ABSTRACT
A great deal of research work worldwide has been devoted to the assessment of the environmental impact of the production of pulp. A large proportion of the research has been performed using different kinds of biomarkers and biological/ecological endpoints. Bleaching of the pulp using chlorine and/or chlorine dioxide has been suspected to be the cause behind observed responses in organisms. Laboratory and mesocosm investigations on biochemical responses in fish do not give evidence that bleaching per se is the reason behind hepatic phase I and phase II detoxification enzymes in fish. Neither is it possible to relate other biochemical effects in fish to bleaching. Effluents from unbleached, chlorine bleached and non-chlorine bleached pulp production as well as resin acids and phytosterols caused responses in fish when exposed to these effluents under controlled laboratory and mesocosm conditions.
