DDT, DDE and DDD in human milk from South Africa.

Human breast milk samples (n=30) were collected from mothers within the age range of 19-40 years from Thohoyandou area, South Africa. DDT and its metabolites were extracted from the milk samples using diethyl ether. The crude extracts were subjected to column chromatography. The eluates were then evaporated on a stream of nitrogen up to 0.5 mL. One microliter of the cleaned extracts were injected into GC-ECD for selected organochlorine compounds. The sum total of DDT and its metabolites from each village ranged from not detectable for DMS, GNN and THN to 1,930 ng g(-1) fat wt for BDL while SigmaDDE ranged from 1.32 ng g(-1) fat wt for GNN to 2,570 ng g(-1) fat wt for TKD. SigmaDDD ranged from not detectable for GNN to 4,060 ng g(-1) fat wt for MNN. SigmaDDE was the most predominant followed by SigmaDDD and finally SigmaDDT. This was an indication of breakdown of the parent compound, DDT. Some villages namely, Lufule and Budeli, and Maniini and Makhuvha exhibited similar DDT occurrence of 89% in their areas. Other villages, DMS, TLM, and MND and TKD showed a similarity percentage of 82% while others showed similarities of 75% for GNN and MTT, 69% and 65% for MPG and THN respectively. A significant cluster of DDT and its metabolites between the infants' weight range of 2.5-3.9 kg/body wt was observed. Increase in lipid content was followed by a decrease in the sum DDT in the older mothers (27-30). The estimated daily intake varied from 260 to 4,696 ng/g, nd-10,551 ng/g and nd-4,237 ng/g for DDE, DDD and DDT respectively. These values are significantly (p<0.05) higher than the FAO/WHO acceptable daily intake (ADI) of 20 ng/g. The SigmaDDT was found to decrease with increasing age of the mothers. The observed high levels of DDE compared to DDT indicated chronic exposure of the mothers to DDT, which is metabolised to DDE and retained in the body.