Standard Operating Difficulties and Practical Limitations in the Conductance of Effluent Toxicity Tests, 1993 Environmental Conference Proceedings

The use of toxicity tests (or biological monitoring) with fish (e.g. fathead minnows, Pimephales promelas) and invertebrates (e.g. water fleas, Ceriodaphnia dubia) to assess the environmental acceptability of industrial and municipal (POTW) effluents discharged to surface water systems has increased steadily over the past several years. While these tests are relatively simplistic in design, straight-forward to set-up and monitor, and tend to reduce the costs associated with demonstrating compliance with discharge permit requirements (as opposed to analytical-based permit requirements), a variety of technical and operational factors can interfere with the completion of a successful test or the identification of the causes for a failed test. These factors include, but are not necessarily limited to test organism health and diet, acceptability of culture and test water, cleanliness of culture and test glassware, and experience levels of both the contractor’s and regulated facility’s staff for conducting effluent toxicity tests. Failure of an individual to perform a critical function in any one area of support can result in test failure. Consequently, successfully conducted effluent toxicity tests require an integrated effort by all personnel involved in the testing effort from sample collection to test completion and data analysis. Examples of common errors and deficiencies in laboratory operations and test conductance are presented to illustrate the above-cited points.