Dorota Napierska and Magdalena Podolska
Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland

Key words: environmental pollution, AChE, GST, flounder Platichthys flesus, biomarker, Baltic Sea.

Abstract.
High-level environmental contamination has been documented as eliciting negative effects on endocrine, reproductive and developmental events across vertebrate groups in the wild. Of particular interest and importance is whether relatively low levels of mixtures of environmental pollutants may have long-term impacts. Muscular Acetylcholinesterase (AChE) and hepatic glutathione S-transferase (GST) activities were measured in each sampled specimen of flounder Platichthys flesus. Statistically significant differences in the activities of both biomarkers were observed between reference and contaminated sites. A decrease of the activity of both enzymes was noted in older fish (over 6 years). GST activity differed with gender, and females had lower activities than males. A seasonal pattern of activity was seen in the case of GST, with the lowest values in June. Flounder muscle and liver tissue were analyzed for polychlorinated biphenyls (PCB congeners: 28, 52, 101, 118, 138, 153 and 180), organochlorine pesticides (α-HCH, β-HCH, γ-HCH, HCB, p,p'-DDE, p,p'-DDD, p,p'-DDT) and trace metals (Pb, Cd, Zn, Cu, Hg, Cr). The results of this study suggest that from endogene related variables, the age of the fish has strong impact on AChE and GST activity. Location has also high influence on the activity of both biomarkers. However, it has not been investigated if the influence of location is caused by pollution or by other location-related factors.