Occurrence of NDL-PCBs, DL-PCBs, PCDD/Fs, lead and cadmium in feed and in rainbow trout (Oncorhynchus mykiss) farmed in Italy

The safety of farmed rainbow trout (Oncorhynchus mykiss) is correlated with the quality of the production process. Polychlorinated biphenyls (PCBs), dioxins (polychlorinated dibenzodioxins and furans - PCDD/Fs), and heavy metals such as lead and cadmium were investigated because they can represent a risk for the consumer. The levels of these compounds in water, feed and specimens of trout farmed with two different feeds (A and B) were assessed. Their accumulation in muscle of A and B trout was evaluated and their dependence on the levels of feed contamination was considered. The results showed a widespread contamination in feed and in the examined trout, although lower than the European Union limits. For all compounds, concentrations in the farming waters were always <LOQs. Mean concentrations of NDL-PCBs in the A feed were significantly higher than in the B feed, except for PCBs 52 and 28. DL-PCB and PCDD/F concentrations were significantly higher in A feed. Lead and cadmium mean concentrations in A feed were 0.26 +/- 0.01 and 0.1013 +/- 0.0009 mu gg(-1), respectively; and in B feed were 0.10 +/- 0.01 and 0.0855 +/- 0.0078 mu gg(-1), respectively. The results showed that intakes for Sigma DL-PCB+Sigma PCDD/F ranged from 4.4% to 12% of the TDI, and for Pb and Cd from 1.9% to 2.7% and from 0.3% to 0.4% of the TDI, respectively.