ABSTRACT
Trends in concentrations of chlorophenolic compounds in incubated mussels from two Finnish pulp mill recipient watercourses during the last ten years are discussed. The results are compared with the loading variables (theoretical concentrations of BOD7, CODCr, suspended solids and AOX) estimated for the receiving watercourses of the pulp mills concerned. The prevailing discharges in watercourses and the dilution of the waste water loading have also been taken into consideration. The trends of the chlorophenolic compounds originating from the pulping industry as well as the trends of tetrachloroguaiacols in incubated mussels have been decreasing. The reasons for these trends are: 1) the improvement of waste water treatment and 2) the decreased use of chlorine in pulp bleaching. The decreasing trend of the chlorophenolics which originate mainly from wood preservation and combustion is also evident.
