Pesticides in drinking water - A case study

Pesticides occupy a unique position among chemicals found in drinking water , since they are deliberately used to control pests in agriculture and publ ic health. They comprise a variety of compounds of various chemical propert ies (many of which being persistent in the environment), toxic potential, a nd mechanism of action. Safety assessment for drinking water is conducted b y allocating health-based guidelines for exposure through this environmenta l medium. The tolerable daily intake (TDI) approach is used by WHO in the c ase of pesticides with assumed thresholds of effect, while low-dose extrapo lation is used in the case of non-threshold carcinogens. Risk management, h owever, can also be based on the precautionary principle. Risk assessment e valuates the risk emanating from a given exposure on the basis of all avail able data. (C) 2000 Elsevier Science Ltd. All rights reserved.