Effects of Topical Phosmet on Fur Residue and Cholinesterase Activity of Dogs

Abstract

Fleas, ticks, and mites are a major problem in many areas of the country for pet owners, and one treatment option involves the use of dips that contain pesticides. In the present study, dogs were dipped with a commercial phosmet (Imidan^R) flea dip using the recommended guidelines for four consecutive treatments to determine the residues available for transfer to humans from the fur of the dogs. Twenty-four dogs of various breeds and weights were dipped, and each animal's fur was sampled with cotton gloves by petting for 5 minutes in a 10″ × 4″ area along the upper back before dipping and at 4 hours, and 1, 3, 7, and 14 days after dipping. Over the 4 dippings the 4-hour samples had a geometric mean of 2653 μg, and the 1-, 3-, 7-, and 14- day samples had geometric means of 877, 316, 84, and 20 μg, respectively. The samples ranged (in μg) from 80 to 16,794 at 4 hours, 44 to 7028 at 1 day, 1 to 4897 at 3 days, 1 to 2691 at 7 days, and 0.3 to 835 at 14 days. The residues removed by the petting did increase with the subsequent dips, but this was probably due to handler experience. The increase is not attributed to accumulation since there was less than 2% of transferable residue on the dog at 14 days post application. There was no significant inhibition of the plasma cholinesterase in the dogs over the study, suggesting that there was either a very low level of dermal absorption of phosmet or there was rapid detoxication (supported by EPA R 825170-01-0).

Keywords :

• Phosmet
• Transferable Residues
• Pesticide Monitoring
• Dog Fur
• Flea Control
• Cholinesterase
• Human Exposure
• Organophosphate Insecticide