Page 1 of 28 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 **OFFICE OF CHEMICA**  **L SA FETY A**  **ND POLLUTION PREVENTION** 
**MEMORANDUM Date**  **:** October 7 , 2010 **SUBJECT:** T etrachlorvinphos. Cattle Oral/Dermal and Poultry Dermal Stud ies . Summary of Residue Data Submitted in Support of Reregistration. **PC Code s**  **:** 083701/083702 **DP Barcode s**  **:** D 320848 , D320858 , D320859, and 381350 **Decision No s**  **.:** 359964, 359967, 386529 **Registr ation No.**  **:** None **Petition No.:** NA **Regulatory Action:** Other Reregistration **Risk Assessment Type: NA**  **Case No.:** 0321 **T XR No.:**  NA **CAS No.:** 22248 - 79 - 9 **MRID No s**  **.:** 47193001 , 47369201, and 47589301 **40 CFR:** § 180. 252 From: Christine L . Olinger, Che mist Risk Assessment Branch VI I Health Effects Division (7509P) Through: Donna S. Davis Chemist

Risk Assessment Branch VI I Health Effects Division (7509P) Michael S. Metzger, Chief Risk Assessment Branch VI I Health Effects Division (7509P) To: James Parker Risk Management and Implementation Branch I Pesticide Re
- evaluation Division (7508P) This document was originally prepared under contract by Dy namac Corporation ( 1901 Research Boulevard, Suite 220 ; Rockville, MD 20850).Page 2 of 28

Dy namac QC Reviewer: Date: 04/01/2009

Sandra Hastings Dy namac Program Manager: Date: 04/01/2009

Danilo Martinez The document has been reviewed by the Health Effects Division (HED) and revised to reflect current Office of Pes t icide Programs (OPP) policies.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 3 of 28 **Executive Summary** Tetrachlorvinphos is an insecticide registered for use as a feed
- through (oral) larvicide for livestock and for direct treatment of beef cattle, dairy cattle, horses, poultry , swine , and livestock premises to control nuisance and public health pests such as flies . No plant uses of tetrachlorvinphos are currently registered. EPA has completed its reregistration eligibility review and decisions on tetrachlorvinphos (EPA 738 - R - 95 - 041 , September 1995 ) . The R esidue Chemistry Science Chapter for Tetrachlorvinphos Reregistration Eligibility

Decision ( RED ) was issued 7/6/ 94 (DP# 199644, F. Suhre). According to the Residue Chemistry Chapter, the formulations registered for use on animals include the granular (G), wettable powder (WP), impregnated material (Impr), dust (D), ready
- to - use (RTU), and emulsifiable concentrate (EC). These formulations may be applied directly

as a spray , backrubber solution, dust
- bag, and dust. The G formulation s are registered as feed supplement s to control fecal fl ies (oral larvicide); the D, WP and EC formulations are registered for animal premise treatments , and

/or topical treatments . In response to the Tetrachlorvinphos RED , KMG Bernuth, Inc., has submitted the results of magnitud e of the residue studies on cattle and poultry as well as a storage stability study and a residue analy

tical method . These studies have been reviewed by HED. This document summarizes the adequacy of these data in fulfilling reregistration requirements. Itis noted that the Tetrachlorvinphos RED also required a new magnitude of the residue study on swine which remains outstanding. The swine study was required in lieu of a swine metabolism study . For the purpose of this action, the end
- use product labels registered to KMG Bernuth were re - examined . Based on the results of the reviewed studies, HED is requiring label revisions for certain products . Tolerances for residues of tetrachlorvinphos are established under 40 CFR §180.252. The current tolerance e xpression is for the combined residues of tetrachlorvinphos [(Z)
- 2 - chloro
- 1 - (2,4,5
- trichlorophenyl)vinyl dimethyl phosphate] and its metabolites, 1
- (2,4,5
- trichlorophenyl)
- ethanol (free and conjugated forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4,5
- trich lorophenyl)
- ethanediol . Time limited t etrachlorvinphos tolerances are established for the animal commodities under 40 CFR §180.252 and were based on the available metabolism data . Inthe RED HED recommended time
- limited tolerances to allow time for the r egistrant to submit new magnitude of residue studies. There are no Codex maximum residue limits (MRL s) established or proposed for residues of tetrachlorvinphos. The qualitative nature of the residue in ruminants following oral or dermal dosing, and in p oultry following dermal application is adequately understood based on previously submitted studies . The Agency has determined that the residues of concern are tetrachlorvinphos, des
- O - methyl tetrachlorvinphos, 1
- (2,4,5
- trichlorophenyl)ethanol (free and co njugated forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4 ,5 - trichlorophenyl)ethanediol. A gas liquid chromatography (GLC) method for the determination of tetrachlorvinphos per se in animal commodities is described in the Pesticide Analy tical Method (PAM), Vol. I I, as Method I . The registrant ha s submitted a method for the determination of tetrachlorvinphos and itsTetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 4 of 28 metabolites , which uses LC /MS/MS, L C/MS, GC/ECD, and GC/MS methods. An independent laboratory

val idation (ILV) must be submitted. Samples coll ected from the animal studies were analy zed for all tetrachlorvinphos residues of c oncern using LC/MS/MS, LC/MS, GC/ECD or GC/MS methods. The limit of quantitation was 0.01 ppm for each analy

te and was defined as the lowest fortification level at which ac ceptable recovery data are obtained . The methods used for analys i s of cattle matrices w ere adequately validated by

fortifying control matrices wi th each analy te at 0.01 - 0.6 ppm , while the method for the poultry

matrices w as validated at 0.01 and 0.1 ppm . No data pertaining to the behavior of regulated tetrachlorvinphos metabolites using FDA's multiresidue protocols have been submitted. As requested in the 1994 Residue Chemistry Chapter, the regulated metabolites of tetrachlorvinphos should be analy zed using the FDA multiresidue protocols as appropriate to ascertain if the methods are capable of accurately quantifying all residues of concern. Samples collected from the magnitude of the residue study on cattle were stored frozen for up to 50 days for mil k and cream, 54 days for liver, fat, and kidney , and 63 days for muscle prior to residue analysis. Samples collected from the magnitude of the residue study on poultry

were estimated (information regarding dates of sample collection and analysis was not p rovided) to be stored frozen for up to 144 days for eggs and 59 days for tissues prior to analysis. Although a companion storage stability study was included in support of the cattle study , the submitted data were deemed inadequate because of the study de sign. S elected samples of various matrices were re - assayed after the initial analysis. C onsiderable degradation may have occurred prior to the initial analysis of storage stability samples. Many

of the matrices did not have quantifiable residues of one or more of the analy tes at the time of initial analysis, so potential degradation upon storage cannot be accurately assessed. A new storage stability study should be conducted with quantifiable ( i.e., fortified) residues of all analy tes in all cattle and poultry matrices. In addition, the registrant needs to submit information pertaining to dates of treatment, collection, extraction, and analysis to verify the maximum storage intervals of all samples collected from both the cattle and poultry studies. Th e submitted magnitude of the residue study on cattle is inadequate but upgradeable pending submission of supporting storage stability data. The residue data reflect a combination of two treatments: oral administration of tetrachlorvinphos for 29
- 31 day s at actual rates of 1.512
- 1.555 and 4.630 g ai/750 kg BW per day (6.3
- 6.5x and 19.3x, respectively , the maximum registered rate of 0.24 g ai/750 kg BW for feed
- through treatment) and dermal spray treatments on three occasions, at ~14 day

intervals, at actua l rates of 10.111 and 19.166
- 19.493 g ai per animal per dose (~0.5 and 1.0x, respectively , the maximum registered rate of 18.9 g ai/animal for direct animal spray

treatment). At the treatment regime approximating the registered uses ( 6.5x oral + 1x dermal ), the maximum total residues of concern (with the maximum residues of the parent in parenthes e s) were: 0.072 (0.036) ppm for milk, 0.078 (<0.01) ppm for cream, 0.158 (<0.01) ppm for liver, 0.278 (0.015) ppm for kidney , 0.272 (0.212) ppm for muscle, 0.842 (0.558) ppm for subcutaneous fat, and 0.747 (0.340) ppm for peritoneal fat. These data will support the registered feed
- through (oral) and direct animal spray uses of tetrachlorvinphos on cattle. The submitted magnitude of the residue study on poultry

i s inadequate but upgradeable pendingTetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 5 of 28 submission of storage stability data/information. The residue data reflect 6
- 7 dermal spray treatments of laying hens with an EC formulation, made at two
- week retreatment intervals, at rates of 0.0908, 0.1816, or 0.544 8 g ai/hen/application. These application rates, respectively, correspond to ~0.5x, 1.0x, or 2. 9 x the maximum registered direct spray treatment rate of 0.19 g ai/bird daily . At ~1.0x, the maximum total residues of concern (with the maximum residues of th e parent in parenthes e s) were: 0.288 (0.026 ) ppm for egg, 0.517 (0.016) ppm for liver, 0.583 (0.022) ppm for kidney , 0.396 (0.082 ) ppm for muscle, 19.405 (6.030) ppm for skin with fat, and 1.298 (0.099) ppm for abdominal fat. No data were submitted ref lecting application of tetrachlorvinphos as a backrubber treatment, direct animal dusting and/or premise spray treatment; also no data were submitted directly reflecting the use of cattle ear tag uses which may still be registered to other companies. The OPPTS 860.1480 Guideline states that when a pesticide may be applied by

more than one mode of treatment, separate studies are required ; however, only oral and dermal spray

studies were required in the TCVP RED . B ecause the oral and dermal treatments are e xpected to result in the highest residue levels, no additional data will be required to support backrubber or premise spray treatments . Data from wetting sprays may be accepted in lieu of data from dust treatments. Analy tical standards for tetrachlorvinp hos are currently available in the EPA National Pesticide Standards Repository ; however, no reference standards are available for the metabolites which are also regulated (TCVPdeme, TCPEone, TCPEol, and TCPEdiol). **Regulatory Recommendations and Residue Ch emistry Deficiencies**  The submitted magnitude of the residue studies on cattle and poultry are inadequate but upgradeable. Since a swine magnitude of residue study has not been submitted, the existing time limited tolerances based on the goat metabolism s tudy should remain until the new study has been submitted. The poultry and cattle tolerances will need modification; refer to Table 9 for tolerance reassessment summary . Itis noted that the metabolite des
- O - methyl tetrachlorvinphos is not included in th e current tolerance expression as determined by the Agency ; therefore 4 0 CFR §180.252 should be amended to include the TCVPdeme metabolite. HED recommends that the tolerance definition should be modified as follow s . Tolerances are established for residu es of the insecticide tetrachlorvinphos , including its metabolites and degradates, in or on the commodities in the table below. Compliance with the tolerance levels specified below is to be determined by measuring only

the sum of tetrachlorvinphos [(Z)
- 2 - chloro
- 1 - (2,4,5
- trichlorophenyl)vinyl dimethyl phosphate ) and its metabolite s c hloro
- 1 - (2,4,5
- trichlorophenyl)
- vinylmonomethyl phosphate, 1 - (2,4,5
- trichlorophenyl)
- ethanol (free and conjugated forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4,5
- trichloroph enyl)
- ethanediol , calculated as the stoichiometric equivalent of tetrachlorvinphos , in or on the commodity . A list of the outstanding residue chemistry deficiencies is presented below.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 6 of 28 860.1200 Directions for Use

• Based on the magnitude of the resid ue study on cattle , the product labels with direct animal spray

uses on cattle (EPA Reg. Nos. 61483
- 43 and 61483
- 50) should be amended to specify a maximum of three applications, with two - week retreatment intervals , at 19 g ai / animal/ dose. The product lab el for Ravap ( EPA Reg. No. 61483 - 50) should also be amended to provide conversion factors to allow calculation of direct animal spray treatment rate in terms of g ai/animal.

• Based on the magnitude of the residue study on poultry , the product labels wi th direct animal spray

uses on poultry

(EPA Reg. Nos. 61483
- 43 and 61483
- 50) should be amend ed to specify

a maximum of seven applications (with two - week retreatment intervals) at 0.18 g ai/hen/application. Note that the label should specify the weight or volume of the product to be applied. 860.1340 Residue Analy

tical Methods

• An Independent Laboratory Validation (ILV) must be submitted for the proposed tolerance enforcement method. 860.1360 Multiresidue Methods

• No data pertaining to the behavior of regulated tetrachlorvinphos metabolites using FDA's multiresidue protocols have been submitted. As requested in the 1994 Residue Chemistry Chapter, the regulated metabolites of tetrachlorvinphos should be analy zed by the FDA multiresidue protocols as a ppropriate to ascertain that the methods are capable of accurately

quantifying all residues of concern. See Decision Tree for MRM in Appendix II - 2 of PAM Vol. Ifor more information. 860.1380 Storage Stability

• New storage stability stud ies should be c onducted with quantifiable ( i.e., fortified) residues of all analy

tes in all cattle and poultry matrices. In addition, the registrant needs to submit information pertaining to dates of treatment, collection, extraction, and analysis to verify the maximum storage intervals of all samples collected from both the cattle and poultry studies. 860.1480 Meat, Milk, Poultry , and Eggs

• A magnitude of the residue study on swine is required. 860.1650 Submittal of Analy tical Reference Standards

• The registrant must submit reference standard s for the TCVP regulated metabolites (TCVPdeme, TCPEone, TCPEol, and TCPEdiol) t o the Analy tical Chemistry

L ab.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 7 of 28 **Background** The chemical names and structures of the regulated residues are presented in Table 1. The phy sicoche mical characteristics of the technical grade of tetrachlorvinphos are presented in Table 2. **T able**  **1. T**  **est Com pound Nom**  **enclature.** Compound P O O H 3 C O O C H 3 Cl

Cl Cl

Cl

Common name Tetrachlorvinphos Company experimental name TCVP IUPAC name (Z)
- 2 - chloro
- 1 - (2,4,5
- trichlorophenyl) vinyl dimethyl phosphate CAS registry number 22248 - 79 - 9 End
- use products registered to KMG Bernuth, Inc. Rabon 50 WP Insecticide (EPA Reg. No. 61483
- 43, 50% WP); Rabon 3% Insecticide Dust EPA Reg. No. 61483
- 45, 3% D); Rabon 97.3 Oral Larvicide (EPA Reg. No. 61483
- 47, 97.3% G); Rabon 7.76 Oral Larvicide Premix (EPA Reg. No. 61483
- 48, 7.76% G); and Ravap EC Livestock, Poultry & Premise Insecticide Spray (EPA Reg. No. 61483
- 50, 23% EC) Compound P O O H O O C H 3 Cl

Cl Cl

Cl O

H C H 3

Cl Cl

Cl

Common name TCVPdeme TCPEol Chemical name des
- O - methyl tetrachlorvinphos 1 - (2,4,5
- trchlorophenyl)ethanol Compound O C H 3

Cl Cl

Cl O

H Cl Cl

Cl O H

Common name TCPEone TCPEdiol Chemical name 2,4,5 - trichloroacetophenone 1 - (2,4 ,5 - trichlorophenyl)ethanediol **T able**  **2. Phy**  **sicochem ical Properties of the**  **Technical Grade Test Com pound:**  **Tetrachlorvinphos .**  Parameter Value Reference 1 Melting point/range 94.5 oC (MRID 41222503) pH 5.5; 1% solution (MRID 41222503) Density 0.83 g/mL (MRID 41222503) Water solubility ( 25 °C) 0.00116 g/100g (MRID 41222503)Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 8 of 28 **T able**  **2. Phy**  **sicochem ical Properties of the**  **Technical Grade Test Com pound:**  **Tetrachlorvinphos .**  Parameter Value Reference 1 Solvent solubility (mg/100mg at 25°C) chloroform 80 methanol 21 acetone 44 hexane 0.8 toluene 28 (MRID 41222503)

Vapor pressure ( 25 °C) 2.6 x 10 - 7 mm Hg (MRID 41222503) Di ssociation constant, pKa non - ionizable (MRID 41222503) Octanol/water partition coefficient, Log(KOW) 3350 average KOW at 25 oC (MRID 41222503) UV/visible absorption spectrum Not available 1 Cited reference was reviewed under CB No. 7468, 4/3/91, R. Pe rfetti. **860.1200 Directions for Use** A search of EPA’s PPL S database conducted 02/04/2009 identified f ive tetrachlorvinphos end
use products registered to KMG Bernuth, Inc. for use as an oral larvicide for livestock or direct treatment of beef cattle, la ctating cattle , horses, poultry , swine, and livestock premises. These products are listed in Table 3A. Only those end
- use products registered to the technical registrant, KMG - Bernuth , are considered in this table. **T able**  **3A. List of**  **Tetrachlorvinphos E**  **nd -**  **Use Products Registered**  **to KMG Bernuth, Inc.** Trade Name EPA Reg. No. Acceptance Date ai (% of f ormulation ) Formulation Type Rabon 50 WP Insecticide 61483 - 43 4/17/2006 50% WP Rabon 3% Insecticide Dust 61483 - 45 10/23/2008 3% D Rabon 97.3 Oral Larvicid e 61483 - 47 09/18/2007 97.3% G Rabon 7.76 Oral Larvicide Premix 61483 - 48 05/04/2006 7.76% G Ravap EC Livestock, Poultry & Premise Insecticide Spray 1 61483 - 50 11/30/2007 23% EC 1 Also contains 5.3% dichlorvos. The tetrachlorvinphos products listed above may be applied directly

to livestock via various methods or used as a feed
- through (oral supplement) . It may also be applied to their living quarters. A summary

of the directions for use for ruminants , poultry , and swine, which are the subject of the re sidue data reviewed herein, are presented in Table 3B . Example calculations for application rates are presented in Table 3C for the product, Rabon 50 WP Insecticide ( EPA Reg. No. 61483 - 43 ), that leads to the maximum application rate. **Table 3B**  **. Summary**  **of Registered**  **Directions for Use of Tetrachlorvinphos .**  **1** Applic ation Ty pe /Mode Formulation

[ EPA Reg. No. ] Application Rate Use Directions and Limitations **Cattle, Beef** Direct animal spray 50% WP [61483 - 43] 0.5 - 1 .0 gal of 0.35
- 0.5%

solution/animal; (equi valent to a maximum rate of 18 .9 g ai/animal ) Apply as a low pressure coarse spray and apply only to point before runoff. No retreatment restrictions are specified. There is no withholding period from last application to slaughter.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 9 of 28 **Table 3B**  **. Summary**  **of Registered**  **Directions for Use of Tetrachlorvinphos .**  **1** Applic ation Ty pe /Mode Formulation

[ EPA Reg. No. ] Application Rate Use Directions and Limitations 23% EC [61483 - 5 0] 0.5 - 1.0 gal of a spray

solution per animal with spray solution made by diluting 1 gal of 23% EC in 75 to 200 gal of water (equivalent to 11 g ai/animal ) Do not treat more often than every 10

days. Do not apply to calves under 6 mo nths of age. Brahman and Brahman
cross cattle should not be treated as they may show hypersensitivity to organophosphate pesticides. Do not apply in combination with other organophosphate pesticides (e.g., trichlorfon). There is no withholding period from last application to slaughter. Feed through (oral) 7.76% G [61438 - 48 ] 70 mg/100 lb BW/day

(equivalent to 0.24 g ai/750 kg B W) For use as an oral larvicide in cattle

feeds to prevent the development of flies in the manure of treated cattle. Concentrate must be mixed with f eed. Direct animal dusting 3% D [61483 - 45] 1.7 - 3.4 g ai/animal Apply to the upper portions of the back, neck, and poll by hand dusting or self
- treating dust bag. Repeat as necessary. **Cattle, Lactating** Direct animal spray 23% EC [61483 - 50] 0.5 gal of a spray solution

per animal with the spray solution made by diluting 1 gal of 23% EC in 200 gal of water (equivalent to 4 g ai/animal) Repeat as necessary (general label

directions specify do not apply more than once a day) . Do not apply to calves under 6 months of age. No milk discard is required. Care should be taken that the spray does not come in direct contact with the cow’s teats unless they are washed with an approved cleansing solution and dried before milking. Apply the spray at least 20 minutes prior to milking or after milking has been completed. Feed through (oral) 97.3% G [61483 - 47] 7.76% G [61438 - 48] 70 mg/100 lb BW/day

(equivalent to 0.24 g ai/750

kg BW For use as an oral larvicide in cattle

feeds to prevent the development of flies in th e manure of treated cattle. Concentrate must be mixed with feed. Direct animal dusting 3% D [61483 - 45] 1.7 - 3.4 g ai/animal Apply to the upper portions of the back, neck, and poll by hand dusting or self
- treating dust bag. Repeat as necessary. **Poultry** Direct animal spray 50% WP [61483 - 43] 1.0 gal of 0.5%

solution/100 birds (equivalent to a maximum rate of 0.19 g ai/bird) Spray the vent and fluff of wire cages from below. Repeat when necessary but do not repeat more than every 14 days. 23% EC [614 83 - 50] 1.0 gal of a spray solution

per 100 birds with the spray solution made by diluting 1 gal of 23% EC in 50 gal of waterTetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 10 of 28 **Table 3B**  **. Summary**  **of Registered**  **Directions for Use of Tetrachlorvinphos .**  **1** Applic ation Ty pe /Mode Formulation

[ EPA Reg. No. ] Application Rate Use Directions and Limitations Direct animal dusting 3% D [61483 - 45] 0.03 lb ai/300 birds For individual treatment of poultry in wire cages. Direct dust to vent and fluff area. Group treatment may be preferred. Dust should reach skin. Wire rungs and corners should also be treated. **Swine** Direct animal spray 50% WP [61483 - 43] 0.25 to 0.5 gal of 0.5%

solution/animal (equivalent to a maximum rate of 9.5 g ai/animal) Apply as a low pressure coarse spray and apply only to point before runoff. Repeat in 2 weeks if necessary. There is no withholding period from last application to slaughter. Feed through (oral) 7.76% G [61438 - 48] 22.7 mg/1000 lb BW;

0.077 g ai /750 kg BW For use as an oral larvicide in swine feeds to prevent the development of flies in the manure of treated cattle. Concentrate must be mixed with feed. Direct dusting of animal 3% D [61483 - 45] 2.6 - 3.4 g ai/animal Apply by conventional hand or power duster to each animal with special attention given to the neck and around the ear. **Horses** Feed through (animal supplement) 7.76% G [61438 - 48] 5.4 mg ai/100 lb BW/day For use as an oral larvicide in horse feeds to prevent the development of flies in the manure of treated cattle. Concentrate must be mixed with feed. The product is not to be used for horses designed for slaughter. 1 Note: Application rates for backrubber and premise treatments are not included in this table as they are likely to l ead to lower exposure than the direct application via sprays and dusts. Only the use directions from products registered by the technical registrant, KMG
- Bernuth, are included. **Table 3C.**  **Calculation of Application Rates for Direct Anim al Spray (EPA Reg**  **. No. 61483 -**  **43) 1**  Pounds Product Percent of ai

in Product V olume

W ater , G allons Solution

Percenta ge V olume

A pplied to Animal, Gallons Application

Rate, lb ai/animal 2 Application

Rate, g ai/animal 3 0.5 50 9 0.35 1 0.0 3 1 3 .6 0.5 50 6 0.5 1 0 .041 7 18.9 0 .5 50 6 0.5 0.5 0.021 9.5 2 50 36 0.35 1 0.02 78 12.6 2 50 25 0.5 1 0.04 18.2 4 50 75 0.35 1 0.0267 12.1 4 50 50 0.5 1 0.04 18.2 8 50 150 0.35 1 0.0267 12.1 8 50 100 0.5 1 0.04 18.2 1 The lb product, % ai, volume values were obtained directly from the label. 2 Calculated by the following formula: (lb product x % ai in product x volume applied to animal)/volume water in spray solution . 3 Calculated by the following formula: lb ai /animal x 454 g/lb . Conclusions . The end
- use product labels of KM G Bernuth, Inc. were examined and are deemed adequate to allow evaluation of the residue data relative to the registered animal use patterns.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 11 of 28 Based on the magnitude of the residue study on cattle , the product labels with direct animal spray uses on cattle ( EPA Reg. No s . 61483 - 43 and 61483
- 50) should be amended to specify a maximum of three applications , with two
- week re treatment intervals , at 19 g ai / animal/ dose. The product label for Ravap ( EPA Reg. No. 61483 - 50) should also be amended to provide convers ion factors to allow calculation of direct animal spray treatment rate in terms of g ai / animal. Based on the magnitude of the residue study on poultry , the product labels with direct animal spray uses on poultry

(EPA Reg. Nos. 61483
- 43 and 61483
- 50) sho uld be amended to specify a maximum of seven applications ( with two
- week re treatment intervals) at 0.18 g ai/hen/application. Note that the labels should state the amount of product (weight or volume) to be applied to the animal so the applicator will not have to calculate the amount of product equivalent to 0.18 g ai/animal. **860.1300 Nature of the Residue -**  **Plants** There are no registrations or tolerances for plant commodities, so these studies are not required for tetrachlorvinphos. **860.1300 Nature of the Residue**  **- Livestock**  Residue Chemistry Memo: DP# 243528, 3/11/98, D. Miller Residue Chemistry Memo: DP# 206721, 9/21/94, D. Miller (Addendum to RED) Residue Chemistry Chapter to Tetrachlorvinphos RED ( D P# 199644, 7/6/94 , F. Suhre ) Residue Chemistry M emo: J. Abbotts , No DP# , 4/93, Results of Metabolism Committee Meeting The qualitative nature of the residue in ruminants following oral or dermal dosing, and in poultry following dermal application is adequately understood based on previously submitted studies. The Agency

has determined that the residues of concern are tetrachlorvinphos, des
- O - methyl tetrachlorvinphos, 1
- (2,4,5
- trichlorophenyl)ethanol (free and conjugated forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4,5
- trichlorophenyl)ethanediol. Th e metabolism of tetrachlorvinphos in ruminants and poultry differs somewhat . The metabolites des
- O - methyl tetrachlorvinphos and 1
- (2,4,5
- trichlorophenyl)ethanediol are found only in hens, and the metabolite 1
- (2,4,5
- trichlorophenyl)ethanol is found only i n goats (following both oral and dermal administration). The difference in metabolic profiles between goats and swine, both mammals, would be expected to be less significant than the difference between goat and hens. Therefore, the requirements for swine metabolism studies have been waived, provided that a magnitude of the residue study with swine is conducted including analysis of all residues of concern. The HED Metabolis m Committee has determined that the residues of concern are tetrachlorvinphos, des
- O - methyl tetrachlorvinphos, 1
- (2,4,5
- trichlorophenyl)ethanol (free and conjugated forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4,5
- trichlorophenyl)ethanediol. Time
limited tolerances for livestock commodities, based on feed
- through and direct dermal use s on livestock, were estimated by the Agency

from the acceptable metabolism data. Permanent tolerances are to be established when adequate magnitude of the residue data for ruminants, swine and poultry

are available.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 12 of 28 **860.1340 Residue Analytical Methods** Residue Chemistry Chapter to Tetrachlorvinphos RED ( D P# 199644, 7/6/94 , F. Suhre ) DER Reference List : 47369201 .der.doc Tolerance Enforcement Methods Analy tical methods for plant commodities are not required because there are no tetrachlorvinphos end
- use products registered for use on any plant commodity . The registrant has submitted a method for tolerance enforcement of livestock commodities (MRID 47369201 , 2007) . This method involves the extraction of TCVP and its four major metabolites from tissues, milk and cream using acetonitrile and the removal of lipid interferences using partition with hexane and a C18 solid phase extraction (SPE) cartridge. TCVP, TCVPdeme and TCPEdiol are isolated on the C18 cartridge and are quantified using liquid chromatogr aphy

with mass spectrometric detection (L C - MS). TCPEone and TCPEol are further cleaned up with an ENVI
- CARB cartridge before quantitation using gas chromatography with electron capture detection (GC
- ECD). Conjugated TCPEol and TCPEdiol are extracted from the initial acetonitrile extract using saturated sodium chloride solution and liberated by hydroly zing overnight under acidic conditions. Further clean up is performed using an ENVI
- CARB cartridge prior to quantitation by GC - ECD (TCPEol) or L C - MS (TCPEdi ol). The method was validated by SRA International using quintuplet sets of control samples of bovine muscle, bovine liver, bovine kidney , bovine fat, milk and cream fortified with TCVP, TCVPdeme, TCPEol, TCPEone and TCPEdiol at 10 and 100 ppb. Individ ual recoveries from fortified samples ranged from 70% to 110%. Standard deviations for each crop/spiking level were no higher than 15%. An independent laboratory validation (ILV) trial has not been submitted to HED for review and radiovalidation data w ere not provided with this method validation trial. Since the extraction scheme is similar to those employed in the metabolism study , and the tissues from the metabolism study

are not likely

still available, the requirement for radiovalidation data is wai ved. Data Collection Methods Egg, m ilk and tissue samples from the cattle and poultry magnitude of the residue stud ies were analy zed for residues of tetrachlorvinphos, (TCVP), des
- O - methyl tetrachlorvinphos (TCVPdeme), 1
- (2,4,5
- trichlorophenyl)ethanol (T CPEol ; free and conjugated), 2,4,5
- trichloroacetophenone (TCPEone), and 1
- (2,4,5
- trichlorophenyl)ethanediol (TCPEdiol ; free and conjugated) using LC/MS, LC/MS/MS, GC/ECD , or GC/MS method s . Briefly , samples were initially extracted with acetonitrile (ACN), and lipid interferences were removed by partitioning with hexane and C18 solid phase extraction (SPE) cartridge.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 13 of 28 TCVP, TCVPdeme, and TCPEdiol were isolated on a C18 cartridge a nd quantified using LC /MS or LC /MS/MS. Separate LC conditions were used for e ach analy te. Quantitation of TCVP residues wa s performed using an e lectrospray interface in the positive ion mode . Quantitation of TCVPdeme resi dues wa s performed using an e lectrospray interface in the negative or positive ion mode . Quantitation of TCPE diol resi dues was performed using LC /MS with an e lectrospray interface in the negative ion mode . TCPEone and TCPEol were further cleaned up by Envicarb cartridge b efore quantitation using GC/ECD or GC/MS . Conjugated TCPEol and TCPEdiol were extracted fro m the initial acetonitrile extract using a saturated sodium chloride solution and liberated by hydroly zing overnight under acidic conditions. Further clean
- up is performed by Envicarb cartridge prior to quantitation by

GC/ECD or GC/MS (TCPEol) or L C/MS (T CPEdiol). The LOQ was 0.01 ppm for each analy te and was defined as the lowest fortification level at which acceptable recovery data are obtained. The estimated limit of detection (L OD) was 0.002 ppm for TCVP (and TCVPdeme in poultry matrices) , 0.005 ppm for TCPEdiol, and 0.0 025 ppm for all other analy

tes . Concurrent method recoveries were within the acceptable range of 70
- 120%. Conclusions . A tolerance enforcement method has been submitted, but the requirement for an ILV remains outstanding. Samples c ollected from the animal studies were analy zed for all tetrachlorvinphos residues of concern using LC/MS/MS, L C/MS , GC/ECD, or GC/MS methods. The limit of quantitation was 0.01 ppm for each analy te and was defined as the lowest fortification level at whic h acceptable recovery data are obtained . The methods used for analys i s of cattle matrices w ere adequately validated by fortifying control matrices with each analy te at 0.01 - 0.6 ppm . However, the poultry methods w ere only

verified at fortification levels of 0.01 and 0.1 ppm. Adequate dilutions were used, so no further validation data are required. **860.1360 Multiresidue Methods** Residue Chemistry Chapter to Tetrachlorvinphos RED ( D P# 199644, 7/6/94 , F. Suhre ) The FDA PESTDAT A database dated 8/93 (PAM Vo l. I , Appendix I I) indicates that tetrachlorvinphos is completely recovered (>80%) using FDA multiresidue method protocol D (section 232.4) but is not recovered using protocol E (Sections 211.1/231.1 and 212.1/232.1, fatty and nonfatty

matrices ) . No data pertaining to the behavior of regulated tetrachlorvinphos metabolites using FDA's multiresidue protocols have been submitted. As requested in the 1994 Residue Chemistry

Chapter, the regulated metabolites of tetrachlorvinphos should be analy zed by the FDA multiresidue protocols as appropriate to ascertain if the methods are capable of accurately

quantifying all residues of concern. See Decision Tree for MRM in Appendix II - 2 of PA M Vol. Ifor more information.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 14 of 28 **860.1380 Storage Stability** Sample S torage C on ditions and Intervals The integrity

of samples collected from the animal studies was maintained by appropriate handling and freezer storage. Sample storage conditions and durations are summarized in Table 4 . **T able 4**  **. Summary of Storage Conditions.**  Matrix Storage Temperature (°C) Actual Storage Duration Interval of Demonstrated Storage Stability

**Cattle Study (MRID 47193001)** Milk
- 20 <30 - 50 days None. Cream <30 - 50 days Liver <30 - 54 days Kidney <30 - 54 days Muscle <30 - 6 4 days Fat, Subcutaneous <30 - 54 days Fat, Peritoneal <30 - 54 days **Poultry Study (MRID 47589301)** Egg - 20 144 days None . Tissues 59 days Storage Stability

Data Residue Chemistry Chapter to Tetrachlorvinphos RED ( D P# 199644, 7/6/94 , F. Suhre ) DER Reference List : 47 193001.de2.doc The 1994 Residue Chemistry Chapter reported that s torage stabili ty studies have been conducted for the parent compound u sing fortified samples of milk and animal tissues. Residues of the tetrachlorvinphos per se are stable for 25 days at 0 ° C in milk, for 31 days at 0 ° C in milk fat, for 3 days at room temperature in muscle, for 4 days at room temperature in kidney , for 5 days at room temperature in liver, and for 11 days at room temperature in fat. The registrant submitted additional stor age stability data for the parent and all residues of concern along with the cow feeding study (MRID 47193001). HED has reviewed the companion study , and the Executive Summary of the Data Evaluation Records is reproduced below. SRA International, Inc., o n behalf of KMG Bernuth, Inc., has included supporting storage stability data in the amended final report of a dairy cattle feeding study

with tetrachlorvinphos. To generate data on the stability of weathered tetrachlorvinphos residues of concern in milk, cream, liver, kidney , muscle, and fat, selected samples of these matrices were re
- assayed after the initial analysis. Initial residue analyses of samples from the cattle feeding study were made after the collected samples were stored frozen for up to 50 day s for milk and cream, 54 days for liver, fat, and kidney , and 63 days for muscle; the registrant reported that the majority of samples were stored for less than 30 days. Samples were re
- analy zed at the following intervals after the initial analysis: 7 4 and 112 days for milk, 70 and 84 days for cream, 57 days for liver, 60 days for kidney , 68 days for muscle, and 63 and 65 days for fat.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 15 of 28 Milk and tissue samples were analy zed for residues of tetrachlorvinphos, TCVPdeme , TCPEol, TCPEone, and TCPEdiol usin g LC/MS, LC/MS/MS, or GC/ECD method s . The validated L OQ was 0.01 ppm for each analy te. The adequacy

of the method for data collection was verified by fortifying untreated samples of milk and tissues with TCVP and its metabolites at 0.01 and 0.1 ppm. Add itional untreated samples of muscle were fortified with TCVP at 0.5 ppm and peritoneal fat were fortified with TCVP and TCPEol each at 0.6 ppm. Concurrent method recoveries were within the acceptable range of 70
- 120%. Considerable variability

in the sample results was observed. Initial analysis for some analy tes showed nondetectable residues, but residues were quantifiable at later intervals (TCPEol
- conjugated) . For some matrices extensive degradation was observed, but extensive increases were observe d for other matrices (e.g., free TCPEol). The registrant concluded that overall results for total TCVP - derived residues did not indicate any consistent or significant losses outside the expected limits of analy tical variation. HED does not concur with the registrant’s conclusion. The samples were stored for at least 50 days prior to the initial assay . Considerable degradation may

have occurred prior to the initial analysis. Many of the matrices did not have quantifiable residues of one or more of the an aly tes at the time of initial analysis, so potential degradation upon storage cannot be accurately assessed . Conclusions . Storage durations of cattle and hen s amples collected from th e magnitude of the residue studies are not supported by adequate storag e stability data. Although a companion storage stability

study was submitted in support of the cattle study , the data were deemed inadequate because considerable degradation may have occurred prior to the initial analysis of storage stability

samples. N e w storage stability stud ies should be conducted with quantifiable (i.e., fortified) residues of all analy tes in cattle and poultry

matrices according to 860.1380 . In addition, the registrant needs to submit information pertaining to dates of treatment, co llection, extraction, and analysis to verify the maximum storage intervals from collection to extraction and analysis of all samples from both the cattle and poultry studies. **860.1400 Water, Fish, and Irrigated Crops** This guideline is not applicable to t etrachlorvinphos as the only use is on livestock. **860.1460 Food Handling** This guideline is not applicable to tetrachlorvinphos as the only use is on livestock. **860.1480 Meat, Milk, Poultry, and Eggs** Residue Chemistry Chapter to Tetrachlorvinphos RED ( D P# 199644, 7/6/94 , F. Suhre ) New r uminant, swine, and poultry magnitude of the residue studies were requested in the 1994 Residue Chemistry

Chapter . The Chapter concluded that n o residue data are required for horses provided that all applicable labels prohibit treatment of horses destined for slaughter. E xamination of the 7.76% G oral larvacide label (EPA. Reg. No. 56493 - 35) , a product registered to the technical registrant, shows that it has been amended to prohibit treatment of horses intended for slau ghter . Itis possible that other registrants may have uses on horses; the productTetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 16 of 28 labels of these other registrants need to be examined to ensure that such restrictions are established. Protocols for the conduct of the required animal studies were review ed by HED in memos dated 06/01/99 (DP# 246716, S. Hummel) and 8/27/ 01 (DP# 277227, M. Metzger). The results of the n ew ruminant and poultry magnitude of the residue studies have now been submitted. HED has reviewed these studies, and the Executive Summaries of the Data Evaluation Records are reproduced below. The requirements for a swine study remain outstanding. Cattle Oral/Dermal Study DER Reference List : 47193001.de1.doc SRA International, Inc., on behalf of KMG Bernuth, Inc., has submitted the am ended final report of a dairy cattle feeding study

with tetrachlorvinphos. The study was designed to quantify the residues of tetrachlorvinphos and its four significant metabolites in the milk and tissues of dairy cows following oral administration of tetrachlorvinphos for 29
- 31 day s and concurrent topical (spray ) application of tetrachlorvinphos on three occasions at two
- week intervals. A summary of the five treatment groups is presented in Table 5 . Groups of lactating dairy cows received tetrachlorvinp hos incorporated twice daily into the concentrate feed in oil suspensions at target levels equivalent to 1.155 or 3.465 g ai/750 kg body weight per day

for 29
- 31 day s. In addition, doses of tetrachlorvinphos were administered by the dermal route on three occasions, at ~14 day intervals, as a solution in water at target levels equivalent to 6.055 and 12.11 g ai per animal per dose. An untreated animal was also included to provide control data. **Table 5. Treatm ent Param**  **eters Used in the Cattle Study.** Grou p Treatment Target and (Actual) Exposure L evel 1 Cow numbers Oral Dermal 1 Control
-- -- 1 2 Oral 1.155 (1.553)
-- 2, 3, 4/16 3 Oral + Dermal 1.155 (1.512) 6.055 (10.111) 5, 6, 7 4 Oral + Dermal 1.155 (1.555) 12.11 (19.166) 8, 9, 10 5 Oral + De rmal 3.465 (4.630) 12.11 (19.493) 11, 12, 13, 14, 15 1 Dose levels are in g ai/750 kg body wt/day for oral doses and g ai/animal/dose for dermal doses. Milk was collected twice daily . A portion of the milk collected on days 14 and 28/29 were separated into skim milk and cream. One cow from each group was sacrificed after 29, 30, or 31 consecutive days of treatment. The following tissues were collected at sacrifice for analysis: subcutaneous fat, muscle, peritoneal fat, liver, and kidney . Two cows fr om treatment group 5 were used in a depuration study to determine how quickly residues in tissues dissipate . Milk was collected from both animals on days 30, 34, 36, and from the remaining cow on days 38 and 43 after the first dose. On study day 37 and 4 4, (7 and 14 days without treatment), the depuration animals were sacrificed, and samples of liver, kidney, muscle, subcutaneous fat, and peritoneal fat were collected for analysis. Milk and tissue samples were analy zed for residues of tetrachlorvinphos, TCVPdeme, TCPEol,Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 17 of 28 TCPEone, and TCPEdiol using L C/MS, L C/MS/MS, or GC/ECD method s . The validated method LOQ was 0.01 ppm for each analy te. The adequacy

of the method for data collection was verified by

fortifying untreated samples of milk and tissues with TCVP and its metabolites at 0.01 and 0.1 ppm. Additional untreated samples of muscle were fortified with TCVP at 0.5 ppm and peritoneal fat were fortified with TCVP and TCPEol each at 0.6 ppm. Concurrent method recoveries were within the acceptable rang e of 70
- 120%. Prior to residue analysis, samples of milk and cream were stored frozen for up to 50 days; liver, fat, and kidney

samples for up to 54 days; and muscle samples for up to 64 days. It is noted that only the storage intervals exceeding 30 days were documented in the report . The storage stability data (refer to 47193001.de2) submitted in conjunction with this study are inadequate. Additional data are required to support the study . The results show that in milk, quantifiable residues occurred as TCVP and TCPEol. TCVP was not present in any

samples from Group 2 (oral treatment only ), but was found in all groups treated both orally

and dermally

(Groups 3, 4, and 5) on Day s 1 and 2, with the highest concentrations occurring in Group 5. No other quantifiable residues of TCVP occurred except on Day 30 in the two animals maintained for depuration. No residues were generally detectable in any groups on Days 7 - 14 and Days 24 - 28. Incream, quantifiable residues occurred mainly as free TCPEol, with so me low quantifiable residues for TCPEone in Group 5 only . Residues of TCVP and other metabolites were below the LOQ in all treatment groups. Intissues, TCVP
- derived residues were overall highest in subcutaneous and peritoneal fat Lower residues occurre d in kidney and muscle, and the lowest residue concentrations were found in liver. Residues generally showed some correlation with exposure levels. In the two depuration animals, tissue residues declined after cessation of dosing, reaching levels below t he LOQ by

14 day s of withdrawal in all tissues except subcutaneous fat, in which a low quantifiable residue of TCVP only

was measured. The maximum individual residues of TCVP, TCVPdeme, TCPEone, TCPEol (free and conjugated), and TCPEdiol (free and conjugated) as well as the maximum total residues in milk and tissues from the dairy cattle feeding study

are presented in Table 6 below. **Table 6. Maxim um**  **Individual/Com bined**  **Residues in Milk and Tissues of**  **Dairy Cattle.** Matrix Residues (ppm) 1

TCVP TCVP d eme TCPEone TCPEol (free) TCPEol

(conj.) TCPEdiol

(free) TCPEdiol

(conj.) Total 2

( TCVP equiv.) **Group 2** Milk <0.01 <0.01 <0.01 0.014 <0.01 <0.01 <0.01 0.014 Cream <0.01 <0.01 <0.01 0.020 <0.01 <0.01 <0.01 0.034 Liver <0.01 0.012 <0.01 <0.01 <0.01 <0 .01 <0.01 0.032 Kidney <0.01 <0.01 <0.01 <0.01 0.044 <0.01 <0.01 0.081 Muscle <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 ND Fat, subcutaneous <0.01 <0.01 <0.01 0.012 <0.01 <0.01 <0.01 0.020 Fat, peritoneal <0.01 <0.01 <0.01 0.024 <0.01 <0.01 <0.01 0.04 4Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 18 of 28 **Table 6. Maxim um**  **Individual/Com bined**  **Residues in Milk and Tissues of**  **Dairy Cattle.** Matrix Residues (ppm) 1

TCVP TCVP d eme TCPEone TCPEol (free) TCPEol

(conj.) TCPEdiol

(free) TCPEdiol

(conj.) Total 2

( TCVP equiv.) **Group 3**  Milk 0.032 <0.01 <0.01 0.015 <0.01 <0.01 <0.01 0.063 Cream <0.01 <0.01 <0.01 0.035 <0.01 <0.01 <0.01 0.077 Liver <0.01 0.031 <0.01 0.017 <0.01 <0.01 <0.01 0.070 Kidney <0.01 0.012 <0.01 0.052 0.039 <0.01 <0.01 0.168 Muscle 0.128 0.021 <0.0 1 <0.01 <0.01 <0.01 <0.01 0.158 Fat, subcutaneous 0.343 0.072 <0.01 0.115 <0.01 <0.01 <0.01 0.485 Fat, peritoneal 0.203 0.024 0.028 0.139 <0.01 <0.01 <0.01 0.485 **Group 4**  Milk 0.036 <0.01 <0.01 0.022 <0.01 <0.01 <0.01 0.072 Cream <0.01 <0.01 <0.01 0. 036 <0.01 <0.01 <0.01 0.078 Liver <0.01 <0.01 0.010 0.056 <0.01 <0.01 <0.01 0.158 Kidney 0.015 <0.01 <0.01 0.075 0.069 <0.01 <0.01 0.278 Muscle 0.212 0.034 <0.01 0.015 <0.01 <0.01 <0.01 0.272 Fat, subcutaneous 0.558 0.111 <0.01 0.098 <0.01 <0.01 <0.01 0.842 Fat, peritoneal 0.340 0.040 0.027 0.198 <0.01 <0.01 <0.01 0.747 **Group 5**  Milk 0.040 <0.01 <0.01 0.018 <0.01 <0.01 <0.01 0.080 Cream <0.01 <0.01 0.016 0.217 <0.01 <0.01 <0.01 0.380 Liver <0.01 0.070 0.011 0.035 <0.01 <0.01 <0.01 0.122 Kidney 0.01 9 0.018 0.023 0.085 0.131 <0.01 <0.01 0.419 Muscle 0.474 0.112 <0.01 0.021 <0.01 <0.01 <0.01 0.625 Fat, subcutaneous 0.534 0.144 0.011 0.153 <0.01 <0.01 <0.01 0.859 Fat, peritoneal 0.318 0.032 0.028 0.246 <0.01 <0.01 <0.01 0.725 1 LOQ = 0.01 ppm fo r each analyte. 2 Total residues, in TCVP equivalents, were calculated by the registrant. To convert to TCVP equivalents, assay results were multiplied by the following factors: TCVPdeme = 1.04; TCPEone = 1.64; TCPEol = 1.62. Conclusions . The submitted magnitude of the residue study on cattle is inadequate but upgradeable pending submission of supporting storage stability data. The residue data reflect a combination of two treatments: oral administration of tetrachlorvinphos for 29
- 31 day s at actua l rates of 1.512
- 1.555 and 4.630 g ai/750 kg BW per day (6.3
- 6.5x and 19.3x, respectively , the maximum registered rate of 0.24 g ai/750 kg BW for feed
- through treatment) and dermal spray treatments on three occasions, at ~14 day intervals, at actual rates of 10.111 and 19.166
- 19.493 g ai per animal per dose ( ~ 0.5 and 1.0x, respectively , the maximum registered rate of 18.9 g ai/animal for direct animal spray treatment) . Among the combination of treatment regimes used in the study , the oral treatment at 1.55 5 g ai/750 kg BW per day (6.5x) plus dermal spray treatments at 19.166 g ai per animal (~1.0x) may be used to estimate residue exposure for the purpose of tolerance reassessment (see Table 9 ) . At this treatment regime (labeled as Group 4 in the study ) , th e maximum total residues of concern (with the maximum residues of the parent in parenthes e s) were: 0.072 (0.036) ppm for milk, 0.078 (<0.01) ppm for cream, 0.158 (<0.01) ppm for liver, 0.278 (0.015) ppm for kidney , 0.272 (0.212) ppm for muscle, 0.842 (0.5 58) ppm for subcutaneous fat, and 0.747 (0.340) ppm for peritoneal fat. These data will support the registered feed
- through (oral) and direct animal spray uses of tetrachlorvinphos on cattle.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 19 of 28 No data were submitted reflecting application of tetrachlorvin phos as a backrubber treatment, direct animal dusting and/or premise spray treatment; also no data were submitted directly reflecting the use of cattle ear tag uses which may still be registered to other companies. The OPPTS 860.1480 Guideline states that when a pesticide may be applied by

more than one mode of treatment, separate studies are required; however, only oral and dermal spray

studies were required in the TCVP RED. Because the oral and dermal treatments are expected to result in the highest res idue levels, no additional data will be required to support backrubber or premise spray treatments . Data from wetting sprays may be accepted in lieu of data from dust treatments. Poultry Dermal Study DER Reference List: 47589301.der.doc SRA Internatio nal, Inc. has submitted the results of a magnitude of the resid ue study with tetrachlorvinphos . Groups of 12 hens were topically (dermally

) treated with an aqueous solution of a 23% EC formulation of tetrachlorvinphos. A total of 6
- 7 applications were ma de at two
week intervals at 0.0908, 0.1816, or 0.5448 g ai/hen/application (0.5x, 1x, or 3x the nominal rate). Another group was treated with water only as the control group. A fifth group of hens was treated at 1.816 g ai/hen/application (10x nominal rate), but because of moderate to severe signs of toxicity

/intolerance indicative of acute cholinergic effects attributed to the test substance, this treatment level was discontinued and excluded from the study . Eggs were collected daily on a group basis. Hens were sacrificed following the last application (0
- day ) from all groups. Subgroups of four hens from a second group of 12 hens, treated at the nominal 3x rate, were sacrificed 7, 14, or 21 days following the last application, for residue depuration. The following tissues were collected at sacrifice for analysis: abdominal fat, liver, kidneys, muscle (breast/leg composite), and skin with underlying subcutaneous fat. Group application rates and sacrifice times are summarized below in Table 7 . **Table 7**  **. Treatm ent Param**  **eters Used in the Poultry**  **Study.** Group Treatment Number of Doses Exposure L evel

(g ai/hen/dose) Sacrifice

(DALA) 1 Hen # 1 Control 7 (water only) -- 0 201 - 205, 208, 211 - 216 (n=12) 2 Dermal (Nx1) 7 0.1816 0 218 - 220, 222 - 228, 230, 231 (n= 12) 3 Dermal (Nx3) 7 0.5448 0 233, 235, 236, 238 - 245, 248 (n=12) 3R Dermal

(Nx3) 7 0.5448 7 246, 247, 252, 253 (n=4) 14 251, 256, 259, 262 (n=4) 21 257, 261, 263, 264 (n=4) 4 Dermal (Nx0.5) 6 0.0908 0 267 - 274, 277 - 280 (n=12) 1 Days after las t treatment (DALA) . Egg and tissue samples were analy zed for residues of tetrachlorvinphos, TCVPdeme, TCPEol , TCPEone, and TCPEdiol using L C/MS, L C/MS/MS, or GC/MS method s . The validated method LOQ was 0.01 ppm for each analy te. The adequacy

of the meth od for data collection was verified by

fortifying untreated samples of eggs and tissues with TCVP and its metabolites atTetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 20 of 28 0.01 and 0.1 ppm. Concurrent method recoveries were within the acceptable range of 70
- 120%. The fortification levels encompassed most residues found in hen eggs and tissues; however, residues exceeding an order of magnitude of the highest fortification level in the concurrent method validation, were observed for TCVP, TCVPdeme, and TCPEol (free) in skin with fat and abdominal fat. The registrant did not provide study dates, but based on the start, sacrifice and experimental end dates, samples may

have been stored for up to 144 days (4.7 months) for eggs and 59 days (1.9 months) for tissues. The registrant did not address storage issues , and no supporting storage stability data were provided. TCVP - derived residues showed a linear dose response with the dosing level . Conjugated residues of TCPEol and TCPEdiol were each below the method L OQ (<0.01 ppm) in all samples of egg and hen tissu es (muscle, kidney , liver, skin with fat, and abdominal fat) from all treatment rates. TCVP - derived residues occurred in eggs from all treatment groups in a cyclical pattern of accumulation and depletion after each application. Residues of TCVP and the m etabolites TCVPdeme, TCPEone, TCPEol (free) and TCPEdiol (free) were detected, with TCPEdiol accounting for the highest levels in eggs. With comparison of the high and low values observed after successive applications to the hens, residues appear to plate au in eggs after the third or fourth treatment. Residues in eggs appear to decline after the final application, but quantifiable residues (free TCPEol and TCPEdiol) were still present in eggs following 21 days of withdrawal. TCVP - derived residues occurre d in tissues from all treatment groups, and TCVP and the metabolites TCVPdeme, TCPEone, TCPEol (free) and TCPEdiol (free) were detected in all matrices, except for TCPEone which was not quantifiable in liver. Residues were highest in skin with subcutaneou s fat by

a significant margin (~30x higher) than those observed in abdominal fat, which bore the next highest levels of residues. Similar lower levels were observed in liver and muscle, and the lowest residue levels were found in kidney . The principal re sidues in hen tissues were free TCPEol and free TCPEdiol in liver and kidney ; TCVP and TCVPdeme in muscle and skin with fat; and free TCPEol in abdominal fat. The registrant states that since similar levels of the parent and TCVPdeme were found in skin w ith fat, the results represent incurred residues and not simply residual contamination with the test substance. Overall residues of TCVP, TCVPdeme, TCPEone, TCPEol (free) and TCPEdiol (free) declined in hen tissues collected following longer withdrawal pe riods; however, quantifiable residues were still present in all tissues following 21 days of withdrawal. The maximum individual residues of TCVP, TCVPdeme, TCPEone, TCPEol (free and conjugated), and TCPEdiol (free and conjugated) as well as the maximum to tal residues in eggs and tissues from the laying hen dermal dosing study are presented below in Table 8 .Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 21 of 28 **Table 8. Maxim**  **um Individual /**  **Com bined Residues in**  **Poultry Eggs and Tissues.**  Matrix Residues (ppm) 1

TCVP TCVP deme TCPEone TCPEol (free) TCPEol

(conj.) TCPEdiol

(free) TCPEdiol

(conj.) Total 2

( TCVP equiv.) **Group 4 (0.5x)**  Egg <0.01 0.019 <0.01 0.021 <0.01 0.066 <0.01 0.154 Liver <0.01 0.018 <0.01 0.031 <0.01 0.145 <0.01 0.284 Kidney <0.01 0.020 <0.01 0.083 < 0.0 1 0.077 <0.01 0.292 Muscle 0.02 9 0.077 <0.01 0.014 <0.01 0.025 <0.01 0.165 Skin with fat 4.393 13.314 0.401 0.940 <0.01 0.038 <0.01 20.462 Fat, abdominal 0.039 0.021 0.069 0.247 <0.01 0.083 <0.01 0.699 **Group 2 (1x)**  Egg 0.026 0.034 0.010 0.037 <0.01 0.114 <0.01 0.288 Liver 0.016 0. 024 <0.01 0.076 <0.01 0.238 <0.01 0.517 Kidney 0.022 0.051 0.015 0.150 < 0.0 1 0.175 <0.01 0.583 Muscle 0.082 0.169 0.011 0.030 <0.01 0.047 <0.01 0.396 Skin with fat 6.030 9.857 0.668 1.489 <0.01 0.094 <0.01 19.405 Fat, abdominal 0.099 0.028 0.139 0.474 <0.01 0.149 <0.01 1.298 **Group 3 (3x)**  Egg 0.065 0.089 0.014 0.097 <0.01 0.230 <0.01 0.584 Liver 0.131 0.120 <0.01 0.184 <0.01 0.882 <0.01 1.865 Kidney 0.056 0.047 0.020 0.227 <0.01 0.238 <0.01 0.848 Muscle 1.017 0.726 0.020 0.068 <0.01 0.090 <0.01 2.0 45 Skin with fat 44.761 42.477 0.971 2.398 <0.01 0.191 <0.01 94.099 Fat, abdominal 0.753 0.101 0.296 1.158 <0.01 0.250 <0.01 3.265 1 LOQ = 0.01 ppm for each analyte. 2 Total residues, in TCVP equivalents, were calculated by the registrant. To co nvert to TCVP equivalents, assay results were multiplied by the following factors: TCVPdeme = 1.04; TCPEone = 1.64; TCPEol = 1.62; TCPEdiol = 1.516 . Conclusions : The submitted magnitude of the residue study on poultry

is inadequate but upgradeable pendi ng submission of additional method validation data, storage stability data/information, and label revisions to specify appropriate retreatment intervals. The residue data reflect 6
- 7 dermal spray treatments of laying hens with an EC formulation, made at two week retreatment intervals, at 0.0908, 0.1816, or 0.5448 g ai/hen/application. These application rates, respectively , correspond to ~0.5x, 1.0x, or 2. 9 x the maximum registered direct spray treatment rate of 0.19 g ai/bird daily . At ~1.0x, the maximum total residues of concern (with the maximum residues of the parent in parenthes e s) were: 0.288 (0.026 ) ppm for egg, 0.517 (0.016) ppm for liver, 0.583 (0.022) ppm for kidney , 0.396 (0.082 ) ppm for muscle, 19.405 (6.030) ppm for skin with fat, and 1.298 (0 .099) ppm for abdominal fat. These data will support the registered direct animal spray

use of tetrachlorvinphos on poultry and may be used to e stimate residue exposure for the purpose of tolerance reassessment (see Table 9). No data are available to s upport the remainder of poultry uses registered to KMG Bernuth such as direct animal dusting and premise spray treatment. However, because the dermal treatments are expected to result in the highest residue levels, no additional data will be required to s upport premise spray

treatments. Data from wetting sprays on poultry may be accepted in lieu of data from dust treatments.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 22 of 28 **860.1500 Crop Field Trials 860.1520 Processed Food and Feed**  **860.1850 Confined Accumulation in Rotational Crops 860.1900 Field Accu**  **mulation in Rotational Crops** N o tetrachlorvinphos end
- use products are currently registered for use on any plant commodity . Therefore, no field residue data, processing data, or confined/field rotational crop studies are required. Previous t olerances on crops have been revoked. **860.1650 Submittal of Analytical Reference Standards** An analy tical standard for tetrachlorvinphos is currently available in the EPA National Pesticide Standards Repository

(personal communication with Theresa Cole , ACB, 8 /3 1 / 1 0) with an expiration date of 2/01/2011 . No reference standards are available for the metabolites which are also regulated ( TCVPdeme, TCPEone, TCPEol, and TCPEdiol). Analy tical reference standards of the TCVPdeme, TCPEone, TCPEol, and TCPEdiol must be supp lied and supplies replenished as requested by

the Repository . The reference standards should be sent to the Analy tical Chemistry

L ab, which is located at Fort Meade, to the attention of either Theresa Cole or Thuy Nguyen at the following address: USEPA National Pesticide Standards Repository /Analy tical Chemistry

Branch/OPP 701 Mapes Road Fort George G. Meade, MD 20755
- 5350 (Note that the mail will be returned if the extended zip code is not used.) **860.1550 Tolerance Reasses**  **s ment**  Residue Chemistry Memo: DP# 243528, 3/11/98, D. Miller The HED Metabolism Committee h as determined that the residues of concern are tetrachlorvinphos, des
- O - methyl tetrachlorvinphos, 1
- (2,4,5
- trichlorophenyl)ethanol (free and conjugated forms), 2,4,5
- trichloroacetophenone , and 1
- (2,4,5
- trichlorophenyl)ethanediol. The current tolerance expression under 40 CFR §180.252 includes all of these residues except des
- O methyl tetrachlorvinphos . To allow separate risk assessments for cholinesterase inhibition (involving parent only

), the tolerances for each animal commodity also specify the maximum residues of tetrachlorvinphos per se from the total residues. The revised tolerance definition should be modified as follows, to be consistent with the Tolerance Expression Guidance issu ed 5/27/09 (S. Knizner). Tolerances are established for residues of the insecticide tetrachlorvinphos , including its metabolites and degradates, in or on the commodities in the table below. Compliance with the tolerance levels specified below is to be de termined by measuring only

the sum of tetrachlorvinphos [(Z)
- 2 - chloro
- 1 - (2,4,5
- trichlorophenyl)vinyl dimethyl phosphate ) and its metabolite s c hloro
- 1 - (2,4,5
- trichlorophenyl)
- vinylmonomethyl phosphate, 1 - (2,4,5
- trichlorophenyl)
- ethanol (free and conjugate d forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4,5
-Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 23 of 28 trichlorophenyl)
- ethanediol , calculated as the stoichiometric equivalent of tetrachlorvinphos , in or on the commodity . T he t ime
- limited tolerances for livestock commodities under §180.252(a), based on fe ed
- through and /or direct dermal uses on livestock, were estimated by the Agency

from the acceptable metabolism data. A tolerance for poultry skin could not be estimated at that time because this matrix was not included in the hen metabolism study . HED re commended time
- limited tolerances to allow time for the registrant to submit new feeding/dermal studies to determine p ermanent tolerances. The submitted magnitude of the residue study on cattle is inadequate but upgradeable pending submission of supportin g storage stability data and label revisions. The reviewed data will support the registered feed
- through (oral) and direct dermal uses . HED has concluded that the oral and dermal data represent the worst
- case and no additional data will be required to su pport other uses such as backrubber treatment and premise spray treatment. The submitted magnitude of the residue study on poultry

is inadequate but upgradeable pending submission of additional method validation data, storage stability data/information, and label revisions. The reviewed data will support the registered direct animal use s. HED has concluded that the dermal data represent the worst
- case and no additional data will be required to support premise spray

treatments. The established

/needed tol erances for hog commodities cannot be reassessed at this time as a magnitude of the residue study on swine is outstanding. A summary

of tolerance reassessment is detailed in Table 9 .Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 24 of 28 **Table 9**  **. Tolerance**  **Reassessm ent**  **Summary for Tetrachlorvinphos.**  Co mmo dity Established T olerance 1 (ppm) Maximum

Residues 2 (ppm) Re assessed

Tolerance 3 (ppm) Comments;

Correct Commodity Definition C attle , fat (of which no more than 0.1 ppm is tetrachlorvinphos per se ) 0.2 0.84 (0.56) subcutaneous fat; 0.75 (0.34) perit oneal fat 1.0 Cattle, fat (of which no more than 0.6 ppm is tetrachlorvinphos per se) Cattle, kidney (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 1.0 -- Remove C attle , liver (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 0. 5 -- Remove C attle , meat (of which no more than 2.0 ppm is tetrachlorvinphos per se ) 2.0 0.27 (0.21) muscle 0.3 Cattle, meat (of which no more than 0.2 ppm is tetrachlorvinphos per se) C attle , meat by products, except kidney and liver 1.0 -- Remove See cattle, meat byproducts C attle , meat by products None 0.16 (<0.01) liver; 0.28 (0.015) kidney; 0.84 (0.56) subcutaneous fat; 0.75 (0.34) peritoneal fat; 0.27 (0.21) muscle 1.0 Cattle, meat byproducts (of which no more than 0.6 ppm is tetrachlorvinphos per se) 4

E gg (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 0.2 0.288 (0.026) 0.3 Egg (of which no more than 0.0 3 ppm is tetrachlorvinphos per se) H og , fat (of which no more than 0.1 ppm is tetrachlorvinphos per se ) 0.2 TBD 5 TBD
Magnitude o f the residue data in hog remain s outstanding . H og , kidney (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 1.0 TBD TBD Hog, liver (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 0.5 TBD TBD H og , meat (of which no more than 2. 0 ppm is tetrachlorvinphos per se ) 2.0 TBD TBD H og , meat byproducts, except kidney and liver 1.0 TBD TBD M ilk , fat (reflecting negligible residues in whole milk and of which no more than 0.05 ppm is tetrachlorvinphos per se ) 0.05 0.07 2 (0.036) for milk ; 0.078 (<0.01) for cream 0.1 Milk (of which no more than 0.04 ppm is tetrachlorvinphos per se) P oultry , fat (of which no more than 7.0 ppm is tetrachlorvinphos per se ) 7.0 1.298 (0.099) abdominal fat 1.4 Poultry, fat (of which no more than 0.1 ppm is tet rachlorvinphos per se) P oultry , liver (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 2.0 Remove See poultry, meat byproductsTetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 25 of 28 **Table 9**  **. Tolerance**  **Reassessm ent**  **Summary for Tetrachlorvinphos.**  Co mmo dity Established T olerance 1 (ppm) Maximum

Residues 2 (ppm) Re assessed

Tolerance 3 (ppm) Comments;

Correct Commodity Definition P oultry , meat (of which no more than 3.0 ppm is tetrachlorvinphos per se ) 3.0 0.40 (0.082) muscle 0.4 Poultry, mea t (of which no more than 0.1 ppm is tetrachlorvinphos per se) P oultry , meat byproducts, except liver 2.0 -- Remove See poultry, meat byproducts P oultry , meat byproducts None 0.5 2 (0.016) liver ; 0.58 (0.022) kidney ; 0. 40 (0.082 ) muscle ; 19.4 1 (6.03 ) skin with fat ; 1.30 (0.099) abdominal fat 20 Poultry , meat byproducts (of which no more than 6.0 ppm is tetrachlorvinphos per se) 4

1 Time - limited tolerances; c urrent tolerance expression is for the combined residues of tetrachlorvinphos [(Z)
- 2 - chloro
- 1 - (2, 4,5 - trichlorophenyl)vinyl dimethyl phosphate] and its metabolites, 1
- (2,4,5
- trichlorophenyl)
- ethanol (free and conjugated forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4,5
- trichlorophenyl)
- ethanediol; should also include des
- O - methyl tetrachlorvinphos . 2 Total residues of tetrachlorvinphos and its metabolites, TCVP - deme, TCPEone, TCPEol (free and conjugated forms), and TCPE diol (free and conjugated), e xpressed in terms of parent equivalents ; the value in parenthes e s represent s the maximum residues of the parent tetrachlorvinphos. 3 Reassessed tolerance is based on the maximum residue from the respective magnitude of the residue study; the maximum re sidues of the parent tetrachlorvinphos are reported in the corrected commodity definition . 4 A ccording to the 18 July 2007 Minutes of the HED ChemSAC meeting, the guidance document will be revised to include language detailing the use of the highest residue data for any tissue ( l iver, kidney, f at, s kin or m

uscle) to determine the tolerance for meat byp roducts. A single tolerance on “meat byproducts” will be recommended based on that highest residue , and individual tolerances will no longer be set on liver, kidney, or meat byproducts (except liver and kidney). 5 TBD = to be determined. Codex and Canadian M RLHarmonization There are no Codex maximum residue limits (MRL s) established or proposed for residues of tetrachlorvinphos. Canada has established MRL s for plant and animal commodities. Canada’s residue definition is 2
- chloro
- 1 - (2,4,5
- trichlorophenyl) vinyl dimethyl phosphate and its low melting isomer. A summary of U.S. and international tolerances and maximum residue limits is presented in Table 10 . At this time the Agency cannot harmonize with the Canadian MRL since the new magnitude of residue dat a support the different tolerances. HED has not examined the Canadian registrations; different use patterns may account for the different residue levels.Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 26 of 28 **Table 10**  **. Sum ma**  **ry of U**  **. S**  **. and International Tolerances and Maxim**  **um Residue Limits .**  Commodity U . S . Tolerances, 40 CFR § 180.252 1 Codex MRL Canada ’s MRL 2

Established U.S. Tolerance, ppm Reassessed U.S. Tolerance, ppm M ilk , fat (reflecting negligible residues in whole milk) 0.5 (of w hich not mo re than 0. 05 ppm is tetrachlorvinphos per se ) milk: 0.1 (of w hich not mo re than 0. 04 ppm

is tetrachlorvinphos per se ) None None

Fat, c attle 0.2 (of w hich not mo re than 0. 1 ppm is tetrachlorvinphos per se ) 1. 0 (of w hich not more than 0.8 ppm is tetrachlorvinphos per se ) None 1.5 3

Muscle meat of cattle an d

hog: 2.0 (of w

hich not more than 2. 0 ppm is tetrachlorvinphos per se ) meat of cattle: 0. 3 ( of

which not more than 0. 2 ppm is tetrachlorvinphos per se ) None 1.5 3

Kidney kidney of cattle and

hog: 1.0 (of w

hich no more than 0.05 ppm is tetrachlorvinpho s per se ) meat byproducts of cattle:

1.0 (of w hich no more than 0.6 ppm is tetrachlorvinphos per se ) None 1.5 3

Liver liver of cattle and

hog: 0.5 (of w

hich no more than 0.05 ppm is tetrachlorvinphos per se ) None 1.5 3

Meat byproducts meat byproducts ,

except kidney and liver of cattle and hog: 1.0 None 1.5 3
Poultry 0.75 poultry fat: 1.4 (of w hich not more than 0. 1 ppm

is tetrachlorvinphos per se ) None 0.75 4 Eggs 0.2 ( of which not

mo re than 0. 05 ppm is tetrachlorvinphos per se ) 0.3 (of w hich not mo re than 0. 03 ppm

is tetrachlorvinphos per se ) None None
Poultry, muscle meat of poultry:

3.0 ( of which not mo re than 3. 0 ppm is tetrachlorvinphos per se ) meat of poultry: 0.4 ( of

which not more than 0 .1 ppm is tetrachlorvinphos per se ) None 0.75 4Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 27 of 28 **Table 10**  **. Sum ma**  **ry of U**  **. S**  **. and International Tolerances and Maxim**  **um Residue Limits .**  Commodity U . S . Tolerances, 40 CFR § 180.252 1 Codex MRL Canada ’s MRL 2

Established U.S. Tolerance, ppm Reassessed U.S. Tolerance, ppm Po ultry, liver 2.0 ( of which not

mo re than 0 .05 ppm is tetrachlorvinphos per se ) meat byproducts of

poultry: 20 ( of which not mo re than 6 . 0 ppm

is tetrachlorvinphos per se ) None 0.75 4
Poultry, meat byproducts meat byproducts,

except liver, of poultry: 2. 0 None 0.75 4 Poultry, fat 7.0 ( of which not

mo re than 7.0 ppm is tetrachlorvinphos per se ) 1.4 ( of which not more

than 0.1 ppm

is tetrachlorvinphos per se ) None 0.75 4
Apples None None None 10 Grapes None None None 10 1 Current US residue definitio n is tetrachlorvinphos , des
- O - methyl tetrachlorvinphos , 1 - (2,4,5
- trichlorophenyl)ethanol (free and conjugated forms), 2,4,5
- trichloroacetophenone, and 1
- (2,4,5
- trichlorophenyl)ethanediol. Hog U.S. tolerances cannot be reassessed at this time (the magnitude of the residue in hogs study is outstanding ); because the current tolerances for hog are time limited, hog tissues were not included in the tolerance and MRL comparison summary. 2 Canada residue definition is 2 - chloro
- 1 - (2,4,5
- trichlorophenyl) vinyl d imethyl phosphate and its low melting isomer . 3 Meat, meat byproducts and fat of cattle and hogs, calculated on the fat content. 4 Meat, meat byproducts and fat of poultry, calculated on the fat content. **References** DP # : 199644 Subject: Tetrachlorvinp hos (Case 0321, Chemical 083701). Product Chemistry Chapter and Residue Chemistry

Chapter for the Reregistration Eligibility Decision Document From: F. Suhre To: L. Propst Dated: 07/6/94 MRIDs: None DP#: 206721 Subject: Tetrachlorvi nphos . Addendum to RED . PTRLResponse to EPA Review of

Nature of Residue Study

(MRID Nos. 42828801 - 03). Request Dated August 11, 1994. CBRS No. 14227; Case No. 0321 . From: D. Miller To: D. McNeilly Dated: 09/21/94Tetrachlorvinphos Summary of Analytical Chemistry and Residue Data DP#s: 3 20848 & 320858

Page 28 of 28 MRIDs: None DP# : 243528 Subject: Tetrachlorvinphos (083701). Development of Tolerance Estimates for Revised

HED Chapter. From: D. Miller To: K. Boyle Dated: 03/11/98 MRIDs: None DP#: 246716 Subject: Tetrachlorvinphos (Case 0321, Chemical 083701). Pro tocol for Combined

Oral/Dermal Livestock Studies From: S. Hummel To: D. Fuller and C. Swartz Dated: 06/01/99 MRIDs: None DP#: 277227 Subject: Tetrachlorvinphos . L ivestock Feeding Study Pro tocols. Response to Questions

from Boehringer Ingelheim From: M. Metzger To: D. Fuller Dated: 0 8 /27 / 01 MRIDs: None Template Version September 200 5