Physiological Disturbances in Fish Living in Coastal Water Polluted with Bleached Kraft Pulp Mill Effluents

Abstract

An extensive trial to examine physiological and biochemical changes in perch (Perca fluviatilis) inhabiting coastal waters polluted by bleached kraft mill effluents (BKME) has been carried out. The investigations were performed at four different times of year. Fish from a reference site and from sampling sites 2, 4.5, 8, and 10 km from the discharge point were examined. The results of the investigation show profound effects of BKME on several fundamental biochemical and physiological functions. Typical symptoms in perch from the polluted areas were reduced gonad growth, enlarged liver, and very strong induction of certain cytochrome P-450-dependent enzyme activities in the liver. Elevated levels of ascorbic acid in liver tissue and abnormal carbohydrate metabolism reflect the effluent's ability to cause metabolic disorders. Marked effects on the white blood cell pattern indicate a suppressed immune defence. Alterations in the red blood cell status and in the ion balance suggest that the demand for oxygen by certain tissues was increased and that gill function was impaired, respectively. The toxic effects were most pronounced in fish living up to 4.5 km from the discharge point, but some disturbances (e.g. cytochrome P-450 induction, reduced gonad size, and hematological alterations) were observed in fish caught as far as 8–10 km from the kraft bleach plant.