DDT, Other Pesticides Found in Breast Milk

University at Buffalo researcher Paul J. Kostyniak said this type of data is critical for estimating the exposure risk of PCBs in newborns. Many contaminants found in Great Lakes fish have been linked to reproductive and developmental problems. For humans, diet is the main source of exposure.

Milk samples were analyzed for 77 PCBs, including DDE, a metabolite of the pesticide DDT, and other pesticides including hexachlorobenzene (HCB) and Mirex. Researchers found DDE and nine PCBs in every milk sample.

"This work supports previous studies that also indicate that lactation is a primary means of removal of these persistent contaminants," said Kostyniak, primary author of the study, which appeared in Environmental Research.

Milk from fish-eaters had significantly higher levels of several PCBs than than for people outside the area. The two most prevalent PCB subtypes, shown to be 30 percent higher, were also the most prevalent contaminants in Lake Ontario fish. DDE level was not related to fish consumption from Lake Ontario.

Findings in the study also showed that concentrations of these toxicants in breast milk declined as the number of children and the time spent breast-feeding increased.

The original study was undertaken in 1991 to determine the health consequences of eating fish from Lake Ontario, known to be the most polluted of the Great Lakes. Examined were licensed fisherman and their spouses or partners living near Lake Ontario -- a total of 10,517 men and 7,477 women.

This followed other studies published in a December issue of the American Journal of Epidemiology that found eating contaminated sport fish from Lake Ontario is associated with shortened menstrual cycles. That study also reported that the fish consumption was associated with a small, but statistically insignificant, delay in the time it took women to become pregnant.