One woman was reportedly sent to Minnesota’s Mayo Clinic and a child was hospitalized after high arsenic levels showed up in household wells on a portion of the Flathead Reservation around Charlo.
About two months ago, the Montana Department of Health and Human Services sent out 89 postcards warning homeowners living within a three-mile radius of Charlo, including Moiese and north toward Ronan, to test their well water for arsenic. The Confederated Salish and Kootenai Tribes and Flathead County Health Department were also notified.
About 40 people responded to the notification and received free arsenic test kits from the Department of Environmental Quality, said DPHHS epidemiologist Connie Garrett. The rest of the homeowners might not have responded because they have out-of-state addresses, Garrett said. The basic test kit costs about $25.
DPHHS learned of the potential problem after hospital staff notified the state that they had treated a woman for arsenic poisoning.
Groundwater in the Mission and Flathead valleys is known to contain arsenic due to glaciers depositing a variety of minerals as they retreated after the last Ice Age. As with a number of minerals and metals, arsenic isn’t a health problem at low levels.
But the cause of the high arsenic is uncertain, Garrett said.
“It’s a detective story. We think it’s glacial, but we don’t know why no one has identified this before,” Garrett said. “The last time the public supply well (for Charlo) was tested, they were fine and they’re going to be tested again sometime this year.”
Normally, larger towns have water quality districts that monitor such things. For example, the Helena water quality district knows arsenic exists in the water north of town. But a tiny town like Charlo could be in a void between Missoula and Kalispell where regular monitoring isn’t carried out, Garrett said.
The DEQ test kits detect the presence of any kind of arsenic, but arsenic-3 or non-oxidized arsenic is the most dangerous. It usually exists in deep bedrock, and while most of the wells in the region of concern are between 350 and 500 feet deep, arsenic-3 usually lies deeper.
If the basic test measures high levels of arsenic, homeowners are advised to get more detailed testing to determine the kind of arsenic, and that’s where people like Ken Crisp came in. Crisp, owner of Crisp Water Testing and Treatment, has the equipment to conduct more detailed tests, which cost around $150. A Kalispell company can also conduct detailed tests.
So far, Crisp has tested 22 wells around Charlo, most of which have excessive levels of arsenic-3, along with arsenic-5.
The Environmental Protection Agency limit for human safety is 10 parts per billion. At higher levels, arsenic can cause flu-like symptoms and can lead to internal disorders, diabetes or cancer.
Crisp said the wells he’s measured have averaged 35 parts per billion of arsenic. Arsenic concentrations of 35 ppb can cause health problems in children after two weeks or less, according to the EPA.
But the family that got sick had a well with levels 10 times higher than recommended. Two wells along Post Creek Road contained 135 and 142 ppb.
“Word of mouth is flying out there. We’ve got neighbors calling neighbors,” Crisp said. “We’re trying to get people tested as soon as possible.”
People with contaminated wells can buy kits to treat the water, so they can still use their wells. However, to avoid health problems, they should test their treated water about every three months to ensure the kits are working.
CSKT spokesman Rob McDonald said the CSKT is monitoring the situation.
Garrett will be meeting with DEQ staff on Monday to determine if additional steps are required.
“If it’s because of Lake Missoula and all those fine-grained sediments, there’s a chance that everyone up there should be testing their wells. When you move into a house, they have you look for fecal coliform in your well, and that’s all they require. But in that part of Montana, it might be wiser to look for other things, including arsenic,” Garrett said.
Contact reporter Laura Lundquist at firstname.lastname@example.org.