Selenium and mercury balance in sea bream obtained from different living environments in Turkey: a risk assessment for the consumer health

The selenium health benefit value (Se-HBV) is the criterion developed for revealing nutritional values or the risks related to mercury (Hg) toxicity which can emerge in relation to consumption of fish. In this study, the conditions of Se and Hg elements in the muscular tissues of sea bream (Sparus aurata) living in different environments in Mugla province were examined. In addition, a benefit/risk assessment was performed in terms of consumer health with the calculation of Se-HBV. In this context, muscular tissues of sea bream obtained from wild species (WS), offshore marine cages species (OS), and soil ponds species (SS) were dissolved with microwave wet digestion and the concentrations of Se and Hg (mg/kg wet weight) were determined by using inductively coupled plasma mass spectroscopy (ICP-MS). According to the obtained results, the highest mean Se level was determined in SS (0.43 ± 0.02 mg/kg) followed by WS (0.35 ± 0.03 mg/kg) and OS (0.34 ± 0.02 mg/kg). The highest mean Hg concentration was detected in WS (0.09 ± 0.02 mg/kg) followed by OS and SS as 0.05 ± 0.01 mg/kg respectively. As a result of risk assessment conducted with Se-HBV, positive values were determined for each one of three sea bream groups.

Selenium-Mercury Balance in Commercial Fish Species from the Turkish Waters

The interactions between selenium (Se) and mercury (Hg) were assessed in order to interpret public health risk, associated with dietary mercury exposure due to fish consumption. For this purpose, the mass and molar concentrations of Se and Hg were determined in the edible tissues of six species of fish, collected from the commercial fishing grounds of Turkey. The Se/Hg molar ratios and selenium health benefit values (Se-HBVs) were also calculated. The main fish species exported from Turkey to Europe were studied to determine the risks or benefits for human health. The mean Hg levels (μg g^-1, wet weight) ranged from 0.01 (in turbot) to 0.45 (in Atlantic bluefin tuna). The average selenium concentrations were between 0.96 μg g^-1 (in thornback ray) and 1.86 μg g^-1 (in turbot). The molar ratios of Se/Hg were above 1 for all species and greater than 100 in turbot, red mullet, and whiting. Positive Se-HBVs were determined for all samples, showing health benefits. Since Se is present in molar excess of Hg in the fish muscles, organic Hg exposures from eating these fish is not a public health concern.

Mercury, silver, selenium and other trace elements in three cyprinid fish species from the Vaal Dam, South Africa, including implications for fish consumers

The levels of Cr, Cu, Zn, Se, Ag, Cd, Hg, and Pb were determined in muscle and liver samples from 30 specimens of fish belonging to the species Labeobarbus aeneus, Labeobarbus kimberleyensis, and Labeo umbratus from the Vaal Dam. Health risks for human fish consumers were estimated using the target hazard quotient (THQ), the Se:Hg-ratio, and Se health benefit value (Se HBV). This is the first comprehensive report on Hg levels in fish from this lake. Mean concentrations ranging from 0.247-0.481 mg/kg dw in muscle and from 0.170-0.363 mg/kg dw in liver clearly show a contamination with this element. Although levels in muscle did not exceed maximum allowances for human consumption, a calculated THQ of 0.12 and 0.14 for the two Labeobarbus species, respectively, showed a potential risk due to additive effects. All Se:Hg-ratios as well as Se HBVs clearly suggested positive effects for fish consumers. Levels of Cu were remarkably high in the liver of L. umbratus, calling for further investigation on this species. Cadmium levels were above the maximum allowances for fish consumption in the liver of all three species (means between 0.190 and 0.460 mg/kg dw), but below the LOD in all muscle and intestine samples. This is also the first report of Ag in fish from South Africa. Levels were below the LOD in muscle, but well detectable in liver; they varied significantly between the two Labeobarbus species (0.054 ± 0.030 and 0.037 ± 0.016 mg/kg dw) compared to L. umbratus (1.92 ± 0.83 mg/kg dw) and showed a positive correlation with Cu levels (63.7 ± 17.0; 70.3 ± 9.0 and 1300 ± 823 mg/kg dw), possibly due to similar chemical affinities to metallothioneins. The detected Ag levels can serve as a basis to monitor the development of this new pollutant in aquatic environments in South Africa and worldwide.

Selenium, total mercury and methylmercury in sardine: Study of molar ratio and protective effect on the diet

The purpose of this work was to evaluate the risk-benefit associated with canned sardine consumption, considering the selenium, the mercury and the methylmercury contents and the Se:Hg molar ratio and the Se-health benefit value (HBV) index. In this study, 63 canned sardine samples were purchased worldwide and for the determination of selenium and mercury species, the inductively coupled plasma optical emission spectrometry and thermal decomposition and amalgamation atomic absorption spectrometry were employed. The mean results obtained for the Brazilian samples varied between 12.6 and 65.5 μg kg^-1 for Hg; <3.7 and 45.4 μg kg^-1 for methylmercury; 310 and 1370 μg kg^-1 for Se. The MeHg/Hg ratio showed that the most toxic forms of Hg (MeHg) is predominant in 52 and 39% of the Brazilian samples conserved in tomato sauce and in oil, respectively. Nevertheless, the Se-HBV index and the Hg:Se and Se:Hg molar ratios indicated that the selenium content in canned sardine samples is enough to provide a protective effect on the Hg species.