Zeldzame aarden in drinkwater en drinkwaterbronnen
[Rare earth elements in drinking water and its sources.]
Verweij W, van den Velde-Koerts T, de Boer JLM, Mennes W
RIVM Rapport 734301003
A survey has been carried out to measure the concentrations of rare earth elements in drinking water and its cources in the Netherlands. Rare earth elements occur in the earth's crust and, by weathering, also in surface water and groundwater. In surface water rare earth elements were found in concentrations up to 1000 ng/L. In drinking water produced from surface water no concentrations above the detection limits were found. In many of the groundwater samples no rare earth elements were found at all. In a few samples, however, high concentrations of up to 30,000 ng/L were measured. No correlation was found between high concentrations and low pH, although this is sometimes suggested in the literature. High concentrations of rare earth elements were only found in phreatic water with low bicarbonate content collected at a relatively low depth. During purification the concentrations decreased to nearly zero at a few pumping stations, but remained high at a few others. The toxicological data on rare earth elements were evaluated, resulting in indicative admissible concentrations. A comparison, showed that at two of the twenty investigated pumping stations one or more indicative admissible concentrations were exceeded. A more detailed assessment of the concentrations of rare earth elements in Dutch drinking water and its sources is recommended.