Arsenic found in Thompson Reservoir

Thompson Falls water problems are raising concern among Thompson Falls residents and Sanders County officials as higher levels of arsenic, copper, lead, zinc and cadmium have been detected in the Clark Fork. In the Clark Fork riverbed, measurements show that the arsenic alone is six times the limit approved by the Environmental Protection Agency (EPA).

The research data comes from scientists at the University of Montana, the U.S. Geological Survey and PPL Montana, owner of the Thompson Falls hydroelectric dam on the Clark Fork. The higher amounts of contaminants are due to the breach in the Milltown Dam last March. Since the dam was breached, arsenic levels in the river have risen 12-fold, high above the EPA’s predictions for the dam breach.

Large quantities of sediment contaminated by mining wastes have been moving downstream, pushed by the combined flow of the Clark Fork and the Blackfoot rivers. While the river water in the Clark Fork is important to Thompson Falls residents, the most serious concern for many is the quality of the drinking water in the wells.

Jon Sonju, a local geologist in the area said that there is potential for wells to be polluted by some of the contaminants such as arsenic. He said that people who have shallow wells between 45 to 50 feet or who have wells that are near the river are most at risk.

“I definitely think that well owners are going to be affected and especially swimmers and fishermen,” Sonju said. “I personally will not eat any fish in the river.”

Sonju’s home is close to the water and he said that on a few mornings he’s noticed there to be a green discoloration in the water he believes might be a result of the contaminants floating downstream.

“I think we should get the local government, the commissioner and the Department of Environmental Quality involved into helping the poorer citizens who will be affected the most with their well water,” Sonju said.

John Cuthbertson of Montana Environmental Laboratory in Kalispell said that testing wells definitely wouldn’t hurt, especially for residents closest to the water. He also advised people to check their wells at least once a year even if they didn’t live near the river.

“The ones that worry me are the ones that say it tastes good, it looks good, it smells good and I’m not going to worry about it — but your kid could get cancer a few years later because of it,” Cuthbertson said. Many contaminants, like arsenic, have the potential to cause cancer if consumed over a long period of time.

The M.E. Lab lists arsenic as a cancer-causing contaminant. The lab defines Arsenic as a naturally occurring semi-metal and describes it as odorless and tasteless. The semi-metal enters the water system when certain rock formations dissolve into bodies of water. They stated that extreme exposure to arsenic can result in stomach pain, nausea, vomiting diarrhea, numbness in hands in feet, partial paralysis and blindness. Long-term effects for smaller levels of arsenic can lead to skin cancer and diabetes.

Another reason to check privately-owned wells is the lack of governmental oversight.

“The government not only doesn’t have any responsibility [to private wells], they don’t even care unless you’re serving the general public, like at a bar or a restaurant,” Cuthbertson said and added that the even those required tests don’t cover all of the potential contaminants that can pollute the well.

Andrew Wilcox, a geomorphologist at the University of Montana who participated in compiling the research said that there is a definite concern for the way the river itself will react to the added contaminants. He added that it would be a good idea to prevent young children from direct contact with the water in the river.

“I just think people should be aware because we don’t know what the impacts are down there but some of the measurements that PPL did in the Thompson Falls Reservoir suggest that some of the metals from Milltown have reached there,” Wilcox said. He mentioned that he did not believe that the contaminated sediment itself could get into the wells but he said he was unsure about the contaminants that were in the water.

Barbara Woodbury, the Sanders County Sanitarian said that the problem was bigger than the county and it would need to be handled by state officials if anything was going to be done. Like Cuthbertson, she said that there was nothing wrong with taking the initiative to test the water in wells just to be safe.

She said that in the last few weeks she’s noticed people coming into her office asking to test for arsenic.

“We’ve had a couple people come in wanting to test there wells for arsenic which has never happened before,” Woodbury said. “I don’t know what the county can do, it’s bigger than us, it’s the state,” she said.

Cuthbertson said that testing for arsenic is a simple process and costs $15, but recommends that people do a more comprehensive test because there are a variety of contaminants that can enter the wells and water supplies. The ME lab does a “Bare Minimum” test that costs $75 and has tests like their “Complete” Inorganic Chemical Analysis Package that costs $350.

For more information the lab can be contacted at 406-257-5359 or through their Web site as www.melab.us. The Environmental Protection Agency’s water information can accessed through their Web site at www.epa.gov/safewater.