Coumaphos Residues Research Articles

Persistence, degradation and leaching of coumaphos in soil

Dissipation, degradation and leaching of fresh 14C coumaphos, alkylated 14C coumaphos and aged residues of 14C coumaphos from vats were studied in alkaline sandy loam soil in soil columns in the field under subtropical conditions in Delhi for a year. Dissipation, degradation and bound residue formation was more in case of alkali treated coumaphos than fresh coumaphos. After 365 days total residues of fresh coumaphos accounted for 33.25% while that of alkali treated coumaphos was 19.12%. Bound residue formation was almost double in case of alkali treated coumaphos (18.95%) than fresh coumaphos (9.53%) after 150 days followed by release of bound residue in both the cases. The proportion of metabolites 4 ‐ methylumbelliferone, chlorferon and potasan collectively was 86.05% in fresh coumaphos extractable residues while the same was 91.74% in alkali treated coumaphos after 365 days. Aged residues from vats containing copper sulphate and buffer were found to be more persistent in soil as total residues remained were 95.58% in comparison with 83.09% total residues of aged residues from vats containing only buffer after 150 days of treatment. Copper sulphate seems to inhibit the degradatiion of coumaphos in soil by microorganisms. Chlorferon was the major metabolite in generally all the samples. Coumaphos did not leach below 10 cm in all the cases.

Determination of Malathion, Coumaphos, and Fluvalinate Residues in Honey by Gas Chromatography with Nitrogen–Phosphorus or Electron Capture Detectors

A rapid, reliable, and inexpensive extraction method was developed to determine acaricide residues in honey by gas chromatography (GC) with nitrogen-phosphorus (NP) or electron capture (EC) detectors. Because of the high selectivity of the NP detector, no interfering peaks were present and no cleanup was necessary. A simple cleanup step is proposed for the GC-ECD analysis. Recoveries from spiked honey samples ranged from 79 to 94.4%, with coefficients of variation of 0.3-18.5%. The quantitation limit obtained was 0.015 mg/kg for malathion, 0.020 mg/kg for coumaphos, and 0.005 mg/kg for fluvalinate. The method was used to determine the disappearance of malathion and coumaphos residues from honey samples collected from beehives treated with these acaricides. The disappearance of both acaricides was rapid and followed a first-order model for the duration of the experiment.

Effects on Varroa jacobsoni from acaricides in beeswax

SUMMARYThe effect from acaricide residues in beeswax on mortality and fertility of Varroa jacobsoni was investigated. Amitraz, coumaphos and fluvalinate were added to acaricide-free wax at 0, 1, 10, 100 ppm each and the wax subsequently was used to produce comb foundation. Amitraz could not be recovered from the foundation, but foundation where coumaphos and fluvalinate had been added to the wax contained approximately the added residue levels. When mites were allowed to enter brood in combs made from this foundation, the effect from coumaphos residues was dramatic. Almost all mother mites died in combs where 100 ppm coumaphos had been added to the foundation and increased mother mite mortality occurred at the 10-ppm level. An effect from fluvalinate was only seen in combs drawn from foundation with 100 ppm fluvalinate. If one brood generation had been present prior to the brood attacked by the mites, no harmful effects to mites from wax contaminants were found, even at the highest contamination levels. This result is probably due to the honey bee cocoon acting as a barrier for acaricide transfer from the wax to the mites in the cells. It is concluded that studies of mite fertility probably do not need to consider if the wax is contaminated with up to 10 ppm of fluvalinate. At 100 ppm in the wax the effect from this acaricide on mite performance is detectable but not dramatic. However, comb drawn from foundation having 10 ppm or more coumaphos, and in which no brood was reared, dramatically reduced mother mite survival. Since frozen combs are often used when mite fertility is investigated, coumaphos in the wax may distort results at contamination levels found in European wax.

Acaricide Residues in Honeys from Galicia (N.W. Spain)

Honey samples (101) from Galicia (N.W. Spain) were analyzed by gas chromatography (electron capture and flame ionization) for the presence of acaricides (amitraz, bromopropylate, coumaphos, and fluvalinate). Seventy-three samples were free from detectable residues. Bromopropylate residues were found in 16 samples in levels ranging from 5 to 60 μg/kg. Fluvalinate residues were found in 11 samples in levels ranging from 10 to 40 μg/kg. One sample contained 100 μg of fluvalinate per kg. Neither amitraz nor coumaphos residues were detected.

Gas chromatographic–mass spectrometric method for the simultaneous determination of amitraz, bromopropylate, coumaphos, cymiazole and fluvalinate residues in honey

A rapid method for determining acaricide residues in honey is proposed. After dissolving honey samples in water, acaricides are subjected to solid-phase extraction with a Sep-Pak C18 cartridge and directly determined by gas chromatography–mass spectrometry. The quantification limit obtained for different acaricides ranged from 10 to 40 µg kg–1 and recoveries from spiked honey samples averaged 85% and ranged from 74 to 96%.

The determination of coumaphos residues in honey by HPTLC with in‐situ fluorimetry

AbstractAn HPTLC method for determining fluorimetrically the residues of coumaphos in honey samples is described. The active ingredient is solid phase extracted with a C‐18 disposable column and determined densitometrically on HPTLC pre‐coated silica plates. The method does not require additional clean‐up steps, is extremely quick and can easily be adapted to routine determinations of a large number of samples. The determination limit is 0‐01 mg kg−1 and recoveries are above 87%.

Determination of Coumaphos and Its Oxygen Analog in Eggs and Milk by Using a Multiresidue Method with Liquid Chromatographic Quantitation and Capillary Gas Chromatographic/Mass Spectrometric Confirmation

A multiresidue method for carbamate insecticides was adapted for the determination of coumaphos and its oxygen analog in eggs and milk. Eggs were extracted with acetonitrile and milk was extracted with acetone. Co-extractives were removed using liquid partitioning and charcoal column procedures described in the carbamate method. Coumaphos and its oxygen analog were determined by using a high performance liquid chromatograph equipped with a fluorescence detector. Recovery studies were performed for the 2 compounds at levels of 0.01 and 0.10 ppm in eggs and 0.01 and 0.02 ppm in milk. Overall average recovery was 100% (range 95-109%). In a trial of the method by another laboratory, the recovery of coumaphos and its oxygen analog from milk averaged 87 and 96%, respectively. Data are presented on the capillary gas chromatographic/mass spectrometric confirmation of coumaphos residues.

Coumaphos as a feed additive for the control of house fly larvae in cow manure.

The mortality of first-stage larvae of the house fly, Musca domestica L., seeded into the manure of dairy cows consuming 0.144 ppm coumaphos in their ration increased as the concentration of coumaphos in the ration was increased. At the 144 ppm level, larval mortality approached 100%. Although coumaphos residues were found in the feces no residues 0.002 ppm) appeared in the milk of cows at any level of coumaphos fed. Neither feed intake nor milk production was affected by the feeding of coumaphos. The blood chokinesterase of 1 cow fed 150 ppm couma-phos. over a 6-week period dropped to 20% of pre-experi mental levels.

Residues of diazinon, coumaphos, Ciodrin, methoxychlor, and rotenone in cow's milk from treatments similar to those used for ectoparasite and fly control on dairy cattle, with notes on safety of diazinon and ciodrin to calves.

Studies were of 3 types: insecticide application to 2 or 3 cows and milk samples carefully taken from individual cows, insecticide application to whole dairy herds and milk samples taken from cans or bulk tanks following milking by normal farm practice, and spraying of insecticide onto calves to note toxicity. Individual cow experiments showed no detectable residue in milk caused by suspensions in water of 0.25% or less methoxychlor at 2 quarts or less per cow, or by dry application of methoxychlor wettable powder. Residues of 0.15 ppm or less were caused by 0.5 or 0.2% methoxychlor suspension in a large-volume spray. Dusting whole herds with 50% methoxychlor wettable powder caused extremely small but definite residues which were probably the result of external contamination. Individual cow experiments showed very small short-lived residues in milk subsequent to spraying cows with a large volume of 0.06% diazinon suspension. Maximum apparent diazinon in milk was 0.33 ppm 1 day after a second spray treatment. In a similar experiment, 0.1 and 0.25% coumaphos sprays caused a maximum of 0.03 ppm residue in milk, with no residue found after the first 2 milkings subsequent to spraying. In a similar experiment, 0.03% Ciodrin® (alpha -methylbenzyl 3-hydroxycrotonate dimethyl phosphate) spray caused a maximum of 0.007 ppm residue in milk, which decreased rapidly within 2 days. No detectable residues in milk were caused by spraying or misting whole dairy herds with rotenone suspensions or emulsions. Complete soaking of young calves with 0.15 to 0.6% Ciodrin caused no symptoms of toxicity. Spraying calves twice with 1% diazinon emulsion (210 ml followed by 405 ml 2 days later) caused no symptoms of toxicity.

The Effects of Coumaphos on Poultry and Its Residues in Tissue and Eggs12

In 1961, coumaphos (Co-Ral®) 50% oral drench powder in capsules at dosages of from 0.5 to 25 mg/kg was fed to laying white leghorn hens for 7 or 10 days. Dosages over 5 mg/kg caused considerable loss of weight and reduction in egg laying. At the 25 mg/kg level, all birds died. Analyses of tissues from treated birds showed no residues in excess of 1 ppm (the established tolerance). However, residues up to 0.09 ppm were recovered from egg yolks. In 1962, colony houses, 10×12 ft, containing laying white leghorn hens were treated as follows: 2 houses received a 5% dust at the rate of 2 oz/30 ft2 of floor space; 2 houses were fogged, using a Halaby fogger, with a suspension of coumaphos 25% wettable powder at essentially the same dosage used in dusted houses. Less than 0.15 ppm coumaphos were found in liver and fat of the exposed birds. The dust application resulted in no detectable residues of coumaphos in egg yolks. In one instance, a marginal residue of 0.03 was found in eggs from birds exposed to fogging.