Persistence of organochlorines in breast milk of women in Victoria, Australia.

Existing information on the exposure of Australian infants to environmental contaminants through maternal milk is inadequate for assessing the safety of breast feeding. This study was undertaken to determine the extent of organochlorine (OC) contamination in the milk of mothers resident in Victoria, to monitor OC elimination by the nursing mother and to estimate the infant's daily intake of OCs from breast milk. Organochlorines were extracted from the lipophilic fraction of the breast milk samples and analysed by selected ion monitoring on a gas chromatograph-mass spectrometer (GC-MS). There was widespread contamination of milk with dichlorodiphenyltrichloroethane (p,p'-DDT) and its metabolite dichlorodiphenyldichloroethene, hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), oxychlordane and hexachlorocyclohexane, with p,p'-DDT and HCB being found in nearly all samples. Dieldrin and heptachlor epoxide were detected in 43 and 30% of samples respectively. PCBs were detected in 79% of samples and chlordane in 76%. A number of infants had daily intakes above the acceptable daily intake for total chlordane, total DDT, dieldrin, heptachlor epoxide and total PCBs. These findings have implications for strategies for the reduction of environmental contamination.