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Title: The control of effluent discharges by a direct toxicity assessment (DTA) approach
Author: I. Johnson
Author: R. Butler
Author: N. Adams
Document Type: Monograph
This report outlines a procedure for using toxicity measurement to control complex and variable discharges. It focuses on the principles underlying the approach such as how the use of toxicity-based control relates to the traditional chemical-specific approach and the reason for each stage of the protocol. The first step in the procedure is to identify and prioritise candidate effluents that may be appropriate for toxicity-based control. This involves a desk based appraisal of available data on effluent composition and variability and the dilution capacity of the receiving water. Collection of toxicity data from a battery of rapid and complementary screening tests is also usually required. For effluents considered suitable there follows in-depth testing with the most appropriate screening test and acute higher organism (alga, invertebrate and fish) tests representative of the water that receives the discharge. The data from the most sensitive of the tests are used to derive an acceptable environmental concentration (AEC) . The AEC is then compared with the receiving water concentration (RWC) of effluent at the edge of a defined mixing zone to assess whether a toxicity-based discharge consent should be derived or the toxicity of the effluent needs to be reduced.
Publisher: National Rivers Authority
Publication Date: 1993
Publication Place: Bristol
Subject Keywords: EffluentsToxicityPollution controlWater quality
Extent: 52
Total file downloads: 293

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