Abstract
The published information on sublethal effects of untreated and biologically-treated bleached kraft mill effluents (BKME) on freshwater fish has been critically reviewed from a Canadian perspective. Despite the vast data base, a clear assessment of BKME effects to fish was difficult. Based on the available information to date, BKME discharges do not seem to cause serious sublethal toxic effects on fish at concentrations expected to be found in Canada's receiving freshwaters. Only the tainting of fish flesh (a non-toxic effect) has been identified to be a possible consequence of BKME discharges at certain dilution levels. In order to properly assess the effect of BKME, future studies should be aimed at identifying possible problems relating to fish tainting compounds, fish reproduction, early development and habitat alteration (e.g. colour, nutrients).