New environmental quality standards for uranium in water Uranium is listed as a specific pollutant in the Dutch decree on monitoring for the Water Framework Directive (Regeling monitoring Kaderrichtlijn water). The compound is frequently detected in Dutch surface waters at concentrations above the current standards. New standards are necessary because the current ones do not comply with the most recent guidelines. On request of the Dutch ministry of Infrastructure and Environment (I&M), the RIVM presents a proposal for these new standards. The ministry has accepted the proposals in this report, and will set the new quality standards when updating the decree on monitoring in 2015.
Emission sources Uranium is a natural compound present in rocks and soils. Its main entry in the environment is through mining, combustion of coal and the use of artificial fertiliser. Because of these sources the environmental concentration of uranium may increase above its natural background concentration. Uranium is commonly known for its radioactivity and use of enriched uranium in nuclear power plants and nuclear weapons. These sources, however, hardly contribute to the anthropogenic emission of uranium to the environment. Furthermore, the chemical toxicity of natural uranium is much more harmful than the potential environmental impact through its radioactivity. Therefore, this proposal is based on the (eco)toxicity of uranium and does not cover radioactivity.
Two quality standards for waterUnder the Water Framework Directive two types of quality standards are handled: the Annual Average Environmental Quality Standard (AA-EQS) and the Maximum Acceptable Concentration EQS (MAC-EQS). The AA-EQS is the concentration which should protect the ecosystem against adverse effects resulting from long-term exposure. The proposed AA-EQS is 0.5 microgram per litre. The MAC-EQS protects aquatic ecosystems from effects due to short-term exposure or concentration peaks. The latter standard did not exist for uranium and is proposed at 8.9 microgram per litre. Both standards are expressed as dissolved uranium, including background levels. The prosed AA-EQS is lower than the current value. Monitoring data indicate that the proposed value is currently exceeded in some of the Dutch surface waters.