Effects of Biologically Treated Bleached-Kraft Mill Effluent Before and After Mill Conversion to Increased Chlorine Dioxide Substitution: Results of an Experimental Streams Study

Abstract

Large‐scale outdoor experimental streams were used to determine the effects of effluent on stream biota before and after conversion of a bleached‐kraft mill to increased chlorine dioxide substitution. Data for long‐term (6 to 9 months) exposures at 1.5 and 5 0% v/v effluent in periods before and after conversion were compared for effluent quality, rainbow trout (Oncorhynchus mykiss) production, growth, survival, and histopathology, and periphyton and macroinvertebrate community characteristics. Data for cytochrome P4501A and ethoxyresorufin O‐deethylase (EROD) biomarkers in trout were obtained in an additional 1 5‐month postconversion exposure. Postconversion effluent was characterized by reduced chlorinated organic constituents and adsorbable organic halides. Rainbow trout in both the pre‐ and postconversion periods indicated a pattern of greater size, fewer numbers, and equal or greater production in the effluent‐exposed populations compared to unexposed controls. Fish health measurements, including histopathology, hematology, and liver somatic indices, did not indicate significant negative effects, contrasting with the biomarkers, where there was a significant, positive dose‐response relationship with similar effluent exposures. The lack of major differences in fish and other stream biota responses following the reductions in effluent chlorinated organic compounds raises questions about the ecological relevance of these compounds at the concentrations tested.

Exposure of Reproductively Maturing Rainbow Trout to a New Zealand Pulp and Paper Mill Effluent

“…Our experimental system, as well as those developed by others (Hall et al, 1991(Hall et al, , 1992Haley et al, 1995;DubeH and Culp, 1996;Lehtinen et al, 1999), has been designed to reduce confounding "eld variables while maintaining a level of environmental relevance. Whether used for individual species studies, or community level impacts assessment, this mesocosm approach provides a useful tool, particularly where "eld level risk assessment is di$cult.…”

Metabolic Enzyme Activities in Fish Gills as Biomarkers of Exposure to Petroleum Hydrocarbons

“…Alterations of carbohydrate metabolism have been observed in several polluted environments, as reported for O. mykiss exposed to sewage e%uent (Wieser and Hinterleitner, 1980), for ¹ilapia mossambica exposed to fenvalerate (Radhaiah and Rao, 1990), and for several "sh species exposed to bleached kraft mill e%uents (Haley et al, 1995;Sandstrom et al, 1988;Adams et al, 1992). Most studies attribute an increased growth rate or larger visceral lipid accumulation of contaminated "sh to an increased abundance of food in a polluted environment, which may partially account for the observed changes.…”

Introduction to special series: Measurement and analysis of the potential long term impact of pulp and paper mill effluent on receiving waters

“…According to the Environment Canada publication EnviroZine (2004), scientists in Canada conclude with a high degree of certainty that paper mill effluents adversely affect fish populations. Yet, a series of long‐term experimental streams studies of warm water (NCASI 1983) and cold water (Hall et al 1991; Haley et al 1995) stream communities found little indication of adverse effects on fish or aquatic food webs at effluent concentrations considerably above those found in North American receiving waters.…”