Organochlorines lace Inuit breast milk.

The Inuit of northern Quebec dine on seal and beluga whale blubber -- food loaded with organochlorine compounds such as the pesticide DDT and PCBs (polychlorinated biphenyls).

Probably as a result of this diet, Inuit mothers exhibit some of the world's highest recorded concentrations of PCBs in breast milk, report Pierre Ayotte and his colleagues at Laval University Hospital in Ste-Foy, Quebec. But omega-3 fatty acids in the blubber may help protect against some of the organochlorines' toxic effects, Ayotte adds.

The milk of the 107 Inuit studied had organochlorine pesticide and PCB concentrations four to seven times higher than the breast milk of Quebec women who don't eat blubber, Ayotte and his team write in the December ENVIRONMENTAL HEALTH PERSPECTIVES.

Though studies have shown that such high concentrations of PCBs in breast milk can impair brain development, Ayotte says his preliminary studies of Inuit children indicate that they are developing normally. He speculates that the mothers' consumption of a diet rich in omega-3 fatty acids may protect against the damage to the central nervous system caused by organochlorines.

Still, the Inuit may pay a price for eating organochlorine-rich food. High rates of infectious disease among their infants may stem from PCB-related immune-system damage, the researchers write.

DDT, certain PCBs, and other organochlorines also possess estrogenic properties. In the Feb. 2 JOURNAL OF THE NATIONAL CANCER INSTITUTE, another Laval University group reports on a small study showing that breasts of Quebec-area women with estrogen-responsive cancer tend to be more heavily contaminated with DDE, a breakdown product of DDT, than breasts of women with tumors unresponsive to estrogen. The findings of this team, led by Eric Dewailly, support the idea that estrogenic organochlorines may foster hormone-responsive breast cancers (SN: 7/3/93, p.10).