of 85

20 100 1000

Short Grass 4.79 2.14 0.68

Tall Grass 2.19 0.98 0.31

Broadleaf plants 2.69 1.21 0.38

Fruits/pods 0.30 0.13 0.04

Arthropods 1.87 0.84 0.27

Seeds 0.07 0.03 0.01

Dietary-based RQs 

(Dietary-based EEC/LC50 

or NOAEC) RQs

Acute Chronic

Short Grass #DIV/0! 1678.66

Tall Grass #DIV/0! 769.38

Broadleaf plants #DIV/0! 944.24

Fruits/pods/seeds #DIV/0! 104.92

Arthropods #DIV/0! 657.47

Note: To provide risk 

management with the 

maximum possible 

information,

it is recommended that both 

the dose-based and 

concentration-based 

RQs be calculated when data 

are available

Bensulide 0

Upper bound Kenaga 

Residues

Mammalian Results

Mammalian Body 

Ingestio

n (Fdry)

Ingestion 

(Fwet)

% body 

wgt FI

Class Weight

(g 

bwt/day

) (g/day)

consum

ed

(kgdiet/da

y)

15 3 14 95

1.43E02

Herbivores/ 35 5 23 66

2.31E02

insectivores 1000 31 153 15

1.53E01

15 3 3 21

3.18E03

Grainvores 35 5 5 15

5.13E03

1000 31 34 3

3.40E02

Mammalian Body 

Adjuste

d Adjusted

Class Weight LD50 NOAEL

15 593.41 16.48
Page 67 of 85

Herbivores/ 35 480.14 13.34

insectivores 1000 207.67 5.77

15 593.41 16.48

Granivores 35 480.14 13.34

1000 207.67 5.77

Dose-Based EECs 

(mg/kg-bw)

Mammalian Classes and Body weight

(grams)

15 35 1000

Short Grass 4001.17 2765.35 641.16

Tall Grass 1833.87 1267.45 293.86

Broadleaf plants 2250.66 1555.51 360.65

Fruits/pods 250.07 172.83 40.07

Arthropods 1567.13 1083.09 251.12

Seeds 55.57 38.41 8.90

Dose-based RQs 

(Dose-based EEC/LD50 or 

NOAEL)

Small mammal Medium mammal Large mammal

15 grams 35 grams 1000 grams

Acute Chronic Acute Chronic Acute 

Chroni

c

Short Grass 6.74 242.73 5.76 207.34 3.09 111.14

Tall Grass 3.09 111.25 2.64 95.03 1.42 50.94

Broadleaf plants 3.79 136.54 3.24 116.63 1.74 62.52

Fruits/pods 0.42 15.17 0.36 12.96 0.19 6.95

Arthropods 2.64 95.07 2.26 81.21 1.21 43.53

Seeds 0.09 3.37 0.08 2.88 0.04 1.54

Dietary-based RQs 

(Dietary-based EEC/LC50 

or NOAEC)

Mammal RQs

Acute Chronic

Short Grass #DIV/0! 27.98

Tall Grass #DIV/0! 12.82

Broadleaf plants #DIV/0! 15.74

Fruits/pods/seeds #DIV/0! 1.75

Arthropods #DIV/0! 10.96

Chemical: Bensulide

LD50 ft-2
Page 68 of 85

INPUTS Do not overwrite these numbers.

Changes to the 

inputs must be 

Application Rate: 16

lbs / 

acre

made in the 

"INPUTS" 

worksheet.

% A.I.: 100.00%

Avian LD50 (20g): 998.52 mg/kg bw

(100g) 1271.16

(1000g) 1795.56

Mammalian LD50 (15g): 593.41 mg/kg bw

(35g) 480.14

(1000g) 207.67

Row Spacing: 35 inches

Bandwidth: 0 inches

Unincorporation: 1%

Row/Band/In-furrow applications

Granular N/A

Intermediate Calculations Intermediate Calculations

# rows acre-1: N/A

mg a.i./1000 ft 

row: N/A

row length (ft): N/A bandwidth: N/A

lb ai/1000 ft row: N/A mg a.i./ft2: N/A

bandwidth (ft): N/A

exposed mg 

a.i./ft2: N/A

mg ai/ft2: N/A

exposed mg ai/ft2: N/A

LD50 ft-2 N/A

wgt class 

(grams)

wgt 

class 

(grams)

Avian 20 N/A Avian 20 N/A

100 N/A 100 N/A

1000 N/A 1000 N/A

Mammal 15 N/A Mammal 15 N/A

35 N/A 35 N/A

1000 N/A 1000 N/A

Broadcast applications

Granular

Intermediate Calculations

mg ai/ft2: 1.67

LD50 ft-2

wgt class 
Page 69 of 85

(grams)

Avian 20 0.08

100 0.01

1000 0.00

Mammal 15 0.19

35 0.10

1000 0.01

Formulas used in the calculations are in the User's Guide

Appendix F: TerrPlant Input and Output (Turf)

Table I.1. Chemical Identity.

Chemical Name Bensulide

PC code 9801

Use Turf

Application Method Broadcast

Application Form EC 

Solubility in Water 

(ppm) 56

Table I2. Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 12.5 y

Incorporation I 1 none

Runoff Fraction R 0.01 none

Drift Fraction D 0.01 none

Table I.3. EECs for Bensulide. Units in y.

Description Equation EEC

Runoff to dry areas (A/I)*R 0.25

Runoff to semi-aquatic areas (A/I)*R*10 2.5

Spray drift A*D 0.125

Total for dry areas ((A/I)*R)+(A*D) 0.375

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 2.625

Table I.4. Plant survival and growth data used for RQ derivation. Units are in y.

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC 

Monocot X 0.75 x 0.38

Dicot 1.3 0.38 x 6

Table I.5. RQ values for plants in dry and semi-aquatic areas exposed to Bensulide through runoff 

and/or spray drift.*
Page 70 of 85

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed #VALUE! #VALUE! #DIV/0!

Monocot listed 0.50 3.50 0.33

Dicot non-listed 0.29 2.02 <0.1

Dicot listed 0.99 6.91 0.33

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.

Appendix G. Review of Open Literature Toxicity Data Available for Bensulide

A review of available bensulide toxicity data in the scientific literature was conducted using 

ECOTOX on 5/21/2007 for the CRLF effects determination (USEPA 2007). ECOTOX was 

searched in September 2015 for any studies submitted since then which may warrant review 

as endpoints more sensitive than registrant submitted data. No such endpoints were found in 

this search, so conclusions from the ECOTOX search in 2015 remain the same as those in the

2007 CRLF determination. 

Appendix H Summary of Bensulide Toxicity 

All available toxicity information for bensulide is below. Explanations are given for studies which are 

not deemed acceptable, or where additional information may be deemed helpful.

The chronic avian studies show that bensulide can impair avian reproduction at relatively low 

dietary concentrations. The most serious effect appears to be a reduction of eggshell thickness, 

which begins to occur at dietary concentrations between 2.5 and 25 ppm a.i. At 250 ppm a.i., the 

reduction in eggshell thickness was severe (11% reduction in MRID 44486901 and 15 % in 

MRID 43616002) which resulted in a significant increase in the number of cracked eggs (MRID 

44486901 and 43616002). Compared to the control, the percentage of eggs cracked at 250 ppm 

a.i. represented a 2. 1x increase in MRID 44486901 and a 24.2X increase MRID 43616002. 

Cracking of eggs usually causes the embryo to die before hatching. Additionally, a dietary 

concentration of 250 ppm a.i. fed to mallards reduced the percentage of eggs hatched and the 

percent survival to the 3-week embryo and 14-day-old chick stages (MRID 44486901 and 

43616002).

Avian

Species % 

a.i.

Endpoint

(ppm a.i.)

Toxicity 

Category

MRID No. Study

Classification

Northern

Bobwhite quail

(Colinus 

virginianus)

Acute Oral

92.9 LD50 = 1386 slightly toxic 158455

Grimes 1986

Acceptable

Northern 

Bobwhite quail

(Colinus 

virginianus)

92.9 5-Day LC50

> 5620 ppm

Practically 

nontoxic

158456

Grimes 1986

Acceptable
Page 71 of 85

Acute Dietary

Mallard duck

(Anas 

platyrhynchos)

Acute Dietary

92.9 5-Day LC50

> 5620 ppm

Practically 

nontoxic

158457

Grimes 1986

Acceptable

Species % 

a.i.

NOAEL 

(ppm a.i.)

LOAEL 

(ppm a.i.)

Endpoint MRID No. Study

Classification

Mallard duck

(Anas 

platyrhynchos)

Reproduction

92.3 2.5 25 Eggshell 

thickness

44860901 Acceptable

Northern 

Bobwhite quail

(Colinus 

virginianus)

Reproduction

92.4 250 600 Several 

endpoints 

concerning the 

hatching and 

survival of 

chicks

43616001 Acceptable

Mallard duck

(Anas 

platyrhynchos)

Reproduction

92.4 Not 

determine

d

(< 250)

250 Eggshell 

thickness, 

percent of eggs 

laid that are 

cracked percent 

of hatchlings 

that survived to 

14 days

43616002 Supplemental

Mammal

Species % 

a.i.

Endpoint Toxicity 

Category

MRID No. Study

Classification

Lab rat

(Rattus 

norvegicus)

Acute oral

92.9 LD50 = 270 mg/kg-bw Moderately 

toxic

92005011 Acceptable

Species % 

a.i.

NOAEL 

(ppm a.i.)

LOAEL

(ppm a.i.)

Endpoint MRID No. Study

Classification

Lab rat

(Rattus 

norvegicus)

Reproduction

92.4 150 900 F2 pup survival

ACH inhibition 

at as low as 23 

mg/kg/day,

43948701 Acceptable

150 900 F2 pup survival

--- 25 Cholinesterase 

inhibition

Other Mammal comments: No developmental effects were observed in rats administered oral doses as great 

as 95 mg a.i./kg/day, which is approximately equivalent to 1900 ppm in the diet (MRID 00146585). Other 

chronic effects have been observed in rats and rabbits at doses between 25 and 95 mg a.i./kg/day (MRID 

00146585 and 00152845), but EFED did not consider them to be ecologically significant. These effects 

included tremors (rabbits), increased liver/body weight (rabbits), decreased body weight, and decreased feed 

consumption.
Page 72 of 85

The registrant has submitted a vegetative vigor and seedling emergence study testing the 

bensulide formulation 4LF (MRID 447463-01) which are considered acceptable. The nonregulatory phytotoxicity endpoint was the most sensitive parameter observed in two species -

Cucumber vegetative vigor: EC25/NOAEC = 1.3 lb ai/A, 0.38 lb ai/A and Ryegrass seedling 

emeregence:EC25/NOAEC > 1.9 lb ai/A, 0.38 lb ai/A. The fresh weight endpoints are used for 

calculating RQs; however, it is noted low application rates can produce phytotoxic effects in 

some plants.

Terrestrial invertebrates

Species % a.i. Endpoint

(ppm a.i.)

Toxicity 

Category

MRID No. Study

Classification

Honey bee 

(Apis mellifera 

L.)

Acute contact

Unknown LD50 > 24.17 μg/bee Practically nontoxic

00036935 Acceptable

Terrestrial plants

Species % a.i. EC25 (lb 

ai/A)

NOAEC 

(lb ai/A)

Endpoint MRID No. Study

Classification 

Monocot –

Corn

(Zea mays)

Vegetative 

Vigor

45.9

> 6.0 0.75 Shoot fresh weight

44746301 Acceptable Dicot – Lettuce

(Lactuca 

sativa)

Vegetative 

Vigor

> 6.0 1.5 Shoot fresh weight

Monocot –

Onion

(Allium cepa)

Seedling 

Emergence

45.9

3.1 0.75 Shoot fresh weight

44746301 Acceptable

Dicot – Could 

not determine 

most sensitive

Seedling 

Emergence

> 6.0 6.0 Shoot fresh weight

The most sensitive acute fish toxicity study utilized the rainbow trout. The study was classified as 

supplemental (due to the lack of raw data), and the LC50 was 0.72 mg a.i./L. (MRID 40098001). 
Page 73 of 85

This study showed bensulide to be highly toxic to freshwater fish. The two other freshwater fish 

LC50s were from an acceptable study - 1.1 mg a.i./L (rainbow trout; MRID 157315) and a 

supplemental study (raw data not available) - 0.81 mg a.i./L (bluegill sunfish; MRID 400980-01).

An acute study (157316) with the rainbow trout was deemed invalid due to the presence of 

precipitates. The fathead minnow study (49378102/49001601) was classified as supplemental 

due to inadequate number of embryos used and pH deviations. That study is considered scientifically 

sound and data are appropriate for use in risk assessment.

Freshwater Fish

Species % 

a.i.

Endpoint

(ppm a.i.)

Toxicity 

Category

MRID No.

Author/Year

Study

Classification

Rainbow trout

(Oncorrhynchus 

mykiss)

Acute 

92.9 LC50 = 1.1 mg ai/L

NOAEC (visually 

estimated) = 0.2 mg ai/L

Moderately to 

highly toxic

157315 Acceptable

Rainbow trout

(Oncorrhynchus 

mykiss)

Acute

95.0 0.72 Highly toxic 40098001 Supplemental 

Raw data not 

available.

Bluegill sunfish

(Lepomis 

macrochirus)

Acute

95.0 0.81 Highly toxic 40098001 Supplemental

Raw data not 

available.

Rainbow trout

(Oncorrhynchus 

mykiss)

Acute

92.9 1.4 -- 157316 Invalid

Presence of 

precipitates.

Species % 

a.i.

NOAEL 

(ppb a.i.)

LOAEL

(ppb a.i.)

Endpoint MRID No. Study

Classification

Fathead 

minnow

(Pimephales 

promelas)

ELS

92.4

374 789 Larval growth 

and survival

44720408 Acceptable

Fathead 

minnow

(Pimephales 

promelas)

Life-cycle

97.7 169 369 Reproduction 

(number of 

spawns, eggs 

per female per 

day, viable 

eggs per 

female per 

day, and 

percent 

viability) 

49378102

49001601

Supplemental

The one supplemental registrant-submitted study testing bensulide, TGAI, toxicity to 

estuarine/marine fish did not have raw data available. This study using a non-guideline species 
Page 74 of 85

yielded the most sensitive endpoint used the spot, Leiostomus xanthurus (MRID 40228401). 

Estuarine/Marine Fish

Species % 

a.i.

Endpoint

(ppm a.i.)

Toxicity 

Category

MRID No. Study

Classification

Sheepshead 

Minnow

(Cyprinodon 

variegatus)

92.0 LC50 = 0.56

NOAEC = 0.282 mg 

ai/L (visually estimated)

Sublethal effects: 

Erratic swimming and 

loss of equilibrium 

Endpoints based on 

mean measured 

concentrations

highly toxic 42750201 Acceptable

Spot

(Leiostomus 

xanthurus

Acute 

95.0 0.32 highly toxic 40228401 Supplemental

USEPA 

Gulfbreeze 

Laboratory 

Data

Species % 

a.i.

NOAEL 

(ppb a.i.)

LOAEL

(ppb a.i.)

Endpoint MRID No. Study

Classification

Sheepshead 

Minnow

(Cyprinodon 

variegatus)

Life-cycle

97.7 36 74 F0 4-week 

length, F0 8-

week length, 

F0 17-week 

survival, F0 

17-week 

length, F0 17-

week female 

length, F0 17-

week wet 

weight, F0 

17-week 

female 

weight, F1 4-

week length 

49059101 Acceptable

The acute daphnid toxicity test (MRID 159322) was classified as supplemental because the 

dissolved oxygen at the four highest test concentrations was unacceptably low (27.2%-

48.9%). However, since the dissolved oxygen problem probably reduced the observed LC50 this 

value can be used to give a conservative (i.e., possibly overprotective) assessment of risk. The 

test with the amphipod (40098001) is considered supplemental because the test procedure 

deviated significantly from the guidelines and notes LC50s are for mature organisms. The 

supplemental study (MRID 45063401) evaluating the chronic toxicity of bensulide on 

daphnids indicated that bensulide concentrations of 0.0042 mg a.i./L (lowest concentration 

tested) could reduce the growth and reproduction of freshwater invertebrates. The study was 

classified as supplemental due to effects occurring at the lowest concentration tested 
Page 75 of 85

(NOAEC non-definitive). The other chronic studies had solvent effects and were either 

classified as invalid (48504301) or supplemental (44720407) with no established NOAECs.

Freshwater Invertebrates

Species % 

a.i.

Endpoint

(ppm a.i.)

Toxicity 

Category

MRID No.

Author/Year

Study

Classification

Waterflea

(Daphnia 

magna)

Acute 

92.9 LC50 - 0.58

NOAEC (visually 

estimated) = 0.10 

1

Sublethal effects: 

Clumping, surfacing, 

lying on the bottom

Highly toxic 159322 Supplemental

Scud

(Gammarus 

fasciatus)

95.0 1.4 Moderately 

toxic

40098001

(R2049421 

mayer and 

elersack 1986)

Supplemental

Species % 

a.i.

NOAEL 

(ppb a.i.)

LOAEL

(ppb a.i.)

Endpoint MRID No. Study

Classification

Waterflea

(Daphnia 

magna)

Life-cycle 

97.7 10.9 16 Reproduction 

(mean number 

of young per 

surviving 

adult) and 

growth (length)

49110401 Acceptable

Waterflea

(Daphnia 

magna)

Life-cycle 

94.3 < 4.2 4.2 Growth and

reproduction

45063401

45303101

(amendment)

Supplemental

Effects 

occurring at the 

lowest 

concentration 

tested. 

Waterflea

(Daphnia 

magna)

Life-cycle 

93.4 < 6.93 6.93 Growth and

reproduction

44720407 Supplemental

Solvent effects

Waterflea

(Daphnia 

magna)

Life-cycle 

94.12 Young/Day 48504301 Invalid

Solvent effects

The chronic mysid test (48424501) was deemed supplemental due to an apparent solvent effect 

on the day 14 endpoints; however, no effects were observed on the 28 day measurements and 

this study’s 28 day chronic endpoints were deemed acceptable for use in risk assessment.
Page 76 of 85

Estuarine/Marine Invertebrates

Species % 

a.i.

Endpoint

(ppm a.i.)

Toxicity 

Category

MRID No.

Author/Year

Study

Classification

Eastern oyster

(Crassostrea

virginica)

Acute

92.0 EC50 = 0.25

NOAEC: Not 

determined due to 

reduced shell deposition 

in all treatment levels

Endpoint: shell growth 

and based on mean 

measured 

concentrations

Highly toxic 42750202 Acceptable

Mysid

(Mysidopsis 

bahia)

Acute

92.0 LC50 = 0.0624

NOAEC (visually 

estimated) = 0.0373 mg 

ai/L

Sublethal effects: 

Lethargy and loss of 

equilibrium 

Endpoint based on mean 

measured 

concentrations

Very highly 

toxic

42750203 Acceptable

Species % 

a.i.

NOAEL 

(ppb a.i.)

LOAEL

(ppb a.i.)

Endpoint MRID No. Study

Classification

Mysid

(Mysidopsis 

bahia)

Life-cycle

94.12 48.5 >48.5 No effects 

were observed

48424501 Supplemental

The registrant has submitted one supplemental vascular plant study testing bensulide, TGAI. 

The vasurlar plant study (447204-06) tested duckweed (Lemna gibba) and failed to establish 

a NOAEC. The freshwater diatom study (44720405) with Navicula pelliculosa was classified

as invalid because the test concentrations were not properly chosen

Aquatic plants

Species % a.i. EC50

(ppm)

NOAEC 

(ppm)

Endpoint MRID No. Study

Classification 

Blue-green 

algae

(Anabaena 

flos-aquae)

93.4 > 3.58 3.58 Density 44720403 Acceptable
Page 77 of 85

Marine diatom

(Skeletonema 

costatum)

93.4 0.78 0.635 Density 44720405 Acceptable

Green algae

(Selenastrum 

capriconutum)

93.4 1.8

EC05 = 

0.93 mg 

a.i./L Density 44720402 Acceptable

Freshwater 

diatom

(Navicula 

pelliculosa)

93.4 0.56 EC05 = 0.31 

(estimated) Density 44720405 Invalid

Duckweed

(Lemna gibba

92.8 0.16 0.0428 Frond number 45334101 Draft review

Duckweed

(Lemna gibba)

93.4 0.140

< 42.1

EC05 = 

(estimated 

0.017)

Density 44720406 Supplemental

Appendix I. Aggregate Incident Report for Bensulide:

No incidents were reported in EIIS or AIMS.

Table I.1. Total Count of Minor Incidents from Aggregated Reports

From Date To Date

Incident 

Package And 

Sequence Page# Product Name

Total Incident 

Count

Incident Type*

WB PB ONT

4/1/2004 6/30/2004 015521 - 00033 34 BENSULIDE 2 0 2 0

1/1/2001 3/31/2001 011545 - 00205 246

GOOSEGRASS

CRABGRASS 

CONTROL 1 0 1 0

4/1/2006 6/30/2006 017747 - 00775 918 BENSULIDE 1 0 1 0

7/1/2005 9/30/2005 016885 - 00124 195

BENSULIDE 

(CANADA) 3 0 3 0

4/1/2005 6/30/2005 016530 - 00600 863 BENSULIDE 6 0 5 0

8/30/2001 1/25/2002 012547 - 00001 1

BENSUMEC 4LF 

PREEMERGENCE 

GRASS & WEED 

HERBICIDE 42 0 42 0

10/1/2005 12/31/2005 017190 - 00068 61

GREENSWEEP 

CRABGRASS 

PREVENTER 1 0 1 0

6/1/1997 6/30/1997 005672 - 00222 127

GREENSWEEP 

PREEMERGENT 2 0 2 0
Page 78 of 85

CRABGRASS 

PREVENTER 

SPRAY-ON 

LIQUID

*WB = Minor Fish and Wildlife; PB = Minor Plant; ONT = “Other Nontarget” Incidents

Appendix J: Aquatic animal and plant risk quotients uses of bensulide

Table J.1. Aquatic animal risk quotients

Application 

Rate

FWF -A FWF-C E/MF - A E/MF-C FWI-A FWI-C E/MI-A E/MI-C

EEC/

LC50 = 

1100 μg 

ai/L

EEC/

NOAEC 

= 169 μg 

ai/L

EEC/

LC50 = 

560 μg 

ai/L

EEC/

NOAEC 

= 6 μg 

ai/L

EEC/

LC50 = 

580 μg 

ai/L

EEC/

NOAEC 

= 11 μg 

ai/L

EEC/

LC50 = 

62.4 μg 

ai/L

EEC/

NOAEC 

= 48.5 μg 

ai/L

Golf course turf, Turf, and Ornamental lawns

Granular - 2 apps@ 16 lb ai/A

FL Turf

(W12834.dvf) 0.23 1.17 0.45 5.47 0.44 20.73 4.07 4.70

PA Turf

(W12834.dvf) 0.40 2.07 0.79 9.72 0.76 36.09 7.05 8.19

TurfBSS

(W13958.dvf) 0.28 1.53 0.54 7.19 0.52 25.45 4.87 5.77

CA TurfRLF

(W23234.dvf) 0.29 1.64 0.58 7.69 0.56 28.00 5.16 6.35

Ground spray - 2 apps@ 12.5 lb ai/A

FL Turf

(W12834.dvf) 0.14 0.78 0.28 3.64 0.27 12.82 2.47 2.91

PA Turf

(W12834.dvf) 0.18 0.95 0.34 4.47 0.33 16.18 3.09 3.67

TurfBSS

(W13958.dvf) 0.16 0.87 0.31 4.08 0.30 14.64 2.79 3.32

CA TurfRLF

(W23234.dvf) 0.15 0.85 0.29 3.97 0.28 14.00 2.60 3.18

Granular - 2 apps@ 12.5 lb ai/A

FL Turf

(W12834.dvf) 0.18 0.91 0.36 4.28 0.34 16.18 3.19 3.67

PA Turf

(W12834.dvf) 0.31 1.62 0.61 7.58 0.59 28.18 5.50 6.39

TurfBSS

(W13958.dvf) 0.22 1.20 0.42 5.61 0.41 19.91 3.80 4.52

CA TurfRLF

(W23234.dvf) 0.24 1.28 0.46 6.00 0.45 21.91 4.15 4.97

Granular - 2 apps@ 7.5 lb ai/A

FL Turf

(W12834.dvf) 0.11 0.55 0.21 2.58 0.21 9.73 1.91 2.21

PA Turf

(W12834.dvf) 0.19 0.97 0.37 4.56 0.36 16.91 3.30 3.84
Page 79 of 85

TurfBSS

(W13958.dvf) 0.13 0.72 0.25 3.36 0.24 11.91 2.28 2.70

CA TurfRLF

(W23234.dvf) 0.14 0.77 0.28 3.61 0.27 13.18 2.50 2.99

Artichokes etc.1

Ground spray - 3 apps@ 6 lb ai/A

FL Peppers

(W12844.dvf) 0.51 3.05 1.01 14.33 0.98 49.91 9.07 11.32

FL Cabbage

(W12842.dvf) 0.35 2.04 0.69 9.56 0.67 33.18 6.23 7.53

CA Lettuce 

(W23273.dvf) 0.50 2.63 0.98 12.33 0.94 45.91 8.77 10.41

CA Avocado 

(W23188.dvf) 0.10 0.60 0.20 2.83 0.19 9.82 1.81 2.23

Ground spray - 2 apps@ 6 lb ai/A

FL Peppers

(W12844.dvf) 0.37 2.08 0.73 9.78 0.71 34.73 6.59 7.88

FL Cabbage

(W12842.dvf) 0.31 1.78 0.60 8.36 0.58 29.09 5.42 6.60

CA Lettuce 

(W23273.dvf) 0.35 1.98 0.69 9.28 0.67 33.09 6.20 7.51

CA Avocado 

(W23188.dvf) 0.07 0.41 0.14 1.92 0.14 6.73 1.27 1.53

Ground spray - 1 app@ 6 lb ai/A

FL Peppers

(W12844.dvf) 0.18 1.04 0.36 4.89 0.34 17.00 3.19 3.86

FL Cabbage

(W12842.dvf) 0.16 0.88 0.31 4.14 0.29 14.36 2.74 3.26

CA Lettuce 

(W23273.dvf) 0.21 1.18 0.41 5.56 0.40 19.73 3.72 4.47

CA Avocado 

(W23188.dvf) 0.05 0.25 0.09 1.19 0.09 4.36 0.83 0.99

Carrot

Ground spray - 1 app@ 6 lb ai/A

TXCorn

(W13958.dvf) 0.15 0.77 0.30 3.61 0.29 13.55 2.69 3.07

Cantaloupe etc.2

Ground spray - 2 apps@ 9 lb ai/A

CA 

Melons_RLF

(W93193.dvf) 0.16 0.91 0.32 4.25 0.31 15.36 2.88 3.48

NJ Melons_Std

(W13781.dvf) 0.24 1.30 0.46 6.11 0.45 21.73 4.17 4.93

Ground spray - 1 app@ 9 lb ai/A

CA 

Melons_RLF 0.10 0.52 0.20 2.44 0.19 9.00 1.78 2.04
Page 80 of 85

(W93193.dvf)

NJ Melons_Std

(W13781.dvf) 0.12 0.66 0.24 3.11 0.23 11.09 2.16 2.52

Table J.2. Aquatic RQs for aquatic plants from bensulide uses

Application Rate

Vascular Plants

non-listed

Vascular Plants 

listed

Non-Vascular Plants 

non-listed

Non-Vascular Plants 

listed

EEC/

EC50 = 140 μg ai/L

EEC/

NOAEC < 42.1

μg ai/L

EEC/

EC50 = 780 μg ai/L

EEC/

NOAEC = 635 μg ai/L

Golf course turf, Turf, and Ornamental lawns

Granular - 2 apps@ 16 lb ai/A

FL Turf

(W12834.dvf) 1.81 N/C 0.33 0.4

PA Turf

(W12834.dvf) 3.14 N/C 0.56 0.69

TurfBSS

(W13958.dvf) 2.17 N/C 0.39 0.48

CA TurfRLF

(W23234.dvf) 2.3 N/C 0.41 0.51

Ground spray - 2 apps@ 12.5 lb ai/A

FL Turf

(W12834.dvf) 1.1 N/C 0.2 0.24

PA Turf

(W12834.dvf) 1.38 N/C 0.25 0.3

TurfBSS

(W13958.dvf) 1.24 N/C 0.22 0.27

CA TurfRLF

(W23234.dvf) 1.16 N/C 0.21 0.26

Granular - 2 apps@ 12.5 lb ai/A

FL Turf

(W12834.dvf) 1.42 N/C 0.26 0.31

PA Turf

(W12834.dvf) 2.45 N/C 0.44 0.54

TurfBSS

(W13958.dvf) 1.69 N/C 0.3 0.37

CA TurfRLF

(W23234.dvf) 1.85 N/C 0.33 0.41

Granular - 2 apps@ 7.5 lb ai/A

FL Turf

(W12834.dvf) 0.85 N/C 0.15 0.19

PA Turf

(W12834.dvf) 1.47 N/C 0.26 0.32

TurfBSS

(W13958.dvf) 1.01 N/C 0.18 0.22
Page 81 of 85

CA TurfRLF

(W23234.dvf) 1.11 N/C 0.2 0.25

Artichokes etc.

1

Ground spray - 3 apps@ 6 lb ai/A

FL Peppers

(W12844.dvf) 4.04 N/C 0.73 0.89

FL Cabbage

(W12842.dvf) 2.78 N/C 0.5 0.61

CA Lettuce 

(W23273.dvf) 3.91 N/C 0.7 0.86

CA Avocado

(W23188.dvf) 0.81 N/C 0.14 0.18

Ground spray - 2 apps@ 6 lb ai/A

FL Peppers

(W12844.dvf) 2.94 N/C 0.53 0.65

FL Cabbage

(W12842.dvf) 2.41 N/C 0.43 0.53

CA Lettuce 

(W23273.dvf) 2.76 N/C 0.5 0.61

CA Avocado 

(W23188.dvf) 0.56 N/C 0.1 0.12

Ground spray - 1 app@ 6 lb ai/A

FL Peppers

(W12844.dvf) 1.42 N/C 0.26 0.31

FL Cabbage

(W12842.dvf) 1.22 N/C 0.22 0.27

CA Lettuce 

(W23273.dvf) 1.66 N/C 0.3 0.37

CA Avocado 

(W23188.dvf) 0.37 N/C 0.07 0.08

Carrot

Ground spray - 1 app@ 6 lb ai/A

TXCorn

(W13958.dvf) 1.2 N/C 0.22 0.26

Cantaloupe etc.

2

Ground spray - 2 apps@ 9 lb ai/A

CA Melons_RLF

(W93193.dvf) 1.29 N/C 0.23 0.28

NJ Melons_Std

(W13781.dvf) 1.86 N/C 0.33 0.41

Ground spray - 1 app@ 9 lb ai/A

CA Melons_RLF

(W93193.dvf) 0.79 N/C 0.14 0.17

NJ Melons_Std

(W13781.dvf) 0.96 N/C 0.17 0.21

N/C – Not calculated
Page 82 of 85

Appendix K: STIR and SIP Inputs and Outputs

Table K.1. STIR Input and Output

Input

Application and Chemical Information

Enter Chemical Name Bensulide

Enter Chemical Use

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) 397.5

Enter Chemical Vapor Pressure (mmHg) 8.20E-07

Enter Application Rate (lb ai/acre) 12.5

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 1386

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 270

Enter Lowest Rat Inhalation LC50 (mg/L) 1.75

Duration of Rat Inhalation Study (hrs) 4

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 1.75E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.21E-03

Adjusted Inhalation LD50 5.01E+01

Ratio of Vapor Dose to Adjusted Inhalation LD50 4.40E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose 

(mg/kg) 1.20E+00

Ratio of Droplet Inhalation Dose to Adjusted 

Inhalation LD50 2.40E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 1.75E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.77E-03

Adjusted Inhalation LD50 1.04E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.66E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose 

(mg/kg) 1.51E+00

Ratio of Droplet Inhalation Dose to Adjusted 

Inhalation LD50 1.45E-02 Exposure not Likely Significant
Page 83 of 85

Table K.2. SIP Inputs

Parameter Value

Chemical name Bensulide

Solubility (in water at 25oC; mg/L) 5.6

Mammalian LD50 (mg/kg-bw) 270

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Mammalian NOAEL (mg/kg-bw) 7.5

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Avian LD50 (mg/kg-bw) 1386

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 2.5*

Bobwhite quail NOAEC (mg/kg-diet) 12.5*

NOAEC (mg/kg-diet) for other bird 

species 0

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird 

species 0

Body weight (g) of 2nd other avian 

species

*Value calculated by dividing NOAEC (mg/kg- diet by 20) = 150/20 –

Mallard; 250/20 - Quail.

Table K.3. SIP Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 9.6320 0.9632

Adjusted toxicity value (mg/kg-bw) 207.6734 5.7687

Ratio of exposure to toxicity 0.0464 0.1670

Conclusion*

Drinking water exposure alone 

is NOT a potential concern for 

mammals

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Table K.4. SIP Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 4.5360 4.5360

Adjusted toxicity value (mg/kg-bw) 998.5153 0.1240

Ratio of exposure to acute toxicity 0.0045 36.5714
Page 84 of 85

Conclusion*

Drinking water exposure alone 

is NOT a potential concern for 

birds

Exposure through drinking 

water alone is 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 85 of 85