Total Mercury In Muscle Tissue Research Articles

Mercury metalloproteomic profile in muscle tissue of Arapaima gigas from the Brazilian Amazon.

Metalloproteomics is an innovative methodology for identifying of protein-associated mercury. Thus, we analyzed the muscle proteome of Arapaima gigas (pirarucu), collected in the Madeira River of the Brazilian Amazon, to identify protein-associated mercury, with the aim of identifying possible mercury biomarkers in fish muscle tissue. After obtaining the protein pellet, we conducted two-dimensional electrophoresis (2D PAGE) to fractionate the muscle proteome. Total mercury in muscle tissue and protein pellets and mapping of mercury content in protein spots of the 2D PAGE gels was determined using graphite furnace atomic absorption spectrometry (GFAAS). The protein-associated mercury identification was performed using liquid chromatography coupled with sequence mass spectrometry (LC‒MS/MS). Total mercury determinations by GFAAS indicated concentrations on the order of 153 ± 1.90mgkg-1 and 142 ± 1.50mgkg-1 (total precipitation of protein fraction) and 139 ± 1.45mgkg-1 (fractional precipitation of protein fraction) in muscle tissue and protein pellets, respectively. Mercury concentrations in the range of 48 ± 0.90 to 165 ± 3.00mgkg-1 were found in twelve protein spots. Among the 2D PAGE protein spots, eleven Hg-binding proteins were identified using LC‒MS/MS, which showed characteristics of mercury exposure biomarkers for important metabolic functions, such as five parvalbumin isoforms, triosephosphate isomerase, cofilin 2 (muscle), and fructose-bisphosphate aldolases.

Harvest and Mercury Levels of Striped Bass in Miramichi River, New Brunswick, Canada

AbstractThe Striped Bass Morone saxatilis is an apex predator that supports recreational, commercial, and First Nations traditional fisheries in the Miramichi River, New Brunswick, Canada. Historic exploitation resulted in steep population declines, forcing a complete fisheries moratorium in 2000. After 13 years of recovery, a recreational fishery was reopened (May 2013) followed by a commercial fishery in 2018. These new opportunities for harvesting raised concerns about mercury levels in fish for human consumption as past levels have exceeded Health Canada guidelines of 0.5 mg/kg. We collected Striped Bass from the northwest Miramichi River in spring during the main recreational and commercial fishing seasons. Fish in the legal harvest slot for the recreational (50–65 cm TL) and commercial (50–80 cm TL) fisheries had total mercury in muscle tissue ranging from 0.08 to 0.43 mg/kg and from 0.08 to 0.63 mg/kg wet weight, respectively. Mercury levels in Striped Bass have decreased since the 1990s, but some individuals were close to or exceeded consumption guidelines. In addition, a preliminary angler creel survey revealed that only 8% of anglers retained their legal, three‐fish limit (average harvest = 0.7 fish/angler/day). However, harvest of oversized fish was observed (11%), and a removal of ˜100,000 adults in the first month of the fishery by the recreational, commercial, and Indigenous fisheries is possible and represents a significant portion of the estimated adult population. We conclude that effective management of the Striped Bass fishery in the Miramichi River will require continued and more detailed angler surveys and population size and structure assessments accompanied by communication of current mercury levels in this species.

Mercury concentrations in reared Atlantic bluefin tuna and risk assessment for the consumers: To eat or not to eat?

This study determines the levels of total mercury in muscle tissue from 268 reared Atlantic bluefin tuna in the Mediterranean Sea, detects variations on mercury concentrations in relation to biological parameters and rearing period and evaluates the health risk posed by fish consumption taking into consideration the size, age and rearing period. A total of 30 pooled samples were analyzed. The total Hg concentrations ranged from 0.49 to 1.60mg/kg w.w. and showed a significant positive relationship with the size and age. It was found that the longer the rearing period, the lower the mercury concentration. The total Hg exceeded the maximum level defined by the European Commission Decision in a proportion of 40.0%. Since the value of Target Hazard Quotient was higher than 1 in all different groups (medium, large, 6months and 18months reared specimens), the maximum possible safe weekly consumption (400g) is suggested.

Mercury bioaccumulation in the spotted dogfish (Scyliorhinus canicula) from the Atlantic Ocean

The annual and life-cycle mercury bioaccumulation pattern in selected tissues of the economically relevant Elasmobranchii species Scyliorhinus canicula was studied, and the risks associated with its consumption evaluated.Preferential mercury bioaccumulation occurred in muscle tissue, and followed the order muscle>heart>liver>gills>pancreas. Total mercury in muscle tissue ranged from 0.13mgkg−1 (wwt) in 1+year old males to 0.8mgkg−1 (wwt) in 8+ year old mature females, with no significant differences found between genders, and no clear lifespan bioaccumulation pattern observed, except for mature females. Organic mercury in the muscle ranged from 0.05mgkg−1 (wwt) to 0.52mgkg−1 (wwt), corresponding to an average of 70% of total mercury content. In mature females, a significant correlation (R=0.99, P=0.01) was found between size and organic mercury fraction, suggesting reproduction as an important factor controlling organic mercury bioaccumulation in the spotted dogfish.

Organic and total mercury in muscle tissue of five aquatic birds with different feeding habits from the SE Gulf of California, Mexico

We measured organic and total Hg in muscle tissue of five species of aquatic birds from the south-eastern gulf of California region, Mexico. Concentrations of total and organic Hg measured in Pelecanus occidentalis were the highest (2.85 and 2.68 μg g −1); lowest values of organic Hg (0.20 μg g −1) and total Hg (0.47 μg g −1) were detected in Anas discors and Anas clypeata, respectively. Differences of Hg levels were related to feeding habits, being concentrations in birds of piscivorous habits more elevated than corresponding values in non-piscivorous species.

Total Mercury and Methylmercury Contamination of Fish from the Skalka Reservoir: A Case Study

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Total mercury in the night shark, Carcharhinus signatus in the western equatorial Atlantic Ocean

Mercury is the only element capable to biomagnificate along the food chain, and carnivorous fish tend to accumulate high concentrations of this element. Total mercury in muscle tissue of Carcharhinus signatus sampled along the western equatorial Atlantic Ocean was measured by atomic emission spectrophotometry with ICP/AES. The average total mercury concentrations were consistently greater than the maximum limit for human consumption established by the Brazilian Health Ministry for carnivorous fishes (1000 µg. kg-1 w.w.). Therefore, an average consumption of 0.1 kg/day of C. signatus would result in an average daily ingestion of 174.2 µg of Hg, more than five times the 30 µg/day intake established by the World Health Organization. In the range of lengths studied, body length could not be used as an indicator of the Hg contamination degree for C. signatus. Also, sex cannot be considered a determining factor in the total mercury accumulation in C. signatus.

Total Mercury in Muscle Tissue of Five Shark Species from Brazilian Offshore Waters: Effects of Feeding Habit, Sex, and Length

This study was carried out to assess mercury levels in fish from Brazilian offshore waters. Generally sharks have relatively high mercury levels which are also affected by diet, age (associated with length), and sex. Total mercury levels were determined in five shark species with different habits (Carcharhinus signatus, Mustelus canis, Mustelus norrisi, Squalus megalops, and Squalus mitsukurii) which were collected during 1997 in southern Brazil's offshore waters. The highest mercury concentrations, all above the limit established by Brazilian legislation (0.5 μg.g−1), were detected in piscivorous species (C. signatus, S. megalops, and S. mitsukurii) with averages of 1.77±0.56, 1.9±0.58, and 2.22± 0.72 μg.g−1, respectively, while species that feed mainly on invertebrates (M. canis and M. norrisi) had averages of 0.41±0.35 and 0.36±0.28 μg.g−1. These results indicate that feeding habits influence total mercury level in sharks. Methylmercury (as a percentage of total mercury) determined in S. mitsukurii and M. canis also showed an influence of feeding habit. Positive correlations between mercury concentration and length were statistically significant (P<0.05) for all species, except M. norrisi. Although mercury levels were generally higher in males than in females for all species (with the exception of S. mitsukurii), a statistically significant correlation was observed only for M. canis.

Biomagnification and bioaccumulation of mercury in an arctic marine food web: insights from stable nitrogen isotope analysis

Several recent studies have shown that the use of delta 15N analysis to characterize trophic relationships can be useful for tracing biocontaminants in food webs. In this study, concentration of total mercury was measured in tissues from 112 individuals representing 27 species from the arctic marine food web of Lancaster Sound, Northwest Territories. Samples ranged from particulate organic matter through polar bears (Ursus maritimus). Using delta 15N values to identify trophic position, we found that total mercury in muscle tissue biomagnified in this food web. Polar bears were a notable exception, having a lower mean mercury concentration than their main prey, ringed seals (Phoca hispida). Most vertebrates showed greater variance in mercury concentration than invertebrates, and there was a trend in seabirds toward increased variability in mercury concentration with trophic position. Within species, we found no evidence of bioaccumulation of mercury with age in the muscle tissue of clams (Mya truncata) or ringed seals. Because stable nitrogen isotopes illustrated the relationship in this biome between trophic position and mercury level on a continuous, quantitative scale, we were able to determine that log10[Hg] ( µg/g dry weight) = 0.2( delta 15N) - 3.3. The measurement of delta 15N values and mercury concentration allowed us to quantitatively assess mercury biomagnification within this extensive arctic marine food web.