In order to conduct oil sands mining operations in the surface mining region of the Athabasca oil sands deposits, most regions require depressurization of the basal sandstone formations. The groundwater produced by depressurization operations is of poor enough quality to be toxic to fish. The purpose of this project was to provide detailed information regarding the acute toxicity this mine depressurization water to both fish and invertebrates. This project was initiated in early 1976 with a general goal "to provide a sequence of toxicity testing applicable to use for on-site studies and to provide a basis for future evaluations of species for experimentation". Other parallel toxicological investigations conducted by AOSERP since then include "Acute and Chronic Toxicity of Vanadium to Fish" (AOSERP Report 41) and "Acute Lethality of Mine Depressurization Water to Trout-Perch and Rainbow Trout Volume I.” (AOSERP Report 23).