Mussel incubation method for monitoring organochlorine compounds in freshwater recipients of pulp and paper industry

Abstract

A biological method based on bioaccumulation and using incubated lake mussels (Anodonta piscinalis) was developed and applied for monitoring organic chlorocompounds originating especially from pulp and paper industry and occurring in the water in very small and fluctuating concentrations. By this method the spreading of the severe PCB-pollution in Lake Kernaalanjärvi was specified, and the limits of the PCB-leakage in the Äänekoski area were defined. Of the other chlorohydrocarbons lindane as well as DDE were detected everywhere in small concentrations. DDT was, on the contrary, very rarely found. Hexachlorobenzene occurred also very commonly, and the highest concentrations were detected in the immediate recipients of pulp mills. Some local pollution cases caused by chlorophenols used in wood preservatives were detected. Airborne chlorophenolics were found everywhere. 2, 4, 6- Trichlorophenol was found to be the main chlorophenolic in the recipient of the sulphite pulp mill. It was possible to clear up the occurrence and transformation of bleaching remnants (S2PCP-group). In addition, there was proof of the transformation of chlorophenols and chloroguaiacols into chloroanisoles and chloroveratroles in the watercourse. Analysis of the S2PCP-group from incubated mussels seems to be very suitable for the monitoring of organochlorine compounds originating from pulp and paper industry. The introduction of biological effluent treatment caused a significant decrease of chlorophenolic compounds. Chlorinated dibenzo-p-dioxins and dibenzofurans were also found with the help of incubated mussels in areas worst polluted by pulping effluents, although in very small concentrations. It was also found that biological treatment of waste water decreases these compounds considerably and that the components occurring after the purification process were clearly less toxic furans. Practical guidelines of the mussel incubation method are presented.