The chemistry of Norwegian groundwaters: I. The distribution of radon, major and minor elements in 1604 crystalline bedrock groundwaters

A quality-controlled hydrogeochemical dataset of 1604 groundwater samples from Norwegian crystalline bedrock aquifers has been obtained and subject to analyses of radon (scintillation counting), major and minor elements (ion chromatography and ICP-AES), pH and alkalinity. Cumulative probability curves may be constructed to assess the risk of given parameters violating drinking water norms. Parameters such as radon and fluoride show clear lithological correlation, occurring at high concentrations in granites and low concentrations in anorthosites. Other parameters exhibit a lower degree of correlation with aquifer geochemistry (e.g. pH, major ions) and are likely to be governed by more universal thermodynamic equilibria (the calcium carbonate system) and kinetic factors. On a national basis 13.9% of the bedrock groundwaters exceed the recommended action level for radon, while 16.1% exceed the drinking water norm for fluoride. Considering pH, sodium, radon and fluoride together, 29.9% of all wells violate drinking water maximum concentrations for one or more of these parameters.