The objective of the Drinking Water Directive [DWD, 1998] "shall be to protect human health from the adverse effects of any contamination of drinking water by ensuring that it is wholesome and clean" (Article 1). The parametric values have been set using the WHO "Guidelines for drinking water quality" and the advice from the Scientific Committee on Toxicology, Ecotoxicology and Environment (SCTEE). The parametric value is selected to ensure that the drinking water can be consumed safely on a life-long basis.