Quantification of total mercury in liver and heart tissue of Harbor Seals (Phoca vitulina) from Alaska USA (original) (raw)
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Pharmacology & Toxicology, 1995
Organs from 10 sledgedogs fed methyl mercury-containing organs and meat from predatory marine animals also eaten by humans in the Thule district of Greenland, were examined histochemically for cellular distribution of mercury, and the organ concentrations of mercury were quantified by atomic absorption spectrometry (total Hg). In selected organs the methyl mercuric level was determined by gaschromatograpby. The highest concentration of total mercury was found in mesenterial lymph nodes followed by liver and kidneys, which indicates that the lymphatic system might play an important role in the regulating transport of mercury to target organs. The concentrations were age-related, and the results suggest that demethylation takes place in all organs except skeletal muscles, but lowest in CNS. The distribution of mercury at cellular and subcellular levels was studied by the autometallographic technique. The atomic absorption spectrometric and autometallographic results were in good agreement. The brain mean concentration in the oldest group was 438 pg/kg, a level much lower than what has been reported to cause effects in the human central nervous system. However, if humans over a period of e.g. 50 years eat Arctic marine meat and accumulate mercury in the same way as dogs, the possibility that this may have health implications cannot be entirely excluded.
Ecotoxicology and Environmental Safety, 2011
The integration of bioaccumulation and effect biomarkers in fish has been proposed for risk evaluation of aquatic contaminants. However, this approach is still uncommon, namely in the context of mercury contamination. Furthermore, a multi-organ evaluation allows an overall account of the organisms' condition. Having in mind the organs' role on metal toxicokinetics and toxicodynamics, gills, liver and kidney of golden grey mullet (Liza aurata) were selected and mercury accumulation, antioxidant responses and peroxidative damage were assessed. Two critical locations in terms of mercury occurrence were selected from an impacted area of the Ria de Aveiro, Portugal (L1, L2), and compared with a reference area. Although kidney was the organ with the highest mercury load, only gills and liver were able to distinguish mercury accumulation between reference (R) and contaminated stations. Each organ demonstrated different mercury burdens, whereas antioxidant responses followed similar patterns. Liver and kidney showed an adaptive capacity to the intermediate degree of contamination/accumulation (L1) depicted in a catalase activity increase. In contrast, none of the antioxidants was induced under higher contamination/accumulation (L2) in any organ, with the exception of renal GST. The lack of lipid peroxidation increase observed in the three organs denunciates the existence of an efficient antioxidant system. However, the evidences of limitations on antioxidants performance at L2 cannot be overlooked as an indication of mercury-induced toxicity. Having in mind the responses of the three organs, CAT revealed to be the most suitable parameter for identifying mercury exposure in the field. Overall, organ-specific mercury burdens were unable to distinguish the intermediate degree of contamination, while antioxidant responses revealed limitations on signalizing the worst scenario, reinforcing the need to their combined use.
2010
Mercury contamination of aquatic ecosystems became a worldwide environmental problem. Thus, the intense mercury contamination observed at Laranjo basin (Ria de Aveiro, Portugal), was the motivation for the present study. The main goal was to improve the knowledge about mercury accumulation dynamics in key tissues of fish. Liza aurata specimens were caged (for 3 days at bottom and surface to evaluate the influence of sediment proximity) within Laranjo basin, at 3 locations differing on their distance to the contamination source. Total mercury (Hg t ) was quantified in three different target tissuesblood, liver and muscle, as well as in water and sediment. Comparative tissues analysis of Hg t accumulation revealed the following hierarchy: liver > blood > muscle, highlighting liver as the preferential tissue to mercury accumulation. Globally, Hg t levels ranged from 0.11 µg/g (muscle) to 1.13 µg/g (liver). Liver and blood showed to reflect the environmental contamination status after a short-term exposure (3 days). Analyzing tissue/tissue ratios, it was possible to infer a buffering action of liver, against mercury accumulation and its subsequent toxicity. In addition, blood role in mercury transportation and redistribution was better understood. Finally, the importance of the direct mercury uptake from the water (via gills) was ascertained.
Journal of the Brazilian Chemical Society
Mercury (Hg) contamination of oceans is rapidly increasing, however Hg bioaccumulation in pinnipeds has been understudied. Here, we report for the first time Hg concentration in liver tissues of South American fur seals (Arctocephalus australis) in South and Southeast Brazil. Hg concentration was determined in twenty-five fur seals’ specimens found stranded along the coast of the Southwestern Atlantic Ocean. Samples were digested using the microwave technique and quantified by cold vapor generation atomic fluorescence spectrometry technique. The average Hg concentration was 6.37 mg kg-1 (wet weight), with a minimum concentration of 0.09 mg kg-1 and the highest concentration of 15.58 mg kg-1. No correlation between biological variables (sex, total length and weight) and Hg concentration in A. australis liver were found. The results presented here are of great importance to establish baselines for future evaluations of Hg contamination in marine mammals and the effects of this environ...
Mercury and methylmercury distribution in tissues of sculpins from the Bering Sea
Polar Biology, 2015
Fish skeletal muscle is often used to monitor mercury concentrations and is used by regulatory agencies to develop fish consumption advisories. However, the distribution of mercury species (MeHg + and THg) in muscle tissue and other organs is not well understood in a number of fish species. Here we evaluate the spatial distribution of THg and MeHg + in skeletal muscle and internal organs (heart, liver, and kidney) of 19 sculpin representing three species: Myoxocephalus scorpius (shorthorn sculpin n = 13), Myoxocephalus jaok (plain sculpin, n = 4), and Megalocottus platycephalus (belligerent sculpin, n = 2). Four subsamples of muscle were taken along the lateral aspect of each fish, from muscle A (cranial) to muscle D (caudal). Using Games-Howell post hoc procedure to compare mean concentrations of all tissues, muscle samples were significantly different from internal organs, although there was no difference between muscle-sampling locations. THg concentrations (ww) were higher in muscle (muscle A through D mean ± SD, 0.30 ± 0.19 mg/kg) than that in heart (0.06 ± 0.05 mg/kg), kidney (0.08 ± 0.06 mg/kg), and liver (0.09 ± 0.08 mg/kg). Percent MeHg + decreased with age in both skeletal muscle and organs (p < 0.05). In contrast to some previous reports for other fish species, this study found significantly higher THg concentrations in muscle than in the liver. This study highlights the importance of using muscle samples when evaluating potential Hg exposure in risk assessments for piscivorous wildlife and human populations, and assumptions related to organ mercury concentrations should be examined with care.
Striped dolphin detoxificates mercury as insoluble Hg(S, Se) in the liver
Proceedings of the Japan Academy. Ser. B: Physical and Biological Sciences, 2001
Sea mammals are known to contain high concentrations of mercury and selenium especially in the liver with no apparent symptoms of poisoning. We examined the chemical form of mercury and selenium in the liver of striped dolphin, Stenella coeruleoalba. Neither mercury nor selenium could be extracted with acetone, 80% ethanol or 0.2 M ammonium acetate. The residue after extraction was digested most effectively with alkaline protease, resulting in solubilization of almost all the material (99% by weight) but still leaving a small amount of insoluble material (1%), which contained 80% of mercury and 66% of selenium of the original amount. This insoluble material was subjected to transmission electron microscopic analysis, X-ray microanalysis, X-ray diffraction analysis and elemental analysis, which revealed that the material contained spherical crystals of Hg(S~ .34, Seo 66) with 5-10 nm in diameter as a major component. These crystals may be the final detoxification product of mercury.
Evaluation of Nonlethal Methods for the Analysis of Mercury in Fish Tissue
Transactions of the American Fisheries Society, 2004
Thousands of fish are sacrificed each year to determine potential human exposure to mercury (Hg) from fish consumption. In this paper, we use lake whitefish Coregonus clupeaformis and northern pike Esox lucius to demonstrate that accurate and reliable measures of fish muscle Hg concentrations can be determined from small samples (Ͻ100 mg) harvested with biopsy tools. Reliability of results primarily depends upon analytical methodology and tissue sample weight. Mercury concentrations estimated by use of cold-vapor atomic absorption spectrophotometry (CVAAS) on small composite tissue samples harvested with a Tru-Cut (TC) biopsy needle (mean sample wet weight ϭ 47 mg) were less precise than estimates from tissue samples harvested with a dermal punch (DP; mean sample wet weight ϭ 126 mg). Precision differences presumably occurred because TC samples weighed less than the prescribed minimum weight (Ͼ100 mg) for CVAAS. There was no difference in precision of Hg concentrations among tissue extraction methods when biopsy samples were analyzed via cold-vapor atomic fluorescence spectrophotometry (CVAFS). Mean tissue Hg concentrations obtained with the biopsy techniques and CVAAS or CVAFS were similar to benchmark concentrations in fillet samples (within 6%), even for TC-CVAAS. A field study of the effects of the DP biopsy method on survival of northern pike showed that tissue harvesting did not reduce survival. Our results clearly demonstrate that analysis of Hg content in muscle harvested with biopsy tools provides Hg measures comparable in accuracy to traditional, whole-fish methods but without causing mortality.
Sensors, 2008
Tissue samples from 1,117 fish of 25 species were collected from 1991 through 1996 at 13 locations along the River Elbe. The principal indicator species were perch (Perca fluviatilis) (n=118), chub (Leuciscus cephalus L.) (n=113) and roach (Rutilus rutilus) (n=138). Mercury (Hg) concentrations in muscle and liver were determined by atomic absorption spectrometry. The liver/muscle index in three indicator species from heavily contaminated and lightly contaminated localities were significantly different. In fish from heavily contaminated localities, Hg was deposited preferentially in the liver (the depository for inorganic and organic forms of Hg), while in lightly contaminated areas, it was deposited preferentially in muscle.
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).
Journal of Environmental Sciences, 2018
The use of biopsy plugs to sample fish muscle tissue for mercury analyses is a viable alternative to lethal sampling; however, the practice has yet to be widely implemented in routine monitoring due to concerns about variability of mercury concentrations in fish muscle tissues. Here we examine distribution of mercury in fillets of four fish species (Walleye, Northern Pike, Smallmouth Bass and Lake Trout), suitability of left/right side of fillet for biopsy sampling, and appropriateness of re-using a biopsy punch. The results showed that average mercury concentrations in left and right fillets of fish are similar. Mercury concentrations in biopsy plug samples, taken from the anterior dorsal area of the fish fillet, were statistically equivalent to the mercury concentrations in homogenized fillets. There was no discernible cross contamination between samples when a biopsy punch was reused after washing in hot soapy water, and as such, biopsy punches can be recycled during sampling to reduce the sampling cost. If a tissue mass collected from a specific site on the fillet is insufficient, then we suggest sampling corresponding locations on the other fillet rather than sampling two adjacent sites on one fillet to obtain more tissue. The results presented here can improve the accuracy of fillet biopsy plug sampling, minimize fish mortality for mercury monitoring, and reduce labor and material costs in monitoring programs.