Abstract
The concentration of mercury, fatty acids and lipid quality indices were determined in three species of fish (European eel, Anguilla anguilla Linnaeus, 1758; Eurasian perch, Perca fluviatilis Linnaeus, 1758; and roach, Rutilus rutilus Linnaeus, 1758). The fish were caught from a reservoir in the Warmia and Mazury region located near Olsztyn (north-eastern Poland). Mercury content was determined by atomic absorption thermal decomposition using Milestone DMA-80 (Italy), whereas fatty acids were measured by gas chromatography using a 7890A Agilent Technologies chromatograph. The total mercury concentration had the following sequence: European perch (0.297 mg/kg) > European eel (0.160 mg/kg) ≈ roach (0.100 mg/kg) (P<0.05). A positive correlation was found between the mercury content and size (the body weight and total length) of these fish (P<0.0001). Based on the THQ, HI (<1.0) and BRQ (1.063), it was concluded that the fish does not pose a health risk and is fit for human consumption. Similarly, low AI and TI values ( <1) are beneficial to human health related to reducing the risk of ischemic heart disease. A low OFA index of C12+C14+C18 and a high index of C18+UFA also indicate that these fish are safe from a nutritional point of view. The fatty acid indices HH (32.10–74.30), NVI (0.83–2.14), DI(18) (65.50–89.28), DI(16) (18.45–32.96), UI (131.93–278.64) and PI (88.60–314.90) were also studied. However, higher PUFA/SFA and de minimis EPA+DHA/Hg ratios compared to the recommended ratios suggest further research in this area is needed.