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What Are the Hazardous Effects of Mercury on Our Earth?

Mercury is a naturally occurring element that can take several forms when it is found in the environment. In its elemental form, it is a shiny, silver-white liquid metal. Combination of mercury with other elements creates mercury compounds, usually in the form of white powders or crystals referred to as organic mercury if they contain carbon and inorganic mercury if they do not. All forms of mercury are considered poisonous. As a pollutant, it is often spread as a byproduct of industrial processes, the incineration of medical waste containing mercury and the burning of fossil fuels such as coal.

  1. Danger to Fish

    • When mercury enters bodies of water, biochemical processes driven by microorganisms transform it into methyl mercury, a highly toxic form of organic mercury that is well-suited to accumulating in muscle tissue. Methyl mercury is passed up the food chain by other animals that prey on these microorganisms, eventually reaching large predatory fish and birds, which tend to have the highest concentrations of the toxin. Nearly all wild fish contain some mercury. When they reach toxic levels, these concentrations can cause death, changes in an animal's behavior and reduced ability to reproduce, impacting every level of ecosystems.

    Danger to Wildlife

    • Many birds are fish eaters, making them one of the populations at greatest risk in the wild from exposure to harmful levels of mercury. Studies examining mallards, great egrets and other aquatic birds have demonstrated that many protective enzymes lose their effectiveness after they have been exposed to mercury. In addition, the developmental damage suffered by embryos in the egg can cause reductions of bird populations over time, as the resulting disorders can make the birds unfit for further reproduction.

    Danger to Humans

    • Nearly all danger of mercury poisoning in humans comes as a direct result of consuming contaminated fish and wildlife. This is because humans tend to eat foods at the top of most food chains, and mercury tends to accumulate in the muscle tissue of animals at the apex of aquatic food chains. A report written in 2000 for the National Research Council stated that the population with the highest risk of mercury poisoning is the offspring of women who consume a large amount of fish and seafood. Developmental neurological disorders such as learning and cognitive disabilities are common effects of mercury poisoning in the womb.

    Ecosystem Restoration

    • One of the many ecological impacts of environmental mercury is its retarding effect on the natural recovery of ecosystems. In most cases, natural processes break down toxins and remove them from the environment or render them non-harmful. Mercury, because it is poisonous in all forms, is an exception to this. Therefore, any transplanted wildlife integral to the re-emergence of a natural ecosystem in areas with high levels of environmental mercury starts with a disadvantage when compared with animals elsewhere, slowing the growth and redevelopment of interdependent biological networks. In addition, relative levels of mercury must be taken into account when proposing human-driven ecosystem restoration projects, as described in a 2011 paper on the restoration of the Everglades.

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