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This study is part of a project aiming to validate the use of the intertidal shanny Lipophorys pholis as a sentinel species in pollution monitoring in NW European marine ecosystems. To this end, a characterisation of acethylcholin (AChE), butyrylcholin (BChE) and propionylcholin (PrChE) esterases in L. pholis muscle was performed and the results indicated that AChE was predominant. Furthermore, the use of eserine sulphate and BW284c51 (0.64-800 microM), and iso-OMPA (0.08-16 mM), confirmed the measurement of true cholinesterases (ChEs) as well as the presence of pseudocholinesterases. The field application of these markers to L. pholis, sampled in seven locations along the Portuguese coast, revealed that fish were likely to be affected by neurotoxic compounds. This was indicated by the significant depletion of AChE (p<0.05) in animals collected at urban and industrialised sites, compared with those from reference locations. The inclusion of a marker of effect, measured as lipid peroxidation levels in muscle tissue, also revealed the existence of site differences. Overall, the study further validates the utility of L. pholis in pollution monitoring studies.

Thirty three PCB congeners were analyzed in three size classes of seabass (Dicentrarchus labrax), from a semi-intensive fish farm, in food and in abiotic compartment. Water and suspended particulated matter (SPM) showed higher concentrations of lower chlorinated PCBs, whereas fish tissues and food showed higher concentrations of CB153 and CB138. In order to examine the influence of different inputs to seabass contamination, bioaccumulation factors (BAF), biota-suspended particulate matter bioaccumulation factors (BSMAF) and biomagnification factors (BMF) were calculated. In general, the log BAF and log BSMAF showed good correlations with log K(ow), for congeners with log K(ow)>6.1. In three fish size classes, PCB congeners with log K(ow)<6.1 were found at concentrations higher than what was expected based on the BAF calculated for the more hydrophobic congeners, suggesting a different contribution of sources. The application of a mass balance model for accumulation of some congeners in seabass estimated concentrations in fish 3- to 38-fold higher than the measured values, probably by overestimating gill absorption. The model was applied with other scenarios in order to maximize uptake from food, which may have a significant influence in accumulation, and not only from diet pellets. Its contribution to fish contamination for highly chlorinated PCBs may reach a maximum of 54-64%, and for lower chlorinated PCBs its contribution is lower than 20%. In this work it was proved that to reduce fish contamination the quality of the water should be controlled.