Mercury in tissues

In summary, physiological differences between four populations of carps from the low Ebro River and their effects correlated well with the amount of Hg found in fishes, with the maximal levels of mercury in tissue and the highest biological impact relocated several kilometers downstream from the discharge site. This probably reveals that the observed effects are more related to long-term and continuous exposure to Hg rather than to current occasional short-term exposures. 

A fatal dose of HgCl2 is in the range of 3 g. Suppose you were involved in the design of an analytical test for the presence of mercury in tissue. By research, you determined that you can convert mercury present in the tissue to metallic mercury via mercury(II) nitrate, which can easily be further treated for detection. The conversion is by... 

R. Wagemann, E. Trebacz, R. Hunt, G. Boila, Percent methylmercury and organic mercury in tissues of marine mammals and fish using different experimental and calculation methods, Environ. Toxicol. Chem., 16 (1997), 1859-1866. 

R. Wagemann, E. Trebacz, G. Boila, W. L. Lockhart, Methylmercury and total mercury in tissues of artic marine mammals, Sci. Total Environ., 218 (1998), 19-31. 

Clarkson TW, Magos L. 1966. Studies on the binding of mercury in tissue homogenates. Biochem J 99 62-70. 

Ichinose N, Miyazawa Y. 1989. Simplification of the thermal decomposition process of silver amalgam during the determination of total mercury in tissue samples by flameless atomic absorption. Fresenius Z Anal Chem 334(8) 740-742. 

Gailer et al. 2000b). Further support for the role of this compound comes from the observation that selenium-treated animals can remain unaffected despite an accumulation of mercury in tissues to levels that are otherwise associated with toxicity (Skerfving 1978). Additional support comes from the 1 1 ratio of selenium and mercury found in the livers of marine mammals and in the bodies of experimental animals injected with mercury and selenium, regardless of the ratio of the administered doses (Hansen 1988). 

GC/AFS (gas chromatography/atomic fluorescence spectrometry) can be used to separate individual mercury species so that the relative contributions of metallic, inorganic and organic mercury in tissues can be established. 

Attempts have been made to measure mercury in tissue by in vivo XRF (Bloch and Shapiro, 1986 Skerfving et al., 1987), but the technique seems to lack adequate sensitivity. 

The element mercury, also known as quicksilver (symbol Hg for hydrargyrum), and its compounds have no known normal metabolic function. Their presence in the cells of living organisms represents contamination from natural and anthropogenic sources all such contamination must be regarded as undesirable and potentially hazardous. Accumulation of mercury in tissues is reportedly associated with an excess risk of myocardial infarction, increased risk of death from coronary heart disease and cardiovascular disease, and accelerated progression of carotid atherosclerosis. 

Among nonhuman mammals, marine pinnipeds contained the highest reported concentrations of mercury in tissues. Total mercury content in all tissues examined of marine mammals - including muscle, brain, blubber, kidney, and liver - generally increased with increasing age of the animal. This was... 

Mercury in pinniped muscle, unlike fiver, was mostly methylmercury in both mothers and pups pups acquired most of their mercury during gestation. The percentage of methylmercury in any tissue from any marine mammal appears to be inversely correlated with total mercury content. For example, fiver of harbor seals from Maine contained a maximum of 7.8 mg total Hg/kg FW vs. 50.9 from those collected from New Brunswick, Canada methylmercury accounted for 13-37% of total mercury in Maine (U.S.) seal fivers but only 2-11% in Canadian seals. Among healthy California sea lions, Zalophus californianus, concentrations of total mercury in tissues in mg/kg FW and percent methylmercury were as follows fiver 74.0 and 3.7% kidney 7.0 and 17.2% muscle 1.2 and 88.6% and heart 0.59 and 88.1%. 

Acatalasemic mice have very low activity of catalase in the RBCs. The influence of oxidation of mercury in RBCs on the fate of mercury has been well been investigated using these animals. Acatalasemic mice exposed to mercury vapor showed a reduced oxidation of mercury vapor in the RBCs and a higher concentration of mercury in tissues than normal mice (Ogata et al. 1985). The amount of mercury released from the RBCs to plasma in vitro was larger in acatalasemic mice than in normal mice (Yamamoto et al. 1992), suggesting that a substantial amount of elemental mercury which escaped from the oxidation in the RBCs is released into the plasma and then distributed to other tissues in acatalasemic mice. 

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