Mercury and selenium in the muscle of piscivorous common mergansers (Mergus merganser) from a selenium-deficient European country (original) (raw)
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Environmental Toxicology and Chemistry, 2008
Despite a large body of research concerning mercury (Hg) in birds, no single tissue has been used consistently to assess Hg exposure, and this has hampered comparisons across studies. We evaluated the relationships of Hg concentrations among tissues in four species of waterbirds (American avocets [Recurvirostra americana], black-necked stilts [Himantopus mexicanus], Caspian terns [Hydroprogne caspia; formerly Sterna caspia], and Forster's terns [Sterna forsteri]
Environmental Science & Technology, 2005
Shifts in tissue nitrogen isotope composition may be a more sensitive general indicator of stress than measurement of high-turnover defensive biomolecules such as metallothionein and glutathione. As a physical resource transmitted along the trophic web, perturbations in protein nitrogen metabolism may also help resolve issues concerning the effects of contaminants on organisms and their consequential hierarchical linkages in ecotoxicology. Snowy egret nestlings (Egretta thula) fed mercury-contaminated diets of constant nitrogen isotope composition exhibited increased relative δ 15 N values in whole liver (p ) 0.0011) and the acidsoluble fraction (ASF) of the liver (p ) 0.0005) when compared to nestlings fed a reference diet. When nitrogen isotope data were adjusted for the source term of the diet, liver mercury concentrations corresponded with both whole liver relative 15 N enrichment (r 2 ) 0.79, slope 0.009, p < 0.0001) and relative 15 N enrichment in the acidsoluble fraction of the liver (r 2 ) 0.85, slope 0.026, p < 0.0001). Meanwhile, significant differences were not observed in hepatic levels of the metal-binding peptides metallothionein and glutathione despite a nearly 3-fold difference in liver mercury content. Because increases in tissue δ 15 N values result from increased rates of protein breakdown relative to synthesis, we propose that the increased relative liver δ 15 N values reflect a shift in protein metabolism. The relationship between ASF and mercury was significantly stronger (p < 0.0001) than that for whole liver, suggesting that the relationship is driven by an increase in bodily derived amino acids in the acid-soluble, free amino acid pool.
Science of The Total Environment, 2010
The concentrations of total mercury (Hg), methylmercury (MeHg) and total selenium (Se) were determined in muscle, liver and brain tissues of young-of-the-year walleye (Stizosedion vitreum) specimens collected from 8 boreal lakes that are located within 107 km around the Sudbury smelters in Ontario, Canada. Dry weight basis concentrations of Hg were highest in muscle and lowest in brain (p b 0.05), those of MeHg were higher in muscle than in liver and brain but there was no significant difference between liver and brain (p b 0.05). The highest Se concentrations were found in liver and the lowest in brain (p b 0.05). Considering the biomass of the studied tissues, muscle was the part of the body where most of Hg, MeHg and Se were accumulated. In fish muscle, the percentage of MeHg over Hg was the highest and this percentage was the lowest in liver. The concentrations of Hg, MeHg and Se in the studied tissues were closely related to the concentrations of total dissolved Se in lake waters which vary with the distance of the lakes from the smelters. Thresholds of Se concentrations in tissues were revealed (6.2, 12.0 and 3.5 mg kg − 1 dry wt., for muscle, liver and brain, respectively), above which a significant reduction of MeHg concentrations was observed in all studied tissues compared to lower Se levels in the same tissues. Based on the collected information and data analysis, possible mechanisms for the biological processes behind the observed inverse relationships between Se and Hg in fish tissues are discussed.
Environmental Pollution, 2020
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THE MERCURY (Hg) CONCENTRATIONS IN FEATHERS OF WILD BIRDS
Applied Ecology and Environmental Research, 2018
In this study, mercury (Hg) concentrations were detected in feathers of 22 bird species from 10 different families living in terrestrial and aquatic ecosystems in Van Lake Basin in Turkey. The mercury rates in feathers were detected based on nutrition status and taxonomic classifications of bird species. Mercury levels were detected in 0.002 ± 0.007 mg/kg and 2.700 ± 0.560 mg/kg dry weight range. It was observed that there was a significant difference between the groups classified taxonomically (p < 0.05). The highest concentrations were detected in European Honey-buzzard (Pernis apivorus) 2.7 mg/kg, Lammergeier (Gypaetus barbatus) 0.45 mg/kg and Long-legged Buzzard (Buteo rufinus) 0.28 mg/kg species from Accipitridae family. And the lowest mercury concentration was detected in Golden Eagle (Aquila chrysaetos) from the same family (0.002 ± 0.007 mg/kg). Mercury was detected in the feather samples taken from the Egyptian Vulture, Lammergeier, Northern Lapwing, and Great Bustard, and these species were determined to be within different endangered categories according to the International Union for Conservation Nature (IUCN). Considering the trophic level (type of food) and systematic groups of the sampled species, it was determined that average mercury level was statistically significant in both cases. It was suggested that the mercury level of the carnivorous ones were higher than that of the herbivorous ones.
Environmental Toxicology and Chemistry, 2015
Mean concentrations of total mercury ([THg]) and selenium ([TSe]) (mass and molar-based) were determined for 5 regions of the heart and 2 regions of the kidney of bearded seals (Erignathus barbatus) harvested in Alaska, USA, in 2010 and 2011. Mean [THg] and [TSe] of bearded seal liver and skeletal muscle tissues were used for intertissular comparison. The Se:Hg molar ratios were used to investigate elemental associations and potential antioxidant protection against Hg toxicosis. Age was an important factor in [THg] and Se:Hg molar ratios in heart and kidney. Small but statistically significant differences in mean [THg] occurred among some of the 5 heart regions (p < 0.05). Mean [THg] was highest in liver, 3.057 mg/g, and lowest in heart left ventricle, 0.017 mg/g. Mean [THg] ranked: liver > kidney cortex > kidney medulla > skeletal muscle > heart left ventricle (p < 0.001). Mean [TSe] was highest in liver, 3.848 mg/g, and lowest in heart left ventricle, 0.632 mg/g. Mean [TSe] ranked: liver > kidney cortex > kidney medulla > skeletal muscle > heart left ventricle (p < 0.001). The Se:Hg molar ratios were significantly greater than 1.0 in all tissues (p < 0.001) and represented baselines for normal [TSe] under relatively low [THg]. Mean Se:Hg molar ratios ranked: heart left ventricle > kidney medulla > kidney cortex (p < 0.001).
Mean concentrations of total mercury ([THg]) and selenium ([TSe]) (mass and molar-based) were determined for 5 regions of the heart and 2 regions of the kidney of bearded seals (Erignathus barbatus) harvested in Alaska, USA, in 2010 and 2011. Mean [THg] and [TSe] of bearded seal liver and skeletal muscle tissues were used for intertissular comparison. The Se:Hg molar ratios were used to investigate elemental associations and potential antioxidant protection against Hg toxicosis. Age was an important factor in [THg] and Se:Hg molar ratios in heart and kidney. Small but statistically significant differences in mean [THg] occurred among some of the 5 heart regions (p < 0.05). Mean [THg] was highest in liver, 3.057mg/g, and lowest in heart left ventricle, 0.017 mg/g. Mean [THg] ranked: liver > kidney cortex > kidney medulla > skeletal muscle > heart left ventricle (p < 0.001). Mean [TSe] was highest in liver, 3.848mg/g, and lowest in heart left ventricle, 0.632mg/g. Mean [TSe] ranked: liver >kidney cortex >kidney medulla >skeletal muscle > heart left ventricle (p < 0.001). The Se:Hg molar ratios were significantly greater than 1.0 in all tissues (p < 0.001) and represented baselines for normal [TSe] under relatively low [THg]. Mean Se:Hg molar ratios ranked: heart left ventricle > kidney medulla > kidney cortex (p < 0.001)