Biomarkers of exposure and effect in flounder (Platichthys flesus) exposedto sediments of the Adriatic Sea

The modifications of several biomarkers were investigated in flounder (Plat ichthys flesus) when exposed in the laboratory to sediment samples collecte d from the Northern Adriatic Sea. Besides clean sand used as a control subs trate, fish were exposed to sediments sampled offshore the delta of the Po River, the harbour of Trieste, and from the industrial harbour of Venice (P orto Marghera). After six days of exposure, the enzyme activities ethoxyres orufin-O-deethylase (EROD), UDP glucuronyltransferase (UDPGT), glutathione S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx), were assayed in fish liver. In addition, the contents of reduced glu tathione (GSH), nonprotein thiols (SH), total sugars and extractable lipids were also determined in hepatic tissue, as well as the number of micronucl eated hepatocytes and biliary concentrations of fluorescent aromatic compou nds (FAC). Despite some variability within treatment groups, differences am ong exposed organisms were evident and consistent with known contaminant le vels of sampled areas. Microsomal activities (EROD, UDPGT) and FAC levels w ere the most sensitive exposure indicators. Variations in the other biomark ers showed only tendencies which although not statistically significant wer e generally consistent with the contamination pattern. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.