Evaluation of Chemical Elements, Lipid Profiles, Nutritional Indices and Health Risk Assessment of European Eel (Anguilla anguilla L.).

The concentrations of ten elements (K, Na, Ca, Mg, Zn, Fe, Hg, Cu, Mn, and Cd) and fatty acids were analyzed in muscles of the European eel (Anguilla anguilla Linnaeus, 1758). The eels were caught in freshwater lakes connected with the Sawica River (north-eastern Poland). On this basis, it was determined whether the consumption of the fish is beneficial and safe for the health of the consumer. The results showed that the metal concentrations followed this order: K > Na > Ca > Mg > Zn > Fe > Hg > Cu > Mn > Cd. The fatty acids gave rise to the following sequence: MUFAs > SFAs > n-3 PUFAs > n-6 PUFAs. The target hazard quotient (THQ) value was below 1.0. The hazard quotient for the benefit-risk ratio HQEFA (0.39) also was below one, indicating that the intake of the recommended dose of EPA + DHA (250 mg/day) and the intake of mercury (0.415 mg/kg) for a person weighing 70 kg does not pose an obvious risk for human health. The lipid quality indices were OFA: 24.69, DFA: 74.36, AI: 0.55, and TI: 0.41. Based on the above statements, the consumption of eel meat is safe from a health point of view. However, the levels of toxic metals in the muscles of eels and their environment should continue to be monitored, as eels occupy a high position in the food chain.

Total Mercury and Fatty Acids in Selected Fish Species on the Polish Market: A Risk to Human Health.

The muscles of lake trout (Salvelinus namaycush Walbaum, 1792), crucian carp (Carassius carassius Linnaeus, 1758), flounder (Platichthys flesus Linnaeus, 1758), gilthead seabream (Sparus aurata Linnaeus, 1758), mackerel (Scomber scombrus Linnaeus, 1758) and tench (Tinca tinca Linnaeus, 1758) were examined. The total mercury (THg) was processed using the Milestone DMA-80 and the fatty acids were analyzed using the 7890A Agilent Technologies chromatograph. The THg content in analyzed fish ranged from 0.024 (lake trout) to 0.092 mg/kg wet weight (gilthead seabream). The muscles of fish examined had lower amounts of SFAs, and n-3 and n-6 PUFAs than MUFAs. The ratio of n-3/n-6 was higher in muscles of mackerel than other fish (p < 0.05). Due to the fact that both the THQ and HI are below 1, the tested fish are safe for the consumer from a nutritional point of view. Similarly, fatty acid indices indicate the safe consumption of selected fish species, and the daily consumption of the recommended dose of EPA + DHA (250 mg/day) and the concentration of mercury in fish calculations showed a hazard quotient for the benefit−risk ratio HQEFA below 1, suggesting that the intake of EPA + DHA poses no evident risk to human health. The ratio was calculated for a person weighing 60 kg. Therefore, it is important to monitor the fish, not only bought in the store, but also caught in various aquatic environments.

Assessment of Fish Quality Based on the Content of Heavy Metals.

The aim of this study was to estimate the fish quality in terms of the Cu, Fe, Mn and Zn contents. The research material was the muscle tissue of the fish crucian carp (Carassius carassius Linnaeus, 1758), flounder (Platichthys flesus Linnaeus, 1758), Gilthead seabream (Sparus aurata Linnaeus, 1758), mackerel (Scomber scombrus Linnaeus, 1758), Blue grenadier (Macruronus novaezelandiae Hector, 1871), rainbow trout (Oncorhynchus mykiss Walbaum, 1792), tench (Tinca tinca Linnaeus, 1758), tilapia (Oreochromis niloticus Linnaeus, 1758), Walleye pollock (Gadus chalcogrammus Pallas, 1814) and perch (Perca fluviatilis Linnaeus, 1758.). Heavy metals were determined with the atomic absorption spectrometry method (AAS). Significantly high concentrations of zinc (19.52 mg/kg wet weight), copper (0.77 mg/kg) and iron (6.95 mg/kg) were found in the muscles of crucian carp (p < 0.05) compared to the other fish studied, whereas Walleye pollock had a higher content of manganese (0.266 mg/kg) (p < 0.05). All studied fish species do not pose a threat to humans from these four metals. This was indicated by quality indexes (THQ and HI) whose values were below one. The values of these metals also did not exceed the maximum allowable concentrations established by the FAO (1983), but monitoring both the aquatic environment and the fish living there is necessary, for example, for the time-changing abiotic and biotic factors that can cause an increase in metals in the organs of fish.

Using Rutilus rutilus (L.) and Perca fluviatilis (L.) as Bioindicators of the Environmental Condition and Human Health: Lake Lanskie, Poland.

The aim of this study was to determine the mercury content and fatty acids profile in roach (Rutilus rutilus L.) and European perch (Perca fluviatilis L.) from Lake Lanskie (Poland). Mercury content was higher in the muscles than other organs in both species (p < 0.05). Mercury accumulates along the food chain of the lake's ecosystem. The value of the bioconcentration factor (BCF) indicated that Hg had accumulated in the highest amounts in muscles and in the other organs as follows: muscles > liver > gills > gonads. The metal pollution index (MPI) and target hazard quotient (THQ) were below 1, which means that these fish are safe for consumers. The values of HIS, GSI and FCF indicators show that both species of fish can be good indicators of water quality and food contamination. There were few differences between fatty acid content in the muscles of perch and roach. Contents of fatty acids having an undesirable dietary effect in humans (OFA-hypercholesterolemic fatty acids) were lower compared to hypocholesterolemic fatty acids (DFA, i.e., the desirable ones). In addition, the lipid quality indices AI and TI in the muscles of fish were at 0.40 and 0.22 (perch) and at 0.35 and 0.22 (roach), respectively. On this basis, it can be concluded that the flesh of the fish studied is beneficial from the health point of view.

Mercury, Fatty Acids Content and Lipid Quality Indexes in Muscles of Freshwater and Marine Fish on the Polish Market. Risk Assessment of Fish Consumption.

Mercury content and fatty acids in muscles of Perca fluviatilis L. (European perch), Leuciscus idus L. (ide), Cyprinus carpio L. (European or common carp), Oncorhynchus mykiss Walb. (rainbow trout), Platichthys flesus L. (European flounder). and Clupea harengus L. (bream) from the Polish market were investigated. The total mercury was processed with AAS. The fatty acids were analyzed by gas chromatography. The concentration of mercury in muscles varied from 0.006 to 0.138 mg/kg and decreased as follows: perch ≈ ide > flounder > herring ≈ bream ≈ rainbow trout > carp (p ≤ 0.05). There were only significant positive correlations between body weight and mercury content in muscle tissue of carp (r = 0.878), flounder (r = 0.925) and herring (r = 0.982) (p ≤ 0.05). The atherogenic index (AI), thrombogenicity index (TI) and flesh-lipid quality index (FLQ) were calculated as follows 0.33-0.70 (IA), 0.16-0.31 (IT) and 13.01-33.22 (FLQ). Hypocholesterolemic (OFA) and hypercholesterolemic fatty acids (DFA) in muscles of fish ranged from 18.26 to 23.01 and from 73.91 to 78.46, respectively. In most cases, there were not significant correlations between size (body weight and total length) and fatty acids in the muscles of the examined fish (p > 0.05). The Target Hazard Quotient (THQ) values were below 1, which shows that there is no non-carcinogenic health risk to the consumer by consuming the examined fish.