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

Abstract

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 µg g(-1), respectively; and in B feed were 0.10 ± 0.01 and 0.0855 ± 0.0078 µg g(-1), respectively. The results showed that intakes for ∑DL-PCB + ∑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.

Contaminants in aquaculture: Overview of analytical techniques for their determination

“…In the work of Perugini et al [34], where the LOD were estimated by multiplying the appropriate one-sided 99% t-statistic by the standard deviation, LOD ranged from 0.1 and 1.4 ng g -1 for PCB 105 and PCB 153, respectively, and the LOQ was set to 2.5 ng g -1 for all PCB congeners. Cirillo et al [8] have only used GC-MS to quantify PCB in fish muscles (Table 1), and the amount of non dioxin-like PCB mean levels (2.7 ng g -1 ) are lower that the European Union limit fixed at 75 ng g -1 but the dioxin-like PCB mean levels are higher (86.6 ng g -1 ) than that reported in legislation [15]. Thus, the lack of contamination found in the analyzed waters for all the chemicals considered, including metals Pb and Cd, suggests that the contamination found in trout may mainly be attributable to feed according to the literature data [8].…”

“…Cirillo et al [8] have only used GC-MS to quantify PCB in fish muscles (Table 1), and the amount of non dioxin-like PCB mean levels (2.7 ng g -1 ) are lower that the European Union limit fixed at 75 ng g -1 but the dioxin-like PCB mean levels are higher (86.6 ng g -1 ) than that reported in legislation [15]. Thus, the lack of contamination found in the analyzed waters for all the chemicals considered, including metals Pb and Cd, suggests that the contamination found in trout may mainly be attributable to feed according to the literature data [8].…”

“…Cretì et al [6] verified that the different fish tissues show different capacity of accumulation of metals, and levels of both metals (Cd and Pb) in the various tissues significantly vary (p<0.0001) among fish culture systems. Cirillo et al [8] have used the same technique (AAS) and verified that the levels of Pb (0.225 μg g -1 ) and Cd (0.007 μg g -1 ) in muscles of rainbow trout did not exceed the limit fixed at 0.30 and 0.05 μg g -1 , respectively, established by the European Union legislation for fish destined for human consumption [14], which also occurred with the metal levels found in muscles of rainbow trout (below 0.01 μg g -1 for Cd and 0.1 μg g -1 for Pb) in the work of Cretì et al [6]. According to Cretì et al [6], the great amount of Pb in kidney, liver and gills of fish cultured in the extensive farm practice may be the result of a water contamination caused by environmental pollution.…”

“…Thuy et al [36] referred that once antibiotics are released into the waters or sediments, they are subjected to transformation or degradation at various rates, depending on the nature of the antibiotic and environmental factors such as light, temperature, and/or microbial activities. 8 According to Håstein et al [11], the malachite green, which is an industrial dye that has effectively been used to treat fungal infections in fish, is not permitted in aquaculture, but the active substance and its metabolite, leuco-malachite green, are still detected in fish and fish products. Among veterinary drugs, the antibiotics (e.g., enrofloxacin) and their metabolites (e.g., ciprofloxacin) have also been applied in aquaculture production (through medicated feed or by addition directly in water) for the prevention and treatment of bacterial infestations, which can be responsible for serious economic losses [37].…”

“…Regarding chemical contaminants (concentration and duration of exposure), the ingredients of commercial animal feeds can be responsible for food safety risks in aquaculture; the major animal feed contaminants reported are veterinary drug residues, persistent organic pollutants, pesticides, metals and mineral salts (mercury, lead, cadmium, hexavalent chromium, arsenic, and selenium) [7]. The typology of feeds and the quality of waters can be considered important critical factors in fish farming [8]. The exchanges between fish body, water and food can be described by uptake via food and water, and losses via metabolism, growth dilution, egestion, and gills [9].…”