Biological monitoring of environmental contaminants: chlorinated hydrocarbons in eggs of hens.

High concentrations of persistent chlorinated hydrocarbon pesticide residues were detected by gas-liquid chromatography with an electron capture detector (3H), in eggs of hens collected from Lucknow under the pesticide monitoring programme. The present study reveals extremely high contamination of eggs, particularly with DDT and HCH residues. The eggs may be an important source of DDT and HCH build-up in the human body. Residue levels of p,p'-DDT and its metabolites p,p'-DDE and alpha, beta and gamma-isomers of HCH were higher in eggs of poultry-farm hens compared to those of domestic hens. Egg yolk contained higher levels compared with egg white, because of the lipophilic nature of pesticides and the high lipid content in the yolk. Average levels of total DDT and HCH residues in the yolk and white in the whole egg of a poultry-farm hen were found to be 18.5 and 4.6 micrograms respectively, whereas the average levels were 7.4 and 4.1 micrograms, respectively, in the whole egg of a domestic hen.