[Breast milk studies in the Bitterfeld district].

Human milk samples were tested for pesticide residues (particularly chlorinated hydrocarbons) in 1996 in continuation of the environmental medical tests conducted in 1990 and 1993 in Bitterfeld county. Although the overall human milk contamination due to chlorinated hydrocarbons was reduced, there were still higher concentrations of DDT and beta-HCH detected compared to the concentrations found in what was formerly West Germany. The objective of this follow-up testing of 106 human milk samples was to observe overall trends as well as the specific effects of sanitary and environmental protection measures after three years. Sample preparation included fat extraction and chromatographic column studies. The extracts were analyzed by means of two different gas chromatography systems based on electron-catching detectors. Overall, the contamination was reduced compared to the years of 1990 and 1993. Contaminant concentrations did not exceed the "tolerable concentration" while using a safety factor of 10. However, few beta-HCH (2% of the samples), HCB (22%), total DDT (20%), and more than half of total PCB samples exceeded the "tolerable concentrations" while using a safety factor of 100. A major decrease in the average contamination was noticed for total PCB (63% decrease for 0.3 mg/kg of milk fat), beta-HCH (77% decrease for 0.056 mg/kg of milk fat), and HCB (57% decrease for 0.091 mg/kg of milk fat). The concentration of the heptachlorepoxide was even reduced to 1%. Whereas the DDT and DDD concentrations were also reduced compared to 1993 (83% decrease for 0.033 mg/kg of milk fat, and 84% decrease of 0.005 mg/kg of milk fat), the DDE concentration increased (32% increase for 0.755 mg/kg of milk fat). This can be explained by the decomposition of enzymes from DDT to DDE and the extremely high accumulation tendency of this metabolite. The results show that the contamination of women over time was influenced by two contrary factors. On one hand, the internal exposure increases with age; on the other hand lactation eliminates contaminants from the body of the mother. Comparison to other states' data shows that the results match the overall picture of the residue situation in Germany. Results of the environmental-medical investigations from 1996 demonstrate a predominant decrease of contamination with chlorinated hydrocarbons within the human body. This tendency was possibly influenced by two developments. The global usage of persistent chlorinated hydrocarbons was critically observed and regulated more strictly in recent years, which decreased their concentration tremendously. The other reason for the reduction of contamination by chlorinated hydrocarbons in the county of Bitterfeld could be the improving environmental situation in this region.