Extent of available data.
This data layer indicates the level of arsenic in well water. It was developed by the Minnesota Geological Survey using data from the Minnesota Pollution Control Agency. It includes the chemistry of groundwater from 954 water wells that were sampled between 1993 and 1996. Arsenic is a naturally occuring element in Minnesota's groundwater. Exposure to eleveated levels is a human health concern. The Environmental Protection Agency Maximum Contaminant Level for public water systems is 0.01 mg of arsenic per liter of water. This geochemical data provides a regional context for understanding local groundwater chemistry.