REFINERY WATER (INTAKE AND EFFLUENT) QUALITY - UPDATE OF 1970S WITH 1990S TOXICITY TESTING

The quality of two separate refinery intake waters and effluents was i nvestigated: Petro-Canada (Oakville) and Novacor (Corunna Operations). This study comprised eight different test organisms and 22 different toxicity end points, was built on and complemented pioneering 1970s wo rk at the Petro-Canada refinery, and was designed to (a) determine any changes in effluent quality, (b) determine any previously unsuspected effluent toxicity, and (c) determine any potential for chronic toxici ty in the effluent. Although Petro-Canada has steadily reduced contami nants in its effluent since the earlier study, toxicity has not change d and no new toxic effects were identified. Effect thresholds for the most sensitive animal species (Daphnia pulex) were 1 to 10% effluent i n both studies. The Novacor effluent had lesser effects on biota than the Petro-Canada effluent. Intake waters demonstrated toxicity in some tests. Chronic effects on invertebrates and fish in receiving waters are predicted not to occur if the Novacor effluent is diluted 10- to 2 0-fold and the Petro-Canada effluent is diluted 50- to 100-fold.