CHEVAK, Alaska -- Even maps of Alaska often don't identify Kokechik Bay, a small inlet of the Bering Sea in the vast delta between the Yukon and Kuskokwim rivers. No one lives there except for half a dozen contractors manning a Cold War-era radar site, still trained on the former Soviet Union.
But the bay has always been life itself to a few thousand members of Alaska's native tribes in three nearby subsistence villages.
''Our elders always used to tell us, in times of hardship, Kokechik Bay is the place you go, the place you can rely on even in bad times," recalled Richard Tuluq, tribal administrator of Chevak.
In recent years, however, Tuluq said people here and members of other Bering coast tribes in neighboring Hooper Bay and Scammon Bay have virtually ceased harvesting Arctic cod, blackfish, clams, and other traditional foods from Kokechik. While they still fish elsewhere, Alaskan natives are increasingly troubled by evidence of contamination in this corner of the million-square mile Bering Sea -- source of about half of all seafood caught in the United States.
Amid reports of toxic leaks from the radar station at nearby Cape Romanzof, and of pollutants from distant lands carried here by winds and ocean currents, the natives worry that there is a link to rising adult cancer rates among their people and sharp increases in early childhood illnesses such as pneumonia and chronic infections. They complain of increased encounters with tumors and other mysterious abnormalities in fish, shellfish, and bird eggs in the Kokechik Bay region.
''The food from there is not the same as when I was younger," said James Gump, 78, a Hooper Bay native who volunteers at the village school to teach children about traditional hunting and fishing techniques.
Scientists and health specialists don't agree on whether the contamination showing up in fish and wildlife here poses a threat to natives' health. But they do worry that fear is helping drive people from historically healthy subsistence diets to eating more modern processed foods. That shift could be causing some of the ailments people are attributing to pollution, specialists say.
Increasingly vocal native groups are insisting on an accounting. ''We want to find out what's in our environment, because that's our food that's what's in us," said Agatha Napoleon, a Hooper Bay resident who has led efforts to track contaminants from the Cape Romanzof radar station.
The same issues face native peoples from Alaska across Canada to Greenland, where studies have documented elevated levels of mercury, PCBs, pesticides and other toxic substances in the blood, hair, and breast milk of people who eat a lot of wild fish and game.
Scientists and local leaders debate what is known as the Arctic dilemma: how to answer natives' demands to know about the toxicants in their diet, without scaring them away from healthy traditional foods. Evidence of health problems is compelling, even if the reasons are debatable.
''There has been a rise in cancers and other health problems -- native kids in the Yukon-Kuskokwim area in their first year have 10 times the national rate of hospitalization for respiratory infections -- so people are seeing things they've never seen before," said Dr. James Berner, a pediatrician in Alaska since 1974 and director of health for the Alaska Native Tribes Health Consortium in Anchorage.
During the 1990s, studies showed natives here died of cancers at a 30 percent higher rate than whites. Lung and digestive system cancers were prominent.
Berner has found above-normal levels of toxic substances such as cadmium, mercury, and PCBs in blood from infants and their mothers in a number of Yukon delta tribal villages. At high enough levels, he said, such chemicals, in studies from the Eastern Canadian Arctic, do seem to cause significantly greater problems with infections.
A study of Inuit babies in northern Quebec, reported last year, detected subtle nervous-system and behavioral changes that researchers say appear to be linked with mercury and PCB contamination.
''But to date in our data here," Berner said, ''the effects are pretty mild."
There is a host of reasons other than toxic substances in the environment, Berner said, that are more likely causes of health problems: alcohol abuse, smoking, living longer and seeing more cancer develop, better diagnoses, poor sanitation (Hooper Bay has no running water).
The evidence, said Carl Hild, a polar health specialist at the University of Alaska at Anchorage, ''is that while we know there's more environmental contamination than there used to be, the risk to health from the subsistence diet is still mostly theoretical, while its benefits are well documented."
The fish-rich traditional diet of Alaskan natives is enormously high in the omega fatty acids that prevent stroke and heart attack; also low in sugar that can lead to diabetes. Fats and oils, of course, are also where many toxics tend to concentrate, in wildlife and humans.
Health officials also stress that the year-round procuring and preparation of subsistence food is seen as central to maintaining native cultures, whose unraveling is already linked to extraordinarily high rates of suicide, fetal alcohol syndrome, and other problems.
Alaska to date is considered less affected than the eastern Arctic by the array of PCBs, pesticides, mercury, and other pollutants carried northward and eastward in air and ocean currents. But the Alaskan Arctic is little-studied compared with other polar regions, notes Michael Smolen, a toxicologist with the Washington, D.C.-based World Wildlife Fund, who is acting as the tribes' consultant in testing the soil and water around the radar station.
''They are picking up things about their environment -- salmon rotting away, soft eggshells, clamshells that crumble at the touch -- things no scientist knew," Smolen said.