Chlorinated pesticide residues in chicken egg

Two hundred and twenty-one representative samples of chicken eggs of native and commercial strains of Gallus domesticus were collected during January 1975 to August 1977 throughout the Tehran area and the Northern province of Mazandarane. The samples were analyzed for chlorinated pesticide residues by gas-liquid chromatography. The insecticides [1,1,1-Trichloro-2,2-bis (P-Chlorophenyl)ethanel] (DDT), [1,1-Dichloro-2,2-bis (P-Chlorophenyl) ethane] (TDE), [1,1-Dichloro-2,2-bis (P-Chlorophenyl)ethylene] (DDE), isomers of benzene hexachloride (BHC), Aldrin/Dieldrin, Heptachlor/Heptachlor epoxide, Dieldrin, and endrin were detected in varying concentration in the eggs. The eggs of native bred chickens, mainly as a result of their food sources, showed greater concentration of all pesticides except BHC isomers than those of commercial types. Though concentration of DDT compounds in 22% of native bred and 5% of commercial eggs exceeded WHO tolerance limit, the mean concentrations of pesticides residues were not exceeding these limits. There was no correlation between concentrations of pesticides and egg shell thinning.