Study finds little harm in Red Dog dust

That finding is based on a study published this week by the U.S. Geological Survey in cooperation with the National Park Service. The researchers tested voles and a dozen small birds captured near the Red Dog's 52-mile industrial road for toxic metals. Those animals were chosen for the analysis because they are most likely to ingest large amounts of the dust blown off trucks.

Ever since federal officials discovered large amounts of toxic metals on vegetation next to the road, they and the mine have been studying whether the dust that escapes from the mine's ore trucks is causing biological harm. The trucks daily carry zinc and lead concentrate from the open-pit mine -- about 82 miles north of Kotzebue -- to a Chukchi Sea port for smelter shipments. The road passes through the Cape Krusenstern National Monument for about 20 miles.

The USGS study published this week follows on Red Dog's own study of the risks from its dust emissions. The mine's study, published last year, said the metal concentrations in the dust weren't high enough to harm human subsistence food such as fish, caribou or berries, but the dust was damaging tundra plants and might be harming small animals living nearby.

The two studies' results are consistent with each other, said Red Dog environmental superintendent Jim Kulas.

"We're supportive of the work (the federal agencies) are doing," he said.

The USGS dissected sparrows, common redpolls and six voles in lab experiments and found no "clear evidence" of serious biological effects, even though lead concentrations in the blood and livers of the birds and voles were about 20 times higher than similar animals collected for comparison from a reference site nearly 40 miles southeast of the road. The study did not rule out subtle effects such as decreased enzyme activity.

The USGS researchers recommended continuous monitoring of animals near the haul road because of scientific uncertainty in their findings and because, in theory, the animals could become more exposed to the metals from the road in the future. Metals accumulate over time, and chemical processes could make them more available for animal ingestion, according to the Park Service.

Opened in 1989, Red Dog is the largest mine in Alaska and is one of the world's largest zinc and lead producers. In 1999 the Park Service tested the tundra in the national monument -- adjacent to the haul road -- and discovered high levels of metals. That study prompted Red Dog to spend millions of dollars to limit its dust emissions. The mine has drastically reduced but not eliminated its dust emissions, according to federal officials.

The USGS study is not the final word on Red Dog's dust. The mine, working with state environmental regulators, is creating a risk-management plan for dust emissions that might lead to additional controls; also the Park Service and the USGS are both working on additional studies of the dust's impact on tundra vegetation.

"We'll continue to look at this information and see what else we can do," Kulas said.

Find Elizabeth Bluemink online at adn.com/contact/ebluemink or call 257-4317.