Toxicity Measurements and Their Use in Treatment Strategies

The use of measured toxicity for evaluating the effects of a chemical or effluent on the environment, or monitoring the performance of an effluent treatment plant, is becoming increasingly important to complement the analytical techniques which are conventionally used. Although many consents on effluent discharges refer to specific chemical components, regulatory authorities are increasingly realizing the value of toxicity measurements to evaluate a combined effluent effect, particularly in the case of complex effluent streams.
This paper (a) describes the basic principles of conventional methods of measuring toxicity, (b) highlights the benefits and shortcomings of these methods, and (c) outlines some promising methodologies which are being developed. The use of these measurements is then discussed in evaluating treatment alternatives, modifying existing treatment plants and conducting treatment evaluations. Several case studies are outlined to illustrate the use of toxicological measurements in assessing industrial wastewater treatment processes.