OFFICE OF CHEMICAL 

SAFETY AND 

POLLUTION 

PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

 

PC Code: 083702

DP Barcode: D411096

Date: September 22, 2015

MEMORANDUM

SUBJECT: Registration Review: Preliminary Environmental Fate and Ecological Risk 

Assessment Endangered Species Effects Determination for Tetrachlorvinphos

TO: James Parker, Chemical Review Manager

Thomas Moriarty, Team Leader

Neil Anderson, Branch Chief

Pesticide Re-evaluation Division (7508P)

FROM: Mary Clock-Rust, Biologist 

Chuck Peck, Environmental Engineer

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)

REVIEWED

BY: Thomas Steeger, Ph.D., Senior Science Advisor

Jim Carleton, Ph.D., Senior Scientist

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)

APPROVED

BY: Jean Holmes, DVM, MPH, Branch Chief

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)

The Environmental Fate and Effects Division (EFED) has completed a preliminary risk assessment 

for the insecticide tetrachlorvinphos (TCVP). TCVP is currently registered in 47 technical and 

end-use products for use as feed additives, sprays, and dusts for livestock; dips, collars, sprays, 

and dusts for domestic pets; and sprays and dusts for structures and outdoor areas. 

Risk Conclusions

TCVP is very highly toxic to freshwater aquatic invertebrates. When estimates of TCVP exposure 

in aquatic environments are compared to the available ecotoxicity data, the results of the screening-
-Page 2 of 74-

level assessment indicate a potential for acute and chronic risk to federally listed threatened and 

endangered (referred to as “listed”) and non-listed species of freshwater aquatic invertebrates for 

all of the registered uses of TCVP. Although mortality was not observed in the acute avian studies, 

acute risks to birds could not be precluded, as the estimated environmental concentrations (EECs) 

for most of the uses of TCVP exceeded the highest dose tested in the acute toxicity study (2,000 

mg/kg-diet). Screening-level chronic risk quotient (RQ) values for the uses of TCVP exceed the 

level of concern (LOC) for chronic risk to listed and non-listed birds, reptiles, and terrestrial-phase

amphibians exposed to TCVP in the diet. Results of the screening-level assessment indicate a 

potential for acute and chronic risk to listed and non-listed mammals. 

Uncertainties

The terrestrial plant toxicity studies were conducted at an application rate (6.09 lb a.i./acre) that 

was well below the highest application rate on TCVP labels (34.8 lb a.i./acre). Therefore, there is 

uncertainty surrounding the potential toxicity of TCVP to plants at application rates between 6.09 

and 34.8 lb a.i./acre. However, risks for terrestrial plants exposed to TCVP did not result in 

exceedances for any of the registered uses. Therefore, the potential risk to terrestrial plants from 

exposure to TCVP in runoff is considered low.

Risks for terrestrial invertebrates were not quantified. While TCVP is classified as highly toxic to 

adult honey bees, the use pattern for TCVP (application to manure piles, poultry droppings, etc.) 

is likely to preclude exposure to honey bees. However, there is uncertainty regarding the effect of 

treated manure on fields where ground-nesting solitary and social bees may be located.

An analysis evaluating the use of cow manure as a soil amendment was conducted for this risk 

assessment. Manure used as a soil amendment/organic fertilizer could be a source of pesticide 

residues that are contained in the manure excreted from treated livestock. For modeling purposes, 

an “application” rate of TCVP was estimated based on dry weight of manure application for crop 

production. The methodology used for the estimation of manure application is based on equations 

and tables provided in the USDA Part 651 Agricultural Waste Management Field Handbook 

(USDA, 2009). EFED conducted a similar analysis for swine, poultry, and horse manure, however 

cow manure generates the highest TCVP application rates and is considered protective for all 

manure amendment applications.
-Page 3 of 74-

Environmental Fate and Ecological Risk Assessment

for the Registration Review of Tetrachlorvinphos

O

O

P O

O

Cl

Cl

Cl Cl

Tetrachlorvinphos (TCVP)

CAS 22248-79-9 PC Code 083702

September 22, 2015

Prepared by

Mary Clock-Rust, Biologist

Chuck Peck, Environmental Engineer

U.S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division (EFED)

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460 Reviewed by

Thomas Steeger, Ph.D., Senior Science Advisor

James Carleton, Ph.D., Senior Fate Scientist

Jean Holmes, DVM, MPH, Branch Chief
-Page 4 of 74-

Table of Contents

1. Executive Summary.............................................................................................................. 8

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

2.1. Nature of Regulatory Action........................................................................................ 8

2.2. Stressor Source and Distribution ................................................................................ 9

2.2.1. Nature of the Chemical Stressor.............................................................................. 9

2.2.2. Overview of Pesticide Usage .................................................................................. 9

2.3. Receptors .................................................................................................................. 10

2.3.1. Aquatic and Terrestrial Effects........................................................................... 10

2.3.2. Ecosystems Potentially at Risk ........................................................................ 10

2.4. Assessment Endpoints ................................................................................................ 10

2.5. Conceptual Model ..................................................................................................... 11

2.5.1. Risk Hypotheses................................................................................................... 11

2.5.2. Conceptual Diagram............................................................................................ 11

2.6. Analysis Plan ............................................................................................................. 14

2.6.1. Measures of Exposure....................................................................................... 14

2.6.1.1 Measures of Aquatic Exposure ................................................................................................14

2.6.1.2. Measures of Terrestrial Exposure ............................................................................................14

2.6.2. Measures of Effect............................................................................................. 15

2.6.3. Integration of Exposure and Effects ............................................................... 16

3. Analysis............................................................................................................................. 17

3.1 Use Characterization .................................................................................................. 17

3.2. Exposure Characterization ........................................................................................ 19

3.2.1. Environmental Fate and Transport Characterization ...................................... 19

3.2.1.1. Transport and Mobility ............................................................................................................20

3.2.1.2. Degradation..............................................................................................................................20

3.2.1.3. Field Studies ............................................................................................................................21

3.2.1.4. Bioaccumulation ......................................................................................................................21

3.2.1.5. Transformation Products..........................................................................................................22

3.2.2. Measures of Aquatic Exposure............................................................................ 23

3.2.2.1. Aquatic Exposure Modeling ....................................................................................................23

3.2.2.2. Development of Application Rates and Selection of Crop Scenarios......................................24

3.2.2.3. Aquatic Modeling Inputs .........................................................................................................27

3.2.2.4. Estimated Environmental Concentrations in Surface...............................................................28

3.2.2.5. Monitoring Data.......................................................................................................................29

3.2.2.6 Aquatic Exposure from Indoor Uses........................................................................................30

3.2.3. Measures of Terrestrial Exposure....................................................................... 31

3.2.3.1. Ingestion of Surface Residues by Birds and Mammals............................................................31

3.2.3.2. Runoff and Spray Drift to Terrestrial and Semi-Aquatic Plants..............................................34

3.3. Ecological Effects Characterization .......................................................................... 34

3.3.1. Aquatic Toxicity Assessment ............................................................................... 35

3.3.1.1. Toxicity to Freshwater Fish .....................................................................................................35

3.3.1.2. Toxicity to Freshwater Invertebrates .......................................................................................36

3.3.1.3. Toxicity to Estuarine/Marine Fish ...........................................................................................36

3.3.1.4. Toxicity to Estuarine/Marine Invertebrates .............................................................................36

3.3.1.5. Toxicity to Aquatic Plants .......................................................................................................36

3.3.2. Terrestrial Effects Characterization................................................................... 37

3.3.2.1. Toxicity to Birds......................................................................................................................37

3.3.2.2. Toxicity to Mammals...............................................................................................................37
-Page 5 of 74-

3.3.2.3. Toxicity to Beneficial Insects ..................................................................................................38

3.3.2.4. Toxicity to Terrestrial Plants....................................................................................................38

3.3.3. Review of Incident Data ....................................................................................... 39

4. Risk Characterization......................................................................................................... 40

4.1. Screening-Level Risk Quotient (RQ) Values............................................................ 40

4.1.1. RQ Values for Aquatic Organisms...................................................................... 40

4.1.2. RQ Values for Terrestrial Organisms................................................................. 43

4.2. Risk Description.......................................................................................................... 48

4.2.1. Risks to Aquatic Organisms................................................................................. 48

4.2.1.1. Freshwater Fish, Amphibians, and Invertebrates.....................................................................48

4.2.1.2. Estuarine/Marine Fish and Invertebrates .................................................................................48

4.2.1.3. Aquatic Plants..........................................................................................................................49

4.2.2. Risks to Terrestrial Organisms............................................................................ 49

4.2.2.1. Birds, Reptiles, and Terrestrial-phase Amphibians..................................................................49

4.2.2.2. Mammals .................................................................................................................................50

4.2.2.3. Terrestrial Invertebrates...........................................................................................................51

4.2.2.4. Terrestrial Plants......................................................................................................................51

5. Endocrine Disruptor Screening Program (EDSP)........................................................... 51

6. Federally Threatened and Endangered (Listed) Species of Concern ............................ 52

6.1. Taxonomic Groups Potentially at Risk..................................................................... 52

7. Conclusions.......................................................................................................................... 55

8. References............................................................................................................................ 55

8.1. Submitted Product Chemistry and Environmental Fate Studies........................... 57

8.2. Submitted Ecotoxicity Studies................................................................................... 58
-Page 6 of 74-

Tables

Table 2.1. Chemical Profile of TCVP......................................................................................... 9

Figure 2.1. Conceptual Model Depicting Potential Risks to Nontarget Species from the 

Registered Uses of TCVP ........................................................................................................... 13

Table 2.2. Agency Risk Quotient (RQ) Metrics and Levels of Concern (LOC) Per Risk 

Class. ............................................................................................................................................ 16

Table 3.1. TCVP Maximum Application Rates for Labeled Uses......................................... 18

Table 3.2. Chemical Properties and Environmental Fate Parameters of TCVP................. 19

Table 3.3. Table of Transformation Products Formed in Environmental Fate Studies. .... 22

1. Physical and chemical properties for degradates obtained through EPISuite 4.11. ........ 23

Table 3.4. Aquatic Exposure Inputs in TCVP Ecological Exposure Assessment (SWCC)1 27

Table 3.5. Environmental Fate Data Used for Aquatic Exposure Inputs in TCVP 

Ecological Exposure Assessment. .............................................................................................. 28

Table 3.6. Surface Water EECs for TCVP.............................................................................. 28

Table 3.7. Surface Water, Groundwater, and Sediment Monitoring Data ........................... 30

Table 3.8. Input Parameters for Deriving Screening-Level Terrestrial EECs for TCVP (TREX v. 1.5)1. ................................................................................................................................ 32

Table 3.9. Screening-level Dose-based EECs (mg/kg bw) as Food Residues for Birds, 

Reptiles, and Terrestrial-Phase Amphibians from Labeled Uses of TCVP (T-REX v. 1.5).33

Table 3.10. Screening-level Dose-based EECs (mg/kg bw) as Food Residues for Mammals 

from Labeled Uses of TCVP (T-REX v. 1.5). ........................................................................... 33

Table 3.11. Screening-level Dietary-based EECs (mg/kg-diet) as Food Residues for Birds, 

Reptiles, Terrestrial-phase Amphibians, and Mammals from Labeled Uses of TCVP (TREX v. 1.5)................................................................................................................................... 34

Table 3.12. EECs for Terrestrial and Semi-Aquatic Plants Near TCVP Use Areas 

(TerrPlant v. 1.2.2)...................................................................................................................... 34

Table 3.13. Endpoints Used in the TCVP Preliminary Risk Estimation............................... 38

Table 4.1. Acute RQs for Direct Effects to Freshwater Fish from TCVP TGAI................. 41

Table 4.2. Acute and Chronic RQs for Direct Effects to Freshwater Invertebrates from 

TCVP TGAI. ............................................................................................................................... 41

Table 4.3. Acute RQs for Direct Effects to Estuarine/Marine Fish from TCVP TGAI. ..... 42

Table 4.4. Acute RQs for Direct Effects to Estuarine/Marine Invertebrates from TCVP 

TGAI. ........................................................................................................................................... 42

Table 4.5. RQ Values for Direct Effects to Aquatic Vascular and Nonvascular Plants from 

TCVP TGAI. ............................................................................................................................... 42

Table 4.6. Chronic Dietary-Based RQs for Birds, Reptiles, and Terrestrial-phase 

Amphibians of Different Feeding Classes (T-REX v. 1.5)....................................................... 43

Table 4.7. Acute Dose-based RQ values for Mammals Exposed to TCVP (T-REX v. 1.5). 45

Table 4.8. Screening-level Dietary-based Chronic RQs for Mammals from Labeled Uses of 

TCVP (T-REX v. 1.5).................................................................................................................. 46

Table 4.9. RQs for Nontarget Terrestrial Plants Adjacent to TCVP Use Areas (Ground 

Spray)........................................................................................................................................... 47

Table 6.1. Preliminary Conclusions for Potential Direct Effects to Federally Listed Taxa 

Associated with the Registered Uses of TCVP, Based on Best Available Data..................... 53
-Page 7 of 74-

APPENDICES

Appendix A. Chemical Names and Structures of TCVP and its Degradates......................................................60

Appendix B. SWCC Sample Input/Output Data ...................................................................................................62

Appendix C. Example T-REX (v. 1.5) Input and Output for TCVP....................................................................64

Appendix D. Example Terrplant (v. 1.2.2) Input and Output for TCVP ............................................................64

Appendix E. STIR Results. ......................................................................................................................................67

Appendix F. SIP Results...........................................................................................................................................66

Appendix G. KABAM Results..................................................................................................................................67

Appendix H. Application Rate Estimation, Spot Application................................................................................71

Appendix I. Communication with Registrant Re: Use of TCVP Oral Larvicide at Feedlots .............................72

ATTACHMENTS (SEPARATE ELECTRONIC FILE)

Attachment I. Bibliography of ECOTOX Open Literature (December 2013 Refresh)

Attachment II. ECOTOX Data Table (December 2013 Refresh)
-Page 8 of 74-

1. Executive Summary

The preliminary ecological risk assessment (PRA) examines the potential risks to wildlife, 

including non-target plants, associated with labeled uses of the organophosphate insecticide 

tetrachlorvinphos (TCVP). The risk assessment is based on the best available scientific and 

commercial information on the use, environmental fate and transport, and effects of TCVP on nontarget organisms. This PRA includes a screening-level assessment which is consistent with prior 

assessments for TCVP registration actions.

The residues of concern for this assessment were determined to be TCVP parent only. TCVP is 

very highly toxic to freshwater aquatic invertebrates. When estimates of TCVP exposure in aquatic 

environments are compared to the available ecotoxicity data, the results of the screening-level 

assessment indicate a potential for acute and chronic risk to federally listed threatened and 

endangered (referred to as “listed”) and non-listed species of freshwater aquatic invertebrates for 

all of the registered uses of TCVP. Although mortality was not observed in the acute avian studies, 

acute risks to birds could not be precluded, as the estimated environmental concentrations (EECs)

for most of the uses of TCVP exceeded the highest dose tested in the acute toxicity study (2,000 

mg/kg-diet). Screening-level chronic risk quotient (RQ) values for the uses of TCVP exceed the 

level of concern (LOC) for chronic risk to listed and non-listed birds, reptiles, and terrestrial-phase

amphibians exposed to TCVP in the diet. Results of the screening-level assessment indicate a 

potential for acute and chronic risk to listed and non-listed mammals. 

 

2. Problem Formulation

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

ecological risk assessment being conducted for the representative labeled uses of 

tetrachlorvinphos [(Z)-2-chloro-1-(2,4,5-trichlorophenyl)vinyl dimethyl phosphate; CAS 22248-

79-9]; PC Code 083702), which are summarized in the most recent Label Use Information System 

(LUIS) report compiled by the Biological and Economic Analysis Division (BEAD) (November 

7, 2007) of the EPA Office of Pesticide Programs (OPP). The problem formulation sets the 

objectives for the risk assessment and provides a plan for analyzing the data and characterizing the 

risk (USEPA 1998a). As part of the Registration Review process, a detailed Problem Formulation 

(DP Barcode D346879) for this risk assessment was published to the docket [Docket ID: EPAHQ-OPP-2008-0316] in June 2008 (USEPA, 2008a). The following section summarizes the key 

points of that document and discusses any differences between the analysis outlined there and the 

analysis conducted in this risk assessment.

2.1. Nature of Regulatory Action

The risk assessment is conducted as part of the Agency’s Registration Review process for pesticide 

active ingredients. The Registration Review process was established under the Food Quality 

Protection Act (FQPA 1996).
-Page 9 of 74-

2.2. Stressor Source and Distribution

2.2.1. Nature of the Chemical Stressor

Tetrachlorvinphos, hereafter refered to as TCVP, is an organophosphate insecticide that acts by 

inhibiting acetylcholinesterase, an enzyme needed for hydrolyzing the neurotransmitter, 

acetylcholine. 

TCVP was originally registered as a 50:50 mixture of E:Z isomers (CAS No. 961-1 1-5, PC code 

083701), and was later registered as the Z-isomer only (CAS No. 22248-79-9, PC code 083702). 

Products that contain the E-isomer alone (CAS No. 22350-76-1, PC code 083703) have not been 

registered, and products containing the 50:50 isomer mixture have been reformulated to contain 

the Z-isomer only. Therefore, only the Z-isomer (PC code 083702) is considered in this 

environmental fate and ecological risk assessment. 

The chemical profile of TCVP is provided in Table 2.1. Chemical names and structures of the 

isomeric mixtures of TCVP and its degradates are listed in Appendix A. As described in Section 

3.2.1.4, this screening-level ecological risk assessment focuses on TCVP parent only.

Table 2.1. Chemical Profile of TCVP.

Common name TCVP

IUPAC name (Z)-2-chloro-1-(2,4,5-trichlorophenyl)vinyl dimethyl 

phosphate

CAS name (1Z)-2-chloro-1-(2,4,5-trichlorophenyl)ethenyl dimethyl 

phosphate

Structure O

O

P O

O

Cl

Cl

Cl Cl

Pesticide type Insecticide

Chemical class Organophosphate insecticide

CAS number 22248-79-9

Empirical formula C10H9Cl4O4P

Molecular mass 365.96 g/mol

2.2.2. Overview of Pesticide Usage

TCVP is currently registered in 47 technical and end-use products for use as feed additives, sprays, 

and dusts for livestock; dips, collars, sprays, and dusts for domestic pets; and sprays and dusts for 

structures and outdoor areas. Application rates vary by use pattern. Multiple applications are 

allowed, although these are mostly limited to spot, surface, and livestock and pet treatments. 

Specific use rates are discussed in Section 3.1. TCVP can be applied as a feed additive/oral 

larvicide, and, as such, resultant residues in manure applied as a soil amendment on farms are also 

considered an exposure pathway in this risk assessment.
-Page 10 of 74-

2.3. Receptors

2.3.1. Aquatic and Terrestrial Effects

A receptor is a biological entity that is exposed to a stressor (USEPA 1998). Consistent with the 

process described in the Overview Document (USEPA 2004), this risk assessment uses a surrogate 

species approach in its evaluation of TCVP. Toxicity data generated from surrogate test species, 

which are intended to be representative of broad taxonomic groups, are used to extrapolate 

potential effects on a variety of species (receptors) included under these taxonomic groupings.

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

from the available open literature are used to evaluate potential direct effects of TCVP to aquatic 

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

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

for aquatic life, terrestrial plants, and wildlife. 

2.3.2. Ecosystems Potentially at Risk 

Ecosystems at potential risk are often extensive in scope; therefore, it is not possible to identify 

such ecosystems in other than general terms in a screening-level assessment. In general terms, 

terrestrial ecosystems potentially at risk could include treated sites and areas immediately adjacent 

to treated sites that may receive runoff, including that which carries eroded sediment. Such areas 

could include the treated sites themselves and nearby cultivated fields, as well as uncultivated areas 

such as fencerows, hedgerows, meadows, fallow fields, woodlands, wetlands, and other riparian 

habitats. 

Aquatic ecosystems potentially at risk include water bodies adjacent to or downstream from treated 

areas and may include natural or impounded lentic systems (ponds, lakes, reservoirs), and lotic 

(flowing) waterways, i.e., streams and rivers. For uses in coastal areas, aquatic habitat includes 

estuarine and marine ecosystems. Within water bodies, the water column, sediment, and pore 

water are all compartments of potential concern. 

2.4. Assessment Endpoints 

Assessment endpoints represent the actual environmental values that are to be protected, defined 

by ecological entitities (species, community, etc.) and their attributes or characteristics (USEPA

1998). For TCVP, the ecological entities assessed include the following: birds, amphibians, 

reptiles, mammals, freshwater and estuarine/marine fish, terrestrial and aquatic invertebrates, and 

terrestrial and aquatic plants. The assessed attributes for any of these entities may include growth, 

survival, and/or reproduction. (See Table 2.3 in Section 2.6.2, the Analysis Plan, for further 

discussion).

The assessment endpoints are intended to reflect population sustainability and community 

structure within ecosystems, and hence relate to ecosystem risk. If risks are identified for given 
-Page 11 of 74-

species/taxa based on a screening-level assessment, then such risks might be expected to translate 

to higher levels of biological organization.

2.5. Conceptual Model

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

significant amounts. 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 include a source, an environmental transport medium/mechanism, a point (location) of 

exposure, and a plausible route by which exposure occurs there. The conceptual model shown 

herein is intended to provide a written description and visual representation of predicted 

relationships between TCVP, potential routes of exposure, and effects related to Agency 

assessment endpoints. A conceptual model consists of two primary components: a risk hypotheses 

and a conceptual diagram (USEPA 1998).

The conceptual model used to depict potential ecological risks associated with the outdoor uses of 

TCVP relies on the Agency’s current understanding of the environmental fate and ecological 

effects of the chemical. The use of TCVP on residual surfaces may result in aquatic exposure to 

organisms through runoff. Terrestrial and aquatic exposures to TCVP are possible from the uses 

in kennels and spot treatments and as residue in soil amendment. Consistent with the use of TCVP

as an insecticide, potential risk to non-target aquatic vertebrates and invertebrates is expected. The 

conceptual model predicts that TCVP is capable of affecting aquatic vertebrates and invertebrates, 

provided that environmental concentrations are of sufficient magnitude as a result of TCVP’s 

registered uses (Figure 2.1).

2.5.1. Risk Hypotheses

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

Given the registered uses of TCVP and its environmental fate properties, there is possible

acute and chronic exposure to nontarget aquatic and terrestrial organisms. This assessment 

tests the hypothesis that, when used in accordance with the label, TCVP exposure may result 

in adverse effects upon the survival, growth, and reproduction of nontarget aquatic and 

terrestrial plants and animals. 

 

2.5.2. Conceptual Diagram

The potential exposure pathways and effects of the registered uses of TCVP are depicted in Figure 

2.1. Solid arrows depict the most likely routes of exposure and effects; dashed lines depict 

potential routes of exposure that are not considered likely for TCVP. Most of the applications of 

TCVP are spot treatments, surface treatments, or applications to livestock or pets, with limited

exposure to non-target aquatic and terrestrial wildlife. For the registered uses of TCVP as a 

larvicide, residues may pass through a treated animal as manure and remain active. As manure 

containing TCVP residues may be applied to agricultural lands as a soil amendment, an exposure 

pathway exists, potentially exposing non-target ecological receptors to TCVP. Organisms that may 
-Page 12 of 74-

be exposed to TCVP include aquatic receptors (e.g., freshwater and estuarine/marine fish and 

invertebrates, aquatic-phase amphibians, and plants) as a result of movement of TCVP via runoff 

from sites of manure application. Exposure to terrestrial and semi-aquatic wildlife (i.e., mammals, 

birds, terrestrial-phase amphibians, terrestrial invertebrates, and reptiles) and plants could occur 

via application of spot treatments and application of TCVP-containing manure to areas which 

could be used as food sources for terrestrial and semi-aquatic wildlife. The conceptual framework 

for assessment of potential ecological risks associated with TCVP use is depicted in Figure 2.1;

potential endpoints, stressors, and ecological effects are identified based on this model. 

As discussed in the preliminary problem formulation (USEPA 2008) and based on TCVP’s vapor 

pressure (2.6x10-7 torr), the chemical is not expected to readily volatilize and generate inhalation 

concentrations of concern. The Screening Tool for Inhalation Risk (STIR) (see Section 2.6.2), 

which compares inhalation exposure estimates to available avian and mammalian toxicity data,

confirms this assumption, so this assessment does not evaluate potential atmospheric transport in 

estimating environmental concentrations. While the Screening Imbibition Program (SIP) 

conservatively qualitatively indicates that drinking water exposure could be a potential pathway 

of concern, the means to quantify the levels of exposure are currently not available; therefore, the 

current assessment does not evaluate potential risk to wildlife through drinking water exposure.

For aquatic assessments, the major routes of exposure for aquatic animal species are considered to 

be through the respiratory surface (gills) or the integument. Similar to terrestrial organisms, 

exposure of aquatic organisms to TCVP may also occur through ingestion of residues in sediment

and forage. TCVP has an octanol-water partition coefficient (Kow) of 3350 (MRID 41222503). 

Aquatic plants may be exposed via direct uptake and adsorption.
-Page 13 of 74-

Figure 2.1. Conceptual Model Depicting Potential Risks to Nontarget Species from the Registered Uses of TCVP. Solid arrows depict the routes of 

exposure and effects which are assessed for parent TCVP based on the available data; dashed lines depict potential routes of exposure that are not considered 

likely. 

Stressor

Source/

Transport

Pathways

Direct Deposition Runoff

Erosion

Leaching

(Infiltration/

Percolation

Source/

Exposure

Media

Terrestrial Plants

Terrestrial Invertebrates

Terrestrial Plants

Soil

Receiving 

Water 

Body/ 

Sediment

Groundwater

Tested

Exposure

Route

Ingestion Direct Contact

Root Uptake Gill or Integument 

Uptake

Receptors

Attribute

Changes

Terrestrial 

Vertebrates

Terrestrial Plants

Individual Animals:

 Reduced survival, growth, and/or 

reproduction

Aquatic Invertebrates

Aquatic Vertebrates

Individual Plants:

 Seedling emergence

 Vegetative vigor

Individual Animals:

 Reduced survival, growth, 

and/or reproduction

Plant Population:

Reduced population 

growth

Aquatic Plants

Uptake/ 

Adsorption

Spray Drift Volatilization

Atmospheric Transport

TCVP

Direct Contact

Terrestrial 

Invertebrates
-Page 14 of 74-

2.6. Analysis Plan 

2.6.1. Measures of Exposure 

2.6.1.1 Measures of Aquatic Exposure 

Measures of exposure to aquatic animals and plants are concentrations in surface water and benthic 

sediment pore water simulated by the Surface Water Concentration Calculator (SWCC, v 1.106, 

May, 2014), used to generate estimated environmental concentrations (EECs) of TCVP that may 

occur from the chemical’s use for spot treatments and in manure-amended soil. The EECs used in 

assessment of acute risk are 1-in-10 year return frequency daily maximum values (referred to as 

“peak” values). For chronic risk assessment, mean concentrations over a specified duration are 

generated. In both cases, each modeled site is selected to represent a site expected to be more 

vulnerable to runoff than most locations where use may occur (e.g., based on the crop being 

grown). The SWCC simulates pesticide runoff from a treated area to an adjacent water body 

following applications, in addition to loadings that occur directly to the water as a consequence of

spray drift. 

2.6.1.2. Measures of Terrestrial Exposure

Terrestrial wildlife could be exposed to TCVP via consumption of residues on food items via 

applications of spot treatment non-agricultural scenarios where applications result in residues on 

grass and other plants. For applications, the T-REX model (Terrestrial Residue EXposure model; 

v. 1.5.12; June 6, 2013) is used to predict dietary exposure to TCVP residues on foliar surfaces 

and insects using the Kenaga nomogram as modified by Fletcher (Hoerger and Kenaga 1972, 

Fletcher et al. 1994). 

The TERRPLANT (v. 1.2.2; December 26, 2006) model is used to derive EECs relevant to 

terrestrial and wetland plants, assuming that default fractions of the intended application will be 

transported to an adjacent field through runoff. Measures of exposure to terrestrial plants are 

expressed as a fraction of the mass of the TCVP applied. As spray applications of TCVP products 

are typically spot treatments, and manure amendment applications are expected to result in little 

spray drift potential, exposure to spray drift applications of TCVP are expected to be minimal.

The Screening Tool for Inhalation Risk (STIR v.1.0, November 19, 2010) was used to calculate 

an upper-bound estimate of exposure using TCVP’s vapor pressure and molecular weight for vapor 

phase exposure, as well as the rate that would result in TCVP residues applied in manure used as 

soil amendment (see Section 3.2.2.2). Given TCVP’s method of application, spray drift was not 

modeled. STIR incorporates results from several toxicity studies including acute oral and 

inhalation rat toxicity endpoints obtained from the “six-pack” of core studies, which are a series 

of six guideline studies that are submitted to the Registration Division of the Office of Pesticide 

Programs for technical and formulated products of a pesticide (oral LD50 = 1480 mg a.i./kg bw/day, 

MRID 41222504; and inhlation LC50 >3.61 mg/Lair, MRID 00138933, respectively) as well as the 

most sensitive acute oral avian toxicity endpoint (LD50 >2,000 mg/kg bw, MRID 00160000) for 

the mallard duck (Anas platyrhnchos). Based on the results of the STIR model (Appendix E), 
-Page 15 of 74-

exposure via inhalation of vapor phase TCVP was determined not to be a pathway of risk concern 

for either avian or mammalian species on an acute exposure basis.

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 total exposure that has a 

potential for effects to non-target animals. However, the Agency does consider the relative 

importance of other routes of exposure in situations where data indicate that pesticide exposures 

through other routes may be potentially significant contributors to wildlife risk (USEPA 2004). 

The risk characterization section (Section 4.3), 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. Detailed information about STIR 

v.1.0, as well as the tool, can be found on EPA’s website 

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

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

upper-bound estimate of exposure using TCVP’s solubility (11.6 mg/L, MRID 41222503), that 

was in turn compared to the most sensitive acute and chronic avian and mammalian toxicity 

endpoints (see Table 3.22 and 3.23, respectively). In this way, drinking water exposure by itself

was determined to be a potential pathway of concern for avian species on a chronic exposure basis. 

The potential for acute exposure through consumption of drinking water to result in an adverse 

effect was not calculated because the median lethal dose (LD50) for birds is a nondefinitive value 

(LD50 >2,000 mg a.i./kg bw). For a sample of the output generated by SIP v.1.0, please see 

Appendix F.

While the impact of bioaccumulation is considered low, the KABAM model [Kow (based) Aquatic 

BioAccumulation Model, Version 1.0] was used as a screen to estimate potential bioaccumulation 

of hydrophobic organic pesticides in freshwater aquatic food webs and subsequent risks to 

mammals and birds via consumption of aquatic prey contaminated with TCVP. The 

bioaccumulation portion of KABAM relies on a pesticide’s octanol-water partition coefficient 

(KOW) to estimate uptake and elimination constants through respiration and diet of aquatic 

organisms in different trophic levels. Pesticide tissue concentrations in aquatic organisms are 

calculated for different trophic levels of a food web through diet and respiration and are used to 

estimate dose- and dietary-based exposures and associated risk quotients for mammals and birds 

consuming aquatic organisms. The results of the KABAM analysis (Appendix G) indicate that 

the risk to birds and mammals that consume aquatic prey contaminated by TCVP is considered 

low.

2.6.2. Measures of Effect 

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

conducted with a limited number of surrogate test species (Table 2.2). The test species are not 

intended to be representative of the most sensitive species but rather were selected based on their 

ability to thrive under laboratory conditions. Toxicity testing reported in this risk assessment 

utilizes surrogate species to represent all freshwater fish (2000+) and bird (680+) species in the 

U.S. The ECOTOXicology database (ECOTOX), was searched in August 2014 to determine
-Page 16 of 74-

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

more sensitive data were identified.

The acute measures of effect used in this screening-level assessment are the LD50 (Lethal Dose), 

LC50 (Lethal Concentration), EC50 (Effects Concentration), and IC50 (Inhibition Concentration). 

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

organisms. The endpoints for chronic measures of exposure are the NOAEC (No Observed 

Adverse Effect Concentration) and the NOAEL (No Observed Adverse Effect Level). Toxicity 

studies were submitted for freshwater fish and invertebrates, estuarine/marine fish and 

invertebrates, aquatic plants, birds, mammals, bees, and other terrestrial invertebrates. The 

endpoints used for risk characterization were derived from studies which underwent review and 

were classified as “acceptable” (conducted under guideline conditions and considered to be 

scientifically valid) or “supplemental” (conditions deviated from guidelines but the results were 

considered to be scientifically valid). 

2.6.3. Integration of Exposure and Effects

The exposure and toxicity effects data are integrated in order to evaluate the risks of adverse 

ecological effects on nontarget species. For the risk assessment of TCVP, the risk quotient (RQ) 

method is used to compare estimated exposure with measured toxicity endpoints. The RQ method 

involves dividing EECs by the most sensitive acute and chronic toxicity endpoints available. The 

resulting RQs are then compared to the Agency’s Levels of Concern (LOC) (USEPA 2004) (Table 

2.2). Any LOC exceedences are used to indicate uses of TCVP that have the potential to cause 

adverse effects to non-target organisms.

Table 2.2. Agency Risk Quotient (RQ) Metrics and Levels of Concern (LOC) Per Risk Class.

Risk Class Risk Description RQ LOC

Aquatic Animals (fish and invertebrates)

Acute Potential for effects to non-listed animals from acute 

exposures

Peak EEC/LC501 0.5

Acute 

Restricted Use

Potential for effects to animals from acute exposures

Risks may be mitigated through restricted use classification Peak EEC/LC501 0.1

Acute Listed 

Species

Listed species may be potentially affected by acute 

exposures

Peak EEC/LC501 0.05

Chronic Potential for effects to non-listed and listed animals from 

chronic exposures

60-day EEC/NOAEC 

(fish) 1

21-day EEC/NOAEC 

(invertebrates)

Aquatic Plants

Non-Listed Potential for effects to non-listed plants from exposures Peak EEC/LC501 1

Listed Potential for effects to listed plants from exposures Peak EEC/NOAEC 1

Terrestrial Animals (mammals and birds)2

Acute Potential for effects to non-listed animals from acute 

exposures

EEC/LC50 (Dietary) 0.5

EEC/LD50 (Dose)

Potential for effects to animals from acute exposures EEC/LC50 (Dietary) 0.2
-Page 17 of 74-

Risk Class Risk Description RQ LOC

Acute 

Restricted Use

Risks may be mitigated through restricted use classification EEC/LD50 (Dose)

Acute Listed 

Species

Listed species may be potentially affected by acute 

exposures

EEC/LC50 (Dietary) 0.1

EEC/LD50 (Dose)

Chronic Potential for effects to non-listed and listed animals from 

chronic exposures EEC/NOAEC 1

Terrestrial and Semi-Aquatic Plants

Non-Listed Potential for effects to nontarget, non-listed plants from 

exposures

EEC/ EC25 1

Listed Plant Potential for effects to nontarget, listed plants from 

exposures

EEC/ NOAEC

1

EEC/ EC05

1 LC50 or EC50. 2 EEC based on upper bound Kenaga nomogram values for foliar exposure.

3. Analysis

3.1 Use Characterization

TCVP is a broad-spectrum insecticide. TCVP is an active ingredient currently in 47 formulated 

products registered as insect larvicides and adulticides. Labeled trademark names for TCVP 

include Rabon®, Rabex®, Equitrol®, and Equi-Fly®; trademark names no longer labeled include 

Gardona® and Stirofos®. TCVP is registered for use as a spot treatment on kennels, yards, 

recreational areas, poultry droppings, manure piles, and garbage piles; as a surface treatment on 

residual surfaces, such as barn and farm buildings; as an oral larvicide for livestock; and as a dust, 

spray, or dip for pets and livestock. Maximum use pattern information is presented in Table 3.1. 

A review of the current labels for TCVP indicates that the following mitigation measures, specified 

in EPA’s 2006 Tolerance Registration Eligibility Document, have been implemented:

• Restrict outdoor premise uses to spot treatments, one time a year, and along woody 

borders of kennels, yards, campgrounds, recreational parks, and footpaths and roadways

leading to such areas.

• Prohibit the use of outdoor premise treatments by homeowners (indoor use by 

homeowners still permitted).

• Delete the paint-on use with emulsifiable concentrate (EC) formulations.

• Modify directions for use to specify 1⁄3 oz. of powder for every 10 pounds of body weight 

of the cat or dog. 

• For TCVP feed-through products for horses, labels must state that the product is a 

cholinesterase inhibitor, describe signs of cholinesterase inhibition in horses, caution 

against concurrent use with other cholinesterase inhibiting compounds, and direct horse 

owners to consult a veterinarian before using products containing TCVP on debilitated, 

aged, breeding, pregnant or nursing animals.
-Page 18 of 74-

Table 3.1. TCVP Maximum Application Rates for Labeled Uses.

Use Max. Single App. 

Rate (lbs a.i./A)

Annual 

Max. # of 

App.

Min. App. 

Interval (d) EPA Reg. No.

Outdoor Uses

Kennels, yards and recreational 

areas1

3.3 1 Not applicable 11556-162

1.1 1 Not applicable 61483-43, 

67517-33

Residual surfaces (barns, farm 

buildings) around garbage dumps 

and corrals2

13.9 Unlimited None specified 61483-43, 

67517-33,

11556-162

Poultry droppings, manure piles, 

garbage piles1,2

34.8 1 Not applicable 61483-43, 

67517-33,

11556-162

Livestock (feed additive, salt lick)3 0.0017 lbs ai/head Unlimited None specified (Several labels)

Indoor / Homeowner Uses

Dust

0.0010 lbs a.i./cat None 7 2596-78

0.0026 lbs a.i./dog None 7 2596-79

0.0075 lbs a.i./cattle None None 61483-45

0.0075 lbs a.i./swine None 14 61483-45

0.0038 lbs a.i./horse None None 47000-123

0.0001 lbs a.i./chicken None 14 47000-123

Spray

0.04 lbs a.i./cattle None None 61483-46

0.02 lbs a.i./swine None 14 67517-33

0.0004 lbs a.i./chicken None None 67517-33

0.043 lbs a.i./cat None 3 2596-141

Pet dip 0.0033 lbs a.i./use None None 2596-119

Pet sponge 0.044 lbs a.i./use None 7 61483-51

Pet collar 0.016 lbs a.i./collar None (≤7 months) 2596-139 1

Most labels indicate these uses are spot treatments and that only one application per year should occur outdoors. Reg. No. 11556-162 (formerly 

61483-50) no longer includes this language, however the Agency has contacted the registrant and anticipates that this label will be revised in the 

near future to include this language. 2

It is unclear from the labels if these uses are intended only for indoor applications, this PRA assumes these applications are made outdoors. 3

Manure from this use can be collected and broadcast to agricultural fields. Results from manure study (MRID 48956301) will be used to develop 

an equivalent application rate.

Reported usage of TCVP is mainly for animal manure treatment and animal structure applications. 

The BEAD Quantitative Usage Analysis for Tetrachlorvinphos (dated May 12, 2000) indicated a 

national maximum annual usage of 1,816,000 lbs a.i. (USEPA, 2000). The largest market was 

poultry, with a maximum annual lbs a.i. applied of 932,000. According the BEAD assessment, 

the uses with a high average percentage of domestic animals treated included horses (16%), poultry 

(6%), and dogs and/or cats (10%); maximum percentages of animals treated for these uses were 

31%, 11%, and 20%, respectively.

In 2008 BEAD updated the usage report, using National Agricultural Survey Statistics (NASS) 

data from 1997 to 2006 (USEPA, 2008b). Between 1997 and 2006, over 494,000 lbs of TCVP 

was used on livestock and livestock buildings/structures. Approximately 74% of the usage was 
-Page 19 of 74-

on cattle (application method not specified), both beef and dairy, and 25% was used in/around

cattle buildings and structures. The remaining 1% was used in/around swine, sheep, and associated 

livestock facilities. Updated data on poultry were not provided. More recent data on TCVP usage 

on livestock are not available.

3.2. Exposure Characterization

3.2.1. Environmental Fate and Transport Characterization

Chemical and environmental fate characteristics of the parent compound TCVP are listed in Table 

3.2 and are discussed in greater detail in the following sections. The environmental fate data set 

submitted for TCVP is limited, as the data are intended to fulfill the Subart N 40 CFR Part 

158.1300 data requirements1 for a residential outdoor use pattern. These data indicate that TCVP 

is moderately mobile in soil and not stable in terrestrial or aquatic environments. Most of the 

submitted environmental fate studies were conducted on the TCVP cis:trans isomer mixture. 

Bridging between the biodegradation data for the isomer mixture and the Z-isomer has not been 

performed, but the assumption has been made that the isomer data is representative of the Zisomer.

Table 3.1. Chemical Properties and Environmental Fate Parameters of TCVP.

Chemical/Fate Parameter Value Source (MRID)

Chemical name (Z)-2-chloro-1-(2,4,5-trichloropheny1)vinyl 

dimethyl phosphate

Molecular mass (g/mol) 365.96 41222503

Vapor pressure (25°C) (torr) 2.6 x 10-7 41222503

Water solubility (25°C) (mg/L) 11.6 41222503

Octanol-water partition coefficient (KOW) 3,350 41222503

Hydrolysis half-life (d) 

pH 5, 25°C

pH 7, 25°C

pH 9, 25°C

TCVP 41929101

43663501 57.3

29.8

10.3

Aerobic soil metabolism half-life (d)

TCVP Soil1

8.8 Loam (1.6%) 42082401

9.2 Loam (Unknown) 00077821

15.7 Sandy clay loam (1.3%) 48879901

7.95 Sandy loam (1.2%)

Manure dissipation study half-life (d) 152 NA 48956301

Freundlich soil-water distribution 

coefficient (KF); Freundlich organic carbon 

partitioning coefficient (KFOC)

KF KFOC n Soil1 41681301

8.18 520 0.87 Loam (1.6%)

4.04 870 0.83 Sand (0.5%)

 1CFR. 2014. Title 40 (Protection of the Environment), Part 158 (Data Requirements for Pesticides), Subpart N (Environmental Fate), §158.1300 

(Environmental fate data requirements table); http://www.ecfr.gov/cgi-bin/textidx?SID=d610e8a56f8b9045f13341b15f6c9bc9&node=se40.24.158_11300&rgn=div8
-Page 20 of 74-

Chemical/Fate Parameter Value Source (MRID)

0.60 1,000 0.97 Sandy loam (0.06%)

13.7 1,100 0.90 Silty clay (1.3%)

1. % indicates percent of organic carbon in soil or sediment.

3.2.1.1. Transport and Mobility

TCVP is soluble in water at up to 11.6 mg/L, and is not expected to volatilize significantly due to 

a low vapor pressure of 2.6 x 10-7 torr (25°C; MRID 41222503). The compound has an octanolwater partition coefficient of 3350 (i.e., Log Kow of 3.53, MRID 41222503). TCVP appears to be 

slightly to moderately mobile in soil (Kashuba, 2006), with a KFOC range of 520 to 1100 L/kgoc in 

soils representative of use sites (MRID 41681301). Its mobility may be overestimated, however, 

as equilibration was terminated in the provided study after four hours in order to prevent significant 

hydrolysis of the compound. TCVP sorption to soil is related to soil organic matter, i.e., the 

compound is less mobile in soils with higher organic matter. Data regarding the mobility of 

TCVP's degradates have not been submitted. However, an analysis using the Estimation Program 

Interface Suite (EPISuiteTM2; version 4.11) estimates that the degradates are as mobile, and in most 

cases more mobile, than the parent.

3.2.1.2. Degradation

TCVP hydrolyzes in water at a pH-dependant rate. Hydrolysis is relatively rapid in alkaline water 

bodies (half-life of 10.3 days; MRID 41929101, 43663501). In neutral to acidic water bodies, 

TCVP hydrolyzes with moderate to slow half-lives of 30 to 57 days. A major degradate of 

hydrolysis found in the aqueous solution at pH 9 was des-O-methyl tetrachlorvinphos (28% at Day 

21). Photolysis studies of TCVP have not been submitted.

TCVP isomer mixture (50:50, Z:E) readily biodegraded in aerobic soils, with a half-life of 

approximately 9 days (MRIDs 00077821 and 42082401). However the rate of biodegradation for 

the mixed isomer of the parent TCVP was slightly reduced as concentrations decreased, which 

may indicate that microbes metabolize one isomer quicker than the other. As a result, the aerobic 

soil metabolism half-lives reported in the ecological risk assessment written in support of 

Reregistration Eligibility Decision (RED)3 (i.e., t1⁄2 range; 4.4 to 8 days) were shorter than that of 

the mixed isomer because the reviewers did not include the final concentrations in their 

calculations due to the reduction in degradation rates over time. Major degradates in one aerobic 

metabolism study (MRID 00077821) included TCPEol (SD 15509, [l-(2,4,5-

trichlorophenyl)ethanol], 25% at Day 16), TCCEol (SD 15125, [1-(2,4,5-trichloropheny1)-2-

chloroethanol], 28% at Day 16), and TCPEone (CO300, 2,4,5-trichloroacetophenone, 11% at Day 

8). Major degradates in the other aerobic metabolism study (MRID 42082401) included TCPEol 

(31% at Day 4), TCCEol (14% at Day 7), TCPEone (51% at Day 60) and TCBA (2,4,5-

trichlorobenzoic acid, 19% at Day 129. The aerobic transformation of [phenyl-U-14C] TCVP was 

studied in two U.S. soils: a sandy clay loam soil, and a sandy loam soil, for up to 120 days (MRID 

48879901). The half-lives for TCVP ranged from 7.95 to 15.7 days, similar to the half-lives from 

 2 USEPA. 2014. Estimation Program Interface (EPI) SuiteTM. http://www.epa.gov/opptintr/exposure/pubs/episuite.htm 3 USEPA, 1995. TCVP RED. Available: http://www.epa.gov/oppsrrd1/REDs/0321red.pdf
-Page 21 of 74-

the earlier aerobic soil studies for the isomer mixture, indicating that both isomers probably 

degraded at rates similar to those in the earlier studies. Major degradates included TCPEol (41% 

at Day 58), TCCEol (51% at Day 58), TCPEone (23% at Day 14), and TCBA (32% at Day 120). 

Studies on the biodegradation of tetrachlorvinphos in anaerobic soils or water have not been 

submitted.

3.2.1.3. Field Studies

The standard guideline data requirement field study “Terrestrial Field Dissipation” (OCSPP 

Guideline 835.6100) was replaced with the special study "Dissipation of Residues in Livestock 

Manure" because TCVP is used primarily as a feed additive for controlling flies associated with 

livestock, thereby leaving TCVP residues in the feces. A manure dissipation study (MRID 

42848501) was conducted to assess the dissipation of TCVP under simulated field conditions. The 

study measured TCVP (Z-isomer) and its residues bearing the phenyl moiety (radiolabeled

location) present in manure from one treated cow treated orally at 1.55x10-4 lb a.i./100 pounds

bodyweight/day (1.55 mg a.i./kg bodyweight/day) for 14 days prior to analysis. Parent TCVP was 

not isolated in the compost samples at any sampling interval. Total phenyl-bearing residues of 

TCVP did not decline during 6 months in composted manure collected throughout treatment. 

Several degradates were identified in the compost samples. The degradate TCPEol was 69% of the 

recovered radioactivity at day 0, and was 40% of the recovered radioactivity at both 4 and 6 months 

after the treatment period. The degradate TCCEol was 7.1 % of the recovered radioactivity at Day 

0 and declined until not detected by 3 months after treatment. The degradate TCBA was not 

detected until 6 months after treatment, at which time it accounted for approximately 12% of the 

recovered radioactivity. Eight additional degradates were detected in the manure at 0.3 to 5.3 ppm 

(up to 10% of the recovered radioactivity) but were not identified. Unextracted radioactivity was 

up to 27.7% of the recovered radioactivity.

In a subsequent manure dissipation study (MRID 48956301), four female beef cattle received the 

test product (Rabon®, 97.3% TCVP) twice daily for 14 days via the concentrate feed at a dose level 

equivalent to 1.54 mg product per kg bodyweight per day. Manure was collected daily during the 

treatment period (14 days), with the bulk samples transferred to individual compost piles, one for 

each animal, which were maintained outside and allowed to weather naturally. Manure and 

compost samples were analyzed for TCVP and the degradates TCPEol, TCCEol, TCBA, and 

TCPEone (analyses was not conducted for des-O-methyl tetrachlorvinphos and 1-(2,4,5-

trichlorophenyl)ethanediol). TCVP residues were stable in compost. Combining the data for all 

four animals, the calculated dissipation half-lives for TCVP residues in compost were 152 days. 

For the individual animals, the calculated half-lives for TCVP residues in compost ranged from 

133 to 232 days and 478 to 2013 days, respectively. These half-lives are much longer than the 

TCVP half-lives estimated in soil (8-16 days), more than likely the result of the much higher 

organic matter content in the manure as compared to the soil.

3.2.1.4. Bioaccumulation

As the Log Kow for TCVP is slightly higher than 3 (3.52), the potential for bioaccumulation is 

likely to be low. Similarly, the likelihood of bioaccumulation of the degradates is expected to be 
-Page 22 of 74-

low as most of the estimated Log Kow values are less than 4; EPISuiteTM estimates Log Kow values 

for the TCVP degradates range from 2.6 to 3.8. No bioconcentration factor (BCF) studies have 

been submitted for TCVP or its degradates (conditional requirement for residential outdoor uses 

when there is the potential for exposure to fish). Results from the KABAM model (Total BCFs 

and BAFs < 165 μg/kg-ww/μg/L) and those obtained form the PBT profiler (www. pbtprofiler.net, 

BCF of 15) suggest that the potential for bioaccumulation of TCVP is low.

3.2.1.5. Transformation Products

Major aerobic metabolism degradates of TCVP include TCPEol (SD 15509, [l-(2,4,5-

trichlorophenyl)ethanol]), TCCEol (SD 15125, [1-(2,4,5-trichloropheny1)-2-chloroethanol]), 

TCPEone (CO300, 2,4,5-trichloroacetophenone), and TCBA (2,4,5-trichlorobenzoic acid). A 

major degradate in the hydrolysis study includes des-O-methyl tetrachlorvinphos. A sixth 

degradate, identified as a minor degradete in an aerobic soil metabolism study, is 1-(2,4,5-

trichlorophenyl)ethanediol. Chemical names and structures for the residues of concern are 

tabulated in Table 3.3. 

The OPP Health Effects Division (HED) Metabolism Committee identified the residues of 

concern, depicted in Table 3.3, to human health for TCVP metabolism in animals (USEPA, 

1993a), which have since been generally used for dietary risk assessment (USEPA, 2006b). The 

residues of concern for acute and chronic dietary exposure included cholinesterase-inhibiting 

compounds, which were determined to be TCVP parent only. Chemical structures, 

physical/chemical properties, and a summary of detections of the degradates in the fate studies are 

provided in Table 3.3. Appendix A contains a comparison of aquatic toxicity estimates for TCVP 

and its degradates generated using ECOSAR, a structure-activity relationship model designed to 

provide a rapid screen of chemicals for ecotoxicity hazards. Results from ECOSAR indicate the 

degradates are as toxic or less toxic than TCVP, so this ecological risk assessment focuses on only 

the parent TCVP.

Table 3.2. Table of Transformation Products Formed in Environmental Fate Studies.

Chemical Name Structure Physical/Chemical 

Properties1

Presence in 

Fate Studies

Des-O-methyl tetrachlorvinphos

IUPAC: (Z)-2-chloro-1-(2,4,5-

trichlorophenyl)vinyl methyl phosphate

CAS: (1Z)-2-chloro-1-(2,4,5-

trichlorophenyl)ethenyl methyl phosphate

COP(=O)(O)OC(=CCl)c1cc(Cl)c(Cl)cc1Cl

O

O

P O

OH

Cl

Cl

Cl Cl

MW: 351.94 g/mol

VP: 4.27E-08 torr

Solubility: 3.768 mg/L

Log Kow: 3.75

Koc: 702-827 L/kgoc

Hydrolysis: 28%, pH 9

(MRID 41929101)

Aerobic soil: 3%

(MRID 00077821)

1-(2,4,5-trichlorophenyl)ethanediol

C(O)(CO)c1cc(Cl)c(Cl)cc1Cl OH

Cl

Cl Cl

OH MW: 241.5 g/mol

VP: 4.37E-06 torr

Solubility: 250 mg/L

Log Kow: 2.37

Koc: 29-36 L/kgoc

Aerobic soil: 0.7%

(MRID 00077821)
-Page 23 of 74-

Chemical Name Structure Physical/Chemical 

Properties1

Presence in 

Fate Studies

TCPEol (SD 15509, AA849)

1-(2,4,5-trichlorophenyl)ethanol

1-(2,4,5-trichlorophenyl)ethan-1-ol

CC(O)c1cc(Cl)c(Cl)cc1Cl

OH

Cl

Cl Cl

MW: 225.5 g/mol

VP: 2.37E-04 torr

Solubility: 123 mg/L

Log Kow: 3.43

Koc: 319-359 L/kgoc

Aerobic soil: 25%

(MRID 00077821)

Aerobic soil: 31.1%

(MRID 42082401)

Aerobic soil: 40.8%

(MRID 48879901)

Manure: 69.2 %

(MRID 42848501)

Manure: 11.8 ppm

(MRID 48956301)

TCPEone (CO300)

2,4,5-trichloroacetophenone

CC(=O)c1cc(Cl)c(Cl)cc1Cl

O

Cl

Cl Cl

MW: 223.5 g/mol

VP: 6.32E-03 torr

Solubility: 27.4 mg/L

Log Kow: 3.61

Koc: 492-1,828 L/kgoc

Aerobic soil: 11%

(MRID 00077821)

Aerobic soil: 51.4%

(MRID 42082401)

Aerobic soil: 23.2%

(MRID 48879901)

Manure: 2.00 ppm

(MRID 48956301)

TCCEol (SD15125, AA576)

l-(2,4,5-trichlorophenyl)-2-chloroethanol

C(Cl)C(O)c1cc(Cl)c(Cl)cc1Cl

MW: 260 g/mol

VP: 2.11E-05 torr

Solubility: 48.44 mg/L

Log Kow: 3.68

Koc: 494-608 L/kgoc

Aerobic soil: 37%

(MRID 00077821)

Aerobic soil: 14.3%

(MRID 42082401)

Aerobic soil: 51%

(MRID 48879901)

Manure: 7.1%

(MRID 42848501)

Manure: 0.75 ppm

(MRID 48956301)

TCBA (SD 15917)

2,4,5-Trichlorobenzoic acid

C(=O)(O)c1cc(Cl)c(Cl)cc1Cl

MW: 225.5 g/mol

VP: 5.52E-04 torr

Solubility: 35.3 mg/L

Log Kow: 3.47

Koc: 157-166 L/kgoc

Aerobic soil: 18.5%

(MRID 42082401)

Aerobic soil: 31.8%

(MRID 48879901)

Manure: 12.1%

(MRID 42848501)

Manure: 2.57 ppm

(MRID 48956301)

1. Physical and chemical properties for degradates obtained through EPISuite 4.11.

3.2.2. Measures of Aquatic Exposure

3.2.2.1. Aquatic Exposure Modeling

Screening-level EECs of TCVP (parent only) in surface water were generated based on maximum 

labeled use rates (Table 3.4). Using EFED’s Surface Water Concentration Calculator (SWCC, v 

1.106, May, 2014) EECs that may occur in surface water were generated. The SWCC simulates 

pesticide runoff from an agricultural field to an adjacent water body following applications to 

crops, in addition to direct loadings to water from spray drift. As routinely employed in ecological 

risk assessment, the receiving water body is assumed to be a static, 1-hectare pond of 2-meter 

depth (the “standard pond”), into which a 10-hectare cropped field drains (USEPA 2009b).
-Page 24 of 74-

3.2.2.2. Development of Application Rates and Selection of 

Crop Scenarios

For spot treatment uses around kennels, yards, and recreation areas, the maximum application rate 

is 3.3 lbs a.i./A applied once per year. Spot treatment applications to poultry droppings, manure 

piles, and garbage piles have a maximum single application rate of 34.8 lbs a.i./A. Applications 

to residual surfaces, garbage dumps, and corrals have a maximum single application rate of 13.9 

lbs a.i./A. However, unlike pesticides applied to agricultural crops, these applications are to 

limited areas (i.e., spot treatments applied with a back pack sprayer) and are not expected to be 

used on the entire standard farm of 25 acres. It is assumed that an applicator would likely only 

apply, in the course of a year, a container’s-worth of product to a farm when treating spot 

treatments, even in the case of the application to residual surfaces, garbage dumps, and corrals 

which currently have no specified number of uses. The largest container currently on the market 

is a 5 gallon container (Reg. No. 11556-162, 10 lbs a.i./container). A container of this size is 

expected to treat approximately 2.9 acres for kennels, yards, and recreational areas, 0.7 acres for 

residual surfaces, garbage dumps, and corrals, and 0.3 acres for poultry droppings and manure (see 

Appendix H for detailed calculations). Taking this acreage into account, the area-averaged actual 

application rates to a 25 acre farm are approximately 0.4 lbs a.i./A for all three uses. The California 

rangeland and Barton Springs (Texas) rangeland scenarios were selected for modeling these uses, 

as these seemed most representative of livestock farmland. An application date of March 21, the 

first day of spring, was selected for modeling as this is when flies would be expected to begin 

appearing.

Manure used as a soil amendment/organic fertilizer could be a source of pesticide residues that are 

contained in the manure excreted from treated livestock. For modeling purposes, an “application” 

rate of TCVP was estimated based on dry weight of manure application for crop production. The 

following steps were used to calculate the application rate of TCVP. The methodology used for 

the estimation of manure application is based on equations and tables provided in the USDA Part 

651 Agricultural Waste Management Field Handbook (USDA, 2009). The technique is described 

on pages 11-25 to 11-27 of the manual. The following analysis evaluates the use of cow manure 

as a soil amendment. EFED conducted a similar analysis for swine, poultry, and horse manure, 

however cow manure generates the highest TCVP application rates and is considered protective 

for all manure amendment applications.

Step 1: Estimate nutrients in excreted manure 

From Table 4-8 of the Agricultural Waste Management Field Handbook (USDA, 2009), the 

total nitrogen (TN) excreted per day-cow is 0.42 lbs TN/d-cow. The total excreted manure per 

day-cow is 15 lbs manure/d-cow, assuming the wet weight of manure is 125 lbs/d-cow and that 

the moisture content is 88% (taken from Table 4-8 of the manual). Dividing the TN per daycow by the total excreted manure per day-cow and multiplying by the conversion factor of 

2000 lbs /ton yields 56 lbs TN/ton manure.
-Page 25 of 74-

Step 2: Estimate nutrients in wastewater, dropped feed, and added bedding 

It is assumed that there is no contribution of nutrients from wastewater, dropped feed, and 

added bedding,to the field and therefore, the only contribution of nitrogen would come from 

the manure.

Step 3: Estimate nutrients lost during storage

Based on Table 11-5 of the Agricultural Waste Management Field Handbook, it is assumed 

that 50% of the TN is lost during storage, based on storage in an open area that is hot and arid

(conservative assumption). Multiplying the results from Step 1 by 50% yields 28 lbs TN/ton 

manure.

Step 4: Estimate plant available nutrients contained in manure

Based on Table 11-9 of the Agricultural Waste Management Field Handbook, for manure 

stored on an open lot that is hot and arid, 45% of the TN is available the first year. Multiplying 

this by the estimate in Step 3 yields 12.6 lb TN/ ton manure.

Step 5: Determine nutrients required by the crop and soil to produce the yield goal

The manual indicates that “Manure nutrient analysis, soil tests, and State Cooperative 

Extension Service recommendations are the best basis for managing nutrients.” As analysis 

and soil tests are currently unavailable, EFED consulted the Texas Agriculture Extension 

Service’s Crop Nutrient Needs in South and Southwest Texas (Stichler et al., 2001) for nutrient

requirements consistent with hot, arid environments. The following crops have typical 

nitrogen recommendations.

Nitrogen Requirements for Different Crops

Crop N Requirement

(lb TN/A) Crop N Requirement(lb TN/A)

Corn 240 Wheat 105

Sorghum 185 Grass hay 250

TN: Ton (2,000 lbs), A: Acre

Alternatively, the manual recommends consulting the Crop Nutrient Tool in the USDA 

PLANTS Crop Database (http://plants.usda.gov/npk/AboutNutrient) to estimate crop nutrient 

needs. Use of this tool provides similar results to those obtained from Stichler et al. 2001.

Step 6: Compute increased nitrogen to compensate for application loss

Based on Table 11-6 of the manual, it is assumed that 70% of the TN is retained during 

application, where the soil conditions are warm and dry and there is 1 day between application 

and incorporation. Multiplying this by the estimate in Step 4 yields 8.82 lb TN/ ton manure.
-Page 26 of 74-

Step 7: Select nutrient for calculation of manure application rates

Nitrogen is the selected nutrient.

Step 8: Compute the acres on which manure can be applied to use the nutrients available

Manure will be applied on all acres that are modeled.

Step 9: Determine application rate of manure

Dividing the nutrient requirements of the various crops described in Step 5 (lbs TN/A) by the 

available nitrogen in the manure (lbs TN/ton manure) yields the amount of manure to be 

applied for each crop. Manure applications rates are provided in the table below.

Application Rates for Manure Applied as Soil Amendment

Crop TN Manure/A Crop TN manure/A

Corn 27.2 Wheat 11.9

Sorghum 21.0 Grass hay 28.3

TN: Ton (2,000 lbs)

Step 10: Estimate application rate of TCVP TRC

In the manure dissipation field study (MRID 489563-01), manure composted for 0 to 180 days had 

a 90 percent upper confidence limit on the mean concentration of TCVP of 40.64 mg ai per kg dry 

matter in manure. Multiplying this concentration by the manure per acre provide in Step 9 yields 

the following TCVP application rate.

TCVP Residues in Manure Applied as Soil Amendment

Crop lb TCVP/A1 Crop lb TCVP/A

Corn 2.21 Wheat 0.97

Sorghum 1.70 Grass hay 2.30

1

lb TCVP/A = ton dry manure/A x mg TCVP/kg dry manure x 907 kg dry manure/ton dry manure x 2.205x10-6 lb TCVP/mg TCVP

Lastly, based on communications with the registrant (Appendix I, communications with Dr. Bruce 

Bernard, Authorized Representative of Bayer HealthCare, 7/22/14), approximately 2% of cattle in 

feedlots are fed an oral larvicide and less than 1% of cattle in feedlots are fed a TCVP product. 

Beef feedlot managers are typically most concerned with control of house flies (Musca domestica)

and stable flies. Although TCVP products are registered for control of several flies (Stomoxys 

calcitrans), they are primarily used to control face flies (Musca autumnalis) and horn flies

(Haematobia irritans). TCVP oral larvicide is designed to kill larva eggs that may be laid in 

manure and mature during composting. As a result, not all animals need to receive the larvicide 

in order for it to be effective in composted manure. If 2% is used to represent an upper bound for 

animals receiving oral larvicides within a given feedlot and for composted manure that can contain 

TCVP, the application rates would range from 0.019 to 0.046 lbs a.i./A.
-Page 27 of 74-

The scenarios listed in Table 3.4 are those currently approved for Tier II modeling which most 

closely represent the uses for soil amendment applications of manure containing TCVP residues.

3.2.2.3. Aquatic Modeling Inputs

Chemical property and model input values (Table 3.5) were chosen according to the current Input 

Parameter Guidance, (USEPA 2009). Applications of TCVP are assumed to have 100% efficiency 

and 0% spray drift. Based on the potential crops where soil amendments of manure are likely to 

occur, a variety of locations and SWCC scenarios were run to simulate national use of the pesticide.

Table 3.3. Aquatic Exposure Inputs in TCVP Ecological Exposure Assessment (SWCC)

1

Use SWCC Scenario App Rate

(lbs a.i./A)1 App Dates2 Comments

Kennels, yards, 

recreational 

areas

Residual 

surfaces, 

garbage dumps, 

and corrals

Poultry 

droppings, and 

manure and 

garbage piles

CArangelandhayRLF_V2

RangeBSS 0.4 3/21 Spring application

Wheat

CAWheatRLF_V2

NDwheatSTD

ORwheatOP

TXwheatOP

0.019 12/1 Fall/winter application, 

no cover crop

Corn

CA_corn

IA_corn

IL_Corn

IN_Corn

KS_Corn

MN_Corn

MS_corn

NC_cornE

NC_cornW 

ND_corn

NE_Corn

OH_Corn

PA_corn

STX_corn

TX_corn

0.044 12/1 Fall/winter application, 

no cover crop

Sorghum KS_sorghum

TX_sorghum 0.034 12/1 Fall/winter application, no cover crop

Grass Hay CArangelandhayRLF_V2

RangeBSS 0.046 12/1 Fall/winter application, no cover crop

1. See discussion above for details on how application rates for manure applications were developed.

2. For manure amendment applications, as the application is scheduled to occur in the fall/winter timeframe after crops 

have been harvested, and application date of December 1st was selected.
-Page 28 of 74-

Table 3.4. Environmental Fate Data Used for Aquatic Exposure Inputs in TCVP Ecological Exposure 

Assessment.

Input Parameter Value Source/comment

Molecular weight (g/mol) 365.96 MRID 41222503

Vapor pressure (torr @ 25 oC) 2.6 x 10-7 MRID 41222503

Solubility in water (mg/L @ 

20oC) 11.6 MRID 41222503

Henry’s Law Constant (atmm3

/mol) 1.08 x 10-8 Calculated from vapor pressure and solubility where HENRY = (VAPR/760)/(SOL/MWT),

Hydrolysis half-life (t1⁄2 in days) 29.8 MRIDs 41929101 & 43663501

Aqueous Photolysis half-life (t1⁄2

in days) Stable No data, assume stable1

Aerobic Soil metabolism half-life 

(t1⁄2 in days) 13.3

MRIDs 42082401, 00077821, and 48879901. 

Represents the 90 percent upper confidence 

limit on the mean of 4 aerobic soil metabolism 

half-life values (10.4)

1

.

Anaerobic aquatic metabolism 

half-life (t1⁄2 in days) Stable No data, assumed stable1

Aerobic Aquatic metabolism 

half-life (t1⁄2 in days) 26.6 2 x aerobic soil half-life1

Soil partition coefficient KFOC

(mL/goc) 873

MRID 41681301. Average of four KFOC values. 

Coefficient of variance for KFOC data indicate 

more appropriate than KF.

1

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

3.2.2.4. Estimated Environmental Concentrations in Surface 

Water

The EECs listed in Table 3.6 reflect 1-in-10 year return frequency surface water concentrations 

based on maximum application rates for labeled uses of TCVP. In some instances, the 1-in-10 

year 21-day average concentration is higher than the 1-in-10 year “peak” concentration. This is 

an artifact of roll-over of EECs from one year to the next as the application date is close to the end 

of the year. For instance, for the California corn scenario, the maximum concentration (0.18 μg/L) 

occurs in the first year, resulting in a 21-day concentration of 0.24 μg/L, which is the 1-in-10 year 

21-day average concentration. The 1-in-10 year peak concentration happens to occur in a different 

year and is lower than the 1-in-10 year 21-day average concentration.

Table 3.6. Surface Water EECs for TCVP.

Crop Scenario 1-in-10 year 

Peak EEC (μg/L)

1-in-10 year 

21-day average

(μg/L)

1-in-10-year

60-day average

(μg/L)

Kennels, yards, 

recreational areas

Residual surfaces, 

garbage dumps, 

and corrals

Poultry droppings, 

and manure and 

garbage piles

CArangelandhayRLF_V2 0.80 0.49 0.28

RangeBSS 1.68 1.11 0.58
-Page 29 of 74-

Crop Scenario 1-in-10 year 

Peak EEC (μg/L)

1-in-10 year 

21-day average

(μg/L)

1-in-10-year

60-day average

(μg/L)

Wheat

CAWheatRLF_V2 0.09 0.08 0.05

NDwheatSTD 0.002 0.002 0.001

ORwheatOP 0.08 0.06 0.04

TXwheatOP 0.15 0.11 0.06

Corn

CA_corn 0.18 0.24 0.15

IA_corn 0.16 0.10 0.06

IL_Corn 0.14 0.11 0.07

IN_Corn 0.35 0.24 0.16

KS_Corn 0.23 0.23 0.12

MN_Corn 0.03 0.02 0.01

MS_corn 0.62 0.64 0.39

NC_cornE 0.18 0.14 0.09

NC_cornW 0.17 0.15 0.09

ND_corn 0.002 0.002 0.001

NE_Corn 0.05 0.03 0.02

OH_Corn 0.28 0.18 0.11

PA_corn 0.10 0.08 0.05

STX_corn 0.21 0.16 0.07

TX_corn 0.65 0.44 0.25

Sorghum KS_sorghum 0.10 0.11 0.06

TX_sorghum 0.51 0.34 0.20

Grass hay CArangelandhayRLF_V2 0.11 0.12 0.07

RangeBSS 0.28 0.19 0.12

3.2.2.5. Monitoring Data

Limited monitoring data are available for TCVP and its degradates. EFED conducted a search of 

the United States Geological Services (USGS) National Water Quality Assessment (NAWQA) 

Program database (http://infotrek.er.usgs.gov/nawqa_queries/index.jsp), the California 

Department of Pesticide Regulation’s (CDPR’s) surface water and sediment database 

(http://cdpr.ca.gov/docs/emon/surfwtr/surfcont.htm), and the USEPA STOrage and RETrieval 

(STORET) database (http://www.epa.gov/STORET/). The NAWQA database did not list TCVP 

or its degradates as sampled constituents. The CDPR surface water database had 2,097 records 

for surface water samples collected and sampled from the years 2000 to 2011 for TCVP, with just 

2 of these values at or above the detection limit (0.089 μg/L in 2007 and 0.05 μg/L in 2001). 

STORET data for TCVP, in surface water and sediment monitoring samples from 1990 to the 

present, included a number of detections, which are summarized in Table 3.7.
-Page 30 of 74-

A review of available groundwater monitoring data for TCVP was also conducted. An analysis of 

EPA’s Pesticides in Ground Water Database (USEPA, 1992) indicates TCVP was not detected in 

well water (level of detection not reported; degradates not reported). Twelve samples were 

collected in California between 1984 and 1991 and 161 samples were collected in Indiana between 

1987 and 1988. STORET data for groundwater wells from 2006 to 2008 in Florida are presented 

in Table 3.7. Neither the USGS NAWQA database nor the CDPR groundwater sampling site list 

TCVP as a sampled pesticide.

Monitoring data are not available on the degradates of TCVP.

Table 3.7. Surface Water, Groundwater, and Sediment Monitoring Data

Location Sampling Media Concentration 

Range

Number of 

Samples

Number of 

Sample Sites Time Span

Ventura, CA Water, River 0.05 μg/L 1 1 2001

Bartholomew, IN Water, River 0.10 μg/L 1 1 1997

Collier, FL Water, Well 0.05 – 0.23 μg/L 261 70 2006-2008

Glades, FL Water, Well 0.05 – 0.21 μg/L 5 1 2006-2008

Multnomah, OR

Sediment, River, 

Portland Harbor 

Superfund Site

51.4-60.1 μg/kg 2 2 2006

3.2.2.6 Aquatic Exposure from Indoor Uses

The down-the-drain component of the E-FAST model is used to estimate exposure in water bodies 

that receive residential drainage that may contain disposed or washed-off pet dip. Estimate 

assumptions include: no waste water treatment efficiency and, 100% of the applied TCVP is 

washed off the pet and entrained in the waste water or directly disposed of down the drain.

The label for Hartz Rabon® Flea & Tick Dip for Dogs & Cats (EPA Reg. No. 2596-1 19) directs 

users to dilute 2 (fluid) ounces (fl oz) of dip per one gallon of water, but does not advise how much 

solution to prepare per animal specific to size. Applications are to be repeated as necessary. 

Assuming 2 fluid ounces of dip (0.059 L) are prepared per application and assuming that the 

application is subsequently washed off or that the dip is poured down the drain for disposal, at 

3.06% v/v active ingredient (a.i.), 0.0018 L a.i. may flow into waste water per use. With a bulk 

density of approximately 7 lbs/gal (840 g/L), this would represent 1.512 g a.i. per use. Wash off 

of greater solution volumes or disposal of a full container's contents (0.236 L) would produce 

larger amounts of active ingredient per use in waste water.

The 50th percentile per capita daily indoor water usage is estimated for the E-FAST model at 388 

L per person (i.e., 1552 L per day for a family of four). The daily concentration of TCVP in a 

household's waste stream given the above conditions would be 978 μg a.i./L (ppb). However, this 

estimated daily concentration would be diluted by the wastewater flows from other households 

that do not have pets and/or do not use the Rabon® dip and/or are not washing off or disposing of 

Rabon® into the drain on a given day.
-Page 31 of 74-

In a typical 50,000 person municipality, the number of 2 fl oz uses that must be washed off on a 

given day to equal the acute risk to listed species LOC (RQ≥0.05) for freshwater invertebrates (1.9 

μg/L x 0.05 = 0.095 μg/L) and fish (530 μg/L x 0.05 = 26.5 μg/L) would be:

Aquatic Invertebrates:

Number of uses = [(0.095 μg/L)(388 L/person)(50,000 people)]/l.5 x 106 μg/use)

Number of uses = 1.2

Fish:

Number of uses = [(26.5 μg/L)(388 L/person)(50,000 people)]/l.5 x 106 μg/use)

Number of uses = 350

This analysis indicates that in a municipality of 50,000 people, there would be sufficient TCVP in 

the untreated municipal waste water discharge from treatment facilities to exceed the acute risk to 

listed species LOC for invertebrates if just two pets were washed concurrently. For fish, 350 pets 

would need to be washed for concentrations of TCVP in the untreated wastewater to exceed the 

acute risk to listed species LOC.

3.2.3. Measures of Terrestrial Exposure

3.2.3.1. Ingestion of Surface Residues by Birds and Mammals

Terrestrial wildlife exposure estimates are typically calculated for birds and mammals by 

emphasizing the dietary exposure route of uptake of pesticide active ingredients. These exposures 

are considered to be surrogates for exposures to terrestrial-phase amphibians and reptiles. For 

exposures to terrestrial organisms, such as birds and mammals, pesticide residues on food items 

are estimated based on the assumption that organisms are exposed to pesticide residues as a 

function of the pesticide use pattern. For TCVP, the outdoor use sites include spot treatment of 

kennels, yards and recreational areas, poultry dropppings, manure piles, garbage piles, residual 

surfaces (barns, farm buildings, around garbage dumps and corrals), livestock (feed additive, salt 

lick). The indoor use sites include pet or livestock treatment with a dust, dip, sponge, spray 

formulation or with a collar impregnated with TCVP. The potential dietary exposure for terrestrial 

wildlife in this assessment is based on consumption of TCVP residues on food items following 

spray applications. 

T-REX (v. 1.5) is used to calculate dietary and dose-based EECs of TCVP residues on food items 

for mammals and birds generated by spray applications for the labeled uses. Input values for 

deriving EECs using T-REX are located in Table 3.8. The default foliar dissipation half-life of 

35 days was used in the modeling, as foliar dissipation half-life data for TCVP were not available. 

Upper-bound Kenaga nomogram values are used to derive EECs for TCVP exposures to terrestrial 

mammals and birds (Table 3.9-3.11), based on a 1-year time period. Consideration is given to 

different types of feeding strategies for mammals, including herbivores, insectivores and 

granivores. Dose-based exposures are estimated for three weight classes of birds (20 g, 100 g, and 

1000 g) and three weight classes of mammals (15 g, 35 g, and 1000 g).
-Page 32 of 74-

There are four outdoor uses registered for TCVP at this time (See Table 3.1): 1) Kennels, yards 

and recreational areas; 2) residual surfaces; 3) poultry droppings; and 4) livestock. Except for the 

use on livestock which is a feed additive or salt lick, all are intended to be spot treatments. In order 

to estimate exposure resulting from the livestock use, manure from this use can be collected and 

broadcast to agricultural fields (“soil amendment”). However, the use of manure as a soil 

amendment is not expected to result in exposure to non-target plants which could consumed by 

terrestrial animals as food items. Therefore, an assessment of terrestrial plant exposure and 

resulting risk for the soil amendment use was not performed. The maximum application rate for 

manure soil amendment applications is 0.046 lbs a.i./A (grassland, Table 3.4). For the other uses, 

exposure to non-target plants is expected to be possible and was assessed.

For those remaining outdoor uses that are spot treatments, these are assumed to be uses where 

TCVP is sprayed in places as needed (such as on a manure pile) and not as a broadcast application 

over an entire acre of land. However, for modeling purposes, the application rates are given on a 

per-acre basis and estimates of exposure are made using the application rate in terms of lbs

a.i./acre. HED defines a spot treatment as an area not to exceed more than 1000 ft2 and EFED 

does not expect an entire contiguous acre to be broadcast sprayed with TCVP; however, as a 

conservative exposure scenario, EFED assumed that multiple spot treatments could add up to an 

acre or more within a somewhat larger area of surrounding acreage. 

Table 3.8. Input Parameters for Deriving Screening-Level Terrestrial EECs for TCVP (T-REX v. 

1.5)

1

.

Use(s)

Maximum 

Single App. Rate

(lbs a.i./A)2

Minimum Reapplication 

Interval (days)

Maximum 

No. of App.

Foliar 

Dissipation 

Half-Life

(days)

Kennels, yards and 

recreational areas2 3.3 N/A 1

35

Residual surfaces1 13.9 Not specified Unlimited

Poultry droppings, 

manure piles, garbage 

piles2

34.8 N/A 1

1

Residual surfaces include: barns, farm buildings, around garbage dumps and corrals. 2 Most labels indicate these uses are spot treatments (1000 ft2

) and that only one application per year should occur outdoors.
-Page 33 of 74-

Table 3.9. Screening-level Dose-based EECs (mg/kg bw) as Food Residues for Birds, Reptiles, and Terrestrial-Phase Amphibians from Labeled Uses of 

TCVP (T-REX v. 1.5).

Primary Feeding 

Strategy  Herbivores and Omnivores Insectivores Granivores

Animal Size  Small Med Large Small Med Large Small Med Large

Dietary Items 

Short Grass

Tall Grass

Broad-leaf 

Plants

Fruits, pods, 

seeds, etc.

Short Grass

Tall Grass

Broadleaf 

Plants

Fruits, pods, 

seeds, etc.

Short Grass

Tall Grass

Broadleaf 

Plants

Fruits, pods, 

seeds, etc.

Arthropods Seeds, grains, etc.

Use(s) 

Kennels 902 413 507 56 514 236 289 32 230 106 130 14 353 201 90 13 7 3

Residual Surfaces1 3799 1741 2137 237 2167 993 1219 135 970 445 546 61 1488 849 380 53 30 13

Poultry Droppings2 9512 4359 5350 595 5424 2486 3051 339 2428 1113 1366 152 3725 2124 951 132 75 34

1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals. 2 Poultry droppings include: poultry droppings, manure piles, garbage piles.

Table 3.10. Screening-level Dose-based EECs (mg/kg bw) as Food Residues for Mammals from Labeled Uses of TCVP (T-REX v. 1.5).

Primary Feeding 

Strategy  Herbivores and Omnivores Insectivores Granivores

Animal Size  Small Med Large Small Med Large Small Med Large

Dietary Items 

Short Grass

Tall Grass

Broad-leaf 

Plants

Fruits, pods, 

seeds, etc.

Short Grass

Tall Grass

Broadleaf 

Plants

Fruits, pods, 

seeds, etc.

Short Grass

Tall Grass

Broadleaf 

Plants

Fruits, pods, 

seeds, etc.

Arthropods Seeds, grains, etc.

Use(s) 

Kennels 755 346 425 47 522 239 294 33 121 55 68 8 296 204 47 10 7 2

Residual Surfaces1 3181 1458 1789 199 2198 1008 1237 137 510 233 287 32 1246 861 200 44 31 8

Poultry Droppings2 7963 3650 4479 498 5503 2522 3096 344 1276 584 718 80 3119 2156 500 111 76 18

1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals.

2 Poultry droppings include: poultry droppings, manure piles, garbage piles.
-Page 34 of 74-

Table 3.11. Screening-level Dietary-based EECs (mg/kg-diet) as Food Residues for Birds, Reptiles, 

Terrestrial-phase Amphibians, and Mammals from Labeled Uses of TCVP (T-REX v. 1.5).

Primary Feeding Strategy  Herbivores, Omnivores, and 

Granivores Insectivores

Dietary Items 

Short Grass

Tall Grass

Broad-leaf 

Plants

Fruits, pods, 

seeds, etc.

Arthropods

Use(s) 

Kennels 792 363 446 50 310

Residual Surfaces1 3336 1529 1876 209 1307

Poultry Droppings2 8352 3828 4698 522 3271

1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals.

2 Poultry droppings include: poultry droppings, manure piles, garbage piles.

3.2.3.2. Runoff and Spray Drift to Terrestrial and Semi-Aquatic 

Plants

Exposure of non-target terrestrial and semi-aquatic (wetland) plant species is estimated using 

OPP’s TerrPlant (v. 1.2.2) model. Given the application methods of TCVP, loading via spray drift 

to dry, non-target, adjacent areas is assumed not to occur. Runoff is expected to be the only source 

of pesticide loading to non-target areas. TerrPlant calculates EECs as a function of application 

rate, solubility, and default assumptions regarding incorporation. The EECs for terrestrial and 

semi-aquatic plants for a single application of TCVP at the maximum labeled rates for 

representative uses are presented in Table 3.12 (see example output in Appendix D). Applications 

to kennels, residual surfaces, and poultry droppings are spot treatments; therefore, the application 

rates attributed to runoff from semi-aquatic areas are proportioned, as in the aquatic modeling to 

0.38, 0.39, and 0.8 lbs a.i./A, respectively. This was done to account for the 10:1 watershed ratio

used in the semi-aquatic model.

Table 3.12. EECs for Terrestrial and Semi-Aquatic Plants Near TCVP Use Areas (TerrPlant v. 1.2.2).

Use Site

Single Max. 

Application 

Rate

(lbs a.i./A)

EECs (lbs a.i./A)

Runoff Only

Dry Areas Semi-Aquatic Areas

Kennels 3.3 0.066 0.076

Residual Surfaces1 13.9 0.278 0.078

Poultry Droppings2 34.8 0.696 0.16

Soil Amendment3 0.046 0.00092 0.0092

1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals.

2 Poultry droppings include: poultry droppings, manure piles, garbage piles. 3 Soil amendment is the application to fields of manure containing TCVP from livestock oral additives.

3.3. Ecological Effects Characterization 

The ecological effects characterization for TCVP is based upon registrant-submitted toxicity data 

for the TGAI and for specified formulations. The ecotoxicity data for TCVP and its associated 
-Page 35 of 74-

products have been reviewed previously in multiple ecological risk assessments (e.g., USEPA 

2006, 2002, 2000) and in a Preliminary Problem Formulation for Registration Review (USEPA 

2008). These data are summarized briefly in Sections 3.3.1 and 3.3.2. Various studies with 

terrestrial and aquatic plants, birds, and aquatic animals exposed to either the TGAI or formulated 

TCVP have been received since the Problem Formulation was issued; the results of these studies 

are described briefly in this section. Ecotoxicity data recently submitted for TCVP degradates 

indicate that these degradates are generally equally or less toxic than parent TCVP.

The results of a 2014 review of the Ecological Incident Information System (EIIS) are described 

in Section 3.3.3 (USEPA 2012). A search of the ECOTOXicology database in December, 2013,

yielded no new data from suitable studies with more sensitive toxicity endpoints than those from 

the registrant-submitted guideline studies described below. The endpoints from the ECOTOXcatalogued open literature studies are provided in Attachment 2, for reference.

3.3.1. Aquatic Toxicity Assessment

A summary of the most sensitive aquatic toxicity data for TCVP, based on a current Agency review 

of all submitted data, is provided in Table 3.13 and discussed further in Sections 3.3.1.1 through

3.3.1.5. The available data indicate that TCVP technical grade active ingredient (TGAI) is highly 

toxic to freshwater fish and moderately toxic to marine/estuarine fish on an acute exposure basis. 

TCVP is very highly toxic to freshwater invertebrates and highly toxic to marine/estuarine 

invertebrates on an acute exposure basis. Studies on the toxicity of formulated TCVP to aquatic 

organisms have not been submitted. 

3.3.1.1. Toxicity to Freshwater Fish

TCVP is classified as highly toxic to freshwater fish on an acute exposure basis. In 96-hr acute 

toxicity studies summarized in Mayer and Ellersieck (1986; MRID 40098001), bluegill sunfish 

(Lepomis macrochirus) and channel catfish (Ictalurus punctatus) were exposed to technical grade 

TCVP. The reported LC50 was 0.53 mg a.i./L for bluegill under static conditions and >0.50 mg 

a.i./L for channel catfish under flow-through conditions. 

Chronic toxicity to freshwater fish was evaluated in a 33-day toxicity of technical grade TCVP 

(98.7% a.i.) to the early life stage of fathead minnow (Pimephales promelas) under flow-through 

conditions. The NOAEC for juvenile survival, was 0.047 mg a.i./L based on a statistically 

significant (p<0.05) difference in larval survival at treatment concentrations greater than or equal 

to 0.15 mg a.i./L. The NOAEC and LOAEC values for growth (mean dry weight and mean length 

at 28 days post-hatch) were 0.047 and 0.15 mg a.i./L respectively. The NOAEC and LOAEC for 

time to hatch are 0.15 and 0.47 mg a.i./L, respectively.
-Page 36 of 74-

3.3.1.2. Toxicity to Freshwater Invertebrates

TCVP is classified as very highly toxic to freshwater invertebrates on an acute exposure basis. An 

acute 48-hour static toxicity study was conducted to determine the effect of technical grade TCVP

to daphnia (Daphnia magna; MRID 41257101). The 48-h EC50 value was 1.9 μg a.i./L and the 48-

h NOAEC was 0.72 μg a.i./L.

Chronic toxicity of TCVP was evaluated in a 21-day static-renewal toxicity study on D. magna

with technical grade TCVP. Based upon statistically significant (p<0.05) decreases in reproduction 

(total number of offspring) at exposure levels of 0.250 μg a.i./L and greater, the NOAEC and 

LOAEC were 0.125 and 0.250 μg a.i./L, respectively. 

3.3.1.3. Toxicity to Estuarine/Marine Fish

TCVP is classified as moderately toxic to estuarine/marine fish on an acute exposure basis. The 

toxicity of TCVP to spot (Leiostomus xanthurus) is reported in Mayer (1986; MRID 40228401). 

The reported LC50 is >1.0 mg a.i./L. Although acute toxicity tests are typically conducted to the 

limit concentration of 100 mg a.i./L, the solubility limit of TCVP (11.6 mg/L) combined with the 

salinity of the test system precluded testing to concentrations higher than 1 mg a.i./L.

3.3.1.4. Toxicity to Estuarine/Marine Invertebrates

The reported EC50 for technical grade TCVP to pink shrimp (Penaeus duorarum) is 0.28 mg a.i./L 

(Mayer 1986; MRID 40228401). Based on this endpoint, TCVP is classified as highly toxic to 

estuarine/marine invertebrates on an acute exposure basis. 

3.3.1.5. Toxicity to Aquatic Plants

In a 7- day toxicity study, the freshwater vascular plant duckweed (Lemna gibba G3) was exposed 

to TCVP TGAI (100.5% a.i.) The NOAEC and EC50/IC50 values based on all endpoints (frond 

number yield, frond number growth rate, final biomass, and biomass growth rate) were 1158 and 

>4625 μg a.i./L, respectively, in terms of time weighted average (TWA) concentrations. The 

percent growth inhibition of frond number (the most sensitive endpoint) in the treated culture as 

compared to the control ranged from 4 to 43% relative to the negative control. The following 

abnormalities (phytotoxicity) were noted: chlorosis, necrosis, and curled fronds.

In a 96-hour static toxicity study, cultures of freshwater green alga (Pseudokirchneriella 

subcapitata), a non-vascular aquatic plant, were exposed to TCVP TGAI under static conditions. 

The NOAEC and EC50/IC50 values based on cell density were 594 and 3200 μg/L, respectively. 

The NOAEC and EC50/IC50 values based on growth rate were 594 and >4947μg/L, respectively. 

The NOAEC and EC50/IC50 values based on yield were 594 and 3200 μg/L, respectively. 
-Page 37 of 74-

3.3.2. Terrestrial Effects Characterization

A summary of the most sensitive terrestrial animal toxicity data for TCVP, based on a current 

Agency review of all submitted data, is provided in Table 3.13 and is discussed further in Sections 

3.3.2.1 to 3.3.2.3. The available data indicate that TCVP TGAI is practically non-toxic to birds

and is slightly toxic to mammals on an acute oral exposure basis. Subacute avian toxicity data are 

not available for TCVP. TCVP is highly toxic to adult honey bees (Apis mellifera) on an acute 

contact exposure basis.

On a chronic exposure basis, adult female mallard ducks (Anas platyrhynchos) that consumed feed 

containing TCVP had lower body weight gain relative to controls, but no mortality or overt signs 

of toxicity were observed. Bobwhite quail (Colinus virginianus) fed diets containing TCVP had 

fewer live embryos per eggs set and reduced eggshell thickness relative to controls, but no 

mortality or overt signs of toxicity were observed. On a chronic dietary exposure basis, there were 

no adverse effects on growth, survival or reproduction observed in mammals at the highest dose 

tested (100 mg a.i./kg-diet). 

The available data for terrestrial plants exposed to the the formulated product Rabon® (49.14% 

a.i.) provided in Section 3.3.2.4, indicate that TCVP exposure resulted in no dose-related adverse 

effects on seedling emergence or vegetative vigor in ten species of plants (see Table 3.13).

3.3.2.1. Toxicity to Birds

Avian toxicity data are summarized in Table 3.13 below. Based on results of toxicity testing with

an upland game species, mallard duck, TCVP technical is categorized as practically non-toxic to 

birds on an acute oral exposure basis (MRID 00160000). There were no mortalities observed in 

the acute oral toxicity study. An avian reproduction study with the mallard duck (MRID 48951301) 

demonstrated statistically significant (p<0.05) reductions in adult female body weight and the 

weight of 14-day old survivors when parental ducks were exposed to measured concentrations of 

290 mg a.i./kg diet (NOAEC = 96 mg ai/kg diet). In the avian reproduction study with bobwhite 

quail, there were reductions in the number of live embryos per eggs set and reductions in eggshell 

thickness at 979 mg a.i./kg-diet (NOAEC=290 mg a.i./kg-diet). 

3.3.2.2. Toxicity to Mammals

Technical grade TCVP is classified as moderately toxic to rats (Rattus norvegicus) with an acute 

oral LD50 value of 1480 mg a.i./kg-bw (MRID 41222504). Based on the results of this study, TCVP

is classified as slightly toxic to mammals on an acute oral exposure basis. Acute toxicity testing 

with formulated tetrachlorvinphos (75% ai) resulted in an LD50 of 2686 mg a.i./kg-bw (MRID

41223601).

A 2-generation rat reproduction study (MRID 00077802) identified a NOAEC of 330 mg a.i./kgdiet based on increased liver size. However, this sublethal effect is not considered relevant to wild 

mammals. Therefore, the chronic NOAEC for mammals is the highest dose tested (1000 mg/kgdiet).
-Page 38 of 74-

3.3.2.3. Toxicity to Beneficial Insects

TCVP is classified as highly toxic to honeybees on an acute contact exposure basis. In an acute 

contact toxicity study (Atkins et al. 1975; MRID 00036935), honey bees were found to have an 

LC50 for TCVP of 1.4 μg a.i./bee.

3.3.2.4. Toxicity to Terrestrial Plants

Terrestrial plant toxicity studies are required for pesticides that have terrestrial use patterns or may 

move off of the application site. The NOAEL and IC25 (concentration that causes an inhibitory

effect in 25% of the population for the monitored endpoint) values are established for markers of

seedling emergence and vegetative vigor.

Two studies evaluating TCVP exposure in terrestrial plants have been submitted. Both seedling 

emergence (MRID 48728101) and vegetative vigor (MRID 48719901) tests were conducted with 

a formulated TCVP product (Rabon® containing 49.14% a.i.) applied at 6.09 lb a.i./acre (5.7 lb 

a.i./acre for corn (Zea mays) and wheat (Triticum aestivum) in the vegetative vigor study). In the 

seedling emergence test, no reductions of 25% or more were observed in any treatment group 

relative to the controls for any measured parameter of the ten plant species tested. However, 

statistically significant differences (p<0.05) were observed in mean height of ryegrass , emergence 

of wheat, and dry weight of tomato (Lycopersicon esculentum) but these significant reductions 

were not accompanied by adverse effects in other measured parameters (such as height, weight, 

percent emergence or survival) of the species and were not considered to be biologically 

significant. The NOAEC for seedling emergence was not established. The EC25/IC25 and the 

EC05/IC05 were >6.09 lb a.i./acre for seedling emergence. In the vegetative vigor study, there were 

no differences in percent survival between plants treated with TCVP and controls. Mean height of 

beans (Phaseolus vulgaris) treated with Rabon® was 48% lower than control height and mean 

height for treated wheat (Triticum aestivum) seedlings were significantly different (p<0.05) from 

control means. Mean dry weight of bean and tomato plants were significantly different (p<0.05) 

compared to control means (-24% and -18% reductions, respectively). For monocots, the NOAEC 

is 5.7 lb a.i./acre for corn and wheat and 6.09 lb a.i./acre for all other monocots. For dicots, the 

NOAEC is 6.09 lb a.i./Acre. 

The terrestrial plant toxicity studies were conducted at an application rate (6.09 lb a.i./acre) that 

was well below the highest application rate on TCVP labels (34.8 lb a.i./acre). Therefore, there is 

uncertainty surrounding the potential toxicity of TCVP to plants at application rates between 6.09 

and 34.8 lb a.i./acre.

Table 3.13. Endpoints Used in the TCVP Preliminary Risk Estimation

Taxonomic 

Group

Surrogate 

Species

Type of 

Risk

Type of 

Endpoint Endpoint MRID Acute Toxicity Classification

Aquatic

Freshwater Fish

Bluegill Sunfish

Lepomis 

macrochirus

Acute LC50 530 μg a.i./L 4098001 Highly Toxic

Fathead Minnow Chronic NOAEC 47μg a.i./L 48732301 N/A
-Page 39 of 74-

Taxonomic 

Group

Surrogate 

Species

Type of 

Risk

Type of 

Endpoint Endpoint MRID Acute Toxicity Classification

Pimephales 

promelas

(growth)

Freshwater 

Invertebrates

Daphnid

Daphnia magna

Acute EC50 1.9 μg a.i./L 41257101 Very Highly Toxic

Chronic NOAEC 0.125 μg a.i./L

(reproduction) 48792801 N/A

Estuarine/Marine 

Fish

Spot

Leiostomus 

xanthurus

Acute LC50

>1,000 μg 

a.i./L 40228401 Moderately Toxic

Chronic NOAEC No Data

Estuarine/Marine 

Invertebrates Mysid Acute EC50 280 μg a.i./L 40228401 Highly Toxic

Chronic NOAEC No Data

Aquatic Plants Duckweed

Lemna gibba N/A EC50

>4625 μg 

a.i./L 48792401 N/A

NOAEC 1158 μg a.i./L

Freshwater Algae 

(Non-vascular 

aquatic plant)

Green alga 

Pseudokirchnerie

lla subcapitata

N/A EC50

3200 μg a.i./L 48654101 N/A

NOAEC 594 μg a.i./L

Terrestrial

Avian

Mallard

Anas 

platyrhynchos

Acute LD50

>2000 mg 

a.i./kg-bw 00160000 Practically Non-Toxic

Chronic NOAEC 96 mg a.i./kgdiet1

48951301 N/A

Northern 

Bobwhite

Colinus 

virginianus

Chronic NOAEC 290 mg a.i./kgdiet2 48952701 N/A

Mammalian Rat

Acute LD50

1480 mg 

a.i./kg-bw 41222504 Slightly Toxic

Chronic NOAEC

1000 mg 

a.i./kg/diet

(no effects)

000778024 N/A

Terrestrial 

Invertebrates Honeybee Acute LD50 1.4 μg a.i./bee 00036935 Highly Toxic

Terrestrial Plants

Seedling 

Emergence

10 Species3

N/A NOAEC Not 

Established 48728101 N/A

Vegetative Vigor

10 Species3 N/A NOAEC >6.09 lb a.i./Acre 48719901 N/A

1. Endpoint based on reductions in adult female body weight and reductions in 14-day survivor weight

compared to the control.

2. Endpoint based on number of live embryos per eggs set and reductions in eggshell thickness compared to 

the control.

3. Five species of monocotyledonous plants include: onion, Allium cepa; ryegrass, Lolium perenne; wheat, 

Triticum aestivum; corn, Zea mays and five species of dicotyledonous plants include: oilseed rape, Brassica 

napus; cabbage, Brassica oleracea; soybean, Glycine max; lettuce, Latuca sativa; tomato, Lycopersicon 

esculentum; bean, Phaseolus vulgaris.

4. No effects at the highest concentration tested.

3.3.3. Review of Incident Data
-Page 40 of 74-

The Ecological Incident Information System (EIIS), which is maintained by the Agency’s Office 

of Pesticide Programs, was searched to determine if ecological incidents have been reported for 

TCVP. Based on a search of EIIS conducted in July, 2014, the Agency has received one report of 

adverse effects to a red-tailed hawk (Buteo jamaicensis) that has been linked to the use of TCVP. 

The incident is considered highly probable, where the bird apparently died from tetrachlorvinphos 

toxicity after a feather treatment for lice. A search of the American Bird Conservancy (ABC) 

AIMS incident database in July, 2014 did not yield any reported incidents for TCVP and birds.

A lack of reported incidents does not necessarily mean that incidents have not occurred. In 

addition, incident reports for non-target plants and animals typically provide information on 

mortality events only. Reports for other adverse effects, such as reduced growth or impaired 

reproduction, are rarely received.

4. Risk Characterization

4.1. Screening-Level Risk Quotient (RQ) Values

This screening-level assessment of the labeled uses of TCVP relies on the deterministic RQ 

method to provide a metric of potential risks. The RQ provides a comparison of exposure estimates 

to toxicity endpoints (i.e., estimated exposures divided by acute and/or chronic toxicity endpoints

expressed in the same units as exposures, respectively). The resulting unitless RQ values are 

compared to the Agency’s LOCs, as shown in Tables 4.1 through Table 4.9. The LOCs are used 

by the Agency to indicate when the use of a pesticide, as directed by the label, has the potential to 

cause adverse effects to nontarget organisms. For endangered species, LOC exceedances require 

an additional in-depth listed species evaluation to characterize risks for the potential co-occurrence 

of listed species and areas in which new use crops are grown. In this approach, RQs that exceed

non-listed species LOCs necessarily also exceed the corresponding listed species LOCs. Note that 

with plants, unlike with animals, RQ values are not presented for acute versus chronic risk; instead, 

RQ values are presented for listed and nonlisted species based on a comparison of a given EEC to 

NOAEL and EC25 values (for terrestrial plants) and EC50 values (for aquatic plants), respectively. 

A discussion of the RQ values for TCVP and of other information that provides context for the 

interpretation of potential risk to various taxa is presented in the Risk Description in Section 4.2.

 

4.1.1. RQ Values for Aquatic Organisms

Freshwater fish serve as surrogates for aquatic-phase amphibians. RQ values for freshwater fish 

exposed to TCVP are below the LOCs for acute risk for listed (0.05) and non-listed species (0.5) 

(Table 4.1). Similarly, chronic RQ values for freshwater fish are below the chronic risk LOC 

(1.0). Therefore, the likelihood of acute mortality or chronic adverse effects in freshwater fish and 

aquatic-phase amphibians from the registered uses of TCVP is considered low. 
-Page 41 of 74-

Table 4.1. Acute RQs for Direct Effects to Freshwater Fish from TCVP TGAI.

Use(s) App. Rate

(lbs a.i./A)

Peak EECs 

(μg a.i./L)

Freshwater Fish

EC50 = 530 μg 

a.i./L 60-Day EECs

(μg a.i./L)

Freshwater Fish 

NOAEC = 47 μg a.i./L

Acute RQs Chronic RQs

Kennels

Residual surfaces, 

garbage dumps, 

and corrals1

Poultry droppings, 

and manure and 

garbage piles

0.4 1.68

(RangeBSS) 0.003 0.58(RangeBSS) 0.01

Manure as soil 

amendment 0.046 0.654(TX_corn) 0.001 0.39(MSCorn) 0.008

Abbreviations: App. Application. 1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals.

RQ values for freshwater aquatic invertebrates exposed to TCVP on an acute basis exceed LOCs 

for listed (LOC=0.05) and non-listed (LOC=0.5) species (Table 4.2). TCVP use in kennels and 

on residual surfaces, poultry droppings, garbage dumps, corrals and manure piles exceed acute risk 

to listed and non-listed species LOCs, and TCVP in manure (from oral larvicide) used as a soil 

amendment exceeds the acute risk to listed species LOC. RQ values for freshwater aquatic 

invertebrates based on chronic exposure to TCVP exceed LOCs for chronic risk to aquatic 

invertebrates for all of the registered uses assessed. 

Table 4.2. Acute and Chronic RQs for Direct Effects to Freshwater Invertebrates from TCVP TGAI.

Use(s) App. Rate

(lbs a.i./A)

Peak EECs 

(μg ai/L)

Freshwater 

Invertebrates

EC50 = 1.9 μg ai/L 21-day EECs 

(μg ai/L)

Freshwater 

Invertebrates

NOAEC =

0.125 μg ai/L

RQs RQs

Kennels

Residual surfaces, 

garbage dumps, 

and corrals1

Poultry droppings, 

and manure and 

garbage piles

0.4 1.68

(RangeBSS) 0.884 1.11

(RangeBSS) 95

Manure as soil 

amendment 0.046 0.654(TX_corn) 0.343 0.64(MS_corn) 55

Abbreviations: App. Application. 1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals. 3

Exceeds acute risk to listed species LOC (RQ≥0.05).

4

Exceeds acute risk to listed species LOC (RQ≥0.05) and non-listed species LOC (RQ≥0.50). 5

Exceeds the chornic risk LOC (RQ≥1.0)

The acute toxicity endpoint for estuarine/marine spot is indeterminate (i.e., LC50>1000 mg a.i./L); 

therefore, RQ values reported in Table 4.3 are indeterminate (<) as well. RQ values for freshwater 

fish exposed to TCVP are below the LOCs for acute risk to listed (0.05) and non-listed species 
-Page 42 of 74-

(0.5). No chronic toxicity data are available for estuarine/marine fish; therefore, chronic RQ values 

could not be estimated.

Table 4.3. Acute RQs for Direct Effects to Estuarine/Marine Fish from TCVP TGAI.

Use(s) App. Rate

(lbs a.i./A)

Peak EECs 

(μg a.i./L)

Estuarine/Marine Fish

LC50 >1,000 μg ai/L

Acute RQs

Kennels

Residual surfaces, garbage 

dumps, and corrals1

Poultry droppings, and 

manure and garbage piles

0.4 1.68

(RangeBSS) <0.002

Manure as soil amendment 0.046 0.654

(TX_corn) <0.001

Acute RQs for marine/estuarine invertebrates exposed to TCVP are below the LOCs for acute risk 

for listed (0.05) and non-listed species (0.5) (Table 4.4). Therefore, the likelihood of adverse 

effects to marine/estuarine invertebrates from the registered uses of TCVP is considered low. 

Chronic RQ values for marine/estuarine invertebrates were not calculated as chronic toxicity data 

were not available.

Table 4.4. Acute RQs for Direct Effects to Estuarine/Marine Invertebrates from TCVP TGAI.

Use(s) Application Rate

(lbs ai/A)

Peak EECs 

(μg ai/L)

Estuarine/Marine 

Invertebrates

EC50 = 280 μg ai/L

RQs

Kennels

Residual surfaces, 

garbage dumps, and 

corrals

Poultry droppings, and 

manure and garbage piles

0.4 1.68

(RangeBSS) 0.006

Manure as soil 

amendment 0.046 0.654(TX_corn) 0.002

RQs for aquatic vascular and non-vascular plants exposed to TCVP did not result in exceedances

of risk to listed or non-listed plant LOCs for any of the registered uses (Table 4.5). Therefore, the 

likelihood of adverse effects to aquatic plants from exposure to TCVP in surface water is 

considered low.

Table 4.5. RQ Values for Direct Effects to Aquatic Vascular and Nonvascular Plants from TCVP TGAI.

Use(s)

Applicatio

n Rate

(lbs a.i./A)

Peak EECs 

(μg a.i./L)

Aquatic Vascular Plants

EC50 >4625 μg a.i./L

NOAEL =1158 μg a.i./L

Aquatic Nonvascular Plants

EC50 = 3200 μg a.i./L

NOAEL = 594 μg a.i./L

Listed RQs Nonlisted RQs Listed RQs Nonlisted RQs

Kennels 0.4 1.68 <0.01 <0.01 <0.01 <0.01
-Page 43 of 74-

Use(s)

Applicatio

n Rate

(lbs a.i./A)

Peak EECs 

(μg a.i./L)

Aquatic Vascular Plants

EC50 >4625 μg a.i./L

NOAEL =1158 μg a.i./L

Aquatic Nonvascular Plants

EC50 = 3200 μg a.i./L

NOAEL = 594 μg a.i./L

Listed RQs Nonlisted RQs Listed RQs Nonlisted RQs

Residual 

surfaces, garbage 

dumps, and 

corrals

Poultry 

droppings, and 

manure and 

garbage piles

(RangeBSS)

Manure as soil 

amendment 0.046 0.654(TX_corn) <0.01 <0.01 <0.01 <0.01

4.1.2. RQ Values for Terrestrial Organisms

Birds are the surrogate speciesfor reptiles and terrestrial-phase amphibians. Acute dose-based RQs 

for birds were not estimated as the acute oral toxicity endpoint for birds is non-definitive in a study 

conducted up to the limit test dose without any mortality at the highest dose (i.e., LD50>2,000 mg 

a.i./kg).

Screening-level chronic RQ values for the uses of TCVP in kennels and on residual surfaces, 

poultry droppings, garbage dumps, corrals and manure piles exceed the LOC for chronic risk to 

birds, reptiles, and terrestrial-phase amphibians exposed to TCVP in the diet (Table 4.6). Estimates 

of risk from the soil amendment use were not calculated as exposure to plants from this use are 

not expected. Chronic mammalian RQs exceeded the LOC for listed and non-listed mammals for 

uses on residual surfaces and poultry droppings. 

Table 4.6. Chronic Dietary-Based RQs for Birds, Reptiles, and Terrestrial-phase Amphibians of Different 

Feeding Classes (T-REX v. 1.5).

Primary Feeding Strategy  Herbivores, Omnivores, and Granivores Insectivores

Dietary Items 

Short Grass

Tall Grass

Broad-leaf 

Plants

Fruits, pods, 

seeds, etc.

Arthropods

Use(s) 

Kennels1 8.33 3.83 4.63 0.5 3.23

Residual Uses2 353 163 203 2.23 143

Poultry Droppings 873 403 493 5.43 343

1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals.

2 Poultry droppings include: poultry droppings, manure piles, garbage piles.

Dietary-based RQ values are based on the mallard duck NOAEC value of 96 mg/kg-diet (LOAEC=290 mg/kg-diet). 3

A dark shaded cell indicates that the RQ exceeds the LOC for chronic risk to listed and non-listed birds, reptiles, and terrestrial phase amphibians 

(LOC = 1).

Screening-level acute RQs for mammals for the uses of TCVP in kennels and on residual surfaces, 

poultry droppings, garbage dumps, corrals and manure piles exceed the acute risk to listed LOC 
-Page 44 of 74-

(0.1) and non-listed LOC (0.5) (Table 4.7). Screening-level RQ values for chronic exposures to 

listed and non-listed mammals exceeded the LOC for chronic risk (1) for residual uses and the use 

on poultry droppings (Table 4.8)

RQ values for terrestrial plants exposed to TCVP through run-off did not result in exceedances of 

listed or non-listed plant LOCs for any of the registered uses (Table 4.9). Therefore, the likelihood 

for adverse effects to terrestrial and semi-aquatic plants from exposure to TCVP is considered low.

Finally, as a screening measure, the KABAM model was used to estimate potential 

bioaccumulation of hydrophobic organic pesticides in freshwater aquatic food webs and 

subsequent risks to mammals and birds via consumption of aquatic prey contaminated with TCVP 

(Appendix G). RQ values calculated by the KABAM model for birds and mammals do not exceed 

acute or chronic LOCs. Therefore, the risk to birds and mammals that consume aqutic prey 

contaminated by TCVP is low. 
-Page 45 of 74-

Table 4.7. Acute Dose-based RQ values for Mammals Exposed to TCVP (T-REX v. 1.5).

Primary 

Feeding 

Strategy 

Herbivores and Omnivores Insectivores Granivores

Animal Size  Sm Med Lg Sm Med Lg Sm Med Lg

Dietary Items 

Short Grass

Tall Grass

Broad-leaf 

Plants

Fruits, pods, 

seeds, etc.

Short Grass

Tall Grass

Broadleaf 

Plants

Fruits, pods, 

seeds, etc.

Short Grass

Tall Grass

Broadleaf 

Plants

Fruits, pods, 

seeds, etc.

Arthropods Seeds, grains, etc.

Use(s) 

Kennels 0.9 0.4 0.5 0.1 0.4 0.2 0.2 <0.1 0.1 0.1 0.1 <0.1 0.3 0.2 0.1 <0.1 <0.1 <0.1

Residual Uses1 3.7 1.7 2.1 0.2 1.6 0.8 0.9 0.1 0.5 0.2 0.3 <0.1 1.4 0.6 0.2 0.1 <0.1 <0.1

Poultry 

Droppings2 9.2 4.2 5.2 0.6 4.1 1.9 2.3 0.3 1.3 0.6 0.7 0.1 3.6 1.6 0.5 0.1 0.1 <0.1

1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals.

2 Poultry droppings include: poultry droppings, manure piles, garbage piles.

Acute RQ values for mammals are based on the LD50 value of 1480 mg a.i./kg bw.

A bolded number indicates that the RQ meets or exceeds the LOC for acute risk to listed mammals only (LOC = 0.1), a bolded number in a shaded cell

indicates that the RQ meets or exceeds the LOC for acute risk to non-listed mammal species (LOC=0.5) (the LOC for listed species is also met or exceeded).
-Page 46 of 74-

Table 4.8. Screening-level Dietary-based Chronic RQs for Mammals from Labeled Uses of TCVP (T-REX v. 

1.5).

Primary Feeding Strategy  Herbivores, Omnivores, and Granivores Insectivores

Dietary Items 

Short Grass

Tall Grass

Broad-leaf 

Plants

Fruits, pods, 

seeds, etc.

Arthropods

Use(s) 

Kennels 0.79 0.36 0.45 0.05 0.31

Residual Uses1 3.34 1.53 1.88 0.21 1.31

Poultry Droppings2 8.35 3.83 4.7 0.52 3.27

1 Residual surfaces include: barns, farm buildings, around garbage dumps and corrals.

2 Poultry droppings include: poultry droppings, manure piles, garbage piles.

Bolded RQ values exceed the chronic mammalian LOC for chronic risk (1).
-Page 47 of 74-

Table 4.9. RQs for Nontarget Terrestrial Plants Adjacent to TCVP Use Areas (Ground Spray).

Crop

Single Max. 

Application 

Rate

(lbs ai/A)

Monocot RQ Values Dicot RQ Values

Runoff 

(Dry Areas)

Runoff 

(Semi-Aquatic Areas)

Runoff 

(Dry Areas)

Runoff 

(Semi-Aquatic Areas)

1

Nonlisted 

Species

Listed 

Species

Nonlisted 

Species

Listed 

Species

Nonlisted 

Species

Listed 

Species

Nonlisted 

Species

Listed 

Species

Kennels 3.3

N/A

<0.1

N/A

N/A

N/A

<0.1

N/A

<0.1

Residual 

Surfaces 13.9 <0.1 N/A <0.1 <0.1

Poultry 

Droppings 34.8 <0.1 N/A <0.1 <0.1

Soil 

Amendment 0.046 <0.1 N/A <0.1 <0.1

1

As applications to kennels, residual surfaces, and poultry droppings are spot treatments, the application rates for runoff from semi-aquatic areas is proportioned, as in the aquatic modeling to 0.38, 0.39, 

and 0.8 lbs a.i./A, respectively, to account for the 10:1 watershed ratio used in the semi-aquatic model.

Runoff RQ values for nontarget monocot plants are based on the NOAEC of 5.7 lbs a.i./A from the vegetative vigor study. Runoff RQ values for nontarget dicot plants are based on the NOAEC of 6.09 

lbs a.i./A from the seedling emergence study.
-Page 48 of 74-

4.2. Risk Description

This screening-level assessment of the labeled uses of TCVP relies on the deterministic RQ 

method to provide a metric of potential risks. RQ values for freshwater aquatic invertebrates 

exposed to TCVP on an acute and chronic basis exceed LOCs for listed and non-listed species 

(Table 4.2). 

For terrestrial organisms exposed to TCVP, screening-level chronic RQ values for the uses of 

TCVP exceed the LOC for chronic risk to listed and non-listed birds (Table 4.6). Screening-level 

acute RQs for mammals for the uses of TCVP in kennels and on residual surfaces, poultry 

droppings, garbage dumps, corrals and manure piles exceed the acute risk to listed and non-listed 

species (Table 4.7). Finally, screening-level RQ values for chronic exposures to listed and nonlisted mammals exceeded the LOC for chronic risk for residual uses and the use on poultry 

droppings (Table 4.8). Risks to all other organisms did not exceed LOCs.

4.2.1. Risks to Aquatic Organisms

4.2.1.1. Freshwater Fish, Amphibians, and Invertebrates

TCVP is characterized as highly toxic to freshwater fish (and aquatic-phase amphibians for which 

fish serve as surrogates) on an acute exposure basis; however, RQ values for freshwater fish are 

below the LOCs for both listed and non-listed species. The RQ values are based on application 

rates (maximum of 0.4 lbs a.i./A) that have been adjusted based on the assumption that spot 

treatments are not uniform across the entire farm. In order to exceed the acute RQs for listed and 

non-listed species, the application rates would need to be approximately 6.2 and 62 lbs a.i./A, 

respectively, or 3 and 31 gallons of product per acre, which could treat a maximum area of 1.7 and 

17 acres, respectively, if 5 gallons of product is expected to treat a maximum of 2.9 acres (see 

Appendix H). For chronic exposures, the application rate would need to be around 32 lbs a.i./A, 

or 16 gallons of product per acre, in order to exceed the listed and non-listed RQs. This would 

treat a maximum of 9 acres, assuming 5 gallons of product is expected to treat a maximum of 2.9 

acres (see Appendix H).

On an acute exposure basis, TCVP is very highly toxic to freshwater invertebrates. TCVP use in 

kennels and on residual surfaces, poultry droppings, garbage dumps, corrals and manure piles 

exceeds acute risk to listed and non-listed species LOCs, and TCVP use as a soil amendment 

exceeds the acute risk to listed species LOC. RQ values for freshwater aquatic invertebrates 

exposed to TCVP on a chronic basis exceed LOCs for chronic risk to aquatic invertebrates for all 

of the registered uses. Although this assessment provides a conservative, screening-level estimate 

of risk, risk to these organisms is likely given the high acute toxicity of TCVP to freshwater aquatic 

invertebrates. 

4.2.1.2. Estuarine/Marine Fish and Invertebrates

TCVP is moderately toxic to estuarine/marine invertebrates on an acute exposure basis; however, 

the LC50 from the acute toxicity study with L. xanthurus is a non-definitive value and no chronic 

toxicity data were available; therefore, acute RQ values are non-definitive as well. To characterize 

the potential for acute risk to estuarine/marine fish from TCVP, the highest peak surface water 
-Page 49 of 74-

EEC (3.45 μg a.i./L) was compared to the non-definitive acute toxicity endpoint for spot 

(LC50>1000 μg a.i./L). The EEC is less than 4% of the non-definitive LC50. For aquatic animals, 

an acute EEC that exceeds 5% of the effects endpoint would exceed the Agency’s acute risk LOC 

for listed species, and an acute EEC that exceeds 50% of that effects endpoint would exceed the 

acute risk LOC for nonlisted species. Therefore, the likelihood for acute mortality of

marine/estuarine fish from exposure to TCVP in surface water is considered low. The acute RQ 

values are based on application rates (maximum of 0.4 lbs a.i./A) that have been adjusted based 

on the assumption that spot treatments are not uniform across the entire farm. In order to exceed 

the acute RQs for listed and non-listed species, the application rates would need to be 

approximately 12 and 117 lbs a.i./A, respectively, or 5.8 and 58 gallons per product per acre, which 

could treat a maximum of 3.3 and 33 acres, respectively, assuming 5 gallons of product is expected

to treat a maximum of 2.9 acres (see Appendix H).

Although TCVP is characterized as highly toxic to estuarine/marine invertebrates on an acute 

exposure basis, acute RQs for marine/estuarine invertebrates exposed to TCVP are below the 

LOCs for acute risk to listed and non-listed species. Therefore, the likelihood of mortality in

marine/estuarine invertebrates from the registered uses of TCVP is considered low. Chronic RQ 

values for marine/estuarine invertebrates were not calculated as chronic toxicity data were not 

available. The acute RQ values are based on application rates (maximum of 0.4 lbs a.i./A) that 

have been adjusted based on the assumption that spot treatments are not uniform across the entire 

farm. In order to exceed the acute RQs for listed and non-listed species, the application rates 

would need to be approximately 3.3 and 33 lbs a.i./A, respectively, or 1.6 and 16 gallons of product 

per acre, which could treat a maximum of 0.9 and 9 acres, respectively, assuming 5 gallons of 

product is expected to treat a maximum of 2.9 acres (see Appendix H).

4.2.1.3. Aquatic Plants

Since TCVP is moderately mobile it may reach surface water where aquatic plants could 

potentially be exposed. RQ values though for aquatic vascular and non-vascular plants exposed 

to TCVP did not result in exceedances for any of the registered uses. Therefore, the likelihood of 

adverse effects on aquatic plants from exposure to TCVP in surface water is considered low.

4.2.2. Risks to Terrestrial Organisms 

4.2.2.1. Birds, Reptiles, and Terrestrial-phase Amphibians

TCVP is characterized as practically non-toxic to birds on an acute oral exposure basis; however, 

data are not available to assess the subacute dietary toxicity of TCVP to birds. Screening-level 

RQ values for acute exposures were not calculated in the Risk Estimation section of this 

assessment because no mortality was observed at the highest treatment levels tested in the avian 

acute oral toxicity studies. To gain a better understanding of how the EECs for the maximum 

TCVP application rates for the assessed uses relate to the toxicity data currently available for birds, 

dietary- and dose-based EECs from the T-REX model were compared to the highest treatment 

concentrations in the avian acute toxicity tests, where no mortality was observed.
-Page 50 of 74-

The maximum avian dose-based EEC is 3,799 mg a.i./kg bw (small birds consuming short grass) 

for the use on poultry droppings. This EEC is approximately 190% of the maximum dose tested 

(2,000 mg a.i./kg bw) in the acute oral toxicity tests with mallard duck, although no mortality was 

observed in the study (LD50 > 2,000 mg a.i./kg bw). 

No mortality was observed in the acute toxicity test for TCVP up to the limit dose (2,000 mg

a.i./kg-bw). No ecological incidents with birds, reptiles, or amphibians have been reported (ABC 

2007, USEPA 2014). Therefore, risk of acute mortality to birds, reptiles or amphibians from the 

currently registered uses of TCVP is likely low. Additionally, it is unknown whether passerine 

species may be more sensitive to TCVP exposure than the mallard duck; although acute toxicity 

testing with a passerine species is now required per 40 CFR Part 158.630 (2008), a data call-in for 

passerine testing was not issued at the time of Problem Formulation for TCVP.

Screening-level chronic RQ values for the uses of TCVP in kennels and on residual surfaces, 

poultry droppings, garbage dumps, corrals and manure piles and TCVP residues in manure used 

as soil amendment exceed the LOC for chronic risk to birds, reptiles, and terrestrial-amphibians 

exposed to TCVP in the diet. However, as explained earlier in this assessment, the T-REX model 

was used to estimate exposure and risk from TCVP uses. While T-REX is designed to provide 

screening level estimates of exposure from large scale pesticide applications to crop fields, it is 

not ideal for assessing exposure from spot treatment uses, such as is the case with TCVP uses. 

Further, T-REX assumes that 100% of an animal’s diet comes from food items obtained from 

within the large treated area, while spot treatments generally treat much smaller areas. These 

uncertainties are important considerations for understanding potential terrestrial exposure from 

TCVP. The T-REX default foliar dissipation half-life of 35 days was used.

Given the non-standard use patterns assessed herein, it is uncertain to what extent the T-REX 

model exposure estimates reflect actual exposure to birds (and reptiles, and terrestrial amphibians 

for which birds are surrogate species) who may feed on plant food items near treated TCVP use 

sites. 

4.2.2.2. Mammals

TCVP is characterized as moderately toxic to mammals on an acute oral exposure basis. 

Screening-level acute RQs for mammals for the uses of TCVP in kennels and on residual surfaces, 

poultry droppings, garbage dumps, corrals and manure piles exceed the acute listed and non-listed 

LOCs. Screening-level RQ values for chronic exposures also exceeded the LOC for listed and 

non-listed mammals for the residual uses and for use on poultry droppings. However, as explained 

earlier in this assessment, the T-REX model was used to estimate exposure and risk from TCVP 

uses. Given the non-standard use patterns assessed herein, it is uncertain to what extent the T-REX 

model exposure estimates reflect actual exposure to mammals who may feed on plant food items 

near treated TCVP use sites. 
-Page 51 of 74-

4.2.2.3. Terrestrial Invertebrates

RQs for terrestrial invertebrates were not calculated. While TCVP is classified as highly toxic to 

adult honey bees, the use pattern for TCVP (application to manure piles, poultry droppings, etc.) 

is likely to preclude exposure to honey bees. However, there is uncertainty regarding the effect of 

treated manure on fields where ground-nesting solitary and social bees may be located.

4.2.2.4. Terrestrial Plants

RQs for terrestrial plants exposed to TCVP did not result in exceedances for any of the registered 

uses. Therefore, the potential risk to terrestrial plants from exposure to TCVP in runoff is 

considered low.

5. 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 this preliminary risk assessment, 

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), 

TCVP 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 
-Page 52 of 74-

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

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

construed as a list of known or likely endocrine disruptors. TCVP 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 EPA’s EDSP website[2].

6. Federally Threatened and Endangered (Listed) Species of Concern

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

Agency will evaluate risks to listed species from registered uses of pesticides in Registration 

Review. The process for evaluating potential risks to listed species is further described at 

http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm.

6.1. Taxonomic Groups Potentially at Risk 

Based on this screening-level assessment, there are potential risks of direct effects to listed 

freshwater invertebrates, birds, reptiles, terrestrial-phase amphibians and mammals from the use 

of TCVP on some of its registered use sites. Listed species of all 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 freshwater invertebrates, birds, reptiles, terrestrial-phase amphibians and

mammalsfrom the use of TCVP may be associated with modification of Primary Constituent 

Elements (PCEs) of designated critical habitats, where such designations have been made. 

However, at this current stage of the Registration Review process, it is premature to make effects 

determinations for listed species until further scientific analysis and refinements are conducted, 

based on recommendations received from the National Academy of Sciences’ (NAS) National 

Research Council (NRC) April 2013 report, available at

http://www.nap.edu/catalog.php?record_id=18344. The NAS report outlines recommendations on 

specific scientific and technical issues related to the development of pesticide risk assessments that 

are compliant with the ESA and FIFRA.

The EPA along with the USFWS, the 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. 

 

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

of chemicals.

[2] Available: http://www.epa.gov/endo/
-Page 53 of 74-

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 TCVP 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 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 TCVP is used on all use sites. Actual usage data (when 

available) and national land-cover datasets that indicate potential use sites [e.g., National Land 

Cover Dataset (NLCD), Cropland Data Layer (CDL)] may be used to support a more refined 

analysis of where TCVP is reasonably expected to be used. Similarly, refinements on the timing 

of applications and a more in-depth exploration of agronomic practices for TCVP 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.

Table 6.1. Preliminary Conclusions for Potential Direct Effects to Federally Listed Taxa Associated with the 

Registered Uses of TCVP, Based on Best Available Data.

Listed Plant Taxon Potential Direct Effects

Terrestrial and semi-aquatic plants –

monocots and dicots No

Aquatic vascular plants No

Terrestrial Plants No
-Page 54 of 74-

Listed Plant Taxon Potential Direct Effects

Listed Animal Taxon

Potential Direct Effects

Acute Notes Chronic Notes

Terrestrial invertebrates No Highly toxic to 

honeybees Uncertain

No data on 

chronic exposure 

to honeybees

Mammals Yes Exceeds acute 

LOC Yes Exceeds chronic LOC

Birds

No No effects Yes All uses except 

soil amendment Reptiles

Amphibians

Freshwater fish No No exceedances No No exceedances

Freshwater invertebrates Yes Exceeds LOC Yes Exceeds LOCs

Molluscs Yes No exceedances No data

Estuarine/marine fish No No exceedances No No exceedances

Estuarine/marine invertebrates Yes No exceedances No data

ND Not determined.
-Page 55 of 74-

7. Conclusions

The risk hypothesis identified in the problem formulation stated, “Given the uses of TCVP and its 

environmental fate properties, there is a likelihood of acute and chronic exposure to non-target

aquatic organisms. Therefore, when used in accordance with the label, TCVP may result in 

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

animals.” After reviewing the most recent environmental fate and effects data for TCVP, the 

screening-level assessment concludes that registered uses of the insecticide TCVP may result in 

risks to both listed and non-listed species of wildlife; however, direct effects on aquatic organisms 

are limited to freshwater invertebrates. 

TCVP is expected to be slightly to moderately mobile in the environment, and its primary route of 

degradation is expected to be aerobic soil metabolism. The compound is not volatile, but is likely 

to move off-site via a combination of runoff and leaching. TCVP that enters surface waters is 

expected to degrade via hydrolyis. As TCVP is expected to be slightly to moderately mobile,

significant partitioning of TCVP to benthic sediments in most aquatic habitats is not expected. 

Instead, TCVP is likely to remain primarily in the water column, where dilution and degradation 

act to decrease concentrations over time.

When estimates of TCVP exposure in aquatic environments are compared to the available 

ecotoxicity data, the results of the screening-level assessment indicate a potential for acute and 

chronic risk to listed and non-listed species of freshwater aquatic invertebrates. Although 

mortality was not observed in the acute avian studies, acute risks to birds could not be precluded, 

as the EECs exceeded the highest dose tested. Screening-level chronic RQ values for the uses of 

TCVP exceed the LOC for chronic risk to birds, reptiles, and terrestrial-phase amphibians exposed 

to TCVP in the diet. Results of the screening-level assessment indicate a potential for acute risk to 

listed and non-listed species mammals. Chronic risk to mammals are also anticipated, as the 

screening-level assessment indicates a potential for chronic risk to listed and non-listed mammals 

for some of the uses. 

8. References

American Bird Conservancy (ABC). 2010. Avian Incident Monitoring System. Available online 

at http://www.abcbirds.org/abcprograms/policy/toxins/aims/aims/login.cfm.

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the 

EPA food-chain (Kenaga) nomogram, and instrument for estimating pesticide residues on

plants. Environmental Toxicology and Chemistry 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. 

Korte, eds., Environmental Quality and Safety: Chemistry, Toxicology, and Technology, 

Georg Thieme Publ, Stuttgart, West Germany, pp. 9-28.

Kashuba, R., Spatz, D. 2006 Memorandum to Steven Bradbury, Subject: Standard Soil Mobility 

Classification Guidance
-Page 56 of 74-

Stichler, C.; McFarland, M. 2001. Crop Nutrient Needs in South and Southwest Texas. Texas 

A&M University, Texas Agricultural Extension Service. 

(http://publications.tamu.edu/SOIL_CONSERVATION_NUTRIENTS/PUB_soil_Crop%

20Nutrient%20Needs.pdf)

Urban, D.J., and N. Cook. 1986. Ecological Risk Assessment. EPA 540/9–85-001. Office of 

Pesticide Programs. Washington, D.C.: U.S. Environmental Protection Agency. 

U.S. Department of Agriculture (USDA). 2009. Part 651, Agricultural Waste Management Field 

Handbook. USDA. Natural Resources Conservation Service. July 2009. 

U.S. Environmental Protection Agency (USEPA). 2012. Ecological Incident Information 

System, v. 2.1 . Accessed on 7 November 2012. Description online at 

http://www.epa.gov/pesticides/science/models_db.htm.

-- 2009a. Pesticides; Data Requirements for Conventional Chemicals, Technical Amendments, 

and Data Requirements for Biochemical and Microbial Pesticides; Final Rule. FR 

72(207):60933-60988.

-- 2009b. Water models. Available online at http://www.epa.gov/oppefed1/models/water/.

-- 2009c. ECOTOXicology Database, v. 4.0. Accessed on 12 April 2012. Available online at 

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

-- 2009d. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and 

Transport of Pesticides, Version 2.1. U.S. Environmental Protection Agency, Office of 

Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental 

Fate and Effects Division, October 22, 2009. Online at: 

http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

-- 2008a. Registration Review – Preliminary Problem Formulation for the Ecological Risk 

Assessment of TCVP-ammonium. Office of Pesticide Programs. Environmental Fate and 

Effects Division. 5 June 2008. DP Barcode 346879.

-- 2008b. Alsadek, J. Tetrachlorvinphos (Z-isomer) Usage on Livestock, 1997-2006. U.S. 

Environmental Protection Agency, Office of Pesticide Programs, Biological and Economic 

Analysis Division. January 23, 2008

-- 2006a, TerrPlant v. 1.2.2 User’s Guide. Office of Pesticide Programs, Environmental Fate and 

Effects Division, Washington, D.C. December 26, 2006.

-- 2006b. Interim Tolerance Reassessment Eligibility Decision and Reregistration Eligibility 

Decision Addenda for Tetrachlorvinphos, Case 0321. September, 2002.

-- 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, 
-Page 57 of 74-

U.S. Environmental Protection Agency. Endangered and Threatened Species Effects 

Determinations. Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide 

Programs, Washington, D.C. Available online at 

http://www.epa.gov/oppfead1/endanger/consultation/ecorisk-overview.pdf.

-- 2003. SCIGROW: Users Manual. Online at: 

http://www.epa.gov/oppefed1/models/water/#scigrow

-- 2000. Kiely, T. Quantitative Usage Analysis for Tetrachlorvinphos. U.S. Environmental 

Protection Agency, Office of Pesticide Programs, Biological and Economic Analysis 

Division. May 12, 2000

-- 1998. Guidelines for Ecological Risk Assessment. EPA/630/R-95/002F. Published in 63 FR 

26846; May 14, 1998. U.S. Environmental Protection Agency, Washington, DC. April, 

1998.

-- 1993a. Abbotts, J. Results of the HED Metabolism Committee Meeting Held on 9/8/93: 

Tetrachlorvinphos Metabolism in Animals. U. S. Environmental Protection Agency, Office 

of Prevention, Pesticides and Toxic Substances. Memorandum to HED Metabolism 

Committee, Health Effects Division.

-- 1993b. Wildlife Exposure Factors Handbook. EPA/600/R-13/187a. Office of Research and 

Development, Washington, D.C.

-- 1992. Pesticides in Ground Water Database: A Compilation of Monitoring Studies: 1971-1991: 

National Summary. U.S. Environmental Protection Agency, Washington, DC.

Willis, G.H. and L.L. McDowell. 1987. Pesticide persistence on foliage. Reviews of 

Environmental Contamination and Toxicology 100: 23-73.

8.1. Submitted Product Chemistry and Environmental Fate Studies

MRID 00077821 

Beynon, K.I., A.N. Wright. 1968. The Breakdown of the Insecticide Gardona (SD 8447,2-Chloro1-(2',4',5'-trichloropheny1)-v inyl Dimethyl Phosphate) on Plants and in Soils. WP-193-68. 

Unpublished study received Aug 17, 1968 under 9F0739; submit- ted by Shell Chemical Co., 

Washington, D.C.; CDL:091273-F.

MRID 41222503 

Silveira, E. 1989. Technical Rabon Insecticide: Physical and Chemical Characteristics. Project ID 

Y2033.B. Unpublished study prepared by Du Pont de Nemours and Co. 65 p.

MRID 41681301

Blumhorst, M. 1990. Adsorption/Desorption Studies-Batch Equilibrium for Rabon. Lab Project 

Number: 149-001. Unpublished study prepared by EPL Bio-Analytical Services, Inc. 119 p.
-Page 58 of 74-

MRID 41929101

Blumhorst, M. 1991. Aqueous Hydrolysis of Rabon. Lab Project Number: 149-003. Unpublished 

study prepared by EPL Bio-Analytical Services, Inc. 88 p.

MRID 42082401 

Blumhorst, M. 1991. Aerobic Soil Metabolism Study of Rabon. Lab Project Number: 149-002. 

Unpublished study prepared by EPL Bio- Analytical Services, Inc. 190 p.

MRID 42848501

Krautter, G. 1993. The Dissipation of (carbon 14)Tetrachlorvinphos and Its Metabolites in Manure 

from a Beef Cow Following Oral Administration for 14 Consecutive Days. Lab Project Number: 

71 0: 1520. Unpublished study prepared by PTRL East, Inc. 101 p.

MRID 43663501

Blurnhorst, M. 1995. Aqueous Hydrolysis of Rabon: Supplement No. 1. Lab Project Number: 149-

003. Unpublished study prepared by EPL Bio- Analytical Services, Inc. 70 p.

MRID 48879901

Turk, R. (2012) [Carbon 14]Tetrachlorvinphos - Soil Transformation Study Under Aerobic 

Conditions Following OPPTS Guideline 835.4100 and OECD Guideline 307. Project Number: 

14020/6100, 110923/01/TCVPTF, 110923/A/TCVPTF. Unpublished study prepared by Smithers 

Viscient Laboratories. 81p.

MRID 48956301

Dias, N. (2012) Dissipation of Tetrachlorvinphos (TCVP) and its Metabolites in Manure from Beef 

Cattle Following Oral Administration for 14 Consecutive Days: Final Report. Project Number: 

120911/01/KMG UBL0001. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 151p.

8.2. Submitted Ecotoxicity Studies

MRID: 48951301

Stafford, J. (2012) Tetrachlorvinphos: Reproductive Toxicity Test with the Mallard (Anas 

platyrhynchos). Project Number: 14020/4102, 110802/01/TCVPTF, 110802/A/TCVPTF. 

Unpublished study prepared by Smithers Viscient. 360p.

MRID: 48952701

Stafford, J. (2012) Tetrachlorvinphos: Reproductive Toxicity Test with the Northern Bobwhite 

(Colinus virginianus). Project Number: 14020/4101, 110802/02/TCVPTF, 110802/B/TCVPTF. 

Unpublished study prepared by Smithers Viscient. 360p.

MRID: 48728101

Porch, J.; Krueger, H.; Martin, K. (2012) Rabon WP: A Tier I Toxicity Test to Determine the 

Effects of the Test Substance on Seedling Emergence of Ten Species of Plants: Final Report. 

Project Number: 699/101A, 111027/01/TCVPTF, 111027/A/TCVPTF. Unpublished study 

prepared by Wildlife International, Ltd. 68p.
-Page 59 of 74-

MRID: 48719901

Porch, J.; Krueger, H.; Martin, K. (2012) Rabon WP: A Tier I Toxicity Test to Determine the 

Effects of the Test Substance on Vegetative Vigor of Ten Species of Plants: Final Report. Project 

Number: 699/102, 111/27/02/TCVPTF, 111027/B/TCVPTF. Unpublished study prepared by 

Wildlife International, Ltd. 70p.

MRID: 48792401

Dobbins, L.; Kendall, T.; Porch, J. (2012) Tetrachlorvinphos (TCVP): A 7-Day Static-Renewal 

Toxicity Test with Duckweed (Lemna gibba G3) Tier II: Final Report. Project Number: 699P/101, 

120201/01/TCVPTF, 120201/A/TCVPTF. Unpublished study prepared by Wildlife International, 

Ltd. 64p.

MRID: 48654101

Arnie, J.; Porch, J.; Kendall, T. et al. (2011) Tetrachlorvinphos (TCVP): A 96-Hour Toxicity Test 

with the Freshwater Alga (Pseudokirchneriella subcapitata): Final Report. Project Number: 

699A/104, 111012/01/TCVPTF, 111012/A/TCVPTF. Unpublished study prepared by Wildlife 

International, Ltd. 61p.

MRID: 48688401

Schneider, S.; Kendall, T.; Krueger, H. (2011) Tetrachlorvinphos (TCVP): Amphibian 

Metamorphosis Assay for the Detection of Thyroid Active Substances: Final Report. Project 

Number: 699A/102, 110727/01/TCVPTF, 110727/A/TCVPTF. Unpublished study prepared by 

Wildlife International, Ltd. 151p.

MRID: 48838201

Schneider, S.; Martin, K.; Kendall, T.; et al. (2012) Tetrachlorvinphos (TCVP): Fish Short-Term 

Reproduction Assay with the Fathead Minnow (Pimephales promelas): Final Report. Project 

Number: 699A/101, 110701/01/TCVPTF, 110701/A/TCVPTF. Unpublished study prepared by 

Wildlife International, Ltd. 171p.
-Page 60 of 74-

Appendix A. Chemical Names and Structures of TCVP and its Degradates

Chemical Name Structure Physical/Chemical 

Properties1

Presence in Fate 

Studies

Tetrachlorvinphos

IUPAC: (Z)-2-chloro-1-(2,4,5-

trichlorophenyl)vinyl dimethyl phosphate

CAS: (1Z)-2-chloro-1-(2,4,5-

trichlorophenyl)ethenyl dimethyl phosphate

CAS Reg. No. 22248-79-9

COP(=O)(OC)OC(=CCl)c1cc(Cl)c(Cl)cc1Cl

O

O

P O

O

Cl

Cl

Cl Cl

MW: 365.96 g/mol

VP: 2.6E-07 torr

Solubility: 11.6 mg/L

Log Kow: 3.53

Koc: 520-1100 L/kgoc

LC50 (fish): 2.31 mg/L

LC50 (daphnid): 0.004 mg/L

Chronic (fish): 0.011 mg/L

Chronic (daphnid): 0.11 mg/L

Des-O-methyl tetrachlorvinphos

IUPAC: (Z)-2-chloro-1-(2,4,5-

trichlorophenyl)vinyl methyl phosphate

CAS: (1Z)-2-chloro-1-(2,4,5-

trichlorophenyl)ethenyl methyl phosphate

COP(=O)(O)OC(=CCl)c1cc(Cl)c(Cl)cc1Cl

O

O

P O

OH

Cl

Cl

Cl Cl

MW: 351.94 g/mol

VP: 4.27E-08 torr

Solubility: 3.768 mg/L

Log Kow: 3.75

Koc: 702-827 L/kgoc

LC50 (fish): 1.75 mg/L

LC50 (daphnid): 1.60 mg/L

Chronic (fish): 0.23 mg/L

Chronic (daphnid): 0.09 mg/L

Hydrolysis: 28%, pH 9

(MRID 41929101)

Aerobic soil: 3%

(MRID 00077821)

1-(2,4,5-trichlorophenyl)ethanediol

C(O)(CO)c1cc(Cl)c(Cl)cc1Cl OH

Cl

Cl Cl

OH MW: 241.5 g/mol

VP: 4.37E-06 torr

Solubility: 250 mg/L

Log Kow: 2.37

Koc: 29-36 L/kgoc

LC50 (fish): 34.5 mg/L

LC50 (daphnid): 28.3 mg/L

Chronic (fish): 3.31 mg/L

Chronic (daphnid): 5.16 mg/L

Aerobic soil: 0.7%

(MRID 00077821)

TCPEol (SD 15509, AA849)

1-(2,4,5-trichlorophenyl)ethanol

1-(2,4,5-trichlorophenyl)ethan-1-ol

CC(O)c1cc(Cl)c(Cl)cc1Cl

OH

Cl

Cl Cl

MW: 225.5 g/mol

VP: 2.37E-04 torr

Solubility: 123 mg/L

Log Kow: 3.43

Koc: 319-359 L/kgoc

LC50 (fish): 4.33 mg/L

LC50 (daphnid): 3.85 mg/L

Chronic (fish): 0.52 mg/L

Chronic (daphnid): 0.0.92 mg/L

Aerobic soil: 25%

(MRID 00077821)

Aerobic soil: 31.1%

(MRID 42082401)

Aerobic soil: 40.8%

(MRID 48879901)

Manure: 69.2 %

(MRID 42848501)

Manure: 11.8 ppm

(MRID 48956301)

TCPEone (CO300)

2,4,5-trichloroacetophenone

CC(=O)c1cc(Cl)c(Cl)cc1Cl

O

Cl

Cl Cl

MW: 223.5 g/mol

VP: 6.32E-03 torr

Solubility: 27.4 mg/L

Log Kow: 3.61

Koc: 492-1,828 L/kgoc

LC50 (fish): 6.58 mg/L

LC50 (daphnid): 4.33 mg/L

Chronic (fish): 0.77 mg/L

Chronic (daphnid): 0.64 mg/L

Aerobic soil: 11%

(MRID 00077821)

Aerobic soil: 51.4%

(MRID 42082401)

Aerobic soil: 23.2%

(MRID 48879901)

Manure: 2.00 ppm

(MRID 48956301)
-Page 61 of 74-

Chemical Name Structure Physical/Chemical 

Properties1

Presence in Fate 

Studies

TCCEol (SD15125, AA576)

l-(2,4,5-trichlorophenyl)-2-chloroethanol

C(Cl)C(O)c1cc(Cl)c(Cl)cc1Cl

MW: 260 g/mol

VP: 2.11E-05 torr

Solubility: 250 mg/L

Log Kow: 3.68

Koc: 494-608 L/kgoc

LC50 (fish): 2.61 mg/L

LC50 (daphnid): 2.36 mg/L

Chronic (fish): 0.26 mg/L

Chronic (daphnid): 0.42 mg/L

Aerobic soil: 37%

(MRID 00077821)

Aerobic soil: 14.3%

(MRID 42082401)

Aerobic soil: 51%

(MRID 48879901)

Manure: 7.1%

(MRID 42848501)

Manure: 0.75 ppm

(MRID 48956301)

TCBA (SD 15917)

2,4,5-Trichlorobenzoic acid

C(=O)(O)c1cc(Cl)c(Cl)cc1Cl

MW: 225.5 g/mol

VP: 5.52E-04 torr

Solubility: 35.3 mg/L

Log Kow: 3.47

Koc: 157-166 L/kgoc

LC50 (fish): 88.6 mg/L

LC50 (daphnid): 57.6 mg/L

Chronic (fish): 10.2 mg/L

Chronic (daphnid): 8.2 mg/L

Aerobic soil: 18.5%

(MRID 42082401)

Aerobic soil: 31.8%

(MRID 48879901)

Manure: 12.1%

(MRID 42848501)

Manure: 2.57 ppm

(MRID 48956301)
-Page 62 of 74-

Appendix B. SWCC Sample Input/Output Data

Kennel

Variable Volume Water Model, SWCC Compatible Version

*******************************************

Performed on: 9/18/2014 at 13: 6

Peak 1-in-10 = 1.68 ppb

Chronic 1-in-10 = 0.120 ppb

Simulation Avg = 0.442E-01 ppb

4-day avg 1-in-10 = 1.56 ppb

21-day avg 1-in-10 = 1.11 ppb

60-day avg 1-in-10 = 0.581 ppb

90-day avg 1-in-10 = 0.423 ppb

Benthic Pore Water Peak 1-in-10 = 0.357 ppb

Benthic Pore Water 21-day avg 1-in-10 = 0.352 ppb

Benthic Conversion Factor = 35.3 -Pore water (ug/L) to (total mass, ug)/(dry 

sed mass,kg)

Benthic Mass Fraction in Pore Water = 0.105E-01

YEAR Peak 4-day 21-day 60-day 90-day Yearly Avg Benthic Pk Benthic 21-day

 1 5.51E-02 4.90E-02 3.23E-02 1.82E-02 1.33E-02 3.92E-03 1.16E-02 1.14E-02

 2 2.77E-01 2.51E-01 1.69E-01 1.16E-01 9.16E-02 2.68E-02 6.99E-02 6.89E-02

 3 2.02E+00 1.79E+00 1.16E+00 5.93E-01 4.29E-01 1.21E-01 3.64E-01 3.59E-01

 4 7.23E-02 6.43E-02 4.25E-02 2.98E-02 2.63E-02 1.04E-02 2.70E-02 2.97E-02

 5 2.34E-01 2.13E-01 1.57E-01 9.47E-02 7.08E-02 2.12E-02 6.21E-02 6.11E-02

6 3.36E-01 2.99E-01 2.11E-01 1.15E-01 8.43E-02 2.47E-02 7.26E-02 7.16E-02

 7 3.25E-01 3.02E-01 2.29E-01 1.32E-01 9.69E-02 2.82E-02 7.92E-02 7.85E-02

 8 1.85E-01 1.64E-01 1.27E-01 7.85E-02 6.17E-02 1.91E-02 5.36E-02 5.28E-02

 9 1.16E+00 1.04E+00 6.98E-01 4.72E-01 3.60E-01 1.06E-01 2.95E-01 2.91E-01

10 2.83E-01 2.49E-01 1.71E-01 9.02E-02 6.54E-02 2.14E-02 6.04E-02 5.95E-02

11 1.15E-01 1.03E-01 6.71E-02 3.53E-02 2.64E-02 8.22E-03 2.26E-02 2.23E-02

12 4.77E-01 4.20E-01 2.93E-01 1.53E-01 1.11E-01 3.17E-02 9.46E-02 9.32E-02

13 2.82E-01 2.53E-01 1.75E-01 1.47E-01 1.12E-01 3.37E-02 9.17E-02 9.05E-02

14 4.35E-01 3.88E-01 2.65E-01 1.90E-01 1.51E-01 4.52E-02 1.15E-01 1.13E-01

15 5.34E-01 4.77E-01 3.09E-01 1.85E-01 1.36E-01 3.98E-02 1.11E-01 1.10E-01

16 1.13E+00 1.02E+00 6.84E-01 4.35E-01 3.25E-01 9.57E-02 2.70E-01 2.66E-01

17 8.80E-01 7.95E-01 5.75E-01 3.06E-01 2.34E-01 7.06E-02 2.05E-01 2.02E-01

18 4.25E-01 3.78E-01 2.47E-01 1.85E-01 1.39E-01 4.14E-02 1.12E-01 1.12E-01

19 4.77E-01 4.28E-01 3.40E-01 2.12E-01 1.79E-01 5.46E-02 1.26E-01 1.24E-01

20 2.89E+00 2.58E+00 1.70E+00 9.34E-01 6.88E-01 1.96E-01 5.50E-01 5.43E-01

21 1.78E-01 1.57E-01 1.10E-01 6.82E-02 5.09E-02 1.88E-02 4.87E-02 4.79E-02

22 4.74E-01 4.26E-01 2.83E-01 1.80E-01 1.35E-01 4.16E-02 1.18E-01 1.16E-01

23 1.74E+00 1.61E+00 1.20E+00 6.68E-01 5.03E-01 1.46E-01 3.93E-01 3.89E-01

24 1.44E-02 1.44E-02 1.51E-02 1.74E-02 1.98E-02 4.11E-03 3.16E-02 3.48E-02

25 7.78E-02 6.93E-02 4.55E-02 2.53E-02 2.10E-02 6.27E-03 1.45E-02 1.43E-02

26 3.27E-01 2.89E-01 2.48E-01 1.39E-01 1.01E-01 2.86E-02 8.58E-02 8.46E-02

27 9.59E-02 8.42E-02 6.60E-02 3.48E-02 2.53E-02 8.30E-03 2.36E-02 2.32E-02

28 5.14E-02 4.58E-02 3.37E-02 3.15E-02 2.57E-02 7.89E-03 2.07E-02 2.04E-02

29 2.84E-01 2.54E-01 1.71E-01 1.46E-01 1.15E-01 3.46E-02 9.04E-02 8.90E-02

30 3.82E-01 3.39E-01 2.64E-01 1.43E-01 1.03E-01 2.97E-02 8.88E-02 8.75E-02

************************************************************************************************
-Page 63 of 74-

Corn Scenario

Variable Volume Water Model, SWCC Compatible Version

*******************************************

Performed on: 8/17/2014 at 12:38

Peak 1-in-10 = 0.648 ppb

Chronic 1-in-10 = 0.327E-01 ppb

Simulation Avg = 0.137E-01 ppb

4-day avg 1-in-10 = 0.583 ppb

21-day avg 1-in-10 = 0.440 ppb

60-day avg 1-in-10 = 0.254 ppb

90-day avg 1-in-10 = 0.190 ppb

Benthic Pore Water Peak 1-in-10 = 0.162 ppb

Benthic Pore Water 21-day avg 1-in-10 = 0.160 ppb

Benthic Conversion Factor = 35.3 -Pore water (ug/L) to (total mass, ug)/(dry 

sed mass,kg)

Benthic Mass Fraction in Pore Water = 0.105E-01

YEAR Peak 4-day 21-day 60-day 90-day Yearly Avg Benthic Pk Benthic 21-day

 1 2.55E-02 2.29E-02 1.26E-02 4.42E-03 2.95E-03 7.59E-04 4.03E-03 1.85E-03

 2 3.78E-01 3.39E-01 2.40E-01 1.10E-01 7.35E-02 1.97E-02 9.32E-02 7.67E-02

 3 1.44E-01 1.50E-01 1.82E-01 1.56E-01 1.20E-01 2.07E-02 9.79E-02 9.69E-02

 4 5.97E-02 5.37E-02 3.68E-02 2.37E-02 1.90E-02 6.18E-03 1.49E-02 1.48E-02

 5 9.36E-01 8.36E-01 5.62E-01 2.38E-01 1.59E-01 4.63E-02 1.94E-01 1.72E-01

 6 2.29E-01 2.38E-01 3.49E-01 3.13E-01 2.37E-01 3.35E-02 1.96E-01 1.94E-01

 7 2.87E-01 2.58E-01 1.55E-01 5.44E-02 3.63E-02 1.03E-02 4.87E-02 2.59E-02

 8 1.23E-01 1.28E-01 1.75E-01 1.07E-01 8.19E-02 1.61E-02 6.27E-02 6.21E-02

 9 7.14E-01 6.43E-01 4.54E-01 1.83E-01 1.22E-01 3.20E-02 1.56E-01 1.30E-01

10 2.23E-01 2.33E-01 3.31E-01 2.62E-01 2.00E-01 3.12E-02 1.62E-01 1.60E-01

11 6.77E-01 6.11E-01 4.50E-01 1.93E-01 1.29E-01 3.28E-02 1.56E-01 1.34E-01

12 1.96E-01 2.04E-01 3.06E-01 2.56E-01 1.93E-01 2.65E-02 1.58E-01 1.57E-01

13 3.32E-02 3.03E-02 2.24E-02 1.43E-02 1.10E-02 3.89E-03 1.04E-02 1.03E-02

14 6.18E-02 5.58E-02 3.83E-02 1.39E-02 9.33E-03 4.49E-03 1.23E-02 8.89E-03

15 1.14E-01 1.03E-01 3.56E-02 2.27E-02 1.81E-02 5.57E-03 1.36E-02 1.35E-02

16 1.54E-01 1.39E-01 9.81E-02 4.06E-02 3.06E-02 1.35E-02 3.40E-02 2.51E-02

17 5.82E-02 6.07E-02 9.21E-02 6.01E-02 4.67E-02 7.87E-03 3.68E-02 3.65E-02

18 1.57E-01 3.83E-02 7.32E-03 2.59E-03 1.75E-03 1.39E-03 1.94E-03 1.67E-03

19 1.49E-01 1.42E-01 1.06E-01 6.25E-02 4.75E-02 1.77E-02 3.71E-02 3.68E-02

20 8.08E-02 8.49E-02 7.17E-02 5.06E-02 3.92E-02 9.63E-03 3.21E-02 3.18E-02

21 1.89E-02 1.74E-02 2.30E-02 1.73E-02 1.40E-02 2.81E-03 1.07E-02 1.07E-02

22 4.89E-02 4.39E-02 3.38E-02 1.49E-02 9.97E-03 2.67E-03 1.22E-02 9.91E-03

23 3.70E-02 3.38E-02 2.71E-02 2.62E-02 2.11E-02 4.61E-03 1.60E-02 1.59E-02

24 1.64E-01 1.47E-01 8.81E-02 3.09E-02 2.07E-02 7.11E-03 2.74E-02 1.45E-02

25 8.20E-02 7.88E-02 1.02E-01 6.03E-02 4.58E-02 1.13E-02 3.59E-02 3.56E-02

26 2.71E-01 2.45E-01 1.86E-01 6.88E-02 4.60E-02 1.50E-02 5.96E-02 3.36E-02

27 1.67E-01 1.75E-01 1.91E-01 1.24E-01 9.46E-02 1.89E-02 7.56E-02 7.49E-02

28 4.00E-02 3.59E-02 3.34E-02 1.92E-02 1.46E-02 4.47E-03 1.29E-02 1.27E-02

29 1.75E-02 1.61E-02 2.20E-02 1.64E-02 1.35E-02 2.84E-03 1.01E-02 9.96E-03

30 7.28E-03 6.54E-03 4.56E-03 2.95E-03 2.24E-03 7.52E-04 1.93E-03 1.91E-03

************************************************************************************************
-Page 64 of 74-

Appendix C. Example T-REX (v. 1.5) Input and Output for TCVP

Upper Bound Kenaga, Acute Avian Dose-Based EECs and Risk Quotients from T-REX

TCVP-Application Rate=34.8 lb ai/Acre and HL=13.3 days

Summary of Risk Quotient Calculations Based on Upper Bound Kenaga EECs

Table X. Upper Bound Kenaga, Acute Avian Dose-Based Risk Quotients

Size 

Class

(grams)

Adjusted

LD50

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

20 1038.45 9512.09 9.16 4359.71 4.20 5350.55 5.15 594.51 0.57 3725.57 3.59 132.11 0.13

100 1322.00 5424.20 4.10 2486.09 1.88 3051.11 2.31 339.01 0.26 2124.48 1.61 75.34 0.06

1000 1867.37 2428.49 1.30 1113.06 0.60 1366.02 0.73 151.78 0.08 951.16 0.51 33.73 0.02

Table X. Upper Bound Kenaga, Subacute Avian Dietary Based Risk Quotients

LC50

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

0 8352.00 N/A 3828.00 N/A 4698.00 N/A 522.00 ##### 3271.20 N/A

Size class not used for dietary risk quotients 

Table X. Upper Bound Kenaga, Chronic Avian Dietary Based Risk Quotients

NOAEC 

(ppm)

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

96 8352.00 87.00 3828.00 39.88 4698.00 48.94 522.00 5.44 3271.20 34.08

Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Acute Mammalian Dose-Based Risk Quotients 

Size 

Class

(grams)

Adjusted

LD50

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods Granivore
-Page 65 of 74-

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 3252.79 7962.99 2.45 3649.70 1.12 4479.18 1.38 497.69 0.15 3118.84 0.9588 110.6 0.034

35 2631.85 5503.49 2.09 2522.43 0.96 3095.71 1.18 343.97 0.13 2155.53 0.819 76.437 0.029

1000 1138.36 1276.00 1.12 584.84 0.51 717.75 0.63 79.75 0.07 499.768 0.439 17.722 0.0156

Table X. Upper Bound Kenaga, Acute Mammalian Dietary Based Risk Quotients

LC50 

(ppm)

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

0 8352.00 N/A 3828.00 N/A 4698.00 #DIV/0! 522.00 ##### 3271.20 N/A

Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Chronic Mammalian Dietary Based Risk Quotients

NOAEC 

(ppm)

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds/Large 

Insects Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

330 8352.00 25.31 3828.00 11.60 4698.00 14.24 522.00 1.58 3271.20 9.91

Size class not used for dietary risk quotients 

Table X. Upper Bound Kenaga, Chronic Mammalian Dose-Based Risk Quotients

Size 

Class

(grams)

Adjusted 

NOAEL

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 0.00 7962.99 N/A 3649.70 N/A 4479.18 ##### 497.69 N/A 3118.84 ##### 110.60 #####

35 0.00 5503.49 N/A 2522.43 N/A 3095.71 ##### 343.97 N/A 2155.53 ##### 76.44 #####

1000 0.00 1276.00 N/A 584.84 N/A 717.75 ##### 79.75 N/A 499.77 ##### 17.72 #####

Broadcast applications

Liquid

Intermediate Calculations

mg ai/ft2: 362.37

LD50 ft-2

wgt class (grams)

Avian 20 17.45

100 2.74

1000 0.19

Mammal 15 7.43

35 3.93

1000 0.32
-Page 66 of 74-

Appendix D. Example Terrplant (v. 1.2.2) Input and Output for TCVP

TerrPlant v. 1.2.2

Green values signify user inputs (Tables 1, 2 and 4). 

Input and output guidance is in popups indicated by red arrows.

Chemical Identity.

Chemical Name TCVP

PC code 83702

Use Poultry Droppings

Application Method Spray

Application Form Spray

Solubility in Water (ppm) 11.6

Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 34.8 lb ai/A

Incorporation I 1 none

Runoff Fraction R 0.02 none

Drift Fraction D 0.01 none

EECs for TCVP. Units in lb ai/A.

Description Equation EEC

Runoff to dry areas (A/I)*R 0.696

Runoff to semi-aquatic areas (A/I)*R*10 6.96

Spray drift A*D 0.348

Total for dry areas ((A/I)*R)+(A*D) 1.044

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 7.308

Seedling Emergence

Plant type EC25 NOAEC EC25

Monocot x x x

Dicot >6.09 x >6.09

Plant Type Listed Status Dry Semi-Aquatic

Monocot non-listed #VALUE! #VALUE!

Monocot listed #VALUE! #VALUE!

Dicot non-listed #VALUE! #VALUE!

Dicot listed #VALUE! #VALUE!
-Page 67 of 74-

Appendix E. STIR Results.

Input

Application and Chemical Information

Enter Chemical Name TCVP

Enter Chemical Use insecticide

Is the Application a Spray? (enter y or n) n

If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 365.96

Enter Chemical Vapor Pressure (mmHg) 1.08E-08

Enter Application Rate (lb a.i./acre) 0.7

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 2000

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 1.58

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 1480

Enter Lowest Rat Inhalation LC50 (mg/L) 3.61

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) 2.13E-04

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.67E-05

Adjusted Inhalation LD50 1.96E+01

Ratio of Vapor Dose to Adjusted Inhalation LD50 1.36E-06 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 not applicable not applicable

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 2.13E-04

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.36E-05

Adjusted Inhalation LD50 2.15E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 1.56E-07 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 not applicable not applicable
-Page 68 of 74-

Appendix F. SIP Results.

Table 1. Inputs

Parameter Value

Chemical name

Solubility (in water at 25oC; mg/L) 11.6

Mammalian LD50 (mg/kg-bw) 1480

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Mammalian NOAEL (mg/kg-bw) 0

Mammalian test species

Body weight (g) of "other" mammalian 

species

Avian LD50 (mg/kg-bw) 2000

Avian test species mallard duck

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 96

Bobwhite quail NOAEC (mg/kg-diet) 290

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) 1.9952 1.9952

Adjusted toxicity value (mg/kg-bw) 1138.3576 0.0000

Ratio of exposure to toxicity 0.0018 0.0000

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Due to insufficient data, 

risk cannot be precluded

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 9.3960 9.3960

Adjusted toxicity value (mg/kg-bw) 1038.4508 4.7628

Ratio of exposure to acute toxicity 0.0090 1.9728

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for birds

Exposure through 

drinking water alone is a 

potential concern for 

birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when 

aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water may contribute 

to a total exposure that has potential for effects to non-target animals.
-Page 69 of 74-

Appendix G. KABAM Results

Estimated concentrations of TCVP in ecosystem components.

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)* 2 N/A N/A N/A

Water (freely dissolved)* 2 N/A N/A N/A

Sediment (pore water)* 0 N/A N/A N/A

Sediment (in solid)** 12 N/A N/A N/A

Phytoplankton 261 13067 N/A 261.35

Zooplankton 192 6395 0.22 191.65

Benthic Invertebrates 201 6709 0.56 200.71

Filter Feeders 133 6642 0.36 132.49

Small Fish 260 6497 2.29 257.58

Medium Fish 262 6538 4.25 257.26

Large Fish 275 6873 7.62 267.32

* Units: μg/L; **Units: μg/kg-dw

0

50

100

150

200

250

300

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 70 of 74-

Total BCFand BAF values of TCVP in aquatic trophic levels.

Trophic Level

Total BCF 

(μg/kgww)/(μg/L)

Total BAF 

(μg/kgww)/(μg/L)

Phytoplankton 160 156

Zooplankton 114 114

Benthic Invertebrates 120 120

Filter Feeders 79 79

Small Fish 154 155

Medium Fish 154 156

Large Fish 160 164

Lipid-normalized BCF, BAF, BMF and BSAF values of TCVP 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 7992 7778 N/A 42

Zooplankton 3803 3807 0.49 21

Benthic Invertebrates 3985 3993 1.04 22

Filter Feeders 3945 3954 1.03 21

Small Fish 3839 3867 0.99 21

Medium Fish 3839 3892 0.99 21

Large Fish 3996 4091 1.05 22

Calculation of EECs for mammals and birds consuming fish contaminated by TCVP.

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 0.118 0.20

rice rat/star-nosed 

mole 0.1 0.107 0.484 0.011 0.096 0.20

small mink 0.5 0.079 0.293 0.048 0.077 0.26

large mink 1.8 0.062 0.229 0.168 0.060 0.26

small river otter 5.0 0.052 0.191 0.421 0.050 0.26
-Page 71 of 74-

large river otter 15.0 0.042 0.157 1.133 0.043 0.27

Avian

sandpipers 0.0 0.228 1.034 0.004 0.2057 0.20

cranes 6.7 0.030 0.136 0.211 0.0271 0.20

rails 0.1 0.147 0.577 0.010 0.1334 0.23

herons 2.9 0.040 0.157 0.120 0.0365 0.23

small osprey 1.3 0.054 0.199 0.069 0.0522 0.26

white pelican 7.5 0.029 0.107 0.228 0.0294 0.27

Calculation of toxicity values for mammals and birds consuming fish 

contaminated by TCVP.

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 3107.85 N/A 105.00 1000

rice rat/star-nosed 

mole 2108.26 N/A 71.22 1000

small mink 1389.87 N/A 46.96 1000

large mink 982.79 N/A 33.20 1000

small river otter 761.27 N/A 25.72 1000

large river otter 578.44 N/A 19.54 1000

Avian

sandpipers 1038.45 0.00 N/A 96

cranes 2483.95 0.00 N/A 96

rails 1253.13 0.00 N/A 96

herons 2190.74 0.00 N/A 96

small osprey 1930.94 0.00 N/A 96

white pelican 2526.33 0.00 N/A 96
-Page 72 of 74-

Calculation of RQ values for mammals and birds consuming fish 

contaminated by TCVP.

Wildlife Species

Acute Chronic

Dose 

Based

Dietary 

Based

Dose Based Dietary 

Based

Mammalian

fog/water shrew 0.000 N/A 0.001 0.000

rice rat/star-nosed 

mole 0.000 N/A 0.001 0.000

small mink 0.000 N/A 0.002 0.000

large mink 0.000 N/A 0.002 0.000

small river otter 0.000 N/A 0.002 0.000

large river otter 0.000 N/A 0.002 0.000

Avian

sandpipers 0.000 N/A N/A 0.002

cranes 0.000 N/A N/A 0.002

rails 0.000 N/A N/A 0.002

herons 0.000 N/A N/A 0.002

small osprey 0.000 N/A N/A 0.003

white pelican 0.000 N/A N/A 0.003
-Page 73 of 74-

Appendix H. Application Rate Estimation, Spot Application 

The following estimates were made considering Reg. No. 11556-162, Ravap EC, which appeared 

to have the largest container size of 5 gallons that an applicator might use.

For applications to kennels, yards and recreational areas, Reg. No. 11556-162 indicates to mix 1 

gallon of product with 50 gallons of water and that 1 gallon of diluted mixture treats 500 square 

feet. Based on this information, 5 gallons of product would be mixed with 250 gallons of water 

and the mixture would treat approximately 125,000 square feet, or roughly 2.9 acres. Given an 

application rate of 3.3 lbs a.i./A, the adjusted application rate over a 25 acre field would be 0.4

lbs a.i./A (3.3 lbs a.i./A x 2.9 A/25A).

For applications to residual surfaces, garbage dumps, and corrals, Reg. No. 11556-162 indicates 

to mix 1 gallon of product with 12.5 gallons of water and that 1 gallon of diluted mixture treats 

500 square feet. Based on this information, 5 gallons of product would be mixed with 62.5

gallons of water and the mixture would treat approximately 31,250 square feet, or roughly 0.7

acre. Given an application rate of 13.9 lbs a.i./A, the adjusted application rate over a 25 acre 

field would be 0.4 lbs a.i./A (13.9 lbs a.i./A x 0.7 A/25A).

For applications to residual surfaces, garbage dumps, and corrals, Reg. No. 11556-162 indicates 

to mix 1 gallon of product with 25 gallons of water and that 1 gallon of diluted mixture treats 

100 square feet. Based on this information, 5 gallons of product would be mixed with 125

gallons of water and the mixture would treat approximately 12,500 square feet, or roughly 0.3

acres. Given an application rate of 33.3 lbs a.i./A, the adjusted application rate over a 25 acre 

field would be 0.4 lbs a.i./A (34.8 lbs a.i./A x 0.35 A/25A).
-Page 74 of 74-

Appendix I. Communication with Registrant Re: Use of TCVP Oral Larvicide at Feedlots

From: Bruce Bernard [mailto:bernard@sra-intl.com] 

Sent: Tuesday, July 22, 2014 8:24 PM

To: Ballard, Kelly

Subject: TCVP Manure Issue

Dear Kelly,

With regard to your issue 2, we have investigated your question concerning the use of Rabon 

Oral Larvicide (ROL) in cattle housed in feedlots. This is what we found:

1. Only 2% of cattle in feedlots are fed some sort of oral larvicide.

2. ROL market-share of that 2% is less than 1%. (The reason for this is easy to determine. Beef 

feedlot managers are typically most concerned with house flies and stable flies. Although the 

product is registered for control of several flies, ROL is primarily used to control face flies 

and horn flies; control of house and stable flies can be achieved more economically through 

methods other than ROL, like pour-ons and sprays).

3. Confined beef producers typically use more corn and forage than they can produce. It would 

be safe to assume that 99% of the manure from confined beef farms is applied to land 

producing crops intended to be fed back to their animals. 

4. In a previous submission (discussed at the meetings with Lois Rossi), the previous registrant 

(KMG) evaluated over 20 years of USDA and FDA survey data and in all that time there 

have never been any detections of residues of TCVP or its metabolites in meat.

I trust this is the information you were looking for.

Sincerely,

Bruce Bernard

Authorized Representative of 

Bayer HealthCare

(202.422.5920)