1992 Volume 38 Issue 1 Pages 52-56
Chlorpyrifos and pyridaphention, organophosphorus insecticides, have been utilized for termite control as a substitute of chlordane from 1987 in Japan. In order to investigate the human exposure of these domestic pesticides, the analytical procedure for chlorpyrifos and pyridaphention in human milk sample, as an indicator of the domestic human exposure, was established, and the analyses of chlorpyrifos and pyridaphention levels in the breast milk of women living in the houses treated with termite control were carried out. Milk fat was extracted twice with diethylether-hexane from the milk sample. Defatting was performed by means of the Florisil dry column method ; pesticides were eluted with CH3CN-H2O=70-30, and reextracted with 20% ether-hexane from acetonitrile layer. Chlorpyrifos and pyridaphention were analysed by gas chromatography (NPD-GC) equipped with a capillary column after clean-up on a silica gel column (chlorpyrifos was eluted with 4% ether-hexane, and pyridaphention with 75% etherhexane). The minimum detectable residues of chlorpyrifos and pyridaphention were 0.025 ppm on fat basis in each by NPD-GC. Chlordane was detected in all 19 human milk samples (termiticide treated year, 1961-1988), however, chlorpyrifos and pyridaphention were both below the detection limit.
