The aims of this study were to measure the concentrations of selected toxic and essential elements in the muscle tissue of five common freshwater fish species (roach (Rutilus rutilus), freshwater bream (Abramis brama), prussian carp (Carassius gibelio), crucian carp (Carassius carassius) and common carp (Cyprinus carpio)) from Lake Burgas and Lake Mandra (Bulgaria). In all samples the levels of Cd, Cr, Cu, Mn, Ni, Pb, Fe and Zn were under the maximum allowed concentrations for safe human consumption in Bulgaria and ranged as follows: Cd 0.02–0.05; Cr 0.03–0.06; Cu 0.11–0.20; Mn 0.05–0.71; Ni 0.06–0.11; Pb 0.15–0.27, Fe 1.68–5.86 and Zn 1.94–9.06 mg/kg wet weight. The concentration of As was under detection limit. An assessment of the human risk by calculation of the target hazard quotients (THQ), hazard index (HI) and target risk (TR) was performed. The target hazard quotient (THQ) for individual elements and HI for combined metals were lower than 1, indicating no health risk for consumers due to the intake of either individual or combined metals. The target risk for iAs, Pb and Ni was below 10⁻⁶, indicating no carcinogenic risk. According to these results, the consumption of these freshwater fish species is safe for human health.

The unique, closed ecosystem of the Black Sea is of significant global importance. The levels and health risk of some trace elements (As, Cd, Cr, Cu, Fe, Ni, Pb and Zn) in wild and farmed mussels (Mytilus galloprovincialis) collected from the Bulgarian part of the Black Sea were determined and using different approaches such as Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), Hazard Index (HI), Target risk (TR), human health risk levels were assessed. The mean maximum concentrations of the elements Cd, Cr, Cu, Fe, Ni, Pb and Zn in all mussel samples were below the maximum permissible limits (MPLs) except that which exceeded the limit of 2.00 mg/kg ww. Eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) were the major polyunsaturated fatty acids. The fatty acids profile studied mussels showed that the farmed mussels had higher PUFA/SFA ratios, DHA and EPA + DHA content and lower SFA, AI and TI values. The target risk (TR) values for Pb, Cr, Ni and As were calculated, evaluated and showed acceptable or negligible levels. Target hazard quotients (THQs) and hazard index (HI) from elemental intake were below 1 indicated no hazard from consumption. The benefit–risk ratio indicated that wild and cultured M. galloprovincialis are safe for human consumption.

This study aimed to provide data on selected toxic (Cd, Pb and Ni), essential (Cr, Cu, Fe, Mn and Zn) and microelement (Na, K, Ca and Mg) concentrations in edible tissues of the Mediterranean mussel (Mytilus galloprovincialis), striped venus clam (Chamelea gallina) and the wedge clam (Donax trunculus). Samples were collected from the Black Sea (Bulgaria) four times over, a period of one year (2022). In comparison with the maximum permissible levels set by the EU and USFDA, all elemental concentration found in the bivalve species were lower than the prescribed limits. An estimation of the dietary metal intake through calculation of the target hazard quotients (THQ), hazard index (HI) and target risk (TR) was performed. The target hazard quotient (THQ) for individual metal and HI for combined metals were lower than 1, indicating no health risk for consumers due to the intake of either individual element or combined ones. The target risk value for toxic inorganic Pb and Cr was below 10⁻⁶, indicating no carcinogenic risk. According to these results, the consumption of these bivalve species is completely safe for human health.

Today, the distribution and consumption of canned products have become widespread due to the convenience of using processed fish products. This study aims to evaluate elements of toxicological concern and essential elements (Cd, Al, Cu, Cr, Mn, Fe, Pb, Ni, and Zn), the fatty acid composition, and the fat-soluble vitamin and antioxidant pigment contents of various canned fish products purchased on the Bulgarian market. The estimated weekly intake and human health benefit–risk ratio based on metal elements and n-3 LC-PUFA contents in canned fish products were assessed. The contents of the analyzed elements in the canned samples were found to be below the limits set by various health organizations. Al was detected in only one sample. The profile of fatty acids showed that the canned fish had high PUFA/SFA ratios, EPA + DHA contents and low SFA, AI and TI values. The analyzed canned fish contained significant contents of fat-soluble vitamins. The Atlantic bonito in a jar sample was characterized by a high percentage of vitamin A (26.7% RDI) and vitamin D3 (142% RDI) per 100 g portion. The calculated EWI value shows that the consumption of canned fish products did not present any risk. The benefit–risk ratio indicates that the canned fish species are safe for human consumption, except for one sample regarding Cr.

This study evaluated the effects of domestic cooking methods (pan-frying, smoking, and grilling) on the concentrations of elements of toxicological concern and essential elements (Cd, Cr, Cu, Fe, Mn, Ni, Zn, and Pb) in the traditionally consumed Black Sea bluefish (Pomatomus saltatrix). The investigation also included an assessment of the associated health risks and benefits by calculating carcinogenic and non-carcinogenic effects as well as benefit–risk ratios. Toxic heavy metals such as Cd, Ni, and Pb were found to be below the maximum residual limits (MRLs) established by relevant food safety authorities. Cooking generally led to increased concentrations of both essential and toxic elements compared to raw samples, with the highest increases observed in grilled and smoked samples. Furthermore, evaluations of (a) estimated weekly intakes (EWIs), (b) target hazard quotients (THQs) for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn, and (c) hazard quotient ratios for essential fatty acids (HQ_EFA) relative elements indicated that consumption of these cooked bluefish species does not pose significant health risks to consumers.