### Page 1 of 5 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 **OFFICE OF CHEMICA** **L SA FETY**  **AND POLLUTION PREVENTION**  

### MEMORANDUM Date: **April 5**  **, 2011** SUBJECT: **Tetrachlorvinphos .**  Request for Waiver of a Swine Magnitude of Residue Study **PC Code:** 0 837 01 /083702 **DP Barcode:** D3 20857 **Decision No.:** 35 9967 **Registration No. :**  Not Applicable **Petition No.:** Not Applicable **Regulatory Action:** Re registration Follow

- up **Risk Assessment Type:** Not Applicable **Case No.:** 0 321 T **XR No.:** Not Applicable **CAS No.:** 22248

- 79

- 9 **MRID No s**  **.:** None **40 CFR:** 180. 2 52


### FROM: Christine L . Olinger, Chemist

Risk Assessment Branch VII Health Effects Division (7509P) Office of Pesticide Programs THRU: Alexandra LaMay , Biologist

Michael S. Metzger, Chief, Risk Assessment Branch VII Health Effects Division (7509P) Office of Pesticide Programs TO: James Parker , CRM

Risk Managem ent and Implementation Branch I I Pesticide Re

- evaluation Division (7508P) Office of Pesticide Programs Tetrachlorvinphos is an organophosphate insecticide used as a direct animal treatment and feed through on poultry , ruminants, and swine. In a recent review of poultry and ruminant magnitude of residue (MOR) studies HED reiterated the reregistration requirement to also conduct a magnitude of residue study in swine (C. Olinger; 10/7/10; D320848, D320858, D320859, and D 381350 )

. HED had previously recommended for this study in the Residue Chemistry Chapter to the Reregistration Eligibility Decision (RED) ( F. Suhre, DP Barcode D199644 , 7/6/94) and the HED Chapter to the RED (C. Swartz, 12/8/99, D261626 ). In response, SRA International, on behalf of the Tetrachlorvinphos Task Force (TCVPTF) , has requested a waiver of this study

. The Pesticide Re

- evaluation Division (PRD) has requested HED review of th is submission

.

### Page 2 of 5

**R E**  **GISTRANT WAIVER REQUEST** KMG

- Bernuth, Inc. (KMG) has performed and submitted to the Agency two MOR studies, one in dairy cows (MRID No. 47193001) and one in poultry (MRID No. 4758301) as well as nature of the residue (NOR) studies in both animal species. The metabolite profile was identified and quantified in animals as a result of these studies. TCVPTF believes that the ruminant study would likely

produce higher residues than a swine study , since the material would likely remain in a ruminant digestive s ys tem longer than swine. According to their submission, it is well

- documented that residence time in swine intestines is significantl y shorter relative to that in a ruminant; a swine study would not be expected to provide any more meaningful information than can be inferred from the existing feeding studies. In addition, the TCVPTF has stated that b oth the NOR and MOR studies demonstrated the very poor absorption o f TCVP following both oral and dermal administration. This poor absorption is designed into Rabon Oral L arvicide products (by requiring [specifying] a very large particle size) because product efficacy

is predicated upon TCVP passing through the animal an d being excreted intact in order for it to be effective.
**HED RECOMMENDATION** HED has considered the product use information, existing guidance, and the registrant’s submission. The magnitude of residue data show that most of the residues are found as a result of the dermal treatment; residues from livestock treated onl y with the feed through were substantially

less than the residues from both dermal and feed

- through treatment. This is consistent with the registrant ’ s discussion on the poor oral absorption. The application rates for ruminants and swine are generall y comparable as noted in Table 1 at the end of this review (and is copied from the 10/7/10 review). Note that in residu e monitoring of livestock from 2001

- 2009 USDA Food Safety

and Inspection Service (FSIS) has never detected residues of tetrachlorvinphos per se and the USDA Pesticide Data Program (PDP) has detected tetrachlorvinphos twice in milk at very low levels. Resi dues in swine are not likely to be higher than the residues in ruminants. Therefore, HED recommends for the waiver of the swine magnitude of residue study and will translate the ruminant data to swine . The recommended tolerance levels for swine (hog) meat, meat b yproducts, and fat may

be found in Table 2

. **Table 1**  **. Summary of Registered Directions for Use of Tetrachlorvinphos. 1**  Application Ty pe/Mode Form ulation [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; (equivalent 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 i s no withholding period from last application to slaughter.

### Page 3 of 5

**Table 1**  **. Summary of Registered Directions for Use of Tetrachlorvinphos. 1**  Application Ty pe/Mode Form ulation [EPA Reg. No.] Application Rate Use Directions and Limitations 23% EC [61483

- 50] 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 pestic ides (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 BW) 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 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. **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 the 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 [61483

- 50] 1.0 gal of a spray solution

per 100 birds with the

### Page 4 of 5

**Table 1**  **. Summary of Registered Directions for Use of Tetrachlorvinphos. 1**  Application Ty pe/Mode Form ulation [EPA Reg. No.] Application Rate Use Directions and Limitations

spray solution made by diluting 1 gal of 23% EC in 50 gal of water 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. 1 Note: Application rates for backrubber and premise treatments are not included in this table as they are likely to lead 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 2**  **. Tolerance**  **Reassessment Summary for**  **Tetrachlorvinphos for Hog Commodities**  **. Comm**  **odity Established**  **Tolerance 1**  **(ppm) Maximum** 

**Residues 2**  **(ppm) Reassessed** 

**Tolerance 3**  **(ppm) Comments;** 

**Correct Commodity Definition** H og , 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) peritoneal fat 1.0 Hog , fat (of which no more than 0.6 ppm is tetrachlorvinphos per se) H og , kidney (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 1.0

-- Remove See hog , meat byproducts Hog, liver (of which no more than 0.05 ppm is tetrachlorvinphos per se ) 0.5

-- Remove See hog , meat byproducts H og , meat (of which no more than 2.0 ppm is tetrachlorvinphos per se ) 2.0 0.27 (0.21) muscle 0.3 Hog , meat (of which no more than 0.2 ppm is tetrachlorvinphos per se)

### Page 5 of 5

**Table 2**  **. Tolerance**  **Reassessment Summary for**  **Tetrachlorvinphos for Hog Commodities**  **. Comm**  **odity Established**  **Tolerance 1**  **(ppm) Maximum** 

**Residues 2**  **(ppm) Reassessed** 

**Tolerance 3**  **(ppm) Comments;** 

**Correct Commodity Definition** H og , meat byproducts, except kidney and liver 1.0 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 Hog , meat byproducts (of which no more than 0.6 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 parentheses represents the maximum residues of the parent tetrachlorvinphos. 3 Reassessed tolerance is based on the maximum residue f rom the respective magnitude of the residue study; the maximum residues of the parent tetrachlorvinphos are reported in the corrected commodity definition. 4 According to the 18 July 2007 Minutes of the HED ChemSAC meeting, the guidance document will be r evised 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).