HEAVY-METAL CONTENT AND BIOTRANSFORMATION ENZYMES IN 2 FISH SPECIES FROM THE NW MEDITERRANEAN

Trace metal concentrations (Cd, Cu, Fe, Zn) and total-calcium content were measured in the gills of 2 marine fish (painted comber Serranus c abrilla and striped mullet Mullus barbatus) sampled in different stati ons in the cove of Cortiou, where the outlet collecting the waste wate rs of Marseille, France, is situated (NW Mediterranean). In parallel, the activity rates of some phase I enzymes (ethoxyresorufin-0-dealkyla se, EROD; pentoxyresorufin-0-dealkylase, PROD) and phase II enzymes (g lutathione-S-transferase, GST) were determined in the livers of both s pecies of fish. Cadmium and copper concentrations were highly variable for both species. Two sampling stations situated in the dispersion ar ea of waste waters seemed affected by chemical pollution. At these sta tions, iron concentrations appeared to be higher in gills of S. cabril la and M. barbatus. Elevated iron concentrations were thought to be du e to the water treatment plant, which uses iron chloride as a floccula nt. Likewise, at both stations calcium and cadmium concentrations were higher in M barbatus. EROD and PROD activities appeared to be general ly lower in the livers of S. cabrilla collected at both 'polluted' sta tions; GST activities did not differ according to the sampling station s. Enzyme activities (PROD and GST) in M barbatus were lower at the st ations in the dispersion area of waste waters. The results imply that heavy metals, which can also be accumulated in some target organs of f ish, may lower biotransformation enzyme activities which are induced i n the livers of fish exposed to organics.