The chemistry of Norwegian groundwaters: III. The distribution of trace elements in 476 crystalline bedrock groundwaters, as analysed by ICP-MS techniques

Four hundred and seventy-six groundwater samples from boreholes in Norwegian crystalline bedrock have been analysed by ICP-MS techniques. The results for 53 trace elements are presented as cumulative frequency distribution diagrams and are compared with relevant international drinking water norms. A range of trace elements appear to be enriched in granitic waters and depleted in anorthositic waters which is to be expected as generally granitic rocks are enriched in trace elements above those in anorthosites. A selection of elements which may be toxic in excess when present in drinking water are further discussed (Be, Tl, Th, U, Cd, Pb, As, Ni, and Hg). For uranium, 18% of the samples exceed the American maximum admissible concentration of 20 micrograms/l; 7% of the samples fail to meet the Russian drinking water norms for beryllium of 0.2 microgram/l. For some parameters such as U, Be and Tl, no Norwegian drinking water regulations are set, while the American and the Russian norms differ significantly from each other. Between 0 and 1.5% of the wells exceed Norwegian drinking water norms for each of the other selected elements.