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.