2022 01-18 CC Minutes - Laserfiche WebLink

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City of Gem Lake City Council Meeting Minutes January 18, 2022 3 | Page Gem Lake Infrastructure Issues MPCA Well Report – Tim Grape Michal Ginsbach, hydrogeologist, was joined by Tim Grape, both from the MPCA to give an overview of the well testing that has been completed over the last several months to the City Council and residents in attendance. Recent water sampling from private wells in this area revealed the presence of the chemical 1,4-dioxane above state health risk limits. Where results are above the health-risk limit residents have been provided bottled water as a short-term solution. The agency is working to identify and implement the best long-term solution to provide clean safe drinking water. Municipal wells supplying White Bear Township were tested and 1,4- dioxane was not detected. The Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health (MDH) are actively investigating in this area to determine the impacted area and source of contamination. Residents within the study area have received requests from the MDH, MPCA, or a consultant to sample their well. The main use of 1,4-dioxane was as a stabilizer for the chlorinated solvent 1,1,1-trichloroethane (often used for industrial purposes). 1,4-dioxane can also be an unintended contaminant in the production of certain products, including some cleaners, detergents, adhesives, inks, automotive fluids, etc. Groundwater contaminated with 1,4-dioxane is largely caused by the historical use and disposal of chlorinated solvents. Concentrations detected in well water in Gem Lake are just above the HRL of 1 ppb and present a very low health risk. Information about the health effects of 1,4-dioxane comes mainly from studies of laboratory animals. 1,4-dioxane is considered a likely human carcinogen, based on studies of animals exposed to very high amounts. There are currently no human studies that show a direct link between exposure to 1,4-dioxane and cancer. The HRL of 1 ppb is based on a negligible cancer risk of one additional cancer in 100,000 people consuming the water on a daily basis for a lifetime. If the MPCA cannot find a responsible party, the state will step in and the state can use tax money to continue the investigation. The MPCA website is updated with any and all new information. In the spring the MPCA will go back out and resample all the wells that were contaminated to check on the levels of 1,4-dioxane. Municipal wells generally sit deeper than private wells. 1,4-dioxane is also dissolved within the water and cane move through dispersion. Some of the questions that the MPCA answered were: Is Gem Lake the only one affected by this contamination or are other cities as well? It is more common than the MPCA would like to see. Why is my well impacted, but my neighbors is not? There are many layers below our feet and is viewed as 3 dimensional and the layers can be different on the z-axis. In some areas you may have to go lower in order to reach the optimal filtration area below ground. The neighbors well could be shallower or deeper compared to yours. Where has testing been completed? White Bear Lake has been tested and have come back clean. Vadnais Heights has also been tested and the MPCA is waiting on the results. Resident Tom Bolfing asked the MPCA is they have any thoughts on the potential source of the contamination. The MPCA responded saying that because it is an ongoing case that information is not available to the public at present. The MPCA is looking at nearby industrial facilities that have hazardous waste licenses and have noticed that there are higher concentrations to the North.