The document provides NPDES permitties with procedures to assess the nature of effluent toxicity to aquatic organisms. It is intended for use by those permitties having difficulty meeting their permit for whole effluent aquatic organism toxicity limits or permitties required, through special conditions, to reduce or eliminate effluent toxicity. The document does not address human health toxicity concerns such as those from bioconcentration, water supplies and recreational uses. The methods are applicable to identifying the cause of toxicity for samples other than effluents which display acute toxicity, such as ambient water samples, elutriates and pore waters from sediments, and possibly leachates. While the authors generally refer to effluents, the application of the techniques for any aqueous sample is implied. These methods may have applicability to effluents and other types of samples that exhibit chronic toxicity as well.

Cover title. "February, 1991." "EPA-600/6-91/003." Includes bibliographical references.