The effects of pulp and paper mill effluent on physiological and hematological endpoints in fingerling largemouth bass (Micropterus salmoides)

Abstract

The purpose of this study was to evaluate the effects of bleached kraft mill effluent on selected physiological and hematological endpoints in fingerling largemouth bass (Micropterus salmoides). Fish were exposed for 35 days to surface water collected at sites up- and downstream from a pulp and paper mill treatment-effluent discharge. The condition factor, spleen somatic index, and pronephros cellularity were statistically significantly decreased in fish exposed to the downstream site, compared to the upstream site. There was also a shift from lymphocytes to neutrophils in peripheral blood of fish exposed to the downstream site. Hematocrit values and the liver somatic index were statistically significantly increased in fish in the downstream exposure. These results indicate that in-stream exposure to elemental-chlorine-free pulp and paper mill effluents produce a generalized stress response, leading to potential immunosuppression in fish.

Keywords::

• Pulp and paper mill
• Largemouth bass
• Physiological and hematological endpoints

Acknowledgments

The authors thank Rebekah Gibble and Nancy Baer for their technical assistance and Kirk Cormier from the Louisiana Department of Environmental Quality for location and access to the sampling sites.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.