Farm Horizons, June 2016
Arsenic concerns bubble up in private wells
By Marie Zimmerman
When Alissa Carlson and her husband, Trevor, moved to her grandparents’ farm near Silver Lake, testing the well water there was top-of-mind. But, after living there more than a year, other important tasks cropped up, and the couple still hasn’t had a certified water test.
“It’s something we did think about, we just never did it,” Alissa Carlson said, adding her grandparents lived until they were 90 and had no significant health problems, which gives the couple peace of mind.
But, McLeod County Environmental Services Director Roger Berggren warns, the county’s rural water supply is not all well and good.
“I don’t think a lot of people know we’re a high-risk county for arsenic,” Berggren said. “So, it’s definitely something where people should be more aware of it, and do the testing.”
Glacial deposits thousands of years ago created high concentrations of arsenic in local soil and rocks, which then dissolve into groundwater. The element accumulates in the body and can cause nervous system problems, skin disorders, high blood pressure, and developmental delays in children, according to the Minnesota Department of Health (MDH). Studies have also linked long-term exposure to arsenic in drinking water to increased risk of cancer.
Arsenic can be found almost anywhere in Minnesota, but high levels are most likely from the Twin Cities and west, to the border with the Dakotas. Levels can vary from one well to the next, even if they are close to each other.
“There’s no way of predicting where it’s going to be,” Berggren said.
Starting in 2008, all new private wells in the state are tested for arsenic before being placed in service. MDHS data from 2008 to 2013 show that, on average, 10.4 percent of new wells have arsenic levels above 10 parts per billion, the recommended safe limit.
“When we talk about parts per billion, one drop of water in 16,000 gallons would be equivalent to one part per billion,” Berggren explained.
In 2012, McLeod County did countywide testing. Of 54 samples collected, 61 percent were within the acceptable range, Berrgren said. Of those outside the acceptable range, the highest was 65.9 parts per billion. The lowest was .5 parts per billion.
Water testing services are available from state and county health agencies and private laboratories certified by MDH to test drinking water for arsenic. Minnesota Valley Testing Laboratories in nearby New Ulm is certified and charges $24 for the arsenic tests; its many other water quality tests range from $16 to $45.
Immanuel Evangelical Lutheran Church, just north of Hutchinson, checks its well regularly for lead, copper, and arsenic. The well serves the church, teacherage, parsonage, and a pre-kindergarten through eighth grade school, and state requirements surrounding the school prompted the church to test its well. Arsenic levels in the water were above the allowed limit.
“We’ve been testing for arsenic for probably three years,” said Alex Vandenberg, Immanuel’s principal. “When we first were made aware of it, most of the church members didn’t really care because they’ve been drinking the water at church for years and they didn’t think it was really affecting them.”
Immanuel spent about a year working with the state health department to figure out a treatment system, and it continues to have the water sampled regularly.
“Since the water treatment system was put in, I don’t think I’ve heard any complaints about the water really,” Vandenberg said.
When arsenic is found above the recommended limit, making it safe for cooking or drinking involves a water treatment system.
“The most common type is what they call a reverse osmosis,” Berggren said, adding another option is to buy bottled water.
If a well tests under the limit for arsenic, Berggren said it’s not necessary to test again for at least 10 years.
“If you’re up there by 10 or a little above, you may want to check it again (next year),” he said. “Once you get over that 10 (parts per billion), it gets more critical.”
In addition to arsenic, Berggren recommends testing wells for nitrates and bacteria.