Persistent organic pollutants in sea bass (Dicentrarchus labrax L.) in two fish farms in the Mediterranean Sea.

We analyzed polychlorobiphenyls (PCBs), perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) in the edible part of farmed sea bass reared in two fish farms in Liguria (Northern Italy). The aim was to determine the contamination levels and human exposure to these chemicals through fish consumption. Concentrations of "dioxin-like" PCBs (DL-PCBs) ranged from 0.033 to 0.759pg ΣTEQ-PCBg(-1) whole weight (w.w.) in fish farm 1 and from 0.032 to 1.60pg ΣTEQ-PCBg(-1) w.w. in fish farm 2, and the six indicators of "non-dioxin-like" (NDL-PCBs) from 0.538 to 9.33ng Σ6PCBg(-1) w.w. and from 1.62 to 27.6ng Σ6PCBg(-1) w.w. Concentrations were generally lower in farm 1 than in farm 2. One reason for this difference might be the proximity of farm 2 to the seaport of La Spezia, which could be a punctual source of pollutants influencing the contamination of the water in the farm. Principal component analysis (PCA) showed differences also in the congeners profiles for the two sites, with higher-chlorinated PCBs more abundant in farm 1, and lower-chlorinated PCBs were more abundant in farm 2. Most of the concentrations of PFOS and PFOA were below the limit of detection (LOD 0.05ngg(-1) w.w.). Only about 10% of the samples analyzed had levels slightly higher than the LOD. Assessments of exposure using these data showed that consumption of farmed fish may contribute significantly to PCBs through the diet, whereas the contribution of PFOS and PFOA seems to be low.