Arsenic (As) is an element that occurs naturally in the bedrock and soil as sulphide minerals and dissolved to the groundwater. Arsenic concentrations are naturally high at the central and southern parts of the Pirkanmaa region. High arsenic concentrations may also occur due to anthropogenic reasons, caused for example by minig activities, metal refinement or by the combustion of fossil fuels.
In areas with naturally elevated arsenic concentrations, arsenic typically resides in the soil, near the surface of the underlying bedrock. In regions like these, arsenic does not typically cause any major risks for health unless the soils are disturbed for example by groundworks. Therefore it is important to assure that arsenic is not transported to ground- or surficial waters during major groundworks or excavations of rock products. Long-term use of drinking water containing high concentrations of arsenic may be harmful and cause health risks.