Mercury - Impact, Measurement and Abatement

Mercury Impacts to the Environment

Mercury is a poison that acts on the nervous system and is of significant ecological and public health concern. Of all forms, methyl mercury (MeHg) is by far the most potent and harmful to humans and ecosystems, exacerbated by its biomagnification through the food web. To protect human health, the United States Environmental Protection Agency (EPA) set a fish tissue criterion for MeHg at 0.3 micrograms per gram

?At present atmospheric deposition is the dominant mechanism for the presence of mercury in the biosphere and combustion of coal, most prominently from generators of electricity, is the dominant source. ?It is emitted in three species, namely Hg0??? ?, Hgll ?, Hgp??? Elemental, Divalent and Particulate Mercury respectively.

?Divalent or ionic forms of mercury (HgII) are highly reactive and are most readily converted to MeHg. The methylation process takes place within aquatic sediments with low or no oxygen present, and through the action of sulfur reducing bacteria. It has been established that higher levels of sulfur, as from acidic deposition entering aquatic systems, will result in higher levels of MeHg production in those systems. It has been hypothesized that the increased temperatures anticipated with climate change may speed the methylation process.?

?Much of Earth′s atmospheric mercury load is carried across the globe in the stratosphere (upper atmosphere), with concentrations increasing due to the rapid expansion of uncontrolled coal combustion in Asia.

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Effects on Wildlife

Mercury concentrations are high enough in wildlife that consumes fish to cause adverse behavioral, physiological, and reproductive effects, including: subtle visual, cognitive, and neurobehavioral deficits in small mammals and birds. MeHg concentrations of 1 μg g-1 lead to death in less than a year.

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Climate Change

Future global temperatures are expected to increase mobilization of legacy reservoirs of mercury increasing methylation rate. In addition, increases in elemental mercury atmospheric residence time due to these rising temperatures will lead to wider global distribution by as much as 66 percent due to background bromide and rising ground-level ozone interactions. Much of Earth′s atmospheric mercury load is carried across the globe in the upper atmosphere, with concentrations increasing due to the rapid expansion of uncontrolled coal combustion in Asia. Severe rainstorms may tap into this upper atmosphere reservoir, bringing these increased mercury concentrations to the lower atmosphere, and ultimately to Earth′s surface. This has been hypothesized as a factor in the recent extremely high concentrations of mercury in rain water

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Human Race

Perhaps most concerning of all, mercury has been proven to have a particularly damaging impact upon the human body. Given that seafood provides the principal source of protein for approximately one billion people across the globe, measuring its concentration in aquatic environments is of paramount concern in safeguarding human health. The same goes for atmospheric levels of the substance, since prolonged exposure to airborne mercury can have similarly detrimental effects on human health.

These effects are especially potent in young children. Exposure to mercury from a young age can contribute to the contraction of neurological disorders in later life and can hamper mental development as children grow up, possibly affecting motor skills and other physical functioning. Other adverse effects observed in adult humans include damage to the circulatory system, as well as brain or kidney failure. As such, mercury measurement is hugely important for the planet and for every living thing upon it.

https://www.thermofisher.com/blog/identifying-threats/low-level-measurement-and-calibration-of-mercury-emissions/