Sublethal toxicity findings by the pulp and paper industry for cycles 1 and 2 of the environmental effects monitoring program

摘要

Sublethal toxicity tests successfully measured the improved quality of pulp mill effluents from the first cycle of environmental effects monitoring (1992-1996)to the second cycle(1997-2000). Test endpoints showed notable shifts to higher concentrations(less toxic). During the second cycle of monitor- ing, significantly more tests showed no effect in full-strength effluent. Five case studies were considered as part of this exercise. Most of the improvement came with installation of secondary treatment. Twelve Ontario mills with secondary treatment showed reduced toxicity, compared to results with primary treatment.