Dietary fish oil used in aquafeed transfers marine pollutants to farmed fish. However, the entire transfer route of marine pollutants in dietary fish oil from ocean to table fish has not been tracked quantitatively. To track the entire transfer route of marine pollutants from wild fish to farmed fish through dietary fish oil and evaluate the related human health risks, we obtained crude and refined fish oils originating from the same batch of wild ocean anchovy and prepared fish oil-containing purified aquafeeds to feed omnivorous lean Nile tilapia and carnivorous fatty yellow catfish for eight weeks. The potential human health risk of consumption of these fish was evaluated. Marine persistent organic pollutants (POPs) were concentrated in fish oil, but were largely removed by the refining process, particularly dioxins and polychlorinated biphenyls (PCBs). The differences in the POP concentrations between crude and refined fish oils were retained in the fillets of the farmed fish. Fillets fat content and fish growth were positively and negatively correlated to the final POPs deposition in fillets, respectively. The retention rates of marine POPs in the final fillets through fish oil-contained aquafeeds were 1.3%–5.2%, and were correlated with the POPs concentrations in feeds and fillets, feed utilization and carcass ratios. The dietary crude fish oil-contained aquafeeds are a higher hazard ratio to consumers. Prohibiting the use of crude fish oil in aquafeed and improving growth and feed efficiency in farmed fish are promising strategies to reduce health risks originating from marine POPs.

The presence of toxic elements in fish represents a hazard for human health, especially in Mediterranean countries and other regions with high per-capita fish consumption. The present research, carried out along the northern Catalan coast (NW Mediterranean), aimed to determine the levels of trace metals and arsenic in the muscle of white seabream Diplodus sargus (L.), a common demersal species of growing interest for fisheries and aquaculture. Average mercury concentrations widely exceeded the limits imposed by EU despite the low contamination levels previously reported for the study area, stressing the potential risk associated to the consumption of medium-sized, non-predatory fishes. The other analyzed elements fell within the recommended limits. Preliminary results about the feeding habits of D. sargus are reported, in order to determine feeding habitat and items of the analyzed specimens.

The concentrations of 16 elements (Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Cd, Ba, and Pb) were determined in four fish species (Carassius auratus, Squaliobarbus curriculus, Pelteobagrus fulvidraco, and Silurus asotus) collected in the Xiang River, a mine-impacted river in Southern China. The mean values of the elements analyzed in fish muscles were in the decreasing order of Mg > Ca > Zn > Fe > Sr > Al > Cu > Mn > Ba > As > Cr > Pb > Ni > V > Co > Cd. The concentrations of Mg, Ca, Sr, Ba, and Cu in omnivorous species were found to be significantly higher (p < 0.05) than those in carnivorous species. Negative correlations observed between most element concentrations and fish sizes indicated the younger individuals accumulated more elements than the older ones. Principle component analysis and orthogonal partial least squares discriminant analysis were employed to characterize the effects on element bioaccumulation using the element concentration matrix. The elemental profiles preferred to cluster according to differences in fish species rather than in sampling sites. The potential health risk evaluated through Monte Carlo simulation showed no appreciable adverse impact on human health from exposure to trace elements in fish muscles through consumption.

The contamination level of 12 antibiotics in 8 species of fish and shrimp from the Dongting Lake, China, was firstly studied. In total, the concentrations of antibiotics in fish and shrimp were lower, which were far lower than the maximum residue limits. The most abundant compound was enrofloxacin followed by sulfadiazine, sulfamethoxazole, sarafloxacin, and sulfadimidine with the highest content from 0.37 to 1.06 ng g⁻¹. The concentrations in Silurus asotus, Cyprinus carpio, and Palinuridae were higher. Concentrations in fish and shrimp from different water layers showed spatial difference, with the order of benthos and middle-lower species > middle-upper species. In addition, the antibiotic content could be affected by the diet, which showed the concentration level of antibiotics decreased in the order of carnivorous > omnivorous > phytophagous species. Human health risk assessment based on potential fish consumption indicates that main antibiotic risk factors were enrofloxacin and sarafloxacin, and main risk species were Silurus asotus and Palinuridae. The daily risk quotient of these antibiotics to rural residents was lower than townsmen. This study is the first report of antibiotic content in fish and shrimp from the Dongting Lake, which could enrich the research of emerging pollutants in aquatic products.

Since introduction into the Chesapeake Bay watershed in the 1970s, blue catfish (Ictalurus furcatus) populations have increased, impacting native species. One strategy suggested to limit their growing numbers is to expand the existing commercial fishery. However, the promotion of human consumption of this large, omnivorous fish may increase exposure to contaminants of concern (COC). However, there are few published data on contaminants in blue catfish. To evaluate this possibility, we measured COC (PCBs, PBDEs, OCs, Hg) in individual fillets and compared levels to established consumption advisory limits. James River (near Richmond, Virginia) and Upper Potomac River (downstream of Washington DC) fish exhibited higher burdens of most COC than those from the lower James and rural Rappahannock rivers. Fish sex and δ¹⁵N values (surrogate for trophic position) did not correlate with COC concentrations. Potomac River fish exhibited greatest δ¹⁵N, perhaps related to local wastewater inputs. Despite differences in human population densities among watersheds, fish mercury (Hg) levels were similar. Most fillets surpassed US EPA advisory limits for unrestricted consumption (> 16 meals/month) for Hg and PCBs. Hg and PCB advisories in the region typically restrict consumption to two 220 g meals/month. Hence, individuals who rely on fish for a large portion of their diet may be exposed to unacceptable Hg and PCB concentrations. COC levels typically increased with fish length; in particular, fish > 550 mm often exceeded unrestricted consumption limits for chlordanes and DDTs. PBDEs, pentachloroanisole, hexachlorobenzene, and mirex levels were generally below established advisories. However, because fish advisories are based on the expected consequences from single contaminants and a single or limited number of toxicological endpoints, consumers face greater risks due to cumulative effects from all coincident COCs, as well as additional exposure pathways, such as other food and air. The additional data on contaminant levels reported here will increase the accuracy of forecasted risks. However, it also illustrates the complexity in communicating the risks from multi-contaminant exposure.

In this study, 15 representative surface waters and sediments and seven typical fish were collected during the wet season in 2016 to explore the occurrence, chemical fractionation, and ecological risk of heavy metals (Cu, Zn, Pb, Cd, Cr, Hg, As, and Ni) in aquatic ecosystems of Dongting Lake in China. In surface water, the concentrations of all elements were lower than the third grade of the surface water quality standards (GB3838-2002). The highest concentrations of Zn, Pb, Cd, Ni, and Cu were found in the outlet of Dongting Lake, whereas As and Cr were highest in the Xiangjiang River Delta area. In surface sediments, the concentration decreased in the order of Zn > Cr > Pb > Cu > Ni > As>Cd > Hg; the highest concentration of all elements, except for Hg, was located in the Xiangjiang River Delta area; for chemical fractionation, Cr, Hg, Zn, As, Ni, and Cu were mainly residual fractionation; and Pb and Cd were mainly in a reducible state and fraction soluble in acid, respectively. In fish muscle, the concentrations of all elements were lower than relevant standards; the highest concentration appeared in fish living in the middle-lower and demersal layers. As for the feeding habits of fish, the average concentration decreased in the order of carnivorous > omnivorous > herbivorous fish. The potential ecological risk and the ratio of secondary phase to primary phase assessment showed that Cd and Hg had the highest ecological risk and that Cd and Pb had a high risk of secondary release. A health risk assessment showed that drinking water and fish for consumption in urban and rural areas around Dongting Lake were in the acceptable level.