ST. PAUL — So far, 15 families in Gem Lake are drinking bottled water, courtesy of the state.
Minnesota Pollution Control Agency (MPCA) officials tested 100 private wells in the small community in July and August and discovered 1,4-dioxane at levels exceeding state guidelines in 15 of them.
The source of the contamination remains under investigation.
At a media briefing Sept. 23 to announce test results, MPCA Assistant Commissioner Kirk Koudelka said the federal government has no drinking water standard for 1,4-dioxane, which prompted the state Department of Health (MDH) to develop its own. That threshold, called the health risk limit, is 1 part per billion (ppb).
Most Gem Lake levels were only slightly above the health risk limit, reported Koudelka. Those homes were provided the bottled water. The maximum amount found was 3.3 ppb.
"This is a chemical we looked at years ago because of its potential for detection in groundwater," said Jim Kelly, MDH manager of environmental surveillance and assessment. "It has potential to be carcinogenic based on studies in laboratory animals exposed to high concentrations."
Gem Lake wasn’t the only community with contaminated wells. Andover’s Red Oaks neighborhood, located near a closed landfill, also showed levels higher than 1 ppb. One well on the neighborhood’s south side contained 2,000 ppb of 1,4-dioxane. Of 120 wells sampled, 43 are contaminated. Those residents are also receiving bottled water from the state.
The chemical is not new to the MDH or the MPCA.
They know where the chemical is found, usually at old, abandoned sites due to "historical releases," like the Twin Cities Army Ammunition Plant in New Brighton, and how it’s used.
The potential carcinogen works as a stabilizer for solvents like TCE and is a byproduct of manufacturing. The chemical is found in cosmetics, detergents, adhesives and automotive fluids.
The good news, according to Koudelka, is 1,4-dioxane’s use in commerce is decreasing. "But we still have to deal with legacy issues," he said.
MPCA is working to determine the source of contamination in both cities, noting that the agency removed hazardous waste from the WD Landfill in Andover a few years ago. "There is potential that another source is the cause," Koudelka stated. In the Gem Lake case, he noted the chemical was found in wells near the edge of another investigation site: Water Gremlin.
The agency is working with the communities on both short- and long-term solutions and is close to finishing initial investigations, continued the assistant commissioner. Andover has a municipal water system so residents on private wells could connect to the city utility. Gem Lake does not have city water, so a long-term and costly solution would be to pull drinking water from neighboring communities.
Asked if the state will attempt to recoup costs if the contamination source is found, Koudelka replied, "Yes. If a responsible party is found and we can link (contamination) to the facility, we will go after them to seek cost recovery. In the meantime, our efforts are to check folks’ wells and provide safe drinking water."
Gem Lake Mayor Gretchen Artig-Swomley said her city is working closely with MPCA to determine the source of the problem. "There is no negotiating the fact that clean water is crucial," she said. "Our goal will be to keep that in mind as we plan for the future. We expect to have more information on this matter in the next few weeks."