Special Report No. 90-11: A Review of Recent Scandinavian Research on the Aquatic Effects of Bleached Pulp Mill Effluents

Some recent Scandinavian research has (a.) documented the presence of disruptions to the ecosystem in vicinity of Norrsundet on the Gulf of Bothnia, and (b) prompted some to conclude that chlorinated organic chemicals (i.e. adsorbable organic halides or AOX) from a nearby bleached pulp mill are a primary causative agent. In this report, Dr. William Owens of the Procter & Gamble Co. use these data to identify AOX as the causative agent is limited because of confounding effects related to (a) environmentally significant loadings of a variety of non-chlorinated compounds and conventional pollutants (e.g. Resin acids, BOD, and TSS), and (b) important hydrological differences between the sites used in this research to characterize the effects of bleached and unbleached pulp mill effluents. It appears likely that the observed disruptions are primarily related to the effects of conventional pollutants in primary-treated wastewaters discharged under conditions providing little opportunity for mixing. One of the observations made near a bleached kraft mill in the Gulf of Bothnia was the presence of elevated levels of the enzyme ethoxyresorufin-o-deethylase (EROD) in fish, a biological response that can be caused by exposure to certain chlorinated organic chemicals.