ECOLOGICAL SUSTAINABILITY AND THE USE OF CHEMICALS - IS ECOTOXICOLOGICAL RISK ASSESSMENT DOING ITS JOB PROPERLY - AN INTRODUCTION TO CHEMICAL TIME BOMBS

Ten million chemical substances are registered scientifically, but onl y 1 per cent, 100 000, are known to be traded internationally, and onl y a fraction of these are assessed to establish (eco)toxicological ris ks through international and national authorities. Only a few of the s ubstances are natural or systemic; most are xenobiotic and poorly eval uated with respect to their environmental effects. It is not only the chemical accidents that make newspaper headlines, but the creeping acc umulation of pollutants in soils, sediments and groundwater which degr ade the environment for future generations. Ecotoxicological risk asse ssment still neglects this 'hidden pollution', as it usually deals onl y with the bioavailable fractions of chemicals in the environment. The 'lost' (residue) fractions, however, can have non-linear and time-del ayed effects (chemical time bombs). As governments need to protect the ir natural resources (soils, sediments, groundwaters) against negative impacts from chemicals, an ecosystem approach may help them to overco me the shortsightedness of current 'acute' ecotoxicological risk asses sments. The Netherlands' risk philosophy on chemicals in the environme nt is discussed as an example. The National Environmental Policy Plan- 2 (1994) stresses the chain of events associated with a chemical from the raw material, the side effects of its transport, production, use a nd disposal, to its final effects in the ecosystem, including the time -delayed responses of pollution. A revised ecotoxicological assessment policy under the new NEPP will have to take account of such chemical time bombs.