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Effects of biologically treated bleached‐kraft mill effluent before and after mill conversion to increased chlorine dioxide substitution: Results of an experimental streams study
Author(s) -
Haley Richard K.,
Hall Timothy J.,
Bousquet Theresa M.
Publication year - 1995
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620140214
Subject(s) - effluent , rainbow trout , environmental chemistry , biota , chemistry , trout , ecology , environmental science , biology , fish <actinopterygii> , fishery , environmental engineering
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.