Chlorinated pesticide residues in milk of Iranian nursing mothers.

One-hundred-thirty-one samples of human milk were collected during October, 1974, to January, 1976, throughout the Tehran area. Sources included four maternity hospitals as well as individual nursing mothers outside of hospitals. The samples were collected 1 to 8 days after child birth from women 14 to 42 yr old and from all social strata. The samples were analyzed for chlorinated pesticide residues by gas-liquid chromatography. Insecticides 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) (with its metabolites), isomer of benzene hexachloride (gamma BHC), and dieldrin were detected in varying concentration in 101, 108, and 47 samples, respectively. The means and ranges were .024 (.001 to .333) ppm, .008 (.001 to .046) ppm, and (.001 to .028) ppm. These concentrations in human milk represented insecticidal ingestion by infants. The mean dieldrin exceeded the World Health Organization limit and may pose a health hazard. There was no significant relationship between economic status of donors and pesticide in the milk; however, milk from the older nursing mothers contained more DDT than that from young mothers.