Dioxins: Another Uninvited Visitor to the North

At northern latitudes, urban unpleasantries are easy to leave behind. Folks frazzled by traffic noises or tired of squinting past streetlights to see the aurora can remedy both problems by driving out of town. Airborne pollutants are harder to escape. For years, scientists have found PCBs, pesticides and other harmful substances in remote patches of the Arctic. Researchers in New York recently tracked the journey of one of these nasty compounds, dioxin, from sources down south to Nunavut, Canada.

Dioxins are large, toxic molecules created when things-especially things containing chlorine-burn. PVC plastics used in hospitals give off a good dose of dioxins when burned, as do many of the ingredients in household garbage that end up in trash-burning plants or metal drums in backyards.

In 1997, researchers tested the breast milk of Inuit women and found a level of dioxins two times higher than women from southern Quebec. The Inuit women live in Nunavut, in the former Northwest Territories of Canada, a place thousands of miles from giant incinerators. Barry Commoner is one of several scientists trying to find out how dioxins are invading Nunavut and other areas of the north. Commoner is the director of the Center for the Biology of Natural Systems at City University in New York.

Commoner and his colleagues used a computer model to track puffs of dioxin released from each of 44,091 sources in North America, a list that includes trash-burning facilities, medical-waste burning plants, and even trash burned in barrels by residents of every county in the Lower 48 states. For one year, the scientists followed puffs of dioxins as weather patterns scattered them from their sources. Winds took some of the pollution north in a hurry. Riding strong air currents, dioxin molecules can travel 400 kilometers in one day, according to Mark Cohen, an atmospheric scientist who adapted the model for the study. Cohen works at the National Oceanic and Atmospheric Administration in Silver Spring, Maryland.

The north is often the resting place for pollutants because of what Commoner calls the "grasshopper effect," in which chemicals travel on air currents in warm weather, then fall out with rain or snow as they cool by travelling farther north or to higher altitudes. After the compounds reach the ground, warm weather can again liberate them into the air, where they continue the journey north."When they get to the north, there's no where else to go," Commoner said from his office in New York City.

A dioxin's trip from a smokestack in Indiana to the breast milk of a woman in Coral Harbour, Nunavut, probably goes something like this: After riding air currents northward, dioxins drop with snowflakes into Hudson Bay. In water, algae absorb the dioxins. A fish eats the algae; a bearded seal eats the fish, and dioxins build up in the animal's fatty tissue. The woman in Coral Harbour eats the seal meat, and her body transfers the dioxins to the fatty molecules of her breast milk.

Dioxins sometimes fall out on land and contaminate lichens, the main meal of caribou. Because dioxins cling to the fat of fish and game, the Eskimos, Inuit and other northern people that eat them are at risk from pollution sources thousands of miles away.

"This is an important issue for indigenous people in the Arctic," Commoner said. "There's no way of protecting (areas from dioxin fallout). You can't put an umbrella over Nunavut."

Commoner hopes the study will show American policymakers that dioxins not only latch on to the fat cells of cows in New Jersey, but to those of walruses in the Arctic Ocean. The solution lies not in having arctic people cut fat from their diets, but from cutting dioxin production at the sources, he said. Disposal methods other than burning would cut down on dioxins, and more extensive recycling programs down south could also make the Arctic a cleaner place.