COUMAPHOS JMPR 1972 Explanation This insecticide was previously evaluated in 1968 (FAO/WHO, 1969) at which time a temporary acceptable daily intake and temporary tolerances were recommended. A requirement for further information was indicated on the required rates and frequencies of application, preharvest intervals and the resultant residues from countries other than U.S.A. and Canada. Since the previous evaluation, additional data have become available. At the Sixth Session of the Codex Committee on Pesticide Residues it was requested that the FAO/WHO Joint Meeting on Pesticide Residues evaluate the proposed temporary tolerances in meat, milk and eggs, taking into account any new data received. RESIDUES IN FOOD AND THEIR EVALUATION USE PATTERN The compound, as Asuntol WP, is generally applied in a concentration of 500 ppm a.i. to domestic animals for the control of ticks and other ectoparasites. "Asuntol liquid" (16% and 20% E.C.) is used in concentrations of 250 ppm a.i. (maximum). Only in the U.S.A. and Canada a concentration of 2 500 ppm is used for the control of some pests, including warble fly larvae (Bayer, 1972). In countries where one-host ticks occur (i.e., Australia and South America), Asuntol WP is usually applied in intervals of 3-4 weeks. In Africa the average interval is about 2 weeks. The frequency of application of the liquid formulation is identical with that of the wettable powder (Bayer, 1972). RESIDUES RESULTING FROM SUPERVISED TRIALS In animals New data was received from the U.S. Department of Agriculture (1972) on residues in meat, poultry, eggs and milk arising from carefully conducted experiments, at rates required for effective control and reflecting good agricultural practice. One application of 0.5% dust was applied by hand to individual birds. No detectable residues were found in the eggs. Residues in poultry meat from this application are shown in Table 1. TABLE 1 Coumaphos residues in poultry meat Days after application Residues (ppm) 0 0.014;0.071;0.063 3 0.044;0.053;0.064 7 0.028;0.035;ND1 14 0.012;0.036;ND 28 0.014;0.012;0.006 1 ND = not detectable. In other experiments, when coumaphos was fed to poultry at 40 ppm in the feed, residues in heart, liver and gizzard ranged from 0.02 to 0.06 ppm, while residues in eggs ranged from 0.005 to 0.018 ppm. Dust applied at a rate of 1 oz, /bird of 0.5% material gave rise to residues in meat of 0.05 to 0.60 ppm and in eggs of 0.020 to 0.058 ppm. Cattle receiving one application of 0.05% spray had no detectable residues in meat. However, fat samples had the residues shown in Table 2. TABLE 2 Coumaphos residues in fat of meat of cattle Samples stored 6-7 months before analysis Days after application Residues (ppm) 6 0.13 13 0.14 21 0.18 Samples stored 2-5 months before analysis Days after application Residues (ppm) 7 0.12 14 0.06 25 ND1 28 ND 1 ND = not detectable. Pigs received six treatments with 0.5% spray at 14-day intervals. Samples of muscle taken 8-29 days after last treatment had no detectable residues. Samples of fat had residues shown in Table 3. TABLE 3 Coumaphos residues in fat of meat of pigs Days efter last treatment Residues (ppm) 7 0.15 14 0.02 29 ND1 1 ND = not detectable. Sheep received six applications of 0.25% spray at 14-day intervals. Samples taken after last treatment had the residues shown in Table 4. TABLE 4 Coumaphos residues in meat of sheep Sample Days after last Residues (ppm) treatment Sheep muscle 8 ND1 to 0.11 15 ND to 0.20 29 ND to 0.12 Sheep fat 8 1.3, 1.7, 1.2 15 0.3, 0.4, 0.1 29 0.1, 0.4, 0.2 1 ND - not detectable. Cattle receiving a saturation spray of 1 gallon/animal of 0.5% a.i. had residues in meat (steak) samples taken 0 to 3 days after treatment of 0.12 to 0.80 ppm. Daily exposure of cattle to 1.0% a.i. in a backrubber had residues in meat ranging from not detectable to 0.43 ppm. Daily exposure to 5% a.i. in a dust bag gave residues in fat of 0.2 to 0.8 ppm. Dairy cows were fed 0-144 ppm coumaphos in their ration for seven days. No residues (<0.002 ppm) appeared in the milk at any level of coumaphos fed (Miller et al., 1970). In supervised trials in Australia (Hurwood, 1966) dairy cattle were sprayed with either 0 025% coumaphos or 0.050% coumaphos, and excretion in milk was examined in samples taken during a 5-day post-treatment period. The results are summarized in Table 5. APPRAISAL The requirement from the 1968 Joint Meeting for information on the use pattern in countries other than Canada and U.S.A. was met with data from the manufacturer. New data from supervised trials in U.S.A. was received on residues in meat, poultry, eggs and milk and from Australia on residues in milk. TABLE 5 Residues of coumaphos in butterfat and milk following spray treatment of dairy cattle Treatment Time after Residues (ppm) treatment Butterfat Milk (h) Before treatment N D1 N D Coumaphos, emulsion ) 5 0.34 - 1.10 0.021 - 0.050 0.025% ) 21 0.11 - 0.39 0.004 - 0.013 29 0.03 - 0.16 0.001 - 0.006 45 0.04 - 0.14 0.001 - 0.006 53 N.D. - 0.03 N.D. - 0.001 69 N D N D Coumaphos. wettable ) 5 0.94 - 1.56 0.028 - 0.051 powder, 0.050% ) 21 0.59 - 1.14 0.019 - 0.036 29 0.28 - 0.57 0.013 - 0.030 45 N.D. - 0.21 N.D. - 0.004 53 N D N D 1 N D = not detectable (0.005 ppm). Poultry receiving dust treatment of 1 ounce/bird of 0.5% a.i. had residues of 0.05 to 0.60 ppm in the meat and 0.020 to 0.058 ppm in eggs. This "Registered Use" has no time limitation between last application and slaughter. Cattle receiving a saturation spray of 1 gallon/animal of 0.5% a.i. had residues in meat at 0 to 3 days after treatment of 0.12 to 0.80 ppm. Daily exposure to 5% a.i. in a dust bag resulted in residues in fat of 0.2 to 0.8 ppm. These "Registered Uses" have no time limitation for slaughter stock. Pigs receiving six treatments at 14-day intervals with 0.5% spray had no detectable residues in muscle samples taken 8-29 days after last treatment. Fat samples had residues of not detectable to 0.15 ppm. Dairy cattle receiving a single spray treatment of either 0.025% emulsion or 0.050% wettable powder had residues in butterfat of 0.03 to 0.16 ppm from the first treatment and 0.20 to 0.57 ppm from the second treatment at 29 hours after the treatment. Sheep receiving six applications at 14-day intervals of 0.25% spray had residues in muscle samples taken 8-29 days after last treatment of not detectable to 0.20 ppm. Fat samples ranged from 1.7 ppm at 8 days to 0.4 at 15 days to 0.1 ppm at 29 days. For this rate and manner of application to sheep, the "Registered Use" reads: "Do not apply within 15 days of slaughter". On the basis of the new data summarized above and taking into account the time limitations applicable to the types of treatment employed, a need for revision of the previously recommended tolerances was indicated. RECOMMENDATIONS TEMPORARY TOLERANCES The temporary tolerances recommended in 1968 for meat including poultry (fat basis) are replaced by the following revised and additional/temporary tolerances. The tolerance figures include the oxygen analogue. ppm Poultry, fat of meat of cattle 1 Fat of meat of sheep, pigs, goats milk and milk products (fat basis) 0.5 Eggs (shell free basis) 0.05 TEMPORARY ADI The data on which the temporary ADI for coumaphos were based were re-evaluated and it was decided to extend the temporary ADI for a further three-year period. FURTHER WORK OR INFORMATION None REFERENCES Bayer, A.G. (1972) Personal communication. FAO/WHO. (1969) 1968 evaluations of some pesticide residues in food. FAO/PL: 1968/M/9/1; WHO/Food Add./69.35. Miller, R.W., Gordon, C.H., Morgan, N.O., Bowman, M.C. and Morton Beroya. (1970) Coumaphos as a feed additive for the control of house-fly larvae in manure. J. Econ. Entomol., 63(3): 853-855. U.S. Department of Agriculture. (1972) Data submitted to the Joint Meeting. Hurwood, I.S. (1966) Studies on pesticide residues. 1. Excretion of pesticides in milk following dermal treatment of dairy cattle with coumaphos and dioxathion. Bulletin No. 120, Queensland Department of Primary Industries, Division of Animal Industry.
See Also: Toxicological Abbreviations Coumaphos (ICSC) Coumaphos (FAO/PL:1968/M/9/1) Coumaphos (WHO Pesticide Residues Series 5) Coumaphos (Pesticide residues in food: 1978 evaluations) Coumaphos (Pesticide residues in food: 1980 evaluations) Coumaphos (Pesticide residues in food: 1983 evaluations) Coumaphos (Pesticide residues in food: 1990 evaluations Toxicology)