The Toronto Star

March 22, 2000, Wednesday, Edition 1

BYLINE: Peter Calamai

OTTAWA - Toxic contaminants raining down on the Arctic from as far away as Mexico and China are making Inuit babies more vulnerable to infections, most likely because of chemical assault in the womb before they are born.

The first direct evidence of long-suspected harm to the immune system is revealed by Quebec health researchers in the March issue of Environment Health Perspectives, published by the U.S. National Institutes of Health.

The findings have direct relevance to the Great Lakes region, where recent studies have warned of potential health hazards from rising accumulations in the environment of similar chemicals, especially PCBs.

The Quebec researchers report that serious ear infections were twice as common among Inuit babies whose mothers had the highest concentration of toxic chemicals in their breast milk. More than 80 per cent of the 118 babies studied for the entire 12 months in various Nunavik communities had a serious ear infection in their first year, with many having several bouts.

Contaminants most common in the Inuit breast milk were three pesticides - dieldrin, mirex and DDE - and two industrial chemicals - polychlorinated biphenyls (PCBs) and hexachlorobenzene. The researchers could not pinpoint which specific chemicals were responsible for making the Inuit babies more vulnerable.

Contamination in the breast milk was used by the scientists to indicate which babies were likely exposed to the greatest chemical assault while still in the womb. There was no difference in ear infections between breast- or bottle-fed babies, leading the researchers to suggest that prenatal exposure to the contaminants accounted for the greater vulnerability.

The health evidence comes as delegates from 120 countries are meeting in Bonn for a fourth attempt to eliminate the use worldwide of the dozen most toxic chemicals, known collectively as persistent organic pollutants, or POPs.

Most of these chemicals, such as DDT, PCBs and dieldrin, have been banned or severely cut back in Canada and other developed countries. But they are still widely used in poorer nations, evaporate from the ground there and are then wafted by long-range air currents until they precipitate in cold spots like the Arctic and the Rocky Mountains.

This long-range contamination hits northern dwellers like the Inuit especially hard because they eat a diet rich in fat from sea mammals such as the ringed seal and beluga whale. This fat is loaded with the long-lived toxic chemicals which become more concentrated as they move up to food chain.

Previous studies have shown that the Inuit have 10 times greater levels of such chemicals in their bodies than southern Canadians. The chemicals can be passed to babies through the placenta and breast milk.

Laboratory research and population surveys in the Great Lakes region have suggested that accumulation of such chemicals in people can damage the neurological development of children and suppress the immune system in a fetus.

Other studies have pointed to potential disruption of normal hormonal development and possible links with cancer, but the Quebec research provides the most direct evidence of harmful health effects which the previous studies had merely forecast.

Dewailly is the researcher who accidentally discovered the Inuit were heavily contaminated by PCBs, chemicals once widely used in electrical transformers.