COMPARATIVE-STUDY OF DNA-ADDUCTS LEVELS IN WHITE SUCKER FISH (CATOSTOMUS-COMMERSONI) FROM THE BASIN OF THE ST-LAWRENCE-RIVER (CANADA)

The levels of DNA adducts in the hepatic tissue of the white sucker fi sh species Catostomus commersoni were determined by P-32-postlabelling . The fish were caught at four sites: two sites near the city of Winds or (Quebec, Canada) on the St. Francois River, a downstream tributary of the St. Lawrence River, and two sites in the St. Lawrence River its elf near the city of Montreal (Quebec, Canada). The latter sites are k nown to be contaminated by many pollutants including polycyclic aromat ic hydrocarbons. Total adduct levels in all fish ranged from 25.1-178. 0 adducts per 10(9) nucleotides. White sucker from the selected sites of the St. Lawrence River had a significantly higher mean level of DNA adducts than those of the St. Francois River (129.4 vs 56.8, respecti vely). These results suggest that the effluents of many heavy industri es (e.g. from a Soderberg aluminium plant) flowing in the St. Lawrence River are more likely to produce genotoxic damage to fish than those released in one of its tributary, and mainly associated to the activit ies of a small town and a nearby pulp and paper mill.