ANCHORAGE - Researchers have found elevated levels of heavy metals in moss and soil samples collected along the Red Dog Mine haul road.
Researchers last summer took samples along the 55-mile road that cuts across 24 miles of Cape Krusenstern National Monument, north of Kotzebue.
Over the past 11 years, ore trucks have used the road to haul up to 5,000 tons of lead-zinc concentrate daily from the mine to a port. The samples, tested over the past year, turned up elevated levels of lead, zinc and cadmium.
The amount of lead near the road was greater than 400 parts per million, researchers found. The U.S. Environmental Protection Agency cleanup trigger for lead in a residential area is 400 parts per million or greater, and the industrial limit is 1,200 parts per million, said Bud Rice, a Park Service environmental specialist.
Rice told the Anchorage Daily News that it's too early to tell if there's a health risk, but regulators worry about heavy metals because, although often naturally occurring, they have been known to cause medical problems.
"I don't believe it's appropriate to apply an industrial cleanup standard to this site. It's a national monument. In the National Park Service, we're charged with keeping the area clean and unimpaired for future generations," said Linda Stromquist, contaminated site program manager for the federal agency.
Cominco, the mining company that operates Red Dog, the world's largest lead and zinc mine, acknowledges the report's findings and is "improving operations to minimize impacts to the surrounding environment," said spokeswoman Charlotte MacCay.
One step is to switch this summer to newer trucks with hydraulically sealed lids instead of tarp-covered trucks more prone to lose ore on the trip to the port.
The study found high heavy metal levels as far away as one mile from the road, where the research stopped.
The researchers compared results with similar data from arctic Alaska, the circumpolar Arctic and industrialized Europe. In most cases, the samples taken near Red Dog exceeded the highest amounts found in these polluted foreign sites, the researchers said.
Dust found on willow and birch trees along the haul road also contained "very high levels" of heavy metals. To the researchers this suggests that heavy metal from mining activities not only affect the haul road corridor "but also the Omikviorok River drainage as a whole."
The Park Service is funding a more extensive study this summer that will test for lead, zinc and cadmium throughout Cape Krusenstern National Monument.
Exposure to heavy metals at toxic levels has been linked with developmental retardation, cancer, kidney damage and immune system disorders.