Barnacles (Balanus trigonus and Balanus perforatus) as new bioindicators for ecotoxicological assessment of Mediterranean off-shore extraction

The aim of this study is to validate a methodology based on biomarker responses in the barnacles Balanus perforatus and Balanus trigonus to assess ecotoxicological effects associated with off-shore oil extraction. This research is a part of the “Biomare” project, between the Department of Environmental Sciences (Siena University) and ENI Exploration and Production Division. During laboratory phase (I) the most sensitive biomarker responses in barnacles exposed to gasoline (10, 100, 1000 ppm) and produced waters were investigated. In field phase (II) biomarkers in barnacles were validated during a biomonitoring program in the Mediterranean Sea. The off-shore selected platform was “Cervia B” in the northern Adriatic; the “Paguro” platform, sunk in 1965, was chosen as a comparison site. Several biomarkers (MFO activities (BPMO, Reductases), AChE, antioxidant enzymes, porphyrins) and contaminants (Polycyclic Aromatic Hydrocarbons (PAHs) and trace metals) were measured. Laboratory studies showed high sensitivity of response in both species for all biomarkers tested, particularly MFO and esterases, and high bioaccumulation capacity. Field results showed differences in biomarker responses and PAH levels between barnacles collected at the two sites and between the two species. In conclusion, this study provided innovative results for the use of the selected bioindicators and for the responses generated after chronic and acute exposure to petroleum derivatives. These results suggest that barnacles could be used in future biomonitoring programs to evaluate both the effects of petroleum derived contamination, and the level of contamination itself.