When Greenwood Township's supervisors set out this fall to test their smelly township well water, it was mercury they were concerned about.
There was no mercury, it turns out. But there was arsenic. A lot of it: 102 parts per billion, or 10 times the acceptable limit.
"This was a really bad surprise," said Greenwood Township supervisor Barbara Lofquist. "It was much worse that we expected."
The results were so unbelievable Lofquist thought it must be a mistake, and asked the company to run the test again. It did, but the results didn't budge.
The St. Louis County township, a community of about 900 people on Lake Vermilion in northeast Minnesota, is scrambling now to find a workable water treatment.
The township doesn't have a municipal water supply piping water to homes the way it's done in larger towns. Instead it has a deep well that pipes water out a spigot on the side of the Greenwood Township Hall. Locals drive up, fill jugs and haul the water home. The free water is a popular amenity and Lofquist estimates at least 100 households rely on it. Most property owners in the area are seasonal.
"Many times I've had to wait in line," Lofquist said.
When the board got the test results in November, it took the spigot off the wall and posted a sign that the water was nonpotable. Board members are still investigating the next step.
Arsenic occurs naturally in soil and rock, much of it in Minnesota left by glaciers. It's a common water contaminant.
The Minnesota Department of Health (MDH) reports it's been detected in about 40 percent of new wells in Minnesota since 2008. About 10% of private wells have arsenic levels above 10 parts per billion, the maximum the U.S. Environmental Protection Agency allows in community water systems. The MDH website carries this warning: "MDH highly recommends you take action if arsenic levels are above 10 [parts per billion]."
Anita Anderson, supervisor of MDH's noncommunity water supply unit, said the agency is working with the township to address the issue. She called 102 parts per billion "high."
"We've seen higher," Anderson added.
She said that because of the small population served by the Greenwood Township well, the state regulates it only for acute contaminants such as nitrate and bacteria that would sicken people immediately. The agency doesn't regularly test or monitor these wells for contaminants such as arsenic.
Anderson said that most of the people tapping the Greenwood Township spigot probably aren't in any danger because they don't drink the water every day.
"I don't think they are in a high health risk," she said. "If someone had been drinking it for many years, every day, definitely my level of concern would be higher."
Anderson said there have been a few other wells in the area that have tested high for arsenic, and she recommends private well owners in the area get a test.
MDH officially limits arsenic in drinking water to 10 parts per billion but acknowledges that consuming lower amounts long term can increase the risk of cancer, diabetes and cardiovascular and respiratory diseases, as well as lower intelligence in children and skin problems.
Lofquist called the state's minimal testing requirements for township wells such as Greenwood's "atrocious" and said their experience offers an important lesson.
"People should be testing their water more often," she said.