Summary of Results from the Swedish Project ‘Environment/Cellulose'

The biological effects of effluents from pulp industries, especially from bleaching processes, on aquatic ecosystems were studied in a joint biological/chemical project field consisting of several sub-projects. The principal study was devoted to the effects of biologically active chlorinated organic compounds.

A receiving body of water for pulp bleach plant effluents at the Gulf of Bothnia was chosen for the three year study. Near the effluent outlet the fish biomass was low, and the species composition of the fish community had changed. Perch (Perca fluviatilis L.) exhibited reduced reproduction and disturbed physiology in all parts of the receiving body of water. The effluent also affected the diversity, biomass and distribution of invertebrates and plants. To further study the effects, fish and benthic-living organisms were exposed in the laboratory to sediment from the receiving water and to various mixtures of bleach plant effluents. The level of extractable organic chlorine (EOC1) of the perch decreased along a gradient from the effluent outlet towards the open sea. In sediment outside the Swedish coast, the level of EOC1 and the occurrence of compounds related to bleach mill effluents indicated a distribution of such substances over large areas.