Letter to the Editor

SETAC-Europe Award

Letter to the Editor

The Evaluation of Pesticides and Their Primary Toxic Degradation Products in Drinking Water from the Viewpoint of Human Toxicology: Is it Adequate? 1Hermann H. Dieter, 2Gitta M. Zimmermann 1 Institute for Water, Soil and Air Hygiene, Federal Environmental Agency, D-14195 Berlin, Germany 2 Fresenius Consult, D-65232 Taunusstein-Neuhof, Germany

In our society, decisions on scientifically based or justified concentration limits and their field of application are made on three levels: 1. On the scientific level by judging the comprehensiveness and quality of the data base. 2. On the level of eco- and human toxicology by evaluating the scientifically described effects as being 'hazardous' and by defining corresponding 'safe' limits of exposure. 3. On the social level by assigning certain concentration limits expressed as maximum rated values (limiting values) to defined environmental compartments. The evaluation criteria valid on levels 2 and 3 reflect the interests in the different environmental compartments expressed by different groups of the society, including scientists of various special fields. Drinking water is our most important food item. Since 1986 in the EC, the limiting value (maximum rated value) for pesticides and their primary toxic degradation products (PBSM, in the sense of the German Drinking Water Regulations TrinkwV) in drinking water of 0.10/ag/1 per structural unit and of 0.50/ag/l as a cumulative value has been valid on level 3. This value is not based on the strictly toxicological evaluation criteria of level 2. However, in the sense of the Federal Communicable Disease Act (Bundesseuchengesetz), it serves to prevent health risks which cannot be assessed in time, leaving scope for action in drinking water management.

Raw water from which drinking water is used is also part of the water cycle and the basis of life for aquatic ecosystems. In addition to the aspect of human toxicology, ecological reference data are therefore required for the establishment of limiting values for pesticides in raw water and drinking water. Data obtained from several field experiments performed in rivers and lakes permit the conclusion that, already at the present time, limiting values for pesticides could be derived which are in part lower than those set in the EC Drinking Water Directive. Limit concentrations which fulfil the claim of considering all the influences of pesticides on an ecosystem cannot be set on the basis of experimental science alone. Frequently, long periods will pass until changes in the ecosystems become evident and are also necessary for the repair of anthropogenic damage. By analogy with the precautionary values prescribed in the EC Directive on Water for Human Consumption, precautionary values in the EC Directives which directly refer to aquatic ecosystems must instead be set on level 3. As long as the ecological aspect has not been included in these Directives and corresponding maximum rated values have not been incorporated in legislation, the precautionary value set by the EC Directive on Water for Human Consumption should be maintained although this value can hardly be supported from the ecotoxicological point of view.

News & Views SETAC-Europe ABC Laboratories Environmental Education Award

68

Otto

HUTZINGER t~h.D.,

Professor

of

Ecological Chemistry a t the University of Bayreuth, Germany, receivedthe above mentioned award at the opening plenary session of the Fifth SETAC-EuropeAnnual Meeting in Copenhagen, June 25 - 28, 1995.

He received this award as an outstanding scientist and educator. Followinghis research over the years, he has made significant contributions to environmental science. AH

ESPR-Environ. Sci. & PoUut. Res. 2 (2) 68 (1995) 9 ecomed publishers, D-86899 Landsberg, Germany

SETAC-Europe ABC Laboratories Environmental Education Award.

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