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Environmental Fate and Ecological Risk Assessment for the 

Registration Review of Profenofos

Profenofos

O-(4-bromo-2-chlorophenyl) O-ethyl S-propyl phosphorothioate

CAS Registry Number 41198-08-7

PC Code 111401

Prepared by:

Michelle Colletti, Chemist

Michael Wagman, Biologist

William P. Eckel, Ph.D., Senior Science Advisor, ERB VI

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch VI

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington DC 20460

Reviewed by:

Nathan Miller, Biologist, ERB VI

Paul Mastradone, Senior Chemist, EISB

Mark Corbin, Branch Chief, ERB VI

September 15, 2015

Page 4 of 75

Table of Contents

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

2. Problem Formulation ............................................................................................................................................12

2.1. Nature of Regulatory Action .......................................................................................................................12

2.2. Mode of Action..............................................................................................................................................12

2.3. Use Characterization....................................................................................................................................12

2.4. Conceptual Model.........................................................................................................................................14

3. Analysis...................................................................................................................................................................20

3.1. Exposure Characterization ................................................................................................................................20

3.2. Ecological Effects Characterization ..................................................................................................................26

4. Risk Characterization ...........................................................................................................................................35

4.1. Risk Estimation...................................................................................................................................................35

4.2. Risk Description..................................................................................................................................................39

5. Federally Threatened and Endangered (Listed) Species Concerns.............................................................44

5.1. Action Area ...................................................................................................................................................46

5.2. Taxonomic Groups Potentially at Risk.......................................................................................................46

6. Literature Cited .....................................................................................................................................................48

Appendix A–Summary of Risk Conclusions by Taxa.........................................................................................50

Appendix B—Input Parameters and Output for the STIR model ....................................................................51

Appendix C—Chemical Structure and Characteristics of Profenofos Degradates .........................................53

Appendix D. Example Input and Outputs for the SIP Model...........................................................................55

Appendix E. Example Input and Outputs for the KABAM Model.................................................................56

Appendix F. Predictive Data for Parent Profenofos and its Degradates from QSAR Modeling using 

ECOSAR v1.11.......................................................................................................................................................62

Appendix G. Length of Time for Profenofos Residues to Decrease Below LOCs after Application. .............68

Appendix H. AgDrift Analysis of Spray Drift Effects to Off-field Organisms. ...............................................75
Page 5 of 75

1. Executive Summary

EFED has completed the Registration Review draft ecological risk assessment for profenofos. 

Profenofos is an insecticide/miticide belonging to the organophosphate class of pesticides. 

Profenofos is registered for use only on cotton and must be applied by enclosed cab ground 

application equipment. It is used to control cotton bollworm, tobacco budworm, and certain other 

insects, and mites. The only currently registered end-use product, Curacron® 8E InsecticideMiticide (EPA Reg No. 100-669), is an emulsifiable concentrate that is diluted with water and/or 

vegetable oil. Current label restrictions prohibit profenofos applications within 100 feet of any 

body of water and treating crops within 14 days of harvest when diluted with water or 30 days 

when diluted with oil. 

Profenofos is fairly non-persistent and degrades primarily by microbial metabolism as well as the 

abiotic process of hydrolysis. Degradation from hydrolysis varies with pH, with half-lives ranging 

from less than a day for alkaline (pH 9) waters to over 100 days for acidic (pH 5) waters. Although 

not highly mobile, profenofos may reach surface waters through spray drift or runoff. Profenofos 

is not likely to volatilize.

The major degradates tracked in submitted studies appear to have limited toxicity compared with 

the parent profenofos. O-ethyl-S-propyl phosphorothioate was not tracked in the submitted 

studies through radiolabeling and no empirical information on its fate or toxicity is available. 

This degradate may degrade further into O-ethyl phosphate and 1-propanethiol.

Risk Conclusions

Aquatic Organisms

Multiple lines of evidence indicate potential for risk to aquatic organisms. These include the 

modeled exposure values, ecotoxicity information, and incident data. This assessment considered 

the toxicity of parent profenofos only, but Quantitative Structure Activity Relationship (QSAR) 

analysis indicates that certain degradates for which empirical data are not available, may have 

toxicity approaching the parent, although the stability of these degradates is uncertain. If these 

degradates are stable, then risk to fish may be greater than presented in this assessment.

KABAM analysis indicates that profenofos has the potential to bioaccumulate, and cause adverse 

effects to birds and mammals that consume fish, especially on a chronic basis.

Aquatic Invertebrates

There is potential for acute and chronic risk to both listed and non-listed species of 

freshwater and estuarine/marine aquatic invertebrates. Acute RQs range from 4.3 to 11.3 

while chronic RQs range from 23—25. Incident data confirm the hazard to aquatic 

invertebrates. No sediment toxicity studies were available to evaluate the risk of 

profenofos to benthic invertebrates in the sediment; however, since the maximum benthic 

pore water estimated environmental concentrations (EECs) are approximately an order of 

magnitude lower than water column EECs and risk to aquatic invertebrates is already 

indicated with the available data, the lack of sediment toxicity data is not considered a 
Page 6 of 75

major data gap. Modeled benthic pore water concentrations however are sufficiently 

high enough that listed and non-listed species of benthic invertebrates would likely be 

considered to be at risk if they are of similar sensitivity as other aquatic invertebrates for 

which data is available.

AgDrift analysis indicates that the spray drift of profenofos residues have the potential to 

adversely impact listed aquatic invertebrate species habitating water bodies at distances 

between 265 feet (using low booms and nozzles producing coarser droplet spectra) and 

810 feet (using high booms and nozzles producing finer droplet spectra) from the edge of 

the application area. 

Fish

There is potential for acute and chronic risk to both listed and non-listed species of 

freshwater and estuarine/marine fish (and aquatic-phase amphibians, for which fish are 

considered surrogates). Acute RQs range from 0.73 to 1.34, while chronic RQs range 

from 12 to 21. Incident data confirm the hazard to fish. Current labeling, which 

specifies hazards to fish and restricts application near water, may address this risk 

concern to some degree. 

Aquatic Plants

Potential for risk to listed and non-listed species of vascular plants is unlikely. Although 

there is some uncertainty regarding the toxicity of profenofos to non-vascular plants, the 

screening-level risk assessment indicates that risk to this taxon is also unlikely and the 

lack of this data is not considered a major data gap for the risk assessment.

Terrestrial Organisms

The screening-level risk assessment for birds and mammals uses conservative assumptions such 

as a default half-life value for foliar dissipation and conservative acute avian toxicity endpoints. 

However, even when refined assessment measures are used, the potential for risk persists overall 

for these taxa, although not all terrestrial animals would be considered to be at risk. 

Birds

There is potential for acute and chronic risk to both listed and non-listed avian species (as 

well as reptiles and terrestrial-phase amphibians, for which birds are considered 

surrogates). Acute RQs range from 0.18 to 92 while chronic RQs range from >50 to 

>800. Chronic risk to birds is likely to be higher than assessed in this risk assessment 

due to the quantitative use of the lowest observed adverse effects concentration (LOAEC)

in lieu of a no observed adverse effects concentration (NOAEC) due to the (nondefinitive 

(i.e. “less tha n”) nature of the NOAEC. A major data gap in the risk assessment is the 

lack of a chronic dietary dose concentration that does not result in effects to birds.

AgDrift analysis indicates that profenofos residues from spray drift have the potential to 

adversely impact off-field listed birds species at distances between 15 feet feet (using low 

booms and nozzles producing coarser droplet spectra) and 125 feet (using high booms 

and nozzles producing finer droplet spectra) from the edge of the application area. 
Page 7 of 75

Mammals

There is potential for acute and chronic risk to both listed and non-listed species of 

mammals. Acute RQs range from 0.01 to 2.25 while chronic RQs range from 6 to 951.

Beneficial Terrestrial Invertebrates

There is potential for acute and chronic risk to both listed and non-listed species of 

beneficial terrestrial invertebrates based on acute contact exposure to residues from spray 

drift or from direct application when applications are made and beneficial invertebrates 

are present. As this pesticide is an insecticide/acaricide, it is also likely to have effects on 

beneficial terrestrial invertebrates. The acute contact RQ for honey bees on the field 

exposed to profenofos through spray droplets is 14.2. The current label language may 

mitigate risk from acute contact basis to honey bees because it prohibits treatment while 

bees are foraging in/or adjacent to the treatment area. However, other, non-Apis bees and 

other beneficial insects may still be at risk, as their presence may be less conspicuous to 

the pesticide applicator. Additionally, dietary risk to both adult and juvenile life stages of 

terrestrial invertebrates cannot be precluded due to the lack of acute and chronic oral data 

with adult and larval honey bees, which is considered a major data gap in the risk 

assessment. 

AgDrift analysis indicates that profenofos residues from spray drift have the potential to 

adversely impact non-listed off-field terrestrial invertebrates at distances between 10 feet 

(using low booms and nozzles producing coarser droplet spectra) and 90 feet (using high 

booms and nozzles producing finer droplet spectra) from the edge of the application area. 

Terrestrial Plants

The results of this screening-level risk assessment indicate that the current use of 

profenofos is not expected to cause direct adverse effects to listed and non-listed 

terrestrial plants. Although there is some uncertainty regarding the toxicity of profenofos 

formulations to the vegetative vigor of terrestrial plants, the screening-level risk 

assessment indicates that risk to this taxon is unlikely and the lack of vegetative vigor 

data with a typical end-use product (TEP) is not considered a major data gap for the risk 

assessment. There is some potential for risk to listed species occurring on the agricultural

field as application rates are higher than the endpoints from the available seedling 

emergence study.

Incident Reports

From 1989 to 1999, there were 23 incidents reported where fish or aquatic invertebrates suffered 

mortalities and profenofos was considered to be at least a “possible” cause of the incident. The 

incident data provide additional lines of evidence for risk conclusions to aquatic fish and 

invertebrates. 
Page 8 of 75

Designations of “uncertain” for taxa in this assessment are a result of incomplete ecotoxicology 

data. Where uncertainty designations are made for a taxon, efforts have been made to 

characterize the risk picture. For instance, multiple lines of evidence support the potential for 

effects to fish and aquatic invertebrates, whereas for nonvascular aquatic plants, available lines 

of evidence indicate that the potential for risk may be lower.

Table 1 summarizes the taxa that may potentially be directly at risk from exposure to profenofos. 

Additional description is further summarized in Appendix A.

Table 1: Summary of Risk Determinations for Profenofos1

Use Fish2 Aquatic 

Invertebrates3

Aquatic 

Plants4 Terrestrial Plants Birds5 Mammals Terrestrial Invertebrates

AcuteChronicAcuteChronicListedNonListed

Monocots Dicots Listed Non

AcuteChronicAcuteChronicAcuteChronic

-

ListedListedNonListed

Cotton X X X X X X X X X Ua

1 A bolded and shaded “X” indicates risk is expected to listed and non-listed species. A “U” indicates that risk is uncertain due to a lack of 

data. A blank box indicates that no risk is expected. See Risk Characterization section for more information. 2 Fish includes both 

estuarine/marine and freshwater fish and are also considered surrogates for aquatic-phase amphibians. 3 Aquatic Invertebrates includes both 

estuarine/marine and freshwater invertebrates. 4 Aquatic Plants includes both vascular and non-vascular plants. 5 Birds are considered 

surrogates for reptiles and terrestrial-phase amphibians. 

a Chronic risk is uncertain due to a lack of chronic oral data for adult and juvenile honey bees.

Potential effects to federally-listed endangered and threatened species (listed species) based on 

LOC exceedances require an in-depth listed species evaluation determining the potential cooccurrence of listed species and use pattern of profenofos. Only species in cotton-growing areas 

are expected to be at risk of exposure. Identified potential risks to listed species are summarized 

in Table 2.

Table 2. Potential Effects to Federally Listed Taxa Associated with Direct Effects from the 

Registered Use of Profenofos.

Listed Plant Taxon Potential Direct Effects

Terrestrial and semi-aquatic 

plants – monocots and dicots No

Aquatic nonvascular plants1 No

Aquatic vascular plants No

Listed Animal Taxon Potential Direct Effects

Acute Chronic

Terrestrial invertebrates Yes Uncertain2

Mammals Yes Yes

Birds Yes Yes

Reptiles Yes Yes

Amphibians3 Yes Yes

Freshwater fish Yes Yes

Freshwater invertebrates Yes Yes

Estuarine/marine fish Yes Yes

Estuarine/marine invertebrates Yes Yes

1 There are currently no listed species of aquatic non-vascular plants.
Page 9 of 75

2 Chronic risk to listed species of terrestrial invertebrates is uncertain due to the lack of chronic data for juvenile and adult 

honey bees.

3 Acute and chronic risk to this taxa is expected for both the terrestrial and aquatic-phase in the amphibian life cycle.
Page 10 of 75

Basic Uncertainties 

 The risk assessment is based on parent profenofos only. Empirical ecotoxicicity data are 

only available for the degradate, 4-bromo-2-chlorophenol effects’ to aquatic non-vascular 

plants. Therefore, this assessment uses QSAR to characterize potential risk from other 

profenofos degradates. There is some evidence that certain degradates have toxicity 

approaching that of parent profenofos, but their stability is uncertain and their inclusion 

would not change any risk conclusions.

 Chirality of the compound creates uncertainty around the fate characterisitcs (i.e. 

microbial degradation) and ecotoxicity of the compound. Therefore, the assessment may 

underestimate or overestimate the potential risk posed by the use of profenofos. None of 

the submitted data addressed the issue of chirality or identify which chiral isomer was 

used in each study.

 Aerobic Aquatic Metabolism (OCSPP Guideline 835.4300). No quantitatively acceptable

data are available for aerobic aquatic metabolism. Therefore, estimates for modeling 

were based on defaults derived from the EFED Input Parameter Guidance (EFED, 2009). 

 Dislodgeable Foliar Residue Data on Cotton (OCSPP Guideline 875.2100). This 

assessment assumed the default foliar dissipation half-live of 35 days. A limited amount 

of data indicates that profenofos residues may dissipate at a substantially faster rate (~1 

day). However, EFED needs 3 separate foliar dissipation half-lives in order to use an 

alternate half-life quantitatively in the risk assessment. The limited empirical data are 

used qualitatively to characterize risk in the assessment. Additional dislodgeable foliar 

residue data would decrease uncertainties associated with the use of the default half-life.

 Non-vascular aquatic plant testing (OCSPP Guidelines 850.4500 and 850.4550). No 

acceptable data are available for green algae, blue-green algae, nor freshwater or 

saltwater diatoms. The available qualitatively supplemental data on green algae indicate 

that non-vascular aquatic plants may be more sensitive than vascular aquatic plants, for 

which acceptable data are available. Given that the data indicate that profenofos is 

substantially less toxic to aquatic plants than other taxa (e.g. aquatic invertebrates) and 

would need to be considerably (at least 1 order of magnitude) more toxic to non-vascular 

plants than to vascular plants in order to create a risk concern for non-vascular aquatic 

plants, this is considered a minor data gap. 

 For avian reproduction (OCSPP Guideline 850.2300), concentrations tested were not 

sufficiently low to achieve a NOAEC. This assessment has used the lowest dose from 

that study (the LOAEC) in the risk assessment quantitatively in lieu of the NOAEC. 

Avian chronic risk quotients are thus uncertain and therefore this assessment may 

underestimate the chronic risk of profenofos to avian species. This is considered a major 

data gap in the risk assessment.
Page 11 of 75

 Acute and chronic dietary data are not available for either juvenile (larval) or adult honey 

bees. Therefore, the risk posed by profenofos residues on pollen and nectar to adult, 

foraging honey bees is uncertain as is the risk from contaminated nectar and pollen

brought back to the hive and fed to larval honey bees. Given that profenofos is an 

insecticide and is very highly toxic on an acute contact basis to bees, oral risk to bees and 

other beneficial terrestrial invertebrates may be likely where profenofos residues are 

present in pollen and/or nectar (Non-Guideline Studies). This is considered a major data 

gap in the risk assessment.

 Risk to terrestrial plants from spray drift is uncertain as no data are available to assess the 

risk of typical end-use products (TEP) of profenofos on the vegetative vigor of terrestrial 

plants (OCSPP Guideline 850.4150). Profenofos TEP formulations may contain 

surfactants and adjuvants that increase the absorption and toxicity of the active ingredient

to plants. The test substance used in all available terrestrial plant vegetative vigor studies 

was technical grade active ingredient (TGAI). Given that the available data indicate that 

profenofos is comparatively less toxic to terrestrial plants than other taxa (e.g. terrestrial 

invertebrates), and would need to be considerably more toxic than the seedling 

emergence data with TGAI to cause a concern for off-field terrestrial plants from spray 

drift, this is considered a minor data gap. 
Page 12 of 75

2. Problem Formulation

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

ecological risk assessment in support of the Registration Review of the insecticide / miticide 

profenofos. The problem formulation sets the objectives for the risk assessment, establishes a 

risk hypothesis and conceptual model depicting potential risk, and provides a plan for analyzing 

the data and characterizing the risk associated with the uses of profenofos (USEPA, 2004). 

2.1. Nature of Regulatory Action

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

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

Agency (EPA or the Agency). To determine whether a pesticide can be registered, the EPA 

evaluates the product’s safety to non-target species based on a wide range of environmental and 

health effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act (FQPA), 

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

Registration Review1. The registration review program is intended to ensure that as the ability to 

assess risk evolves and as policies and practices change, all registered pesticides continue to meet 

the statutory standard of no unreasonable adverse effects to human health and the environment. 

Changes in science, public policy, and pesticide use practices will occur over time. Through the 

registration review program, the Agency periodically reevaluates pesticides to make sure that as 

changes occur, products in the marketplace can be used safely.

Additionally, potential effects to federally listed endangered and threatened species (hereafter 

referred to as “listed”) and their designated critical habitat are also considered under the 

Endangered Species Act (ESA) in order to ensure that the continued registration of profenofos is 

not likely to jeopardize the continued existence of listed species or adversely modify their critical 

habitat. In order to meet the requirements of FIFRA and the ESA, this assessment follows EPA 

guidance on conducting ecological risk assessments (USEPA, 1998) and the Office of Pesticide 

Program’s Overview Document, which contains guidance for assessing pesticide risks to nonlisted and listed species (USEPA, 2004).

2.2. Mode of Action

Profenofos is an insecticide/miticide belonging to the organophosphate class of pesticides. The 

toxicity of organophosphates is based on the inhibition of the enzyme acetylcholinesterase,

which cleaves the neurotransmitter acetylcholine. Inhibition of acetylcholinesterase by 

organophosphate insecticides interferes with proper neurotransmission in cholinergic 

neurosynapses and neuromuscular junctions. 

2.3. Use Characterization

Profenofos is only registered for use on cotton. The only currently registered end-use product

(EPA Reg No. 100-669) is an emulsifiable concentrate that is diluted with water or vegetable oil. 

 

1 http://www.epa.gov/oppsrrd1/registration_review/
Page 13 of 75

Current use restrictions prohibit application of profenofos within 100 feet of any waterbody and 

treating crops within 14 days of harvest when diluted with water or 30 days when diluted with oil. 

The environmental hazards section of the label also adds prohibitions to the application of 

profenofos in Reeves County, Texas and the Dexter National Fish Hatchery in New Mexico due 

to the hazard to endangered fish. Profenofos can only be applied by enclosed cab ground 

application equipment to control cotton bollworm, tobacco budworm, aphids, plant bugs, Lygus 

bugs, and mites. Aerial application is not permitted. The maximum single application rate of 

profenofos is 0.5 pounds of active ingredient per acre (lb a.i. /A) with a minimum application 

interval of 5 days and a seasonal maximum application rate of 5 lb a.i. /A (maximum of 10 

applications per season). The use pattern for profenofos is summarized in Table 3, below. 

Table 3 Maximum Application Parameters for Profenofos

Application

Use site Maximum Rate Interval Date Maximum Seasonal 

Cotton 0.5 lbs a.i./A

5 days

(up to 10

applications per 

season)

First application date on 

emergence in SWCC 

(June 1) 

5 lbs a.i./A

A screening level estimate of current usage of profenofos is presented in Table 4. This screening 

level assessment presents usage data on an annual basis and is derived from USDA’s National 

Agricultural Statistics Service with data reported from 2004 to 2011. 

Table 4. Profenofos Screening Level Usage Analysis (SLUA) Conducted on August 1, 2013

The Biological and Economic Analysis Division (BEAD) more recently published information 

on the use of profenofos from 1998 - 2012 (USEPA, 2014). For the most recent periods on 

record (2007 - 2012), only Arkansas, California, Georgia, Missouri, Mississippi and Texas 

reported use.

Table 5. Profenofos Usage on Cotton in the U.S., Three-year Averages, 1998-20121

Percent Crop Treated

No. Crop Lbs. A.I. Average Maximum

1 Cotton 30,000 <1 <2.5

1998-2000 2001-2003 2004-2006 2007-2009 2010-20122

Total Lbs Applied 447,154 159,067 67,938 19,757 6,767

Total Acres Treated 696,415 197,499 107,316 25,044 9,454

Proportion of Acres

Treated Aerially 50% 17% 24% 34% 0%

Percent Crop Treated 1.7% 1.4% 1.1% 0.6% 0.7%
Page 14 of 75

1 States reporting use in 1998-2006: AL, AZ, AR, CA, FL GA, LA, MS, MO, NC, OK, SC, TN, TX; 

States reporting use in 2007-2011: AR, GA, MS, MO, TX, CA

2 No usage reported in 2012

Source: Proprietary Usage Data, 1998-2012

2.4. Conceptual Model

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

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

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

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

for ecological receptors, and a feasible route of exposure. 

The conceptual model for profenofos provides a written description and visual representation of 

the predicted relationships between profenofos, potential routes of exposure, and the predicted 

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

hypothesis and a conceptual diagram (USEPA, 1998).

Based on preliminary estimated environmental concentrations (EECs) and effects data, 

preliminary risk quotients (RQs) were calculated for aquatic animals and terrestrial animals and 

plants. Based on maximum application rates and available fate data for profenofos, estimated acute 

and chronic RQ values are sufficient to exceed levels of concern (LOCs) for Federally-listed 

threatened/endangered (listed) and non-listed fish and invertebrates. Risks are also expected for 

non-listed and listed birds and mammals due to acute and chronic exposures to profenofos. Risks 

are expected as well for non-listed and listed species of dicot plants inhabiting semi-aquatic areas 

based on exposures of profenofos originating from the maximum application rate. Because of the 

potential risk from direct effects to the listed and non-listed taxa described above, listed species in 

all taxa may potentially be affected indirectly due to alterations in their habitat and prey items (e.g., 

foods sources, shelter, and areas to reproduce). These preliminary conclusions are used to derive 

the risk hypothesis and conceptual diagram discussed below.

The following risk hypothesis is presumed for this assessment:

Based on the application methods, mode of action, fate and transport, and the sensitivity 

of non-target aquatic and terrestrial species profenofos has the potential to reduce 

survival, reproduction, and/or growth in non-target terrestrial and aquatic organisms 

when used in accordance with the current label. These non-target organisms include

federally listed threatened and endangered species as well as non-listed species.

Conceptual Diagram

The environmental fate properties of profenofos indicate that runoff, spray drift, volatilization 

and direct spray represent potential transport mechanisms of profenofos to aquatic and terrestrial 

habitats where non-target organism may be exposed. These transport mechanisms (i.e., sources) 

are depicted in the conceptual models below (Figures 1 and 2) along with the receptors of 

concern and the potential attribute changes in the receptors due to exposures of profenofos.
Page 15 of 75

1

2 Figure 1. Conceptual model for profenofos effects on aquatic organisms. Dotted lines indicate exposure pathways that have a low likelihood of 

3 contributing to ecological risk.
Page 16 of 75

4

5

Stressor

Source

Receptors

Attribute

Change

Profenofos applied to cotton

Direct

application Spray drift

Birds / Terrestrial-phase 

amphibians / reptiles / 

mammals

Juvenile

Adult

Terrestrial 

insects

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Terrestrial/riparian plants

grasses/forbs, fruit, seeds (trees, 

shrubs)

Runoff

Mammals

Exposure

Media

Soil

Ingestion

Ingestion

Ingestion

Ingestion

Dermal uptake/Ingestion

Long range 

atmospheric transport

Root uptake

Wet/dry deposition

Birds / Amphibians

Ingestion

Drinking water

Figure 2. Conceptual model for profenofos effects on terrestrial organisms.
Page 17 of 75

Analysis Plan

Residues of Concern

The predominant degradate of profenofos is 4-bromo-2-chlorophenol. Also formed in equimolar 

parts with this degradate is O-ethyl-S-propyl phosphorothioate. Additional degradates formed in 

greater than 10% include 4-bromo-2-chlorophenyl ethyl ether (BCPEE), 2-thioethylenecarboxy4-hydroxyphenyl methyl ether (THPME), and cyclohexadienyl sulfate. The major degradates, 

other than O-ethyl-S-propyl phsophorothioate, appear to have limited toxicity compared with the 

parent profenofos. Available ecotoxicological information for these degradates is discussed in 

the ecological effects characterization in Section 3.2. Profenofos, is considered the only residue 

of concern for this assessment.

Mixtures

No currently registered profenofos products are co-formulated other pesticidal active ingredients. 

Evaluation of pesticide environmental mixtures from tank mixes or due to the presence (e.g. on 

foliage) of residues of other pesticides is beyond the scope of this assessment because of a myriad

of factors including identification of other possible co-contaminants and their concentrations, 

differences in the pattern and duration of exposure among contaminants, and the differential effects 

of other physical/chemical characteristics of the receiving waters (e.g. organic matter present in 

sediment and suspended water). However, it is acknowledged that not considering mixtures could 

over- or under-estimate risks depending on the type of interaction and factors discussed above. 

Measures of Exposure

EFED uses standard models to evaluate potential exposures to aquatic and terrestrial organisms 

as described at http://www.epa.gov/pesticides/science/models_db.htm.

The most up to date procedures and models are used in this Registration Review exposure

assessment.

The drinking water exposure pathway for birds and mammals was screened using the Screening 

Imbibition Program (SIP) screening method. The inhalation exposure pathway was screened 

using the Screening Tool for Inhalation Risk (STIR) method. The potential for bioaccumulation 

of profenofos in aquatic food webs and subsequent risks to mammals and birds via consumption 

of contaminated aquatic was evaluated using the Kow-based Aquatic BioAccumulation Model

(KABAM) model. These models are normally used as screening models during the problem 

formulation phase of the registration review risk assessment process. However, the problem 

formulation for profenofos (USEPA, 2008) predates the development (2009 - 2010) of these 

screening tools.

STIR (STIR v.1.0, November 19, 2010) was used to calculate an upper bound estimate of 

inhalation exposure using vapor pressure and molecular weight for vapor phase exposure as well 

as the maximum application rate and method of application for spray drift. STIR incorporates 
Page 18 of 75

results from several toxicity studies including the acute oral and inhalation rat toxicity endpoints 

(LD50 of 300 mg/kg-bw and LC50 of 3.6 mg/L, respectively) obtained from the “acute toxicity sixpack” of studies (which are a series of six guideline studies that are submitted for every registered 

pesticide product) and the most sensitive acute oral avian toxicity endpoint (mallard LD50 of 55 

mg/kg-bw). Based on the results of the STIR model, inhalation exposure alone was not 

determined to be a potential pathway of concern for avian/mammalian species on an acute basis. 

For a sample of the output generated by STIR v1.0, please see Appendix B.

The analysis of the inhalation route in STIR does not consider that aggregation with other 

exposure pathways - such as dietary, dermal, or drinking water may contribute to a total exposure 

that has a potential for effects to non-target animals. However, the Agency does consider the 

relative importance of alternate routes of exposure in situations where data indicate that other 

routes may be potentially significant contributors to wildlife risk (USEPA, 2004). The risk 

description section (Section 4.2), discusses the impact of consideration of other routes of 

exposure that have been identified as potentially important and the degree of certainty associated 

with screening-level risk assessment conclusions. 

SIP (SIP v.1.0, Released June 15, 2010) was used to calculate an upper bound estimate of 

exposure using profenofos’ solubility (20 mg/L), the most sensitive acute and chronic avian 

toxicity endpoints (mallard LD50 of 55 mg/kg-bw and northern bobwhite LOAEC of 1 mg/kgdiet, respectively). Drinking water exposure alone was determined to be a potential pathway of 

concern for mammalian species on a chronic basis and avian species on both an acute and chronic 

basis. For a sample of the output generated by SIP v.1.0, please see Appendix D.

The KABAM tool (KABAM v.1.0, Released April 7, 2009) was used to estimate potential 

bioaccumulation of hydrophobic organic pesticides in freshwater aquatic ecosystems and risks to 

mammals and birds consuming organisms which have bioaccumulated these pesticides. Model 

inputs for KABAM include profenofos’ octanol-water partition coefficient (log Kow of 4.83), 

sorbtion (Koc of 3890), the maximum modeled aquatic concentrations (21-day based on the time 

to steady state according ot the Kow) determined in Section 3.1.2 below, and the most sensitive 

acute and chronic avian and mammalian endpoints (Section 3.2.2).

KABAM indicates that there is potential for acute dietary-based risk (RQs range from 0.23 - 0.45) 

and chronic dietary-based risk (RQs range from 13 - 26) for all six of the default modeled avian 

species consuming fish contaminated by profenofos residues. This analysis likely underestimates 

chronic risk for avian species consuming contaminated fish residues as it necessitated the use of 

the LOAEC, since a NOAEC was not acceptable. Additionally, KABAM indicates acute dosebased risk for two (sandpipers and rails) of the six default modeled avian species consuming 

profenofos contaminated fish (RQs range from 0.03 - 0.47). KABAM did not indicate potential 

acute dose-based risk for mammals consuming fish contaminated with profenofos residues (RQs 

range from 0.02 - 0.07), but did indicate potential chronic dose- (RQs range from 10 - 28) and 

dietary-based (RQs range from 1.7 - 3.5) risk for all six of the default modeled mammalian 

species consuming fish contaminated by profenofos residues. For an example of the inputs for 

and output generated by KABAM v.1.0, please see Appendix E.
Page 19 of 75

Measures of Effect

Selected toxicity data are used to calculate risk estimates. Any additional information submitted 

by the registrant or found in the open literature is also considered. The open literature studies are 

identified using EPA’s ecotoxicity (ECOTOX)2database, which employs a literature search engine 

for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation 

of both sources of data can provide insight into the direct and indirect effects of pesticides on biotic 

communities from loss of species that are sensitive to the chemicals and from changes in structure 

and functional characteristics of the affected communities.

Endocrine Disruptor Screening Program (EDSP)

As required by FIFRA and the Federal Food, Drug, and Cosmetic Act (FFDCA), EPA reviews 

numerous studies to assess potential adverse outcomes from exposure to chemicals. Collectively, 

these studies include acute, subchronic and chronic toxicity, including assessments of 

carcinogenicity, neurotoxicity, developmental, reproductive, and general or systemic toxicity. 

These studies include endpoints which may be susceptible to endocrine influence, including effects 

on endocrine target organ histopathology, organ weights, estrus cyclicity, sexual maturation, 

fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard 

assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental and 

reproductive effects in different taxonomic groups. As part of the Preliminary Problem 

Formulation for Registration Review (USEPA, 2008, 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), Profenofos is subject to the endocrine 

screening part of the Endocrine Disruptor Screening Program (EDSP). 

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

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a 

“naturally occurring estrogen, or other such endocrine effects as the Administrator may 

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

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

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

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

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

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

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

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

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

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

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

identified for EDSP screening was published on June 14, 2013[1] and includes some pesticides 

 

2 http://cfpub.epa.gov/ecotox/

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

chemicals.
Page 20 of 75

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. Profenofos is not on List 1. For 

further information on the status of the EDSP, the policies and procedures, the lists of chemicals, 

future lists, the test guidelines and Tier 1 screening battery, please visit our website[2].

2.5 Previous Assessments

The most recent major risk assessment on profenofos was for the Reregistration Eligibility 

Decision (USEPA, 1999). The assessment noted significant data gaps regarding the persistence 

of profenofos under the acidic soil and water conditions that characterize its major use areas. 

However, additional fate data were not requested because fish kill incident reports were taken to 

provide evidence that profenofos will persist for sufficient time at concentrations that result in 

fish mortality within the use area. 

For aquatic organisms, the risk assessment predicted acute risk to listed freshwater fish species 

and listed and non-listed saltwater fish species, as well as acute and chronic risk to both listed 

and non-listed species of freshwater and saltwater invertebrates. However, chronic risk was not 

predicted for fish. 

For terrestrial organisms, the risk assessment predicted acute risk to listed avian species feeding 

on all dietary items and non-listed avian species feeding on all dietary items except for 

seeds/fruit. Chronic risk was predicted for avian species feeding on all dietary items. For small 

and medium mammals, risk was predicted for listed and non-listed species feeding on short grass 

and listed species only consuming forage and small insects. For large mammals, only listed 

species consuming short grass were considered at risk. 

Listed and non-listed terrestrial plants were expected to be at risk from channel runoff only. 

In 1989, the U.S. Fish and Wildlife Service issued a biological opinion for 109 pesticides, 

including profenofos (USFWS, 1989). USFWS concluded jeapordy for 21 aquatic species. This 

opinion predates the new approach for national-level pesticide Endangered Species Act 

assessmentmnets based on the National Academy of Sciences (NAS) report (National Research 

Council, 2013).

3. Analysis

3.1. Exposure Characterization

3.1.1. Environmental Fate and Transport Characterization

The major route of dissipation of profenofos in the environment is by microbial metabolism as 

well as by the abiotic process of hydrolysis. Profenofos is fairly non-persistent, with aerobic and 

 

[2] Available: http://www.epa.gov/endo/
Page 21 of 75

anaerobic soil metabolism half-lives of 2.3 and 2.1 days respectively. Degradation due to 

hydrolysis varies with pH, with half-lives ranging from 107 - 475 days for acidic (pH 5) waters, 

24.4 - 69.9 days for waters with neutral pH (pH 7), and 0.32 - 0.43 days for alkaline waters (pH 

9). Profenofos has a slight mobility potential to leach in soils. The organic carbon partition 

coefficient (KOC) was determined to be 3890. 

The predominant degradate of profenofos is 4-bromo-2-chlorophenol. Also formed in equimolar 

parts with this degradate is O-ethyl-S-propyl phosphorothioate. Additional degradates formed in 

excess of 10% include 4-bromo-2-chlorophenyl ethyl ether (BCPEE), 2-thioethylenecarboxy-4-

hydroxyphenyl methyl ether (THPME), and cyclohexadenyl sulfate. The major degradates, other 

than O-ethyl-S-propyl phosphorothioate, appear to have limited toxicity compared with the 

parent profenofos. O-ethyl-S-propyl phosphorothioate was not tracked in any submitted studies; 

therefore, its rate of formation and decline are unknown. However, one hydrolysis study (MRID 

41939001) suggests that O-ethyl-S-propyl phosphorothioate further degrades into O-ethyl 

phosphate and 1-propanethiol. 

Surface Water Impact

Profenofos breaks down rapidly under aerobic and anaerobic conditions and dissipates in neutral 

to alkaline soils with a half-life of several days. Acidic conditions typical of the areas where most 

profenofos use occurs favor a slower breakdown. Although not highly mobile, profenofos may 

reach surface waters through spray drift or runoff.

Surface water advisory included on current product label:

“This pesticide is acutely toxic to fish and wildlife. Use with care when applying to areas

frequented by wildlife or adjacent to any body of water. Due to the hazard to endangered 

fish, the application of this product is prohibited in Reeves County, TX and within one 

mile of the Dexter National Fish Hatchery in NM. For terrestrial uses, do not apply 

directly to water, or to areas where surface water is present, or to intertidal areas below 

the mean high water mark. Do not contaminate water by cleaning of equipment or 

disposing of equipment wash water. Because of the potential for surface water runoff 

from treated areas and the possibility of fish kills, do not apply to saturated soil, and do 

not treat while precipitation is occurring or while conditions favor runoff from the 

treated area.”

Table 6 lists the environmental fate properties of profenofos in the submitted environmental fate 

and transport studies. 

Table 6. Summary of Profenofos Environmental Fate Properties

Study Value (units) MRID # Study Status

Vapor Pressure 3.46E-06 torr 41905001 Supplemental

Octanol-water Partition 

Coefficient (log KOW)

4.83 @ 25 °C 42854201 Acceptable
Page 22 of 75

Study Value (units) MRID # Study Status

Hydrolysis T1⁄2 (at 25 C)1

107 – 475 @ pH 5

24.4 – 69.9 @ pH 7

0.32 -0.43 @ pH 9

41627309, 

41939001

Acceptable,

Acceptable

Aquatic Photolysis T1⁄2

1 266 Days 41939002 Acceptable

Aerobic Soil Metabolism T1⁄2

1 2.3 days @ 25 °C 42334302 Acceptable

Anaerobic Soil Metabolism 

T1⁄2

1

2.1 days @ 25 °C 42334303 Acceptable

Anaerobic Aquatic 

Metabolism, T1⁄2

1 3.8 days @ 25 °C 42218101 Acceptable

Sorption Koc 3890 (mL/g) 48612101 Supplemental

Fish Bioconcentration Factor 

(BCF)

29x (body)

45x (head)

682x (viscera)

92148059 Supplemental

1 Half-lives were recalculated using PestDF (EFED, 2014)

3.1.2. Measures of Aquatic Exposure

Aquatic exposures are quantitatively estimated for the only use site, cotton, with modeling 

scenarios that represent high potential exposures for profenofos use. 

Profenofos environmental fate data used for generating model parameters are listed in Table 7. 

Chemical property input values were chosen in accordance with current input parameter 

guidance (USEPA, 2009). 
Page 23 of 75

Table 7. Summary of environmental fate parameters for profenofos and values used for 

modeling (SWCC).

Parameter Range Value Used in Model Source

Molecular Weight 373.63 (g/mol) 373.63 (g/mol) Product chemistry

Solubility in water 20 mg/L 20 mg/L IRED (USEPA 2000)

Vapor Pressure 9.30 x 10-7torr 9.30 x 10-7torr The Pesticide Manual, 

1997, p. 1006

Hydrolysis T1⁄2 (at 25 C)1

107 – 475 (pH 5)

24.4 – 69.9 (pH 7)

0.32 -0.43 (pH 9)

69.9 days MRID 41627309, 

41939001

Aquatic Photolysis T1⁄2

1 T1⁄2 = 266 days 266 days MRID 41939002

Aerobic Soil Metabolism 

T1⁄2

1 2.3 days @ 25 °C 6.9 days

2.3 days x 3

MRID 42334302

(EFED, 2009)

Anaerobic Soil 

Metabolism T1⁄2

1 2.1 days @ 25 °C MRID 42334303

Water Column 

Metabolism T1/2

1

13.8 days @ 25 °C

6.9 days x 2 (EFED, 2009)

Anaerobic Aquatic 

Metabolism, T1⁄2

1 3.8 days @ 25 °C 3.8 days @ 25 °C MRID 42218101

Sorption Koc 3890 (mL/g) 3890 (mL/g) MRID 48612101

Application Efficiency 0.99 ground spray (EFED, 2009)

Foliar Half-Life 35 days (EFED, 2009)

Spray Drift % 0.0042

AgDrift (v 2.1.1)

with a 100 ft buffer 

Henry’s Law Constant 2.38 x 10-7

atm-m3

mol-1

2.38 x 10-7atm-m3

mol-1

(EFED, 2008)

1 Half-lives were recalculated using PestDF (EFED, 2014)

Results from the Surface Water Concentration Calculator (SWCC v1.1) model evaluating all 

available cotton scenarios are presented in Table 8. Each scenario was designed to represent a 

general geographical area. Maximum peak EECs were found in the Texas-cotton scenario, while 

the Mississippi-cotton scenario produced the maximum chronic concentrations. Maximum 

benthic pore water EECs were also calculated by the MS-cotton scenario with peak 

concentrations of 1.22 ppb and 21-day concentrations of 0.753 ppb (Table 9).

Table 8. Tier II Concentrations of Profenofos in Surface Water.

Estimated Environmental Concentrations (EEC) of profenofos residues for cotton in the 

EPA Pond with the SWCC model.

The simulations used the maximum labeled number (10) of applications and application rate (0.5 lb. 

a.i./A/application), and a maximum seasonal application rate (5 lb. a.i./A). 

1-in-10 year Profenofos Concentration (μg/L)
Page 24 of 75

Scenario -State Crop Peak 21-Day Average 60-Day Average

CA – Cotton 1.64 1.12 0.764

MS – Cotton 10.3 5.05 2.75

NC – Cotton 9.48 4.36 2.59

TX – Cotton 10.9 4.76 2.39

Table 9. Tier II Concentrations of Profenofos in Benthic Pore Water

Estimated Environmental Concentrations (EEC) of profenofos residues 

for cotton in Sediment Interstitial Water (Pore Water) with the SWCC 

model.

The simulations used the maximum labeled number (10) of applications and application 

rate (0.5 lb. a.i./A/application), and a maximum seasonal application rate (5 lb. a.i./A). 

1-in-10 year Profenofos Concentration (μg/L)

Scenario -State Crop Peak 21-Day Average

NC – Cotton 1.22 0.753

TX – Cotton 0.95 0.66

Monitoring Data

Monitoring data for profenofos was downloaded from the Water Quality Portal database

(http://waterqualitydata.us/) on June 4, 2015. The Water Quality Portal integrates data from the 

USGS National Water Information System (NWIS), EPA’s STORET data warehouse, and 

USDA ARS STEWARDS platform. A total of 2,336 records were retrieved for the analysis of 

profenofos. The data covered a time period from 1993 to March 2015. Twenty eight states were 

represented in the data set including (states that are bold represent current cotton growing states): 

AZ, CA, AL, AR, CO, CT, FL, GA, HI, IN, KY, MA, MD, MI, MN, MO, NC, NE, NV, NY, 

OH, OR, PA, TX, VA, WA, and WI. All of the samples were non-detects.

Data from California Department of Pesticide Regulation was also accessed for this assessment

on June 8, 2015. The sampling period for which profenofos was monitored in surface and 

ground water was 2002 - 2005 and 2007 - 2009. A total of 735 records were retrieved, all of 

which were non-detects with a limit of quantitation of 0.05 ppb. The CADPR surface water 

database can be found at: http://www.cdpr.ca.gov/docs/emon/surfwtr/surfcont.htm.

Groundwater monitoring data provided by the Texas Commission of Environmental Quality

(TCEQ) to the EPA returned 245 results. A total of 245 results were retrieved and occurred in 

the years 1987, 1988, 1990, and 2003. All of the results were non-detects with a limit of 

quantitation of 0.0059 ppb.

None of the data listed above is a result of sampling targeted to profenofos use. That coupled 

with a less robust sample frequency would suggest that the monitoring results are probably

missing the peak concentrations of profenofos.
Page 25 of 75

3.1.3. Measures of Terrestrial Exposure

3.1.3.1. Terrestrial Animals

Ingestion of Food Items Based on Foliar Application

Exposure estimates for terrestrial animals assumed to be in the target area or in an area exposed to 

spray drift are derived using the T-REX3(Terrestrial Residue EXposure model) model (version 

1.5.2., 6/11/2013). This model incorporates the Kenaga nomograph, as modified by Fletcher et al.

(1994), which is based on a large set of actual field residue data. The upper limit values from the 

nomograph represent an approximation of the highest residue value observed in the data set 

(Hoerger and Kenaga 1972). Consideration is given to different types of feeding strategies for 

mammals and birds; including herbivores, insectivores and granivores. For dose-based exposures, 

three weight classes of birds (20, 100, and 1000 g) and mammals (15, 35, and 1000 g) are 

considered. Two studies are available with dislodgeable foliar residue data for profenofos (MRIDs 

42815303 and 42851304) indicating foliar dissipation half-lives of less than one day. However, 

EFED requires three foliar dissipation half lives in order to use this data quantitatively in the risk 

assessment. Therefore, the default foliar dissipation half-life of 35 days is used based on the work 

of Willis and McDowell (1987) for risk estimation. The impact of the potentially shorter foliar 

dissipation half-lives derived from empirical data will be characterized in the risk description 

section. This assessment assumes a maximum single application rate of 0.5 lbs a.i./A with 10

applications of profenofos per year (5 day minimum reapplication interval) to estimate terrestrial 

exposure for this assessment. The dietary-based EECs (upper bound Kenaga) on a variety of food 

items from the use of profenofos applied at the maximum label rate is provided in Table 10; dosebased EECs are provided in Table 11. 

Table 10. T-REX Calculated Dietary-Based EECs of Profenofos on Food Residues.

Food Type Cotton Use Site

Maximum Dietary-based EECs (mg/kg)

Short Grass 800

Tall Grass 367

Broadleaf plants 450

Fruits/pods/seeds 50

Arthropods 313

 

3 USEPA. 2013. Pesticides: Science and Policy. Terrestrial Models, T-REX Version 1.5.2 

http://www.epa.gov/oppefed1/models/terrestrial/
Page 26 of 75

Table 11. T-REX Calculated Maximum Dose-Based EECs of Profenofos Use on Terrestrial 

Food Residues (Cotton Use Site)

Food Type

Dose-based EECs

(mg/kg-bw)

(birds)

Dose-based EECs

(mg/kg-bw)

(mammals)

Small

(20 g)

Medium

(100 g)

Large

(1000 g)

Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Short grass 911 520 233 763 527 122

Tall grass 418 238 107 350 242 56.0

Broadleaf plants 513 292 131 429 297 68.8

Fruits/pods 56.9 32.5 14.5 47.7 33.0 7.64

Arthropods 357 203 91.1 299 206 47.9

Seeds (granivore) 12.7 7.22 3.23 10.6 7.32 1.70

3.1.3.2. Terrestrial Plants

Profenofos exposure to terrestrial and semi-aquatic plants is estimated using the TerrPlant4

(version 1.2.2) model. The model generates EECs for plants residing near a use area that may be 

exposed via runoff and/or spray drift. The EECs are generated from one application at the 

maximum rate for a particular use and compound-specific solubility information. Only a single 

application is considered because it is assumed that for plants, toxic effects are likely to manifest 

shortly after the initial exposure and that subsequent exposures do not contribute to the response.

Hence, the model estimates EECs based on application rate, the solubility factor, and default 

assumptions of drift. The EECs for terrestrial and semi-aquatic plants for a single application of 

profenofos at the maximum label rate are presented in Table 12. 

Table 12. Max EECs for Terrestrial and Semi-Aquatic Plants Near Profenofos Use Areas.

Single Max. 

Application Rate

(lbs a.i./A, Cotton Use 

Site)

EECs (lbs a.i./A)

Total Loading to 

Adjacent Dry Areas 

(sheet runoff + drift)

Total Loading to SemiAquatic Areas 

(channelized runoff + 

drift)

Drift EEC

0.5 0.0105 0.105 0.005

 3.2. Ecological Effects Characterization

The ecological effects characterization for profenofos is based on data generated from guideline 

studies submitted by the registrant and from open literature studies in the ECOTOX database 

(http:/www/epa.gov/ecotox). 

A brief description of available aquatic and terrestrial toxicity data used to calculate RQs is 

provided below in Sections 3.2.1 and 3.2.2. Section 3.2.3 describes the available reports of 

ecological incidents involving the use of profenofos.

 

4 USEPA. 2013a. Pesticides: Science and Policy. Terrestrial Models, TerrPlant Version 1.2.2. 

http://www.epa.gov/oppefed1/models/terrestrial/
Page 27 of 75

Some open literature data is available that indicates that chiral isomers of profenofos can have 

differential toxicity. For example, Leader and Casida (1982) found that the (-) isomer was 4 - 23 

times more toxic to mice and several insect species than the (+) isomer. However, none of the 

acceptable registrant-submitted or open literature data identify the proportion of each isomer 

utilized in the ecotoxicity studies. Therefore, there is potential for this assessment to over- or 

under-estimate risk to non-target organisms depending on the production and fate of profenofos 

isomers in the environment and the actual ratio of isomers used in the ecotoxicity studies. 

3.2.1. Aquatic Effects Characterization

The most sensitive aquatic toxicity data for animals and plants are summarized in Table 13. For 

freshwater and estuarine/marine fish and invertebrates (and for aquatic-phase amphibians, for 

which fish are considered surrogates), the compound is considered very highly toxic. Many of the 

aquatic studies conducted using profenofos may have underestimated the actual toxicity of the 

compound since they did not analytically measure concentrations, and the endpoints are reported 

using nominal concentrations. Many of these were older studies conducted in static conditions 

and often in somewhat alkaline water (>8.0 pH) where profenofos is most likely to degrade 

quickly. Therefore, the reported nominal concentrations may represent an overestimate of actual 

profenofos exposure and the effects endpoints would therefore be more sensitive than reported. 

Fish

The most sensitive acute endpoint for freshwater fish that may be used quantitatively was the 96-

hour LC50 for bluegill (Lepomis machrochirus) of 14.1 μg/L from Mayer and Ellersieck (1986, 

MRID 400980-01). Although this study used nominal concentrations, pH was maintained at 7.1 

in the study; therefore, actual concentrations may not differ significantly from the nominal levels. 

In the open literature, a more sensitive acute freshwater fish study (Pandey et al., 2011, ECOTOX

reference number E158179) using spotted snakehead (Channa punctatus) determined an LD50 of 

2.31 μg/L after exposure to the profenofos formulation CELCRON (50% a.i. in an emulsifiable 

concentrate formulation that is not currently registered in the U.S.). EFED has reviewed this study 

and under the current guideline standards considered the study to be supplemental (due to lack of 

measured residues and pooling of study data collected from different times). The endpoint may 

be used qualitatively in risk assessment. The most sensitive acute endpoint for estuarine/marine 

fish was the 96-hr LC50 for pinfish (Lagodon rhomboides) of 7.7 μg/L (MRID 000859-60). 

Although this study used nominal concentrations, pH at 0 hours was 8.0 but decreased to 7.5 - 7.6 

by test termination; therefore, actual concentrations may not differ significantly from the nominal 

levels. 

Although chronic study data are not available for the most sensitive freshwater and 

estuarine/marine species, an early life stage test using fathead minnow (Pimephales promelas; 

MRID 000859-58) determined a 31-day NOAEC of 2.0 μg a.i./L based on 31% reduced survival 

and 10% reduced total length of juveniles at 4.4 μg a.i./L compared to control fish. Using the 

available acute fathead minnow endpoint of 122 μg a.i./L (MRID 492906-01) and the chronic 

fathead minnow endpoint, an acute-to-chronic ratio (ACR) of 61 was generated and applied to the 

most sensitive acute freshwater and saltwater fish endpoints to result in conservative estimates of 

0.23 μg a.i./L and 0.13 μg/L chronic endpoints for bluegill and pinfish, respectively. 
Page 28 of 75

Aquatic Invertebrates

The most sensitive acute endpoint for freshwater invertebrates that may be used quantitatively was 

the 48-hour LC50 for Daphnia magna of 0.91 μg/L (MRID 00108015). Although this study used 

nominal concentrations, pH remained below 7.50; therefore, actual concentrations may not differ 

significantly from the nominal levels. The most sensitive acute endpoint for estuarine/marine 

invertebrates was 2.4 μg/L (96-hr LD50 for the mysid, Americamysis bahia, MRID 00085963). 

The chronic daphnid NOAEC is 0.20 μg/L based on visual inspection of figures in the study report 

on ~70% increased mortality and ~75% reduced offspring production at 0.33 μg/L. The chronic 

mysid NOAEC is 0.22 μg/L based on 45% increased mortality and 76% reduced offspring 

production at 0.35 μg/L. In the open literature, a much more sensitive acute LC50 endpoint for 

freshwater invertebrates of 0.041 μg/L for Ceriodaphnia dubia, based on nominal concentrations, 

was reported from Woods et al., 2002 (Ecotox reference number E158195) using TGAI. EFED 

has reviewed this study and, under the current guideline standards, considered the study to be 

supplemental, and the endpoint may be used qualitatively in risk assessment. The potential impact 

of the more sensitive open literature data on the risk assessment is discussed below in Section 

4.2.1 The pH in this study was slightly basic (8.0 ± 0.1) and given profenofos’ degradation 

potential under basic conditions, it is possible that actual exposure concentrations in this study may 

be less than the nominal concentrations. No ecotoxicological data is available for benthic aquatic 

invertebrates. 

Aquatic Plants

For aquatic vascular plants, the IC50 for duckweed (Lemna gibba) was 3,460 μg a.i./L (timeweighted average concentration) based on decreased frond number. At the duckweed NOAEC of 

1,270 μg a.i./L, there was an approximately 13% inhibition of frond number. No quantitative data 

is available for aquatic non-vascular plants. A non-vascular plant study with the green algae 

(Pseudokirchneriella subcapitata, MRID 48612104) was considered supplemental because the 

time duration was only 72 hours under regular lighting conditions (i.e. 4-5 klux) with low 

replication (3 replicates) and narrowly did not meet several of the control performance criteria 

(i.e.. growth and variability criteria for control plants) established by EPA guidelines for aquatic 

nonvascular plant testing (OCSPP 850.4500 guideline). The 72-hour IC50 and NOAEC endpoints 

of 508 μg a.i./L and 130 μg a.i./L, respectively, from this study may only be used qualitatively in 

risk assessment. As control algae did not meet the established performance criteria and the study 

was not conducted for the guideline requirement of 96-hours, the estimated endpoints may 

somewhat underestimate actual toxicity to green algae. No other aquatic, non-vascular plant data 

is available for profenofos and this is considered a data gap, but this study indicates that nonvascular plants may be more sensitive than vascular aquatic plants. 

Profenofos Degradates

For the degradate, 4-bromo-2-chlorophenol, the only ecotoxicological data was for a marine green 

algae, Tetraselmis marina (Liu and Zhang, 2014) which was reported to have an EC50 of 120 μM 

(equivalent to 24,900 μg/L). No empirical aquatic ecotoxicological data is available for the 

degradate, O-ethyl-S-propyl phosphorothioate which is predicted to form on an equimolar basis 

with the 4-bromo-2-chlorophenol degradate, or any of the other degradates. 
Page 29 of 75

EFED attempted to see if QSAR could be used to estimate the toxicity of profenofos degradates 

(Appendix F). This analysis found that QSAR models performed well, or reasonably well, in 

predicting the toxicity of parent profenofos to algae, acute toxicity to daphnia, chronic toxicity to 

freshwater fish, acute and chronic toxicity to mysids; however, it did not perform well when 

predicting the chronic toxicity of profenofos to daphnids, acute toxicity to freshwater fish, or acute 

and chronic toxicity to saltwater fish. For those taxa where the model performed well predicting 

the toxicity of parent profenofos, the only degradates for which the predicted toxicity approached 

the predicted toxicity of parent profenofos was the O-ethyl-S-propyl phosphorothioate degradate. 

This degradate was predicted to be approximately 3x less toxic to algae, 1.6x less toxic to daphnids 

on an acute basis, of identical toxicity to freshwater fish on a chronic basis, 1.5x less toxic to 

mysids on an acute basis, and 1.6x less toxic to mysids on a chronic basis. The O-ethyl phosphate

metabolite from O-ethyl-S-propyl phosphorothioate which was predicted to be 2.5x less toxic to 

freshwater fish on a chronic basis than its parent compound(s). This degradate may be 

metabolically produced as a detoxifying mechanism by CytP450 in animals and therefore the 

existing toxicity studies may potentially already account for its toxicity (despite not tracking its 

formation in those studies). All additional degradates were predicted to be of low toxicity 

compared to parent profenofos.

Table 13. Summary of the Acute and Chronic Toxicity Data used for Risk Estimation for 

Aquatic Animals Exposed to Profenofos. Bolded values represent the endpoints used for 

risk estimation.

Species Test 

substance

(% a.i.)

Acute Toxicity Chronic Toxicity

96-hr 

LC50/EC50

(μg a.i./L)

48-hr EC50

(μg a.i./L)

Toxicity 

Classification 

(MRID, study 

classification)

NOAEC/

LOAEC

(μg a.i./L)

Endpoints

(MRID, study 

classification)

Bluegill sunfish

(Lepomis macrochirus)

TGAI

90.6%

14.1

(nominal) --

Very Highly 

Toxic

(40098001, 

Supplemental)

0.23 ACR 

Calculation1

Fathead minnow

(Pimephales promelas)

TGAI

93.2%

122

(meanmeasured)- -

Highly Toxic

(49290601, 

Acceptable)

2.0/4.4

(31-Day

endpoint, 

meanmeasured)

Mortality, Total 

Length

(00085958, 

Acceptable)

Waterflea

(Daphnia magna)

TGAI

90.4 % a.i. --

0.91

(nominal)

Very Highly 

Toxic

(00108015, 

Acceptable)

(42-days) 

0.2/0.33

(meanmeasured)

Mortality, 

Reduced 

Reproduction

(00085964

Acceptable)

Pinfish

(Lagodon rhomboids)

TGAI

90.6%

7.7

(nominal) --

Very Highly 

Toxic

(00085960, 

Acceptable)

0.13 ACR 

Calculation2

Mysid shrimp

(Americamysis bahia)

TGAI 

90.6%

2.4

(meanmeasured)

--

Very Highly 

Toxic

(00085963, 

Supplemental)

(28-days) 

0.22/0.35

(meanmeasured)

Mortality, 

Reduced 

Reproduction 

(00085963, 

Acceptable)

Aquatic Plants
Page 30 of 75

Species Test 

substance

(% a.i.)

Acute Toxicity Chronic Toxicity

96-hr 

LC50/EC50

(μg a.i./L)

48-hr EC50

(μg a.i./L)

Toxicity 

Classification 

(MRID, study 

classification)

NOAEC/

LOAEC

(μg a.i./L)

Endpoints

(MRID, study 

classification)

Duckweed

(Lemna gibba)

TGAI

93.2% a.i. N/A N/A N/A

7-day IC50

= 3,460

7-d NOAEC/

LOAEC = 

1,270/

2,450

(TWA)

Frond numbers 

(48612103, 

Acceptable)

Non-vascular aquatic 

plants N/A N/A N/A N/A No Data No Data

1 Since the acute bluegill LD50 is more sensitive than the acute fathead minnow endpoint and chronic data is only 

available for the fathead minnow, an acute-to-chronic ratio (ACR) was generated from the acute and chronic 

fathead minnow endpoints and applied to the bluegill LD50 to conservatively evaluate chronic effects to the most 

sensitive freshwater fish. 

2 No data is available for chronic effects of profenofos to estuarine/marine fish. An ACR was generated from the 

acute and chronic fathead minnow endpoints and applied to the pinfish LD50 to evaluate chronic effects to 

estuarine/marine fish.

3.2.2. Terrestrial Effects Characterization

Toxicity values for terrestrial animals and plants are summarized in Tables 14 and 15, 

respectively. Profenofos is classified as moderately toxic to mammals on an acute oral basis, 

moderately to highly toxic to birds on an acute oral basis and highly toxic to birds on a subacute 

dietary exposure basis. 

Birds

In an acute oral study with the canary (Serinus canaria), several canaries regurgitated profenofos 

administered in the diet at 20 mg a.i./kg bw (one of which subsequently died). Since the dose these 

birds actually received is uncertain, the risk assessment will use the regurgitation-based NOAEC 

of 10 mg a.i./kg bw as a conservative surrogate for the acute endpoint used in risk estimation. 

Regurgitation was only observed at the nominal 20 mg a.i./kg bw dose and therefore did not appear 

to follow a dose-response relationship. Thus, there is some uncertainty as to whether this was a 

toxic effect of the test substance. Removal of this treatment group resulted in an estimated LD50

of 40.8 mg a.i./kg bw with 95% confidence intervals of 18.3 to 57.4 mg ai/kg bw. This estimated 

LD50 will be used qualitatively to characterize acute risk to avian species. On a chronic basis, 

profenofos resulted in reproductive impairment (i.e. reduction in egg production/viability of eggs) 

to bobwhite quail at all doses tested resulting in a LOAEC of 1 ppm (maximum effect at this 

concentration of 33% inhibition on the number of normal hatchlings per eggs laid). The lack of a 

valid NOAEC for avian reproduction is considered a major data gap. 

Mammals

In chronic two-generation mammalian reproduction studies (MRIDs 43213308 and 43213309), 

profenofos was incorporated continuously in the feed of male and female Sprague-Dawley rats for 

two successive generations at dietary concentrations of 0, 5, 100 and 400 ppm. The NOAEC was 

100 ppm (7.3 mg/kg-diet/day), based on reduced body weights and food consumption of F0 and F1
Page 31 of 75

males and females, and decreased pup body weight of both sexes in F1 and F2 litters at 400 ppm 

(29 mg/kg-diet/day). The maximum percent inhibition at the LOAEC for each of these endpoints 

was approximately 10-15% relative to controls. 

Terrestrial Plants

Concerning profenofos’ effects to terrestrial plants, previously, MRID 41627305 had been 

considered acceptable and used to provide data on vegetative vigor to support the registration of 

profenofos. This study found no effects on any of the ten species tested up to the maximum rate 

tested of 1.0 lb a.i./A. However, the study was conducted with TGAI profenofos (90.4% purity)

in place of a typical end-use product (TEP). Therefore, it has been downgraded to supplemental,

may only be used qualitatively in the risk assessment, and is considered a data gap. Similarly, the 

previously acceptable seedling emergence study (MRID 41627307) has been downgraded to 

supplemental based on the use of TGAI instead of TEP. However, since surfactants and other inert 

ingredients in TEPs are likely to disassociate from the test substance before reaching the plant life 

stage tested in this study, this study may be used quantitatively in the risk assessment. The most 

sensitive species in the seedling emergence study was cucumber with a NOAEC and EC25 of 0.11 

and 0.13 lb a.i./A, respectively. None of the monocots showed any effects after treatment with up 

to 1.0 lb a.i./A.

Table 14. Profenofos Terrestrial Animal Toxicity Summary. Bolded values indicate 

endpoints used in risk estimation.

Parameter Study Type Species Exposure 

Duration

Test 

substance

(% a.i.)

Toxicity Value/

Endpoint Affected

Reference

Toxicity 

Classification

/ Study 

Classification

1. Abundance 

(i.e., survival, 

reproduction, 

and growth) of 

individual 

birds

1a. Acute 

(Dose-based)

Mallard duck

Anas 

platyrhyncho

s

Single oral 

dose

TGAI

(89.4%)

55.0 mg/kg bw 

(LD50)/

Mortality

41627301

Moderately 

Toxic/

Acceptable

Canary

Serinus 

canaria

Single oral 

dose

TGAI 

(93.2%)

10 mg/kg bw

(NOAEC)/

Regurgitation

48612102

Highly Toxic/

Supplemental 

(Quantitative)

1b. Acute 

(Dietarybased)

Northern 

Bobwhite 

Colinus 

virginianus

8-Day dietary TGAI

(92%)

57 mg/kg diet 

(LC50)/

Mortality

43107301

Highly Toxic/

Acceptable

1c. Chronic 

(Dietarybased)

Northern 

bobwhite (C. 

virginianus)

Avian 

reproduction 

study

TGAI

(90.6%)

< 1 mg/kg-diet

(NOAEC)/

Reproductive

impairment

00086661

Acceptable

2. Abundance 

(i.e., survival, 

reproduction, 

and growth) of 

2a. Acute -oral Mouse (Mus 

musculus)

Single oral 

dose

TGAI

(%ai not 

reported)

298 mg/kg bw 

(LD50)

00105226

Moderately 

toxic /

Acceptable
Page 32 of 75

Parameter Study Type Species Exposure 

Duration

Test 

substance

(% a.i.)

Toxicity Value/

Endpoint Affected

Reference

Toxicity 

Classification

/ Study 

Classification

individual 

mammal

Rabbit 

(Oryctolagus 

cuniculus)

Single oral 

dose

TGAI

(%ai not 

reported)

300 mg/kg bw 

(LD50)

00105228

2b. AcuteinhalationRat (Rattus 

norvegicus)

4-hour 

inhalation 

exposure

TGAI

(%ai not 

reported)

3.36 mg/L (LC50) 00109428

2c. Chronic Rat (Rattus 

norvegicus)

2-Generation 

reproduction 

study

TGAI

(92%)

7.3

(NOEL)

LOEL =

29 mg/kg-diet 

based on decreased

F0 and F1 body 

weights, food 

consumption and 

decreased pup body 

weight F1 and F2

43213308

43213309

Acceptable

3. Survival of 

beneficial 

insects 

3a. Acute 

Contact 

(Adult)

Honey Bee 

(Apis 

mellifera)

48 hours TGAI

(90.4%)

0.0953 μg a.i./bee

(LD50)/

Mortality

41627308

Highly Toxic 

Acceptable

3b. Acute Oral 

(Adult) 48 hours N/A No Data No Data

3c. Chronic 

Oral (Adult) 10 days N/A No Data No Data

3d. Acute Oral 

(Larvae) 8 Days N/A No Data No Data

3e. Chronic 

Oral (Larvae) 21 Days N/A No Data No Data

Table 15. Summary of Tier II Terrestrial Plant Toxicity Data for Profenofos

Crop Species EC25 (lbs 

a.i./A)

NOAEC (lbs 

a.i./A)

Most 

sensitive 

parameter

MRID

Seedling Emergence

Monocots

Oat >1.0 1.0 N/A 41627307

Ryegrass >1.0 1.0 N/A 41627307

Corn >1.0 1.0 N/A 41627307

Onion >1.0 1.0 N/A 41627307

Dicots

Lettuce >1.0 0.333 Dry Weight 41627307

Soybean >1.0 1.0 N/A 41627307

Carrot >1.0 1.0 N/A 41627307

Tomato >1.0 1.0 N/A 41627307
Page 33 of 75

Crop Species EC25 (lbs 

a.i./A)

NOAEC (lbs 

a.i./A)

Most 

sensitive 

parameter

MRID

Cucumber 0.130 0.111 Dry Weight 41627307

Cabbage >1.0 0.333 Plant Height, 

Dry Weight 41627307

Vegetative Vigor

Monocots

Oat No Data No Data N/A N/A

Ryegrass No Data No Data N/A N/A

Corn No Data No Data N/A N/A

Onion No Data No Data N/A N/A

Dicots

Soybean No Data No Data N/A N/A

Carrot No Data No Data N/A N/A

Tomato No Data No Data N/A N/A

Cucumber No Data No Data N/A N/A

Cabbage No Data No Data N/A N/A

Lettuce No Data No Data N/A N/A

3.2.3. Review of Incident Data

A review of the Environmental Incident Information System (EIIS, version 2.1.1) database and 

the Incident Data System (IDS) database, which are maintained by the Agency’s Office of 

Pesticide Programs; and the Avian Monitoring Information System (AIMS), which is maintained 

by the American Bird Conservancy, for ecological incidents involving profenofos was completed 

on April 7, 2015. The review specified a total of 23 reported ecological incidents associated with 

the use of profenofos which are summarized in Table 16. 

This total excludes incidents classified as ‘unlikely’ or ‘unrelated’ and only includes those 

incidents with certainty categories5of: ‘possible,’ ‘probable,’ and ‘highly probable’ (for EIIS);

and ‘possible,’ ‘probable,’ ‘likely,’ ‘highly likely,’ and ‘certain’ (for AIMS). Incidents classified 

as ‘unlikely’ the result of, or ‘unrelated’ to, profenofos will not be included in this ecological risk 

assessment conducted for Registration Review.

All of the profenofos incidents, excluding those classified as ‘unlikely’ or ‘unrelated,’ occurred 

between 1992 and 1999 in Alabama, Georgia, Louisiana and Mississippi. Twenty-two of the 

profenofos incidents involved fish and one incident involved crayfish. The certainty categories 

regarding the likelihood that the use of profenofos caused the 23 incidents ranged from ‘possible’

(7 incidents) to ‘highly probable’ (6 incidents). Ten of the incidents were considered registered

 

5 The Ecological Incident Information System (EIIS) used by EPA to store incident data relies on the following certainty indices: 

 Highly Probable: (residues detected in affected organisms and other lines of evidence support cause)

 Probable: (residues were not measured or the measured residues were not sufficient to be considered toxic, but 

pesticide was used in close proximity and would be capable of exerting such an effect)

 Possible: multiple pesticides were used in close proximity and any of them are capable of causing such an effect.

 Unlikely: there are no measured residues and the observed effects are not consistent with those caused by pesticides 

used in the area or there was no pesticide use known in the area.

 Unrelated: effects observed in the incident are unrelated to pesticide use.
Page 34 of 75

uses at the time of the incident, 2 involved misuses, and the legality of use was undetermined in 

11 incidents. Ten of the incidents involved additional chemicals besides profenofos; however, in 

4 of those incidents, profenofos was the only pesticide for which the certainty was greater than 

‘unlikely’. Profenofos residues in water samples were reported in 13 of the incident reports (see 

Table 17). Of those incidents where profenofos residues were reported, 2 incidents had samples 

with maximum residues < 1 ppb profenofos, 7 incidents had maximum measured residues 

between 1 and 10 ppb, 3 incidents reported residues between 10 and 100 ppb, and 1 incident 

reported residues > 100 ppb. Although past and current registrations for profenofos have been 

limited to use on cotton, 14 of the 23 incidents were reported for cotton use, while two of the 

areas were defined as agricultural areas. The remaining seven areas were undefined. Seven of 

the incidents were identified as following aerial application of profenofos (which is no longer 

permitted by the product label), 1 incident was identified as following ground application of 

profenofos, and the remaining 15 incidents did not identify the application method.

In addition to the incidents recorded in EIIS and AIMS, additional 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. For

profenofos, registrants have reported 4 minor fish and wildlife incidents, 0 minor plant incidents, 

and 0 other non-target incidents. These 4 aggregate incident reports were provided to the Agency 

in 1998-1999. Unless additional information on these aggregated incidents become available, 

they will be assumed to be representative of registered uses of profenofos in the risk assessment.

Although the number of reported incidents has dropped considerably since mitigation measures 

were implemented following the 2000 IRED (USEPA, 2000), the lack of incident reports cannot 

be construed as the absence of incidents from the registered use of profenofos. Reporting by 

states is only voluntary, and individuals discovering incidents may not be informed on the 

procedure of reporting these occurrences. Additionally, much of these databases are generated 

from registrant-submitted incident reports. In addition, incident reports for non-target organisms 

typically provide information only on mortality events and plant damage incidents. Impacts to 

non-commercial, beneficial insects and other invertebrates are not likely to be reported. Except 

for phytotoxic effects in terrestrial plants, sublethal effects for organisms such as reduced growth 

or impaired reproduction are rarely reported. Because of these logistical difficulties, EIIS is 

most likely a minimal representation of all pesticide-related ecological incidents and the absence 

of incident reports cannot be construed as the absence of incidents. However, the incident data 

that are available suggest that exposure pathways for profenofos are complete and that exposure 

levels are sufficient to result in field-observable effects.

Table 16. Summary of Ecological Incidents in the Environmental Incident Information 

System (EIIS 2.1.1) Database Associated with Profenofos Use, by Certainty
Page 35 of 75

Incident 

Type Use Type

Certainty

All 

(excluding 

unlikely)

Unlikely Possible Probable Highly 

Probable

Fish and 

Aquatic 

Invertebrates

Misuse 

(accidental) 2 0 0 2 0

Registered Use 10 2 3 4 3

Unknown 11 1 4 4 3

Total 23 3 7 10 6

Table 17. Summary of Ecological Incidents with Measured Profenofos Residues in the 

EIIS Database.

Incident Number Year Location Certainty Profenofos 

Residues (ppb)

I001195-002 1994 Ouachita, LA 3 1.1--12

I001195-001 1994 Richland, LA 3 1.3—2.3

I002211-001 1994 Rankin, MS 3 0.192—36.4

I004875-004 1996 Richland, LA 4 280

I004021-004 1996 Richland, LA 3

0.6—1.1 in 

water (up to 

1,180 ppb in 

tissue)

I004021-005 1996 Richland, LA 3 0.7—1.5

I004468-010 1996 Madison, LA 2 0.2—1.2

I007948-007 1997 Holmes, MS 3 0.7—7.2

I007796-012 1997 Washington, MS 3 26.7—30.4

I008237-001 1998 Holmes, MS 3 1.2—1.8

I002211-003 1994 Humphreys, MS 3 0.4—0.7

I004668-008 1996 Richland, LA 2 0.08—3.58

I004668-009 1996 Richland, LA 2 0.16—0.68

Certainty Code: 0 = Unrelated, 1 = Unlikely, 2 = Possible, 3 = Probable, 4 = Highly Probable.

4. Risk Characterization

4.1. Risk Estimation

4.1.1. Aquatic Organisms 

The peak EECs in surface water generated from the SWCC model (using the maximum application 

rate from cotton) represents acute exposure to fish, aquatic invertebrates, and aquatic plants, and 

the highest 21-day and 60-day average EECs represents chronic exposure to aquatic invertebrates 

and fish, respectively. Acute and chronic RQs for freshwater and estuarine/marine animals and 

aquatic vascular and nonvascular plants are summarized in Table 18.

4.1.1.1. Fish
Page 36 of 75

The listed and non-listed species LOC’s were exceeded for acute risk to freshwater and 

estuarine/marine fish (Table 15; RQs range from 0.73 to 1.34). Chronic data were not available 

for the most sensitive fish species (bluegill sunfish and pinfish), but chronic endpoints for these 

species, generated using the ACR developed from the acute and chronic fathead minnow 

endpoints, resulted in exceedances of the fish chronic LOC for both freshwater and saltwater fish 

(RQs range from 12.0 to 21.2).

4.1.1.2 Aquatic invertebrates

The listed and non-listed species LOC’s were exceeded for acute risk to freshwater and 

estuarine/marine invertebrates (RQs range from 4.29 to 11.3). The aquatic invertebrate chronic 

LOC was exceeded for chronic risk to freshwater and estuarine/marine invertebrates (RQs ranged 

from 23.0 to 25.3).

4.1.1.3 Aquatic Plants

As shown in Table 18, RQs for vascular plants do not exceed the LOC (1.0) for listed or non-listed 

plants for the currently registered use of profenofos (RQs ≤ 0.01). Risk to non-vascular aquatic 

plants cannot be quantified due to a lack of adequate non-vascular aquatic plant data.

Table 18. Summary of Acute and Chronic RQs for Freshwater and Estuarine/Marine Fish,

Invertebrates and Aquatic Plants Exposed to Profenofos

Species Toxicity Endpoint

(ppb)

Maximum

EECs*

Maximum

RQs

Freshwater Fish: 

Bluegill sunfish

(Lepomis macrochirus)

Acute 14.1 10.3 0.73

Chronic 0.23 2.75 12.0

Pinfish

(Lagodon rhomboids)

Acute 7.7 10.3 1.34

Chronic 0.13 2.75 21.2

Freshwater Invertebrates:

Waterflea

(Daphnia magna)

Acute 0.91 10.3 11.3

Chronic 0.2 5.05 25.3

Saltwater Invertebrates: 

Mysid shrimp 

(Americamysis bahia)

Acute 2.4 10.3 4.29

Chronic 0.22 5.05 23.0

Aquatic Non-Vascular Plant

No Data

Non-Listed No Data 10.3 N/A

Listed No Data 10.3 N/A

Aquatic Vascular Plants:

Duckweed (Lemna gibba)

Non-listed 3,460 10.3 <0.01

Listed 1,270 10.3 0.01

* EECs are estimated surface water concentrations based on SWCC model runs. 

4.1.2. Terrestrial Organisms

4.1.2.1. Birds

A valid NOAEC is not available for avian reproduction; therefore, the chronic avian RQs presented 

in Table 19 use the LOAEC and are non-definitive (“greater than”) minimum RQs. Further 

discussion of chronic risk to birds is provided as part of the risk description in Section 4.2.2 as is
Page 37 of 75

different acute endpoints for birds (i.e. estimates of the avian acute oral LD50 compared to the 

regurgitation NOAEC) and the effect of shorter foliar dissipation half-lives based on the available 

dislodgeable foliar residue data for profenofos. 

Using the regurgitation-based NOAEC as a conservative acute endpoint for birds (the canary 

NOAEC of 10 mg/kg-bw and the test organism body weight of 21.5 g), the maximum single and 

annual application rates with minimum reapplication intervals (10 applications at 0.5 lbs ai/A 

application with 5 day intervals), the default 35-day foliar dissipation half-life, and the upper 

bound Kenaga residue values, the acute listed species LOC (0.1) is exceeded for all size classes 

of birds feeding on all dietary items (RQs ranged from 0.18 to 92.10) and the non-listed species 

LOC (0.5) was exceeded for all size classes of birds feeding on all dietary items except for large 

birds feeding on grains (RQ=0.18). For medium sized birds feeding on grains, the exceedance 

was marginal (RQ=0.57). Using the bobwhite sub-acute dietary LC50 of 57 mg/kg-diet, the listed 

and non-listed acute dietary LOCs are exceeded for birds consuming all dietary items (0.88 -

14.03). Similarly, using the non-definitive NOAEC (i.e. the NOAEC was less than the lowest 

dose tested) of 1 mg/kg-diet for bobwhite, the chronic LOC (1.0) would be exceeded for birds 

consuming all dietary items (RQs ranged from >50 to >800). Using the default foliar dissipation

half-life of 35 days, upper bound estimates of residues on dietary items results in exceedances for 

avian species that persist for up to approximately 220 days after the first application (Appendix 

G).

4.1.2.2 Mammals

Using the mouse acute LD50 of 298 mg/kg-bw for mammals and for the maximum single and 

annual application rates with minimum reapplication intervals (10 applications at 0.5 lb ai/A 

application with 5 day intervals), the default 35-day foliar dissipation half-life and the upper 

bound Kenaga values, there were exceedances of the listed and non-listed species acute LOCs

(0.1 and 0.5, respectively) for all size classes of mammals for short grass and broadleaf plants 

(RQs range from 1.08 to 2.25). The listed and non-listed species acute LOCs are also both 

exceeded for small and medium mammals feeding on tall grass and arthropods (RQs range from 

0.75 - 1.03), but only the listed species LOC is exceeded for large mammals feeding on these 

dietary items (RQs 0.40 - 0.47). The listed species acute LOC was marginally exceeded for 

small and medium mammals feeding on fruits/pods/seeds, but not for large mammals feeding on 

these dietary items (RQs 0.06 - 0.14) nor for any size class of mammal feeding on grain (RQs 

0.01 - 0.03).

On a chronic dose basis, using the chronic rat NOAEC of 7.3 mg/kg-diet, the LOC (1.0) is 

exceeded for all size classes of mammals consuming all dietary items (RQs range from 6.05 to

951). On a chronic dietary basis, the LOC is also exceeded for mammals consuming all dietary 

items (RQs range from 6.85 to 110).

Using the default foliar dissipation half-life of 35 days and the minimum application interval, 

upper bound estimates for terrestrial residues result in exceedances for mammalian herbivores, 

insectivores and granivores that persist for up to approximately 280 days following the first 
Page 38 of 75

profenofos application (Appendix G). The effects of shorter half-lives on the duration that 

exceedances persist post application are discussed in the risk description Section 4.2.2 below.

Table 19. Maximum Acute and Chronic Risk Estimates to Birds and Mammals from the 

Maximum Application Rates of Profenofos

Taxa Size 

Class Dietary Items Resulting in Exceedances Cotton Use Site RQ’s1

Acute: Dose-Based

Birds 20 g Short grass, tall grass, broadleaf plants, fruit/pods/seeds, 

arthropods, grain.

1.28 - 92.1

100 g Short grass, tall grass, broadleaf plants, fruit/pods/seeds, 

arthropods, grain.

0.57 - 41.3

1000 g Short grass, tall grass, broadleaf plants, fruits/pods/seeds, 

arthropods, grain.

0.18 - 13.1

Mammals 15 g Short grass, tall grass, broadleaf plants, fruits/pods/seeds, 

arthropods

0.03 - 2.25

35 g Short grass, tall grass, broadleaf plants, fruits/pods/seeds, 

arthropods

0.03 - 1.92

1000 g Short grass, tall grass, broadleaf plants, arthropods 0.01 - 1.03

Acute: Dietary-Based

Birds N/A Short grass, tall grass, broadleaf plants, fruit/pods/seeds, 

arthropods.

0.88 - 14.03

Chronic Dose-Based

Mammals

15 Short grass, tall grass, broadleaf plants, fruit/pods/seeds, 

arthropods, grain.

13.2 - 951

35 Short grass, tall grass, broadleaf plants, fruit/pods/seeds, 

arthropods, grain.

11.3 - 812

1000 Short grass, tall grass, broadleaf plants, fruit/pods/seeds, 

arthropods, grain.

6.05 - 435 

Chronic: Dietary-Based

Mammals N/A Short grass, tall grass, broadleaf plants, fruits/pods/seeds, 

arthropods. 6.85 -109.6

Birds2 N/A Short Grass, tall grass, broadleaf plants, fruits/pods, seeds, 

arthropods >50 - >8002

 1RQs in bold exceed the non-listed species LOC. RQs in bold italics exceed only the listed species LOC.

 2 Chronic bird RQs represent minimum RQs based on upper bound Kenaga residues and the avian reproduction 

LOAEC, since a chronic avian NOAEC is not available.
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4.1.2.3. Terrestrial Invertebrates

On an acute exposure basis, profenofos is classified as ‘highly-toxic’ to non-target terrestrial 

insects including honey bees (honey bee acute contact LD50 = 0.0953 μg a.i./bee. If an RQ were 

calculated for terrestrial invertebrates6, using this LD50 and determining acute contact exposure

from a direct spray of profenofos as the maximum single application rate (0.5 lbs a.i./A) * 2.7 μg 

a.i./bee, the resultant RQ would be 14.2 or 1-2 orders of magnitude greater than the proposed 

terrestrial invertebrate LOC (0.4). Although this is for only a single application of profenofos, it 

may be considered an appropriate estimate of exposure from a direct spray as there is a 5 day 

minimum interval between applications and the lifespan of a forager bee is 4-5 days. However, 

because the label prohibits profenofos applications while bees are foraging in/or adjacent to the 

treatment area, this route of exposure would likely only occur from the drift of profenofos 

applications off the treated site. Since there is no acute or chronic oral toxicity data for adult or 

larval bees and the magnitude of residue of profenofos in blooming cotton parts is unknown, the 

risk to adult bees from consumption of pollen or nectar with profenofos residues cannot be 

determined in this assessment and is a major source of uncertainty.

4.1.2.4. Plants

The RQs for terrestrial and semi-aquatic plants for a single application of profenofos at the 

maximum labeled rate of 5 lbs a.i./A is presented in Table 20. RQs were not exceeded for either 

listed and non-listed monocots or dicots in either dry or semi-aquatic areas, though in semiaquatic areas for dicots the listed LOC was only marginally not exceeded (RQ = 0.95). Risk 

from spray drift alone could not be evaluated due to the lack of vegetative vigor data using a 

TEP.

Table 20. RQ values for plants in dry and semi-aquatic areas exposed to Profenofos through runoff*

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed <0.1 0.11 N/A

Monocot listed <0.1 0.11 N/A

Dicot non-listed 0.12 0.81 N/A

Dicot listed 0.14 0.95 N/A

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.

4.2. Risk Description

The results of this screening-level risk assessment indicate that the registered use of profenofos 

has the potential to cause direct adverse acute and chronic effects to freshwater and 

estuarine/marine fish (and aquatic-phase amphibians, for which fish are surrogates) and 

invertebrates. Registered uses of profenofos are unlikely to cause adverse effects to vascular 

 

6 The employed methodology for calculating an RQ for pollinators was first proposed in the 2012 Pollinator Risk 

Assessment Framework SAP White Paper, and subsequently validated by the panel. The White Paper is accessible 

online at regulations.gov, under docket EPA-HQ-OPP-2012-0543
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aquatic plants, but risk is uncertain to non-vascular aquatic plants. The results of the preliminary

risk assessment also indicate that the registered use of profenofos has the potential to cause direct 

adverse acute and chronic effects to terrestrial mammals and birds (and reptiles and terrestrialphase amphibians, for which birds are surrogates) except for all size classes of granivore mammals 

and large mammals consuming fruits, pods, or seeds. The preliminary risk assessment indicates 

that risk to terrestrial monocots and dicots in dry and semi-aquatic areas from runoff is unlikely, 

but risk of adverse effects due to spray drift is uncertain. 

4.2.1. Risks to Aquatic Organisms

Fish and Aquatic Invertebrates

Modeled EEC values result in exceedances of the listed and non-listed species acute and chronic 

LOCs for aquatic animals. For fish, the available data may underestimate the risk from profenofos 

use, due to both uncertainties regarding the lack of sensitivity of the species tested as well as the 

fact that nominal concentrations without analytical measurements were used in the acute 

freshwater and estuarine/marine fish and acute freshwater invertebrate toxicity tests. For example, 

a qualitatively supplemental study with the spotted snakehead (ECOTOX reference number 

E158179; using a profenofos formulation CELCRON that is not currently registered in the U.S.) 

indicated the species was >6x more sensitive than the bluegill on an acute basis with an LC50 of 

2.31 μg/L. The use of this endpoint would indicate that peak EECs would be approximately 5 

times the concentration that results in mortality of 50% of the test animals. The ACR of 61, 

generated from the acute and chronic fathead minnow data, applied to this endpoint would result 

in a chronic endpoint (0.038 μg/L) for the spotted snakehead that is nearly 2 orders of magnitude 

below the expected chronic EECs. This study also used nominal concentrations, so the actual 

concentrations of profenofos to which the snakehead was exposed to are uncertain, but may be 

lower (resulting in a more sensitive LC50) than described here.

Similarly, for aquatic invertebrates, the qualitatively supplemental open literature study with the 

freshwater invertebrate Ceriodaphnia dubia (ECOTOX reference number E158195) indicated this 

species was >20x more sensitive than Daphnia magna on an acute basis with an EC50 of 0.041 

μg/L. The use of this endpoint would indicate that peak EECs would be >240 times the 

concentration that results in mortality of 50% of these test animals. An ACR of 4.5, generated 

from the acute and chronic daphnid data, applied to the C. dubia acute endpoint would result in a 

chronic endpoint (0.009 μg/L) for C. dubia that is 2-3 orders of magnitude below the expected 

chronic EECs. This study also used nominal concentrations, so the actual concentration of 

profenofos to which C. dubia was exposed to are uncertain, but may be lower (resulting in a more 

sensitive EC50) than described here. 

No ecotoxicological data was available for benthic aquatic invertebrates; therefore, RQs were not 

calculated for this taxa. However, the acute and chronic pore water EECs (Table 9) indicate that 

benthic aquatic invertebrates would have to be approximately an order of magnitude more sensitive 

than the available ecotoxicological data indicate for aquatic invertebrates in surface water in order 

to indicate greater risk to this taxa. Using the daphnid acute and chronic endpoints as surrogates 

for benthic invertebrate endpoints, the modeled pore water EECs would result in acute (RQ ~1.3) 

and chronic (RQ ~ 3.5) risk to listed and non-listed benthic invertebrate species.
Page 41 of 75

The results from the QSAR analysis (Appendix F) also indicate that risk, especially on an acute 

basis to freshwater and saltwater invertebrates and on a chronic basis to freshwater fish and 

saltwater invertebrates, may be underestimated in this assessment if the O-ethyl-S-propyl 

phosphorothioate metabolite is present, as this degradate was predicted to have similar acute 

toxicity to parent profenofos for aquatic invertebrates and similar chronic toxicity to parent for 

freshwater fish and estuarine/marine invertebrates. However, the stability of this degradate is 

uncertain.

Although the last reported incident to fish and aquatic invertebrates was in 1999, before mitigation

measures were enacted following the 1999 RED, the peak and chronic modeled concentrations are 

similar to concentrations observed in water samples taken after many of the reported incidents 

described in Section 3.2.3. 

Aquatic Plants

The calculated peak concentrations are not expected to result in risk to vascular aquatic plants. 

Although quantitative data is not available for profenofos’ effects to non-vascular aquatic plants, 

the 72-hour IC50 and NOAEC to green algae (MRID 48612104) are approximately 1 - 1.5 orders 

of magnitude above the peak EECs. Therefore, even if this study had been conducted for 96 hours, 

it may be unlikely that those endpoints would be 10 - 15x more sensitive than the 72-hour 

endpoints. However, the study does indicate that non-vascular aquatic plants may be more 

sensitive than vascular aquatic plants. Other algal species may also be more sensitive than the 

green algae and no data is available for other algal species including blue-green algae and 

freshwater and saltwater diatoms. A new non-vascular aquatic plant study may reduce these 

uncertainties, but this is not considered a major data gap. 

4.2.2. Risks to Terrestrial Organisms

Based on the results of this preliminary assessment, the registered use of profenofos results in 

potential for direct acute and chronic effects to all size class and dietary combinations of birds and

mammals with the exception of granivore mammals and large mammals consuming fruits, pods 

and seeds. However, the risk assessment may be considered conservative due to the use of the 

default 35 day half-life in T-REX and the regurgitation-based NOAEC as the acute endpoint for 

birds. 

Only two studies are available with adequate foliar dissipation data, but they indicate that 

profenofos residues on foliage may dissipate considerably faster than the default rate. MRID 

42851304 found the half-life for residues in cotton grown in Texas to be 0.431 days, while MRID 

42851303 found the half-life for residues in cotton grown in California to be 0.711 days following 

the single first order degradation pathway. These values were calculated using PestDF (USEPA, 

2015). EFED has attempted to qualitatively characterize the potential risk to terrestrial organisms, 

using the more conservative of these values (0.711 days), here in the risk description section. 

However, due to the uncertainty of only having two studies with adequate foliar dissipation data, 

the final conclusions presented in the Executive Summary reflect the more conservative 35-day 

default assumption.
Page 42 of 75

Birds

The regurgitation-based NOAEC of 10 mg/kg-bw for the canary is a highly conservative surrogate 

for the LD50 endpoint. At this dosage, there was 0% mortality in the acute study with canary 

(MRID 48612102). An LD50 of 40.8 mg/kg-bw (95% Confidence Intervals of 18.3—57.4 mg/kgbw) was estimated from this study by removing the 20 mg/kg-bw treatment group, which was the 

only treatment group reported to exhibit regurgitation of the test substance. However, due to the 

assumption of allometric scaling of toxicity by body weight, the mallard LD50 of 55.0 mg/kg-bw 

is considered a more sensitive estimate of the acute endpoint than the estimated canary acute LD50; 

the mallard endpoint also has less uncertainty associated with it. 

If the half-life from the California study is used (0.711 days) in place of the default 35 day halflife and the mallard LD50 is used instead of the regurgitation-based NOAEC, then for birds on an 

acute basis, the listed species acute dose-based LOC (0.1) would still be exceeded for small and 

medium birds feeding on all dietary items except for grain (RQs would range from 0.03 to 4.82) 

and for large birds feeding on all dietary items except for grain and fruits/pods/seeds (RQs would 

range from 0.01 to 4.82). 

Using identical assumptions, the non-listed species acute dose-based LOC (0.5) would still be 

exceeded for all sizes of birds feeding on short grass (RQs 0.68 - 4.82) and small and medium 

birds feeding on tall grass, broadleaf plants and arthropods (RQs 0.85 - 2.71), but would not be 

exceeded for large birds feeding on any dietary item other than short grass or for small and medium 

birds feeding on grain or fruits, pods and seeds. On an acute dietary basis and using the half-life 

from the California study, the listed species LOC would also still be exceeded for birds consuming 

all dietary items and the non-listed species LOC would still be exceeded for birds consuming all 

dietary items other than fruits/pods/seeds (RQs would range from 0.13 to 2.12) and the chronic 

dietary-based LOC would still be exceeded for birds feeding on all dietary items (RQs would range 

from >7.56 to >121). 

As the chronic avian reproduction test was unable to define a NOAEC, the chronic avian RQs are 

nondefinitive and chronic risk is likely to be greater than identified here. In the past, EFED has 

used the MCnest model tool (USEPA, 2013) as a Tier 2 model to further refine chronic risk to 

birds and determine potential application timings that would mitigate chronic risk to birds. 

However, the lack of an acceptable NOAEC value precludes the use of this model to refine risk. 

Using the California study’s foliar dissipation half-life of 0.711 days and the minimum application 

interval, upper bound Kenaga estimates for terrestrial residues result in expected residues 

remaining higher than the relevant dietary toxicity endpoints (Appendix G) for a much shorter 

time period of less than 50 days compared to the ~220 days when utilizing the default 35 day halflife.

Mammals

If the half-life from the California study is used (0.711 days) in place of the default 35 day halflife, then on an acute dose-basis the non-listed species LOC would not be exceeded for any size 

mammals feeding on any dietary item; while the listed species LOC would only continue to be 

exceeded for all sizes of mammals consuming short grass (RQs would range from 0.16 to 0.34)

and for small and medium sized mammals feeding on tall grass, broadleaf plants and arthropods 
Page 43 of 75

(RQs would range from 0.11 - 0.19). However, even with this shorter half-life, the chronic dietary 

LOC would continue to be exceeded for mammals consuming all dietary items (RQs would range 

from 1.04 to 16.56) and the chronic dose-based LOC would continue to be exceeded for all size 

classes of mammals consuming all dietary items except for large granivore mammals (RQs would 

range from 0.91 to 115). Using the 0.711 day foliar dissipation half-life, the upper bound Kenaga 

estimates for terrestrial residues result in expected residues remainin g higher than the relevant 

dietary toxicity endpoints for a much shorter time period of less than 50 days compared to the ~280 

days when utilizing the default 35 day half-life (Appendix G).

Terrestrial Invertebrates

Only acute contact toxicity data is available for honey bees. The proposed LOC (0.4) for beneficial 

terrestrial invertebrates is exceeded by more than an order of magnitude. The current label 

language may mitigate some risk on an acute contact basis to honey bees since it prohibits 

treatment while bees are foraging in/or adjacent to the treatment area. However, other, non-Apis

bees and other beneficial insects may still be at risk as their presence may be less conspicuous to 

the pesticide applicator. Additionally, dietary risk to bees cannot be precluded due to the lack of 

acute and chronic oral data with adult honey bees. Similarly, hazard to potentially sensitive life 

stages (i.e. eggs, larvae and juveniles) may not be evident from the honey bee contact toxicity test 

that used adult worker honey bees.

Terrestrial Plants

The EECs predicted by EFED’s current screening tool, TerrPlant, indicated no risk to listed and 

non-listed species of monocots and dicots in either semiaquatic or dry habitats. Risk from spray 

drift alone could not be quantitatively evaluated due to the lack of vegetative vigor data with a 

TEP. However, vegetative vigor endpoints from a TEP would have to be 22 times more sensitive 

than the submitted seedling emergence study NOAEC in order to result in exceedances of the listed 

species LOC from spray drift alone according to the TerrPlant model. Although that seedling 

emergence study was also conducted with TGAI and may underestimate a formulation’s toxicity, 

this is less of a concern for seedling emergence studies since adjuvants and surfactants in the TEP 

are expected to disassociate from the active ingredient prior to the seeds’ exposure.

However, it should be noted that the TerrPlant screening level analysis actually evaluates the risk 

to off-field plants based on runoff and spray drift fractions. Given that the seedling emergence 

NOAEC (0.111 lb a.i./A) for the most sensitive species, cucumber, is below the single maximum 

application rate (0.5 lb a.i./A), there is some potential for risk to listed species occurring on the 

field. 

Risk to Off-Field Nontarget Organisms due to Spray Drift

Spray drift exposures from the registered profenofos applications can be an exposure pathway and 

aerial applications will result in larger areas off the application site where sensitive taxa (e.g. 

aquatic and terrestrial invertebrates and birds) may be exposed. Concentrations of 0.046 μg/L in 

water trigger the acute listed species LOC of 0.05 (based on the daphnid acute LD50 of 0.91 μg/L). 
Page 44 of 75

Concentrations on land over 0.0139 lb a.i./A exceed the LOC (0.4) for beneficial terrestrial 

invertebrates, based on the honey bee acute contact LD50 of 0.0953 μg/bee and using the proposed 

upper bound residue value of 2.7 μg a.i./bee for a 1 lb a.i./A application (USEPA, 2014a based on 

work from Koch and Weisser, 1997). Concentrations on land over 0.01 lbs a.i./A exceed the listed 

species LOC (0.1) for avian species, based on the mallard acute LD50 of 55 mg a.i./kg-bw, A full 

range of the output of this model with distances from the edge of field to an exceedance of the 

LOC under a variety of application parameters is described in Appendix H.

Spray drift exposure to profenofos was determined using AgDrift 2.1.1 and the maximum foliar 

single application rate (0.5 lb a.i./A). The distance to the EPA-defined Pond from the edge of field 

was determined for an initial average concentration of 0.046 μg/L in Tier I Ground Aquatic 

Assessments. Using initial conservative conditions of high boom and nozzles producing very finefine droplet spectra, the RQ from spray drift alone exceeds the listed species LOC for aquatic 

invertebrates at distances less than 810 feet. Using more refined application parameters (low 

boom, nozzles producing a droplet size distribution of fine to medium/coarse), the RQ from spray 

drift alone exceeds the listed species LOC for aquatic invertebrates at distances less than 265 feet. 

For off-field beneficial terrestrial invertebrates, the distance was calculated from the edge of the 

applied field to a point where deposition of profenofos residues drops below 0.0139 lb a.i./A in 

Tier I Ground Terrestrial Assessments. Using initial conservative conditions of high boom and 

nozzles producing very fine-fine droplet spectra, the RQ from spray drift alone exceeds the nonlisted species LOC (0.4) at distances less than 90 feet. Using more refined application parameters 

(low boom, nozzles producing fine to medium droplet spectra), the RQ from spray drift alone 

exceeds the non-listed species LOC at distances less than 10 feet. 

For off-field birds, the distance was calculated from the edge of the applied field to a point where 

deposition of profenofos residues from spray drift would drop below 0.01 lb a.i./A in Tier I Ground 

Terrestrial Assessments. Using initial conservative conditions of high boom and nozzles 

producing very fine-fine droplet spectra, the RQ from spray drift alone exceeds the listed species 

LOC (0.1) at distances less than 125 feet. Using more refined application parameters (low boom, 

nozzles producing fine to medium droplet spectra), the RQ from spray drift alone exceeds the nonlisted species LOC at distances less than 15 feet. 

5. Federally Threatened and Endangered (Listed) Species Concerns

Based on this screening-level assessment, there are potential risks of direct effects to listed fish, 

amphibians, aquatic invertebrates, birds, reptiles, mammals and terrestrial invertebrates from the 

use of profenofos on some of its registered use sites. Listed species of these taxa may also be 

affected through indirect effects because of the potential direct effects on listed and non-listed 

species. Potential direct effects on listed fish, amphibians, aquatic invertebrates, birds, reptiles, 

mammals and terrestrial invertebrates from the use of profenofos may be associated with 

modification of Primary Constituent Elements (PCEs) of designated critical habitats, where such 

designations have been made. However, at this 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 
Page 45 of 75

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 profenofos 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 

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 profenofos is used on cotton. 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 profenofos is reasonably expected to be used. Similarly, refinements on the 
Page 46 of 75

timing of applications and a more in-depth exploration of agronomic practices for profenofos 

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.

Based on previous fish kills, use of profenofos is restricted in Reeves County, Texas and near 

Dexter National Fish Hatchery in NM to protect listed fish species.

The federal action addressed herein is the proposed renewed registration of profenofos on 

agricultural use sites, primarily in southern cotton-growing states. It is expected that its use could 

occur nationwide in cotton-growing states. 

5.1. Action Area 

For listed species assessment purposes, the action area is considered to be the area affected directly 

or indirectly by profenofos use and not merely the immediate area where profenofos is applied. 

At the initial baseline, the risk assessment considers broadly described taxonomic groups and 

conservatively assumes that listed species within those broad groups are co-located with the 

pesticide treatment area. This means that listed terrestrial plants and wildlife are assumed to be 

located on or adjacent to the treated site and listed aquatic organisms are assumed to be located in 

a surface water body adjacent to the treated site. The assessment also assumes that the listed 

species are located within an assumed area, which has the relatively highest potential exposure to 

the pesticide, and that exposures are likely to decrease with distance from the treatment area. 

Generally, the action area for profenofos is limited to those areas of the US where cotton is grown. 

This may include southern California, Arizona, New Mexico, Texas, Oklahoma, Missouri, 

Arkansas, Tennessee, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, 

and Virginia.

5.2. Taxonomic Groups Potentially at Risk 

If the assumptions associated with the baseline action area result in RQs that are below the listed 

species LOCs, a "no effect" determination conclusion is made with respect to listed species in that 

taxa, and no further refinement of the action area is necessary. Furthermore, RQs below the listed 

species LOCs for a given taxonomic group indicate no concern for indirect effects on listed species 

that depend upon the taxonomic group for which the RQ was calculated. However, in situations 

where the screening assumptions lead to RQs in excess of the listed species LOCs for a given 

taxonomic group, a potential for a "may affect" conclusion exists and may be associated with direct 

effects on listed species belonging to that taxonomic group or may extend to indirect effects upon 

listed species that depend upon that taxonomic group as a resource. In such cases, additional 

information on the biology of listed species, the locations of these species, and the locations of use 

sites are considered to determine the extent to which screening assumptions regarding an action 
Page 47 of 75

area apply to a particular listed organism. These subsequent refinement steps will consider how 

this information would impact the action area for a particular listed organism and potentially 

include areas of exposure that are downwind and downstream of the pesticide use site.

Assessment endpoints, exposure pathways, and the conceptual models addressing profenofos uses, 

and the associated exposure and effects analyses conducted for the profenofos baseline risk 

assessment are in Sections 2 to 3. The assessment endpoints used in the baseline risk assessment 

include those defined operationally as reduced survival and reproductive impairment for both 

aquatic and terrestrial animal species and survival, reproduction, and growth of aquatic and 

terrestrial plant species from both direct acute and chronic exposures. These assessment endpoints 

are intended to address the standard set forth in the Endangered Species Act requiring federal 

agencies to ensure that any action they authorize does not appreciably reduce the likelihood of 

both the survival and recovery of a listed species in the wild by reducing the reproduction, 

numbers, or distribution of the species. Risk estimates (RQs) which, integrating exposure and 

effects, are calculated for broad based taxonomic groups in the screening-level risk assessment 

presented in Section 4.

Both acute endangered species and chronic risk LOCs are considered in the baseline risk 

assessment to identify direct and indirect effects to taxa of listed species. This section identifies 

direct effect concerns, by taxa that are triggered by exceeding endangered LOCs in the baseline 

risk assessment, with an evaluation of the potential probability of individual effects for exposures 

that may occur at the established endangered species LOC. Data on exposure and effects collected 

under field and laboratory conditions are evaluated to make determinations on the predictive utility 

of the direct effect screening assessment findings to listed species. Potential for direct effects to 

listed taxa are described in Table 21.

Table 21. Potential Effects to Federally Listed Taxa Associated with Direct Effects from 

the Registered Use of Profenofos.

Listed Plant Taxon Potential Direct Effects

Terrestrial and semi-aquatic 

plants – monocots and dicots No

Aquatic nonvascular plants1 No

Aquatic vascular plants No

Listed Animal Taxon Potential Direct Effects

Acute Chronic

Terrestrial invertebrates Yes Uncertain2

Mammals Yes Yes

Birds Yes Yes

Reptiles Yes Yes

Amphibians3 Yes Yes

Freshwater fish Yes Yes

Freshwater invertebrates Yes Yes

Estuarine/marine fish Yes Yes

Estuarine/marine invertebrates Yes Yes

1 There are currently no listed species of aquatic non-vascular plants.

2 Chronic risk to listed species of terrestrial invertebrates is uncertain due to the lack of chronic data for juvenile and adult 

honey bees.

3 Acute and chronic risk to this taxa is expected for both the terrestrial and aquatic-phase in the amphibian life cycle.
Page 48 of 75

6. Literature Cited 

Fletcher, J.S., J.E. Nellesson and T.G. Pfleeger. 1994. Literature review and evaluation of the 

EPA food-chain (Kenaga) nomogram, an instrument for estimating pesticide residues on plants. 

Environ. Tox. And Chem. 13(9):1383-1391.

Hoerger, F. and E.E. Kenaga, 1972. Pesticide residues on plants: correlation of representative 

data as a basis for estimation of their magnitude in the environment. IN: F. Coulston and F. 

Corte, eds., Environmental Quality and Safety: Chemistry, Toxicology and Technology. Vol 1. 

George Theime Publishers, Stuttgart, Germany. pp. 9-28.

Koch, H. and P. Weisser. 1997. Exposure of honey bees during pesticide application under field

conditions. Apidologie. 28: 439—447.

Leader, H. and J.E. Casida. 1982. Resolution and Biological Activity of the Chiral Isomers of O-

(4-Bromo-2-chlorophenyl) O-Ethyl S-Propyl Phosphorothioate (Profenofos Insecticide). J. Agric. 

Food Chem. 30: 546—551. 

Liu, J. and X. Zhang. 2014. Comparative toxicity of new halophenolic DBPs in chlorinated 

saline wastewater effluents against a marine alga: Halophenolic DBPs are generally more toxic 

than haloaliphatic ones. Water Research. 65: 64—72. 

Mayer, F.L. and M.R. Ellersieck. 1986. Manual of acute toxicity: Interpretation and database for 

410 chemicals and 66 species of freshwater animals (resource publication no. 160). United States 

Fish and Wildlife Service, Washington, DC. MRID 400980-01.

National Research Council. 2013. Assessing Risks to Endangered and Threatened Species from 

Pesticides. Committee on Ecological Risk Assessment under FIFRA and ESA, Board on 

Environmental Studies and Toxicology, Division on Earth and Life Studies, National Research 

Council of the National Academies. The National Academies Press, Washington, DC.

Pandey, A.K., N.S. Nagpure, S.P. Trivedi, R. Kumar, B. Kushwaha and W.S. Lakra. 2011. 

Investigation on acute toxicity and behavioral changes in Channa punctatus (Bloch) due to 

organophosphate pesticide profenofos. Drug and Chemical Toxicology. 34(4): 424—428. 

Ecotox Reference Number E158179.

USEPA, 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, U.S. 

Environmental Protection Agency. Washington, D.C. May 14, 1998. Federal Reigster 63(93): 

26846—26924. 

USEPA, 1999. Reregistration Eligibility Decision Environmental Risk Assessment for 

Profenofos. Environmental Fate and Effects Division, Office of Pesticide Programs, Office of 

Prevention, Pesticides, and Toxic Substances. Washington, DC. June 16, 1999. 
Page 49 of 75

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

Programs, U.S. Environmental Protection Agency. Office of Prevention, Pesticides and Toxic 

Substances. Office of Pesticide Programs. Washington, D.C. January 23, 2004.

USEPA, 2009. Input Parameter Guidance. Version 2.1. Environmental Fate and Effects

Division. October 22, 2009

http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

USEPA, 2013. User’s Manual for Basic Version of MCnest—Markov Chain Nest Productivity 

Model. Mid-Continent Ecology Division, National Health and Environmental Effects Research 

Laboratory, Office of Research and Development, U.S. Environmental Protection Agency. 

Duluth, MN. February, 2013.

USEPA, 2014a. Guidance for Assessing Pesticide Risks to Bees. Environmental Fate and 

Effects Division. Office of Pesticide Programs. Washington, D.C. June 23, 2014.

USEPA, 2014b. Profenofos: General Information on its Use and Alternatives to Support 

Registration Review. Biological and Economic Analysis Division. Office of Pesticide 

Programs. Washington, D.C. August 19, 2014. 

USEPA, 2015. Standard Operating Procedure for Using the NAFTA Guidance to Calculate 

Representative Half-life Values and Characterizing Pesticide Degradation. Office of Pesticide 

Programs, U.S. Environmental Protection Agency. March, 23, 2015. 

USFWS, 1989. U.S. Fish and Wildlife Service Biological Opinion on Selected Pesticides. U.S. 

Fish and Wildlife Service. September 14, 1989.

Willis and McDowell. 1987. Pesticide persistence on foliage. Environ. Contam. Toxicol. 100:23-

73.

Woods, M., A. Kumar and R. Correll. 2002. Acute Toxicity of Mixtures of Chlorpyrifos, 

Profenofos, and Endosulfan to Ceriodaphnia dubia. Bull. Environ. Contam. Toxicol. 68: 801—

808. Ecotox Reference Number: E158195
Page 50 of 75

Appendix A–Summary of Risk Conclusions by Taxa

Use Pattern 

Category

Aquatic 

Invertebrates

Fish (surrogate 

for aquaticphase 

amphibians)

Birds, (surrogate for 

terrestrial-phase 

amphibians and reptiles)

Mammals Plants 

Cotton Acute risk:

Expected for 

both listed and 

non-listed 

species, both 

from runoff 

and through 

spray drift.

Chronic risk: 

Expected.

Acute risk:

Expected for 

both listed and 

non-listed 

species.

Chronic risk: 

Expected

Acute risk: 

Dose- and dietary-based risk 

to all listed species regardless 

of size class or dietary 

consumption. Dose-based 

risk to non-listed birds 

species of all size classes 

consuming all dietary items 

except for large birds 

consuming grain.

Chronic risk: 

Expected for all size classes 

regardless of diet.

Acute risk:

Risk to listed species of all 

size classes consuming short 

grass, tall grass, broadleaf 

plants and arthopods. Risk 

not expected for granivores 

or mammals consuming 

fruits/seeds/pods. Risk to 

non-listed species only for 

small and medium 

mammals consuming short 

grass and broadleaf plants

and small mammals 

consuming tall grass.

Chronic risk: 

Expected for all size classes, 

regardless of diet.

Terrestrial:

Risk considered unlik

off-field terrestrial pla

runoff. There is some 

potential for risk to li

species occurring on t

agricultural field. 

Risk is somewhat unc

for plants exposed to 

drift, but is not consid

likely.

Aquatic:

Not expected
Page 51 of 75

Appendix B—Input Parameters and Output for the STIR model

Welcome to the EFED

Screening Tool for Inhalation Risk

This tool is designed to provide the risk assessor with a rapid method for determining the potential

significance of the inhalation exposure route to birds and mammals in a risk assessment.

Input

Application and Chemical Information

Enter Chemical Name Profenofos

Enter Chemical Use Cotton

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) 373.63

Enter Chemical Vapor Pressure (mmHg) 9.30E-07

Enter Application Rate (lb a.i./acre) 0.5

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 55

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 21.5

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 300

Enter Lowest Rat Inhalation LC50 (mg/L) 3.6

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) 1.87E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.35E-03

Adjusted Inhalation LD50 1.79E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 1.31E-03 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 5.28E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 2.95E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg )
Page 52 of 75

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 1.87E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.95E-03

Adjusted Inhalation LD50 2.14E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 1.38E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 6.64E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 3.10E-04 Exposure not Likely Significant
Page 53 of 75

Appendix C—Chemical Structure and Characteristics of Profenofos 

Degradates

Degradate Structure Study Max [%] Time 

(days)

4-bromo-2-chlorophenol (CGA-55960)

Hydrolysis

41627309

4.9% (pH 5) 30

23.0% (pH 7) 30

80.2% (pH 90 1

41939001

8.8% (pH 5) 30

51.6% (pH 7) 30

89.7% (pH 9) 1

Aerobic Soil Metabolism

42334302 72.5% - 79.7% 

(pH 7.8) 5 - 120

Anaerobic Soil Metabolism

42334302 82.50% 60

Anaerobic Aquatic Metabolism

SMILES: C1=CC(=C(C=C1Br)Cl)O 42218101 67.6% - 81.2% 6 - 180

O-ethyl-S-propyl phosphorothioate 

Hydrolysis

41627309 formed in equimolar 

proportions with CGA55960 SMILES: CCCSP(=O)(O)OCC 41939001

4-bromo-2-chlorophenyl ethyl ether 

(BCPEE)

Aerobic Soil Metabolism

42334302 41.7% - 42.6% 

(pH 7.8) 270 - 360

Anaerobic Soil Metabolism

42334302 2.70% 60

Anaerobic Aquatic Metabolism

SMILES: C1=CC(=CC(=C1OCC)Cl)Br 42218101 8.3% - 20.2% 60 - 360

2-thioethylenecarboxy-4-hydroxyphenyl 

methyl ether (THPME) Aerobic Soil Metabolism

SMILES: C1=C(C=C(C(=C1)OC)SCCC(=O)O)O 42334302 9.9% - 10% 180 - 270
Page 54 of 75

2-mercapto-4-hydroxyphenyl methyl ether 

(MHPME) Aerobic Soil Metabolism

SMILES: C1=CC(=CC(=C1OC)S)O 42334302

4.30% 30

4-bromo-2-chlorophenyl methyl ether 

(BCPME) Aerobic Soil Metabolism

SMILES: C1=CC(=CC(=C1OC)Cl)Br 42334302

2.40% 180

chlorophenol-glucose conjugate (CP-G) 

Aerobic Soil Metabolism

42334302 1.90% 30

SMILES: C1=CC=CC(=C1OCC2C(C(C(C(O2)O)O)O)O)Cl
Page 55 of 75

Appendix D. Example Input and Outputs for the SIP Model

Table 1. Inputs

Parameter Value

Chemical name Profenofos

Solubility (in water at 25oC; mg/L) 20

Mammalian LD50 (mg/kg-bw) 298

Mammalian test species other

Body weight (g) of "other" mammalian species 25

Mammalian NOAEL (mg/kg-bw) 0.365

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 55

Avian test species other

Body weight (g) of "other" avian species 1580

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet)

Bobwhite quail NOAEC (mg/kg-diet) 1

NOAEC (mg/kg-diet) for other bird species

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird species

Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 3.4400 3.4400

Adjusted toxicity value (mg/kg-bw) 118.4953 0.2807

Ratio of exposure to toxicity 0.0290 12.2532

Conclusion*

Drinking water exposure alone is 

NOT a potential concern for 

mammals

Exposure through drinking 

water alone is a potential 

concern for mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 16.2000 16.2000

Adjusted toxicity value (mg/kg-bw) 28.5574 0.1063

Ratio of exposure to acute toxicity 0.5673 152.4013

Conclusion*

Exposure through drinking water 

alone is 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 56 of 75

Appendix E. Example Input and Outputs for the KABAM Model

Table 1. Chemical characteristics of Profenofos.

Characteristic Value Comments/Guidance

Pesticide Name Profenofos Required input

Log KOW 4.83

Required input 

Enter value from acceptable or supplemental study 

submitted by registrant or available in scientific literature.

KOW 67608 No input necessary. This value is calculated automatically 

from the Log KOW value entered above.

KOC (L/kg 

OC) 3890

Required input

Input value used in PRZM/EXAMS to derive EECs. Follow 

input parameter guidance for deriving this parameter value 

(USEPA 2002).

Time to steady state 

(TS; days) 21 No input necessary. This value is calculated automatically from the Log KOW value entered above.

Pore water EEC (μg/L) 0.753

Required input 

Enter value generated by PRZM/EXAMS benthic file. 

PRZM/EXAMS EEC represents the freely dissolved 

concentration of the pesticide in the pore water of the 

sediment. The appropriate averaging period of the EEC is 

dependent on the specific pesticide being modeled and is 

based on the time it takes for the chemical to reach steady 

state. Select the EEC generated by PRZM/EXAMS which 

has an averaging period closest to the time to steady state 

calculated above. In cases where the time to steady state 

exceeds 365 days, the user should select the EEC 

representing the average of yearly averages. The peak 

EEC should not be used. 

Water Column EEC 

(μg/L) 5.05

Required input 

Enter value generated by PRZM/EXAMS water column 

file. PRZM/EXAMS EEC represents the freely dissolved 

concentration of the pesticide in the water column. The 

appropriate averaging period of the EEC is dependent on 

the specific pesticide being modeled and is based on the 

time it takes for the chemical to reach steady state. The 

averaging period used for the water column EEC should 

be the same as the one selected for the pore water EEC 

(discussed above). 

Table 2. Input parameters for rate constants. "calculated" indicates that model will calculate 

rate constant. 

Trophic level

k1 

(L/kg*d)

k2 

(d-1)

kD 

(kg-food/kgorg/d)kE 

(d-1)

kM* 

(d-1)
Page 57 of 75

phytoplankton calculated calculated 0* 0* 0

zooplankton calculated calculated calculated calculated 0

benthic invertebrates calculated calculated calculated calculated 0

filter feeders calculated calculated calculated calculated 0

small fish calculated calculated calculated calculated 0

medium fish calculated calculated calculated calculated 0

large fish calculated calculated calculated calculated 0

* Default value is 0. 

k1 and k2 represent the uptake and elimination constants respectively, through 

respiration.

kD and kE represent the uptake and elimination constants, respectively, through diet.

kM represents the metabolism rate constant. 

Table 3. Mammalian and avian toxicity data for Profenofos. These are required inputs.

Animal

Measure of 

effect (units) Value Species

If 

selected 

species is 

"other," 

enter 

body 

weight (in 

kg) here.

Avian

LD50 (mg/kgbw) 55 mallard duck

LC50 (mg/kgdiet) 57 Northern bobwhite quail

NOAEC 

(mg/kg-diet) 1 Northern bobwhite quail

Mineau Scaling 

Factor 1.15

Default value for all species 

is 1.15 (for chemical specific 

values, see Mineau et al. 

1996).

Mammalian

LD50 (mg/kgbw) 298 other 0.025

LC50 (mg/kgdiet) N/A other

Chronic 

Endpoint 7.3

laboratory rat

units of chronic 

endpoint*

ppm

Table 11. Estimated concentrations of Profenofos in ecosystem components.
Page 58 of 75

Ecosystem Component

Total 

concentration 

(μg/kg-ww)

Lipid 

normalized 

concentration 

(μg/kg-lipid)

Contribution 

due to diet 

(μg/kg-ww)

Contribution 

due to 

respiration 

(μg/kg-ww)

Water (total)* 5 N/A N/A N/A

Water (freely dissolved)* 5 N/A N/A N/A

Sediment (pore water)* 1 N/A N/A N/A

Sediment (in solid)** 117 N/A N/A N/A

Phytoplankton 15,674 783681 N/A 15,673.63

Zooplankton 11,892 396409 254.78 11,637.50

Benthic Invertebrates 12,718 423933 640.86 12,077.12

Filter Feeders 8,355 417769 412.81 7,942.57

Small Fish 18,028 450711 2,743.83 15,284.59

Medium Fish 20,241 506014 5,307.86 14,932.69

Large Fish 25,798 644956 10,713.00 15,085.26

* Units: μg/L; **Units: μg/kg-dw

Table 12. Total BCFand BAF values of Profenofos in aquatic 

trophic levels.

0

5000

10000

15000

20000

25000

30000

Zooplankton Benthic

Invertebrates

Filter Feeders Small Fish Medium Fish Large Fish

Concentration (μg/kg)

Trophic Level

Figure 1. Total pesticide concentration 

per trophic level

Contribution due to respiration (μg/kg-ww)

Contribution due to diet (μg/kg-ww)
Page 59 of 75

Trophic Level

Total BCF 

(μg/kgww)/(μg/L)

Total BAF 

(μg/kgww)/(μg/L)

Phytoplankton 3246 3104

Zooplankton 2313 2355

Benthic Invertebrates 2418 2518

Filter Feeders 1590 1655

Small Fish 3111 3570

Medium Fish 3111 4008

Large Fish 3249 5109

Table 13. Lipid-normalized BCF, BAF, BMF and BSAF values of Profenofos in aquatic trophic 

levels.

Trophic Level

BCF 

(μg/kglipid)/(μg/L)

BAF 

(μg/kglipid)/(μg/L)

BMF 

(μg/kglipid)/(μg/kglipid)

BSAF 

(μg/kglipid)/(μg/kgOC)

Phytoplankton 162305 155184 N/A 268

Zooplankton 77102 78497 0.51 135

Benthic Invertebrates 80616 83947 1.09 145

Filter Feeders 79499 82727 1.07 143

Small Fish 77777 89250 1.10 154

Medium Fish 77777 100201 1.16 173

Large Fish 81233 127714 1.27 220

Table 14. Calculation of EECs for mammals and birds consuming fish contaminated by Profenofos.

Wildlife Species Biological Parameters EECs (pesticide intake)

Body

Weight

(kg)

Dry Food 

Ingestion 

Rate (kg-dry 

food/kgbw/day)

Wet Food 

Ingestion 

Rate (kg-wet 

food/kgbw/day)

Drinking 

Water

Intake

(L/d)

Dose Based 

(mg/kgbw/d)

Dietary 

Based 

(ppm)

Mammalian

fog/water shrew 0.02 0.140 0.585 0.003 7.443 12.72

rice rat/star-nosed 

mole 0.1 0.107 0.484 0.011 6.305 13.03

small mink 0.5 0.079 0.293 0.048 5.937 20.24

large mink 1.8 0.062 0.229 0.168 4.639 20.24

small river otter 5.0 0.052 0.191 0.421 3.868 20.24

large river otter 15.0 0.042 0.157 1.133 4.054 25.80
Page 60 of 75

Avian

sandpipers 0.0 0.228 1.034 0.004 13.5278 13.08

cranes 6.7 0.030 0.136 0.211 1.8804 13.84

rails 0.1 0.147 0.577 0.010 8.8765 15.37

herons 2.9 0.040 0.157 0.120 2.5941 16.48

small osprey 1.3 0.054 0.199 0.069 4.0364 20.24

white pelican 7.5 0.029 0.107 0.228 2.7528 25.80

Table 15. Calculation of toxicity values for mammals and birds consuming 

fish contaminated by Profenofos.

Wildlife Species

Toxicity Values

Acute Chronic

Dose 

Based 

(mg/kgbw)

Dietary 

Based 

(mg/kg-diet)

Dose Based 

(mg/kg-bw)

Dietary 

Based 

(mg/kg-diet)

Mammalian

fog/water shrew 323.51 N/A 0.77 7.3

rice rat/star-nosed 

mole 219.46 N/A 0.52 7.3

small mink 144.68 N/A 0.34 7.3

large mink 102.30 N/A 0.24 7.3

small river otter 79.24 N/A 0.19 7.3

large river otter 60.21 N/A 0.14 7.3

Avian

sandpipers 28.56 57.00 N/A 1

cranes 68.31 57.00 N/A 1

rails 34.46 57.00 N/A 1

herons 60.25 57.00 N/A 1

small osprey 53.10 57.00 N/A 1

white pelican 69.47 57.00 N/A 1
Page 61 of 75

Table 16. Calculation of RQ values for mammals and birds consuming fish 

contaminated by Profenofos.

Wildlife Species

Acute Chronic

Dose 

Based

Dietary 

Based

Dose Based Dietary 

Based

Mammalian

fog/water shrew 0.023 N/A 9.711 1.742

rice rat/star-nosed 

mole 0.029 N/A 12.127 1.785

small mink 0.041 N/A 17.321 2.773

large mink 0.045 N/A 19.139 2.773

small river otter 0.049 N/A 20.601 2.773

large river otter 0.067 N/A 28.418 3.534

Avian

sandpipers 0.474 0.230 N/A 13.084

cranes 0.028 0.243 N/A 13.836

rails 0.258 0.270 N/A 15.373

herons 0.043 0.289 N/A 16.479

small osprey 0.076 0.355 N/A 20.241

white pelican 0.040 0.453 N/A 25.798
Page 62 of 75

Appendix F. Predictive Data for Parent Profenofos and its Degradates from 

QSAR Modeling using ECOSAR v1.11

All values are in ppb

ND = No empirical Data

NP = No prediction made for this class. 

Red highlighted cells indicate poor agreement (i.e. > 10x difference) between empirical data and 

predicted values.

Yellow highlighted cells indicate reasonable agreement (i.e. between 5x and 10x difference) 

between empirical data and predicted values.

Green highlighted cells indicate good agreement (i.e. <5x difference) between empirical data and 

predicted values.

The empirical EC50 for green algae was from a 72-hour study (MRID 48612104) and was 

considered of qualitative use. However, the level of predicted toxicity using the Esters class had 

very good agreement with this empirical value while the Esters (phosphate) and Neutral Organic 

SAR classes had reasonable agreement with the empirical data. Using these three classes, the

model predicts the O-ethyl-S-propyl phosphorothioate degradate to be ~3x to ~10x less toxic to 

green algae than parent profenofos. Using the Neutral Organic SAR class (the only class for 

which this degradate and parent profenofos share according to the ECOSAR model), the model 

predicts the 4-bromo-2-chlorophenol degradate to be ~10x less toxic to green algae than parent 

profenofos which is also similar to the empirical data for this metabolite to the marine green 

algae. Other degradates were predicted to be >10x less toxic than parent profenofos to this taxa 

using classes that had reasonable or good predictive power.

Table F1. Empirical and Predicted Green Algae EC50 Toxicity Estimates for Parent 

Profenofos and its Degradates.

Parent/Degradate Empirical 

EC50 (ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 508 

(qualitative)

456 2926 1402 NP

O-ethyl-S-propyl 

phosphorothioate

ND 1560 28,306 4,729 NP

4-bromo-2-

chlorophenol

24,900 

(marine green 

algae, 

qualitative)

NP NP 13,579 11,493

O-ethyl phosphate ND >1,000,000 >1,000,000 >1,000,000 NP

1-propanethiol ND NP NP 38,891

The empirical NOAEC from that same study had good agreement with the Esters chemical class 

and reasonable agreement with the Neutral Organic SAR class. Using these two classes, the 

ECOSAR model predicts the O-ethyl-S-propyl phosphorothioate degradate to be ~2.5x — ~2.8x 
Page 63 of 75

less toxic than parent profenofos. The 4-bromo-2-chlorophenol was predicted to be ~6.7x less 

toxic than parent profenofos, using the Neutral Organic SAR class. Other degradates were 

predicted to be >10x less toxic than parent profenofos to this taxa using classes that had 

reasonable or good predictive power.

Table F2. Empirical and Predicted Green Algae NOAEC Toxicity Estimates for Parent 

Profenofos and its Degradates.

Parent/Degradate Empirical 

NOAEC

(ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 130 

(qualitative)

294 3,172 658 NP

O-ethyl-S-propyl 

phosphorothioate

ND 748 8,963 1,842 NP

4-bromo-2-

chlorophenol

20,750 

(marine green 

alga, 

qualitative)

NP NP 4,411 5,328

O-ethyl phosphate ND 732,950 >1,000,000 >1,000,000 NP

1-propanethiol ND NP NP 38,891 NP

The predicted acute toxicity to daphnids of parent profenofos had good agreement with the 

empirical data only for the Esters (phosphate) class. Using this structural chemical class, the Oethyl-S-propyl phosphorothioate degradate has similar (~1.6x) predicted toxicity as the predicted 

parent toxicity. The O-ethyl-S-propyl phosphorothioate would be considered very highly toxic 

on an acute basis to freshwater aquatic invertebrates according to this predicted toxicity. Other 

profenofos metabolites were predicted to be >10x less toxic than parent profenofos to this taxa 

using the Esters (phosphate) class.

Table F3. Empirical and Predicted Daphnid EC50 Toxicity Estimates for Parent Profenofos 

and its Degradates.

Parent/Degradate Empirical 

EC50 (ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 0.91 1,679 1.24 636 NP

O-ethyl-S-propyl 

phosphorothioate

ND 4,976 2.0 3,039 NP

4-bromo-2-

chlorophenol

ND NP NP 12,222 2,766
Page 64 of 75

O-ethyl phosphate ND >1,000,000 183 >1,000,000 NP

1-propanethiol ND NP NP 57,254 NP

The empirical NOAEC for daphnids does not have good or reasonable agreement with the 

predicted toxicity for any of the chemical classes predicted by ECOSAR (all classes either 

predicted toxicity >10x the empirical values or did not have any prediction). Therefore, the 

QSAR approach should not be used in the risk assessment to evaluate the toxicity of profenofos 

metabolites to freshwater invertebrates on a chronic basis.

Table F4. Empirical and Predicted Daphnid NOAEC Toxicity Estimates for Parent 

Profenofos and its Degradates.

Parent/Degradate Empirical 

NOAEC

(ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 0.20 507 NP 129 NP

O-ethyl-S-propyl 

phosphorothioate

ND 1,953 NP 487 NP

4-bromo-2-

chlorophenol

ND NP NP 1,560 525

O-ethyl phosphate ND >1,000,000 NP >1,000,000 NP

1-propanethiol ND NP NP 5,247 NP

The empirical acute data for freshwater fish also had poor agreement with the predicted toxicity 

for the chemical classes predicted by ECOSAR. Therefore, the QSAR approach should not be 

used in the risk assessment to evaluate the toxicity of profenofos metabolites to freshwater fish 

on an acute basis.

Table F5. Empirical and Predicted Fish LC50 Toxicity Estimates for Parent Profenofos and 

its Degradates.

Parent/Degradate Empirical 

LC50 (ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 14.1 1,095 819 862 NP

O-ethyl-S-propyl 

phosphorothioate

ND 2,943 1350 4,478 NP

4-bromo-2-

chlorophenol

ND NP NP 19,541 5,763

O-ethyl phosphate ND >1,000,000 74,130 >1,000,000 NP

1-propanethiol ND NP NP 103,108 NP

However, the empirical chronic data for freshwater fish had good agreement with the predicted 

toxicity for the Esters (phosphate) structural class and poor agreement with the other classes. 
Page 65 of 75

Using the Esters (phosphate) class, the O-ethyl-S-propyl phosphorothioate degradate predicted 

toxicity is identical to the predicted parent toxicity. The O-ethyl phosphate metabolite of Oethyl-S-propyl phosphorothioate was predicted to be ~ 2.5x less toxic on a chronic basis than 

either the O-ethyl-S-propyl phosphorothioate degradate or parent profenofos. Toxicity was not 

predicted for 4-bromo-2-chlorophenol or other degradates using the Esters (phosphate) class, so 

predictions cannot be made with any certainty regarding these degradates’ toxicity to fish on a 

chronic basis. 

Table F6. Empirical and Predicted Fish NOAEC Toxicity Estimates for Parent Profenofos 

and its Degradates.

Parent/Degradate Empirical 

NOAEC

(ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 2.0 45 8.0 115 NP

O-ethyl-S-propyl 

phosphorothioate

ND 148 8.0 540 NP

4-bromo-2-

chlorophenol

ND NP NP 2,141 678

O-ethyl phosphate ND 730,747 20 >1,000,000 NP

1-propanethiol ND NP NP 9,817

The empirical acute data for the mysid had very good agreement with the predicted toxicity for 

the Esters (phosphate) chemical class. Using this chemical class, the O-ethyl-S-propyl 

phosphorothioate degradate is predicted to have similar (1.5x less toxic) toxicity as parent 

profenofos. According to this predicted toxicity value, this degradate would be considered very 

highly toxic on an acute basis to saltwater aquatic invertebrates. Toxicity was not predicted for 

4-bromo-2-chlorophenol or 1-propanethiol using the Esters (phosphate) class, so predictions 

cannot be made with any certainty regarding this degradate’s toxicity to estuarine/marine 

invertebrates on an acute basis. Other profenofos metabolites were predicted to be >10x less 

toxic than parent profenofos to this taxa on an acute basis.

Table F7. Empirical and Predicted Mysid LC50 Toxicity Estimates for Parent Profenofos 

and its Degradates.

Parent/Degradate Empirical 

LC50 (ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic SAR

Phenols

Parent 2.4 340 4.0 NP NP

O-ethyl-S-propyl 

phosphorothioate

ND 1,512 6 NP NP

4-bromo-2-

chlorophenol

ND NP NP NP NP

O-ethyl phosphate ND >1,000,000 74 NP NP

1-propanethiol ND NP NP NP NP
Page 66 of 75

The available empirical data on profenofos’ chronic toxicity to mysids had reasonable agreement 

with the predicted toxicity using the Esters (phosphate) structural class. Using this chemical 

class, the O-ethyl-S-propyl phosphorothioate degradate is predicted to have a similar (~1.6x) 

chronic endpoint as parent profenofos. The O-ethyl phosphate metabolite is predicted to be 

significantly less toxic (>10x) than parent profenofos using this class. Toxicity was not 

predicted for 4-bromo-2-chlorophenol using the Esters (phosphate) class, so predictions cannot 

be made with any certainty regarding this degradate’s toxicity to estuarine/marine invertebrates 

on a chronic basis. 

Table F8. Empirical and Predicted Mysid NOAEC Toxicity Estimates for Parent 

Profenofos and its Degradates.

Parent/Degradate Empirical 

NOAEC 

(ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 0.22 77 0.032 NP NP

O-ethyl-S-propyl 

phosphorothioate

ND 2,178 0.053 NP NP

4-bromo-2-

chlorophenol

ND NP NP NP NP

O-ethyl phosphate ND >1,000,000 3 NP NP

1-propanethiol ND NP NP NP NP

The ECOSAR model poorly predicts toxicity to saltwater fish on an acute basis compared to the 

empirical data. Therefore, the QSAR approach should not be used in the risk assessment to 

evaluate the toxicity of profenofos metabolites to saltwater fish on an acute basis. Although no 

empirical chronic data are available for saltwater fish, the NOAEC derived using the ACR 

derived from the acute and chronic fathead minnow data was used as the empirical chronic 

saltwater value. The ECOSAR model poorly predicts chronic toxicity to saltwater fish when 

using this value as the empirical chronic endpoint. Therefore, the QSAR approach should not be 

used in the risk assessment to evaluate the chronic toxicity of profenofos metabolites to saltwater 

fish.

Table F9. Empirical and Predicted Saltwater Fish LC50 Toxicity Estimates for Parent 

Profenofos and its Degradates.

Parent/Degradate Empirical 

LC50 (ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 7.7 1,399 664 NP NP

O-ethyl-S-propyl 

phosphorothioate

ND 3,978 826 NP NP
Page 67 of 75

4-bromo-2-

chlorophenol

ND NP NP NP NP

O-ethyl phosphate ND >1,000,000 7,040 NP NP

1-propanethiol ND NP NP NP NP

Table F10. Empirical and Predicted Daphnid EC50 Toxicity Estimates for Parent 

Profenofos and its Degradates.

Parent/Degradate Empirical 

NOAEC 

(ppb)

Chemical Class for Predicted Estimates of Toxicity

Esters Esters 

(phosphate)

Neutral 

Organic

SAR

Phenols

Parent 0.13 (ACR 

value)

334 22 NP NP

O-ethyl-S-propyl 

phosphorothioate

ND 807 31 NP NP

4-bromo-2-

chlorophenol

ND NP NP NP NP

O-ethyl phosphate ND 552,296 730 NP NP

1-propanethiol ND NP NP NP NP
Page 68 of 75

Appendix G. Length of Time for Profenofos Residues to Decrease Below LOCs after Application.
Page 69 of 75

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

900.0

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Concentration (mg ai/kg dietary item)

Days

Terrestrial Residues (upper bound estimates, assuming 35-D half-life)

vs

Mammalian Herbivore/Insectivore LOCs (as dietary concentrations

Short Grass Tall Grass Broadleaf plants

Fruits/pods/seeds Arthropods Chronic LOC

15 g Mammal Acute LOC 35 g Mammal Acute LOC 1000 g Mammal Acute LOC

Time (days)
Page 70 of 75

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

900.0

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Concentration (mg ai/kg dietary item)

Days

Terrestrial Residues (upper bound estimates, assuming 35-D half-life)

vs

Avian LOCs (as dietary concentrations)

Short Grass Tall Grass Broadleaf plants

Fruits/pods/seeds Arthropods Avian Acute Non-endangered LOC

Avian Chronic LOC Avian Acute Endangered LOC

Time (days)
Page 71 of 75

0.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

3500.0

4000.0

4500.0

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Concentration (mg ai/kg dietary item)

Days

Terrestrial Residues (upper bound estimates, assuming 35-D half-life)

vs

Mammalian Granivore LOCs (as dietary concentrations)

Short Grass Tall Grass Broadleaf plants

Fruits/pods/seeds Arthropods Chronic LOC

15 g Mammal Acute LOC 35 g Mammal Acute LOC 1000 g Mammal Acute LOC

15 g Endangered Mammal Acute LOC 35 g Endangered Mammal Acute LOC 1000 g Endangered Mammal Acute LOC

Time (days)
Page 72 of 75

0.0

50.0

100.0

150.0

200.0

250.0

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Concentration (mg ai/kg dietary item)

Days

Terrestrial Residues (upper bound estimates, assuming 0.711-D half life)

vs

Mammalian Herbivore/Insectivore LOCs (as dietary concentrations

Short Grass Tall Grass Broadleaf plants

Fruits/pods/seeds Arthropods Chronic LOC

15 g Mammal Acute LOC 35 g Mammal Acute LOC 1000 g Mammal Acute LOC

15 g Endangered Mammal Acute LOC 35 g Endangered Mammal Acute LOC 1000 g Endangered Mammal Acute LOC

Time (days)
Page 73 of 75

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Concentration (mg ai/kg dietary item)

Days

Terrestrial Residues (upper bound estimates, assumes 0.711-d half life)

vs

Avian LOCs (as dietary concentrations)

Short Grass Tall Grass Broadleaf plants

Fruits/pods/seeds Arthropods Avian Acute Non-endangered LOC

Avian Chronic LOC Avian Acute Endangered LOC

Time (days)
Page 74 of 75

0.0

500.0

1000.0

1500.0

2000.0

2500.0 Concentration (mg ai/kg dietary item)

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Days

Terrestrial Residues (upper bound estimates, assuming 0.711-d half life)

vs

Mammalian Granivore LOCs (as dietary concentrations)

Short Grass Tall Grass Broadleaf plants

Fruits/pods/seeds Arthropods Chronic LOC

15 g Mammal Acute LOC 35 g Mammal Acute LOC 1000 g Mammal Acute LOC

15 g Endangered Mammal Acute LOC 35 g Endangered Mammal Acute LOC 1000 g Endangered Mammal Acute LOC

Time (days)
Page 75 of 75

Appendix H. AgDrift Analysis of Spray Drift Effects to Off-field Organisms.

Profenofos AgDrfit Runs Ground Application at 0.5 lbs a.i./A

Taxa

High Boom, VFFineLow Boom, VFfineHigh Boom, FineCoarseLow Boom, Fine--

Coarse

Daphnid (acute LD50 of 0.91 ppb, therefore 

concentrations higher than 0.0455 ppb exceed 

the listed species LOC) >810 feet >533 >420 >265

Honey bee (LD50 of 0.0953 ug/bee, therefore 

concentrations higher than 0.03812 μg/bee 

exceed the non-listed species LOC) 90 feet 32 feet 18 feet 10 feet

Mallard Duck (LD50 of 55 mg/kg, therefore 

concentrations above 0.01 lbs/A exceed the 

listed species LOC.

>125 feet >45 feet >27 feet >15 feet