Elevated arsenic levels reported in Helena Valley waters

Arsenic Testing Kit
Prickly Pear Creek
Tenmile Creek
Posted at 6:07 PM, Oct 27, 2022

HELENA — Lewis and Clark Public Health says a recent water quality study showed elevated levels of arsenic in some Helena Valley waters. Now, leaders have launched a new program, aimed at getting a better picture of where heavy metals are present.

“We’re trying to just get a better grasp on these different sources and what we’re actually seeing move through the system and how are we going to be able to measure and determine to get those messages out to citizens,” said Madeline McKeefry, a water quality specialist with the Lewis and Clark County Water Quality Protection District.

McKeefry says, in the latest round of testing, Tenmile Creek, Prickly Pear Creek and the Helena Valley Irrigation Canal showed elevated arsenic levels. She said their sampling has generally shown concentrations of 3 to 6 micrograms per liter – higher than normal, but still lower than the 10-microgram “maximum contaminant level” that federal authorities have set as the standard for drinking water.

Tenmile Creek
Tenmile Creek, near McHugh Lane, in the Helena Valley

McKeefry says much of the arsenic is likely naturally occurring. She believes some is coming from the area of Yellowstone National Park, carried down by the Madison and Missouri River systems, then carried by the canal. She said they sampled once in the spring, before the canal was turned on for the year, and once in the fall, just before it was turned off. They found significantly higher levels in the second tests.

“We’re trying to get a better understanding of that source water and how is it impacting the local groundwater in close proximity to the canals,” said McKeefry.

Some wells also go through local geologic formations that contain arsenic.

McKeefry said arsenic in drinking water has been linked to health consequences, including skin irritation and pain, depending on the dosage and length of exposure.

“There’s lots of different components that go into it, but there are health effects that it definitely causes, especially above that MCL and over long periods of time,” she said.

The WQPD is now running a pilot program, encouraging Valley residents to test their wells for arsenic and uranium.

“We’re working with the state environmental laboratory to get these really simple test kits – it’s literally just a bottle and a form that you fill out,” said Joel Ebert, an environmental health technician. “You come to our office here at the City-County Building and you can pick one up. Just fill it up, follow the instructions and take it to the lab.”

The test kits are free to residents. The district used American Rescue Plan Act funding to cover the costs. In addition, if a homeowner’s well tests above the maximum contaminant level, the program will cover up to $300 in reimbursement if they choose to purchase a treatment system, like a reverse osmosis filter.

This program is for people using individual private wells. Public water systems in a city or subdivision should already be checked regularly.

Ebert said, if there’s enough interest in the testing program, the district will start looking for other sources of funding so they can continue it after the ARPA funding expires.

“It’s good for residents in the Valley, individuals, to know what’s in their water,” he said. “But it’s also good for the district to collect as much data as we can, because then we can put a more complete picture of what’s going on with our groundwater situation and get the best information we can out to people.”

Residents can get a testing kit by visiting the Lewis and Clark Public Health Environmental Services Division office at 316 North Park Avenue, Room 224, in Helena. You can get more information by contacting the WQPD at 406-447-8356 or emailing Ebert at