Fish Populations and Biomarker Responses at a Canadian Bleached Kraft Mill Site, 1992 Environmental Conference Proceedings

The impact of bleached kraft mill effluent(BKME) discharges on fish populations and fish health has been studied in a riverine ecosystem in western Canada. The field program included seasonal and biological sampling. Fisheries analyses began with species abundance and distribution and for two target species, longnose sucker and mountain white-fish, included growth, recruitment, age distribution, and fecundity. Few differences were found in population parameters between the BKME exposed Wapiti-Smoky system and the reference stream. Chemical body burdens were concurrently studied with biomarker responses in the target species. EOC1 levels in fillets were similar in longnose suckers and mountain whitefish, but differences in bile EOC1 and 2,3,7,8-TCDD body curdens were observed. Biomarkers measurements included blood chemistry and hematology, histopathology, sex steroid levels, and mixed function oxidase induction - P4501A. The P4501A response was modest in longnose sucker and higher whitefish. However, no biologically significant exposure-related impariments were found in fish exposed to BKME. Radio telemetry confirmed significant mobility of both species. Therefore, the interpretation of P4501A and other biomarker results should be cautious without concurrent, individual chemical compound exposure analyses. In summary, BKME did not have discernible impacts on either fish populations or individual fish health, and P4501A induction was not predictive of biological impacts.