New tests show extremely high levels of uranium in groundwater beneath an abandoned northern Nevada copper mine, and federal regulators say more tests are needed to determine if nearby wells could be contaminated.
The Atlantic Richfield Co. has agreed to provide bottled water to at least 10 households with wells near the mine even though most private wells and all of the municipal wells met U.S. drinking water standards in the latest round of tests. The company is responsible for cleaning up the 3,500-acre former Anaconda mine site that has been mined since 1953.
Tests conducted in December found concentrations of uranium in a monitoring well at the mine at more than 200 times the Environmental Protection Agency's standard for public drinking water. Tests found the well had 7,280 micrograms of uranium compared with the legal limit of 30. One mine collection pond recorded 11,200 micrograms of uranium per liter. Uranium is considered a carcinogen.
Armed with the new data, the EPA, with added pressure from Sen. Harry Reid, D-Nev., is pushing the state to broaden its investigation into how far the pollution may have moved off the site bordering the small, rural community of Yerington.
Aides to Reid resumed talks this week with Gov. Kenny Guinn and the Nevada Department of Environmental Protection to explore whether the state should reverse its long-held opposition to declaring the mine a Superfund site.
"The site practically glows," said Tom Myers, executive director of the Reno-based watchdog group Great Basin Mine Watch.
"It's good to know that apparently the uranium has not yet made its way into Yerington's drinking water," he said. "But some of these (uranium) levels on the site are screaming. To me, this really increases the need for Superfund cleanup that goes as far as removing the contaminated soils and tailings away from the city and to a hazardous waste facility."
Superfund status would put EPA in charge of the cleanup and potentially make additional federal money available.
Of the 29 wells sampled outside the mine property, eight had uranium concentrations exceeding 30 micrograms - mostly in a residential area just to the north. The highest reading was 108 micrograms. Three wells had levels from 33 to 37.
Bureau of Land Management and EPA officials said the new tests confirm uranium still poses threats at the mine.
"This data says the ponds probably leaked processing material that had concentrated uranium in it. ... and that it got into the groundwater. The question is how far in the groundwater has it gone?" said Jim Sickles, a remedial project manager for EPA's regional office in San Francisco.
"We may have caught it before it went very far. That is going to be part of the additional investigation," he said.
Arco officials said the new data does not show any direct connection between uranium on the mine site and in the private wells.
"I don't think we have any evidence right now that the uranium got off the site," Arco environmental manager Dan Ferriter said Friday. He said the company was providing the bottled water as a precaution
Eight of the 10 households with elevated uranium levels have accepted the bottled water, he said.
Earle Dixon, a BLM environmental protection specialist, said there's not enough data to determine if there is "a direct cause and effect relationship between the mine and the wells." But he said the reading of 108 micrograms was a concern and reason to do more testing.
State Environmental Protection Department Administrator Allen Biaggi agreed the reading of 108 "sticks out like a sore thumb" because other wells nearby have much lower levels.
Arco and state officials think the uranium in the private wells most likely comes from naturally occurring uranium ore in the earth.
The state and Arco agreed to the tests in October after the discovery of documents that showed Anaconda considered producing yellowcake uranium at the site in the 1970s because of high radiation levels recorded in evaporation ponds as a byproduct of leaching copper from the ore. The ponds did not have the modern liners used today to keep contaminants from seeping through the soil into the groundwater.
On the Net:
Nevada Division of Environmental Protection: http://ndep.nv.gov/yerington/MINESITE.htm