Pesticide concentrations in Arkansas breast milk.

During an episode of pesticide dairy product contamination in Arkansas in 1986, breast milk samples from 942 women were analyzed for concentrations of chlorinated pesticides. The pesticides found most frequently in quantifiable concentrations were p,p'-DDE (100%), oxychlordane (84%), trans-nonachlor (77%), heptachlor epoxide (74%) and beta-HCH, an isomer of lindane (27%). The pesticides present in highest mean concentrations of all samples analyzed (reported as ppm in milk fat) were p,p'-DDE (0.952 ppm), trans-nonachlor (0.062 ppm), oxychlordane (0.051 ppm), heptachlor epoxide (0.045 ppm), p,p'-DDT (0.039 ppm), and beta-HCH (0.032 ppm). These concentrations are lower than previous reports from similar regions of the US. However, continued persistence in human breast milk is of concern due to potential adverse health effects from these chemicals.