SITE-SPECIFIC ACUTE AND CHROMIC AQUATIC TOXICITY TESTING - WESTERN LAKE SUPERIOR SANITARY DISTRICT TREATMENT PLANT EFFLUENT STUDIES

Abstract

A need exists for the characterization of natural waters regarding their capacities for reducing the toxic effects of discharged wastes to aquatic organisms An understanding of effects of naturally occurring ligands in reducing toxicities of various wastes would facilitate the issuance of variances for discharge permit limits upon an environmentally sound site-specific basis. A study was conducted by the University of Wisconsin-Superior, Superior, WI, to determine the toxicity to aquatic organisms of effluent from the Western Lake Superior Sanitary District (WLSSD) treatment facility in Duluth, MN. Exposures were conducted on site and at the University of Wisconsin-Superior campus with organisms native. to the area and thought to have. a high level of sensitivity to potentially toxic effluent. Water from the. St. Louis River upstream from the WLSSD discharge point and University of Wisconsin laboratory water were used as the control water. Bioassays were conducted using static and flowing conditions with grab and composited samples of two processed waters within the WLSSD treatment plant and seven species of aquatic organisms. Water samples were collected at various times throughout the summer of 1982.