What is the Protection Level of the Drinking Water Directive Concerning our Exposure? Towards an Improved Human Exposure Assessment to Metal Contaminants in Drinking Water Released by Products Used for Water Distribution

Abstract

The combination of parametric values and appropriate sampling methods is essential for compliance checking, for estimating our exposure and for evaluating the protection level of the European Tap Water Directive. At present the Directive does not prescribe a sampling method. Products used in the domestic distribution system can be major contributors deteriorating the quality of tap water with chemical substances compared to products used in the distribution network. This is due to stagnation. Sample volume and stagnation time are the main parameters that determine the concentration of substances migrating from materials in the domestic distribution at the consumers¿ tap. These two parameters need to be selected in such way that they give a good estimate of our exposure. Our results show a strong dependence between the observed concentration of several metals at the tap and sample volume and stagnation time. Very few similar data are available and data on consumption behaviour are difficult to find. Increased monitoring of concentrations and consumption seems to be needed to get a better view on our exposure to contaminants in drinking water released by products used for domestic distribution at European level. All this information could be collected in a database on exposure to drinking water. It may link existing databases in member states and should be regularly updated to follow life-style changes.