No abstract

A study was conducted to determine the metabolic fate of deltamethrin in lactating cows after a 'pour-on' application. Two cows were treated with 0.1 g deltamethrin and two with 1 g of the compound. Urine, faeces, milk and blood were collected over an 8-day period and analyzed for deltamethrin. This preliminary experiment has shown that it is necessary to undertake further experiment of longer duration (1 month). Deltamethrin was rapidly absorbed and slowly excreted. In milk, residues levels were very low: less than 1% of the treatment dose, and maximum levels were reached after 2 days (0.009 micrograms/ml for 0.1 g deltamethrin and 0.053 micrograms/ml for 1 g deltamethrin). For cows 1 and 2 (0.1 g deltamethrin), no residue level was detected at the detection limit (0.001 micrograms/ml) after 8 days. A total of 0.3-0.6% of excreted deltamethrin was present in urine, and no residue was found after 8 days. The major route for elimination was via faeces (about 95% of the total eliminated compound). Maxima were reached after 2 days and were still present after 8 days. Results shown in this study substantiate previously published work.

A method is described for the determination of deltamethrin, particularly in mild and dairy products. Residues and fat were co-extracted with acetone and light petroleum, partitioned with acetonitrile-methylene chloride and centrifuged (-10 degrees C). The extract was purified by gel permeation chromatography. A Florisil clean-up method was tested but did not seem effective enough. Analysis was performed by gas-liquid chromatography with a 63Ni electron-capture detector on 3% SE-30 using a short column (40 cm). Confirmation was effected by gas chromatography-mass spectrometry with an SE-30 capillary column (10 m). Recoveries from fortified samples ranged from 72 to 88% for milk spiked with 0.06 ppm and butter spiked with 2 ppm and was 94% for milk spiked with 0.016 ppm of deltamethrin.