FATE AND EFFECTS OF PULP-MILL CHLOROPHENOLIC 4,5,6-TRICHLOROGUAIACOL IN A MODEL BRACKISH WATER ECOSYSTEM

The fate and effects of the pulp mill effluent compound 4,5,6-trichloroguaiacol (TCG) were tested over 16 months on a model Baltic Sea littoral zone using a Fucus vesiculosus-based mesoscale model ecosystem. Bioaccumulation of TCG and metabolites from water ranged from 50 times for algae up to 700 times for invertebrates and fish, the factor increasing with trophic level. Algae contained chloroguaiacols, chlorocatechols and chloroveratroles and exhibited no major toxic effect. Fucus colonization appeared to be hindered by filamentous algae which covered surfaces otherwise available for new colonization. This unrestricted filamentous algal growth was probably a result of reduced grazing by herbivores, which in turn was apparently caused by reproduction failure in herbivorous crustaceans. Sediment-dwelling organisms appeared less affected than invertebrates in the algal habitat, possibly because of reduced bioavailability of toxic compounds due to binding to sediment particles. TCG and metabolites in the sediment were dominated by catechols; no veratroles were found. Only in the largest size class of sticklebacks was there a dose-related reduction in mean weight. Only 0.5% of the TCG added was recovered in the system after 16 months. Of this, 99% was associated with the sediment. The remainder was divided equally between algae and fauna. The role of algae and sediment in the Baltic Sea littoral zone is therefore paramount to the ultimate fate and effects of such compounds on invertebrates and fish. © 1990.