Seasonal variation of bioaccumulation in Engraulis encrasicolus (Linneaus, 1758) and related biomarkers of exposure.

In the last years, the development of new techniques and the increase of sophisticated assays has improved the environmental monitoring programs by using fish as bioindicators of marine ecosystems, applying a multibiomarkers approach. The aim of this study was to assess the contamination level of the Catania Gulf through bioaccumulation and contaminant exposure response in Engraulis encrasicolus (Linnaeus, 1758). Heavy metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were analyzed in muscle tissue of the species. Furthermore we evaluated biomarkers of exposure to such contaminants: the metallothioneins (MTs), the ethoxyresorufin-O-deethylase (EROD) and stress protein or "heat shock proteins" (HSP70). In total, three sampling of 30 specimens each were performed during 2011. Comparison between classes of contaminants was performed using Student's t-test for paired samples Data showed that: the populations of E. encrasicolus accumulated a certain amount of metals, PAHs and organochlorine compounds in their tissues, that, however, did not exceed the legal limits set by Regulation 1881/2006 for contaminants in fish muscle; essential metals accumulate more during the reproductive periods of the species; the accumulation of heavy metals and PAHs are more closely related to natural and anthropogenic events; the presence of PCBs, although in traces, is the confirmation that banned compounds persist in the environment for several years; the levels of contaminants found in the tissues of the species do not seem to be likely to cause toxic effects both in the studied fish species. In conclusion, environmental risk assessment came out in this study for the Catania Gulf, showed a positive picture, although the contaminants detected are related to a certain degree of anthropic impact, and should be constantly monitored to ensure quality standards of the studied area.