DERIVATION OF ENVIRONMENTAL QUALITY STANDARDS BY ECOLOGICAL RISK ASSESSMENT APPROACH USING AQUATOX MODEL

EU Water Framework Directive considers Environmental Quality Standards (EQS) as key tools in assessing and classifying chemical and ecological status. WFD Guidance Document No 27 on EQS derivation relies on worst-case assumptions and ensures environmental protection. Therefore, it leads to unworkable and/or unrealistically low EQS values. In this study, an alternative approach that is based on the toxicity model, AQUATOX was adopted. This model that predicts the fate of pollutants and their effects on the ecosystem (fish, invertebrates, and aquatic plants) was used for the determination of the toxic concentrations of selected pollutants in a selected water body (a lake) and this way more realistic Maximum allowable concentration (MAC) EQS values specific to the lake studied were calculated for the pollutants of Dieldrin, PCB 180, PCB 101, Fluridone, DDT and Alochlor. Then, these values were compared with the MAC-EQS values determined by the application of the deterministic method provided in the Guidance Document and also the MAC-EQS values provided in the Environmental Quality Standards Directive for four of the pollutants. The results indicate that more realistic EQS values can be determined with the use of the eco-toxicity model AQUATOX for the selected water body.