Report: Arsenic, coliform in Dalton water

By Lisa Kaczke | The Daily Journal

Published 12:00 p.m., June 3, 2009

Traces of coliform bacteria and arsenic were found in Dalton’s water supply in 2008, but it wasn’t enough to cause illnesses, according to Minnesota Department of Health (MDH) staff.

The results were recently released in a MDH report on safe drinking water in Minnesota.

Dalton staff worked with a state engineer to flush out the system to rid it of the coliform bacteria, said Stew Thornley, of MDH’s Drinking Water Protection division. Residents were also notified about the bacteria, he said.

The city of Dalton also has a compliance agreement with MDH to rid the system of arsenic.

To do so, the city is constructing a new water treatment system, Dalton Clerk Dennis Mosher said.

The city currently doesn’t have a system in place to treat the city’s well water, said Bob Schlieman, of Ulteig Engineers in Detroit Lakes, which is constructing the new facility.

The new water treatment facility will treat the water to rid it of iron, magnesium and arsenic, Schlieman said.

In addition, the city is constructing two new water wells to replace the city’s aging existing wells, Schlieman said.

The project began in July 2008 and is expected to be completed in August, Schlieman said.

The compliance agreement for ridding the system of arsenic is due to the limit for the amount allowed in the system being lowered. The limit was 50 parts per billion (ppb), which was lowered by the federal government to 10 ppb in 2006, according to the MDH. Before the modification in 2006, 40 water systems had arsenic levels above 10 ppb. By the end of 2008, 13 community water systems were exceeding the 10 ppb limit, including Dalton, according to MDH.

If the limit had remained at 50 ppb, Dalton’s system would have remained under the limit, Thornley said. But the revised limit has caused the city to test positive for arsenic amounts that are over the limit, he said.

MDH tests Dalton’s system a handful of times per month due to the city’s population of 256, Thornley said. Larger systems are tested hundreds of times per month, he noted.

Arsenic naturally occurs in the environment as a component of underground rock and soil, according to the MDH report. Due to the earth’s crust in Minnesota, arsenic is found in systems in areas of the state, Thornley said. Arsenic wouldn’t cause symptoms of illness immediately, but instead, consuming elevated levels for a lifetime will cause illness, Thornley said.

Thornley noted that the coliform bacteria found in Dalton’s system was a minor case. In the worse cases, the MDH orders water to be boiled, but that measure wasn’t necessary in the case of Dalton.

Meanwhile, MDH also worked with the Minnesota Pollution Control Agency to test groundwater, soil and public water systems for perfluorochemicals (PFCs) that are a result of using Class B firefighting foam. The foam is used for petroleum fires that threaten public health and safety, according to the report.

Perham was one of 17 sites chosen for testing based on the volume of reported use of Class B firefighting foams in training centers and the vulnerability of the wells. No amounts of PFCs were found in Perham’s water when it was tested in February, according to the report.

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