Tuna Consumption, Mercury Exposure, and Knowledge about Mercury Exposure Risk from Tuna Consumption in University Students

Reference intervals for trace elements in the general Danish population and their dependence on serum proteins

Reference intervals that indicate the anticipated results of clinical chemistry parameters in a healthy background population are essential for the proper interpretation of laboratory data. In the present study, we analysed major trace elements in blood samples from 400 randomly selected members of the general Danish population. Reference intervals were established for trace elements in both whole blood and serum, and associations with major plasma transport proteins were investigated. In the case of a statistically significant correlation, a corresponding protein-adjusted reference interval was established for comparison with the unadjusted interval. While several trace elements correlated with albumin, ferritin and transferrin, the overall impact of transport proteins was minor and resulted in only marginal changes in the reference intervals. In conclusion, the updated reference intervals for trace elements can be employed without adjusting for plasma protein concentrations.

Essential and toxic elements in sardines and tuna on the Colombian market

The presence of metals in canned fish has been associated with adverse effects on human health. The aim of this study was to evaluate risk-based fish consumption limits based on the concentrations of eight essential elements and four elements of toxicological concern in sardines and tuna brands commercially available in the Latin American canned goods market. One brand of canned sardines and six of canned tuna were collected and evaluated by ICP-MS and direct mercury analysis. The Hg content was much higher than that previously observed in scientific literature. According to the calculated hazard quotients, all brands may present some risk in terms of this element, especially brand F in which levels up to 3.1 µg/g were measured. Sardine samples surpassed the maximum limits of Mn and As. Stricter quality control in retail chains and industries should be implemented in order to guarantee safe levels in fishery products.

Monitoring of Environmental Hg Occurrence in Tunisian Coastal Areas

Total mercury (Hg) was determined in 450 environmental samples (seawater, sediment plant and fish) from five Mahdia coastal areas (Tunisia). Tolerable Weekly Intake% (TWI) values, according to the European Food Safety Authority (EFSA), were calculated based on the average metal concentration in fish and the average weekly fish consumption rate. Hg was accumulated mainly in fish and in Posidonia oceanica leaves. Hg in sediment ranged from 1.88 μg/kg dry weight (d.w.) to 7.48 μg/kg d.w., while it was between 0.32 μg/kg and 0.19 μg/kg in seawaters. Our study showed high concentration in Posidonia oceanica in S3 (plant = 16.76 ± 4.48 μg/kg d.w.) as compared to those in S4 sites (plant = 5.33 ± 0.05 μg/kg d.w.). Concentrations for S. aurata and S. salpa in the Rejiche area exceeded the EC 1881/2006 legislation with values of 1.9 mg/kg and 2.5 mg/kg, respectively, and consumers may be exposed to high concentrations of Hg that exceeds the EFSA. The results showed that the fish species should be constantly monitored due to their TWI% of 154.5% for S. aurata and 209.8% S. salpa respectively.

Characterization of the mercury-binding proteins in tuna and salmon sashimi: Implications for health risk of mercury in food

Fish consumption is one of the major ways through which humans receive exposure to mercury (Hg). The existing forms of Hg in food, particularly Hg bound to proteins, may affect the absorption of Hg by humans and subsequently its potentially toxic effects. However, the knowledge regarding Hg-binding proteins in edible fish muscle is scarce. In the present study, salmon and tuna fish muscles, collected from seven different regions and countries, were analyzed using metallomics- and proteomics-based techniques. The concentration of Hg in sashimi samples ranged from 4.4 to 317.4 ng/g. Size exclusion chromatography (SEC) coupled with inductively coupled plasma mass spectrometer (ICP-MS) showed that beta-actin was a novel Hg-binding protein from the fish muscles, and this protein could also bind bismuth (Bi), silver (Ag), and copper (Cu). Hg bound to beta-actin accounted for approximately 30.2-37.6% of the total Hg in the tuna muscles and was significantly correlated to total Hg in the fish muscles (r = 0.98, p < 0.01) and in the fraction of soluble proteins (r = 0.94, p < 0.01). These findings suggest that proteins act as the main Hg accumulation sites in edible fish; thus, increasing human exposure to Hg following gastrointestinal digestion.