The radioactivity of domestic water and its elimination

Most Finns rely on water distributed by waterworks or on groundwater from their own wells for their supply of domestic water. The radioactivity of these waters is usually low, and the radiation doses from drinking water are insignificant compared with the mean doses received from all other sources of radiation in Finland. High concentrations of 222Rn and also other natural radionuclides are, however, found in a small percentage of groundwater wells drilled in bedrock. Most of these wells are located in the granitic areas of southern Finland. The arithmetic mean for 222Rn in water in drilled wells is 960 Bq/l, for that in dug wells 85 Bq/l and for that from waterworks 26 Bq/l, the maximum concentrations being 77500, 3500 and 1630 Bq/l, respectively. Uranium is another radionuclide that seems to be rather soluble in Finnish groundwaters. High concentrations of uranium are, however, only found in drilled wells. (orig.)