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(80-42) The relationship between whole effluent toxicity and chemical-based effluent quality assessment in ambient-standard based legislation. Teodorovic, Ivana*,1, Djukic, Nada2, Dalmacija, Bozo3, 1 University of Novi Sad, Faculty of Science and Mathematics, Institute of Biology, Novi Sad, Yugoslavia2 University of Novi Sad, Faculty of Agriculture, Novi Sad, Yugoslavia3 University of Novi Sad, Faculty of Science and Mathematics, Institute of Chemistry, Novi Sad, Yugoslavia ABSTRACT- The purpose of presented study was to examine broad-scale correlation between whole effluent toxicity and chemical-based effluent quality assessment across a range of industry types. Whole effluent toxicity was determined by Daphnia magna acute and chronic tests, while chemical-based toxicity was inferred from concentrations of priority chemicals and effluent quality assessment based on current Yugoslav legislature. With respect to risk assessment procedures, it may be concluded that concentration addition gives a valid estimation of the overall toxicity for complex effluents, particularly if components are of similar mechanisms of action. However, effluent quality assessment and compliance monitoring according to current environmental regulations tend to underestimate the effluent toxicity - measured WET was greater than predicted by chemical-based approach. Additionally, no correlation was found between WET and chemical-based effluent evaluation. Positive toxicity tests were in general followed by "no violation" conclusions drawn from mandatory effluent monitoring, while negative toxicity test were often recorded in effluents characterized by compliance monitoring as a serious hazard to receiving environment. One of possible explanations for such discrepancy could be found in rather short list of priority substances, but in the same time, long list of basic water quality parameters regularly analyzed in effluents. Since Yugoslav legislature is ambient-standard based, the limitations for effluent discharges into the surface water do not even exist. Current regulations are developed to ensure that the discharge does not violate numeric ambient standards and narrative criteria outside the mixing zone. Such monitoring requirements rely solely on basic water quality parameters utterly neglecting the possible hazard deriving from potentially present toxics in toxic amounts, which led to pour correlation between the WET and chemical-based results in this study, and in the end, to failure in protection of aquatic life. Key words: wet testing, Daphnia magna, priority substances, chemical-based assessment |
