Uranium level high in wells near GV
By Erica Meltzer
ARIZONA DAILY STAR
Uranium levels twice the legal limit have been found in groundwater monitoring wells at the Phelps Dodge Sierrita mine west of Green Valley.
And three times the normal levels of some heavy metals have been found in the soil and groundwater at the adjacent Twin Buttes mine.
Cadmium and thallium have been linked to kidney damage and liver problems, beryllium to intestinal lesions, selenium to circulation problems and hair loss, and chromium to skin problems.
The federal Environmental Protection Agency, which cited the contamination findings in a report released last month, is assessing the situation and deciding what action to take.
State environmental officials said the contamination has not affected drinking water wells in the Green Valley area, where in 2005 two wells were closed because of sulfate contamination coming from the mine.
However, water company officials said uranium levels were rising in at least one of the wells before it was closed, though the level still was below the maximum allowed levels.
That report placed a high priority on addressing the situation, and recommended the EPA take the lead in an investigation with the state Department of Environmental Quality.
Pima County officials said the contamination points to the troubled legacy of mining in Arizona. They're using the findings to build a case for prohibiting mineral exploration on public lands in Pima County.
Phelps Dodge spokesman Ken Vaughn said the company is working with the EPA and ADEQ to assess the uranium plume. He said uranium occurs naturally in the area, and the contamination may not be from mining.
"We're going to work with them to understand where this is coming from and why," he said.
The federal and state limit for drinking water is 0.03 milligrams per liter. The most recent data from 2004 show one of three monitoring wells on the Sierrita site at just over the limit while a second is more than double the maximum.
Three more monitoring wells between the mine and the Green Valley drinking water wells show much lower levels of uranium. But the level did rise in at least one Community Water Co. well that was shut down later because of sulfate contamination, not uranium.
Phelps Dodge found the uranium during routine monitoring.
EPA spokesman Mark Merchant said mining activity may have caused the groundwater contamination, and that it is a serious issue.
"There is not an imminent danger, but that doesn't mean there's not a threat to human health and safety," he said.
Merchant said the agency has options short of declaring the area a Superfund site and calling for an emergency response or a time-critical response. Those designations allow for much quicker remediation.
ADEQ spokesman Cortland Coleman stressed that the contamination is contained on the mine site. Monitoring wells between the mine and drinking water wells would indicate if the plume was moving.
"We would have an early indication if it started to migrate off-site, and the plume shouldn't move off-site," Coleman said. "So there's no danger to public health."
The EPA said more than 25 drinking water wells serving 27,500 people lie within four miles of the Sierrita mine. The aquifers there feed into the Santa Cruz basin.
It is not known if the rising uranium level in the Community Water Co. well is related to the uranium plume at the Sierrita mine.
Phelps Dodge helped the water company build two replacement wells in areas not affected by the sulfate plume, one of which is on-line already.
Sulfates are sulfur-based compounds that come from copper production. They are not considered hazardous but can cause diarrhea.
Last year Phelps Dodge entered into an agreement with the state to contain the sulfate plume.
While Coleman said the same process should also stop the spread of uranium contamination, Vaughn questioned that, saying the uranium plume is in a different location.
Uranium was mined and processed at the Twin Buttes mine until 1985. That mine is now closed, but Phelps Dodge leases part of the processing facility there.
Harold Metz, vice president of Twin Buttes Properties Inc., the site's owner since 2003, said no elevated uranium was found in testing at monitoring wells there. He said the company is working with the EPA and ADEQ.
Community Water Co. President Arturo Gabaldon said he was unaware of the elevated uranium levels at the mine, and that he would bring up the issue to the citizens advisory group working with Phelps Dodge on the sulfate issue.
Nancy Freeman, executive director of Groundwater Awareness League, an advocacy group, said the community needs to keep a close eye on uranium contamination.
"It's something we should keep watching," she said. "There is no danger right now, but we have to be aware of it for the future."
She would like Phelps Dodge to move more quickly to contain the sulfate plume, ensuring that other contaminants don't move off the mine site.
County Administrator Chuck Huckelberry said contamination from mine sites often is worse than predicted in environmental impact statements. And financial problems for mines mean a cleanup often falls on the taxpayers.
That's why he's put forward a resolution asking the federal government to remove all public lands in Pima County from mineral exploration. The supervisors are set to vote on that resolution today.
"All the mitigation in the past really hasn't worked," Huckelberry said. "When you think of the existing mines, there has been no real reclamation. The potential public-health problems were not foreseen."
Jamie Sturgess, vice president of projects and environment for Augusta Resource Corp., which wants to operate a mine at Rosemont Ranch in the Coronado National Forest, said Rosemont will be a cleaner, greener mine than the ones Arizona has seen in the past.
"Those types of issues support our approach of building a new mine only after completion of all the appropriate tests and the utilization of the environmental impact statement process," he said. "I don't think we would get approval if our plans weren't very stringent."
The company plans to submit a revised plan of operations to the U.S. Forest Service within 90 days. If the Forest Service accepts the plan, then an environmental-impact statement process would begin.
Freeman, who opposes mining at Rosemont, said she doubts Augusta could eliminate problems similar to those near Green Valley.
"There's nothing they can do about waste metals," she said. "They dig them up, grind them up and release them into the air, soil and water."
● Contact Erica Meltzer at 807-7790 or emeltzer@azstarnet.com.
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