MONITORING OF ORGANOCHLORINE COMPOUNDS IN FINNISH INLAND WATERS POLLUTED BY PULP AND PAPER EFFLUENTS USING THE MUSSEL INCUBATION METHOD

In the summer of 1988 a full-scale monitoring of chlorohydrocarbons, chlorophenols and aromatic chloroethers was carried out in the freshwater recipients of pulp and paper industry using the mussel incubation method, which has been developed and tested in Finland since 1984. The total number of incubation stations was 40. The results showed that the highest concentrations of chlorophenols originating from pulp bleaching processes were found in the vicinity of pulp mills with no biological waste-water treatment plant. Other chlorophenolic compounds - airborne or mainly originating from chloro-disinfection of water, combustion, wood preservation, sawmills etc. - were detected in small amounts at almost all the sites tested. The highest concentrations were found in the recipients of old sawmills. PCB was also detected in considerable concentrations in some recipients. In the summer of 1989 the monitoring was repeated at 20 incubation stations. The results of 1988 and 1989 are compared, with particular reference to those recipients where water protection measures and the construction of new activated sludge treatment plants were carried out during 1988.