The groundwater beneath Charlo is showing high levels of a known toxin: arsenic.
Local well users received the news last December from the Montana Departments of Environmental Quality and Public Health and Human Services, prompting the two agencies to begin testing water and residents to seek treatment.
Arsenic occurs naturally in the Earth’s crust and forms a variety of compounds, some more toxic than others. According to the federal Agency for Toxic Substances and Disease Registry, exposure to low levels of inorganic arsenic, whose atoms aren’t bonded to carbon, can cause skin darkening and lesions, decreased blood cell production, nausea, vomiting, cardiovascular problems, and a “pins and needles” sensation in hands and feet. Research has also linked it to several types of cancer, and the Environmental Protection Agency lists it as a carcinogen.
To minimize these risks, the EPA has set a safety standard of 10 parts per billion for arsenic in drinking water. Public water systems are periodically tested for arsenic levels, and the Montana Department of Environmental Quality recommends that private well users test their groundwater at least once a year for health hazards.
About two months ago, the Missoula Current reported, a woman and child in the Charlo area were each hospitalized with arsenic poisoning. Department of Public Health and Human Services spokesperson Jon Ebelt could not confirm the hospitalizations, but did say that a Charlo family with a contaminated well showed symptoms of arsenic poisoning, and that a physician alerted the department to the situation.
Ebelt wrote that his agency and the Department of Environmental Quality “reached out to approximately 90 residents in the Charlo area in December informing them that a neighbor’s private water well tested high with arsenic and that DPHHS and DEQ would provide free well water testing through the Environmental Lab at DPHHS."
“The lab at DPHHS tested about 35 private wells, about 85 percent of them tested higher than the EPA Maximum Containment Level (MCL) for drinking water,” the ten parts-per-billion standard.
Ebelt did not provide details on the arsenic levels, but Ken Crisp, whose Missoula firm, Crisp Water Technologies Inc., has been involved with the issue, said some tests came in as high as 150 parts per billion, and “a lot of the average counts are around 50 to 80 parts per billion, which is still well over the EPA limit.”
To Crisp, the depth of the affected wells — as much as 500 feet, he said — suggests that the arsenic is leaching from sediments deposited by Glacial Lake Missoula. He believes that recent earthquakes in the Lincoln area may have created new channels for groundwater, and brought it into contact with new minerals.
Whatever the cause, well users in Charlo now have contamination beneath their feet and many of those residents are turning to Crisp Water Technologies for help. ”We’ve got pages of clients that we’re working with dealing with this issue,” said Kelsi Crisp, the firm’s office manager.
The company designs and installs systems that remove arsenic from groundwater prior to use. But properly designing them, Ken Crisp explained, required understanding which types of arsenic a well user was facing: arsenate, more-toxic arsenite, or both.
“People started calling me and asking me how to treat it and I said, ‘we don’t know how to treat it unless we do more tests,” he said.
“What we have to do is about a $150 test to (determine) the difference between the two types of arsenic that they have,” he explained. “We’ve been sending out kits to people.
“And then what we do is design the right size of equipment, the right media” to filter it out. He said a typical filtration system costs less than $3,000 and lasts about four years.
While the cost of mitigation can be high, Crisp said, it’s “very important that people protect their health. ...You can’t see [arsenic], you can’t smell it, it’s completely invisible. It can be a silent killer.”
Well users in the affected area can receive more information on testing from the Montana Department of Environmental Quality’s website, http://deq.mt.gov/Water/DrinkingWater/safewells.
While private wells have drawn the most concern so far, the area is also served by the Charlo Water and Sewer District, which has about 170 connections served by two active wells, said its clerk and manager, Leila Roberts.
The Charlo district is sampled every three years, and was last tested in September 2016. That tests’s report showed an arsenic level of four parts per billion, well below the EPA’s threshold of 10. Roberts expects another round of arsenic sampling to take place within the next two weeks.
“It’s tested regularly, it’s monitored, and it’s safe as far as we know,” she said, citing the state's data.