What is Mercury?
Summary of Mercury:
Mercury (Hg) is a normally occurring chemical element. It can exist in the forms of elemental mercury (metallic mercury), ionic mercury compounds, organic mercury, or methyl mercury. In the environment, mercury tends to be in the forms of metallic mercury, mercuric sulphide, mercuric chloride, and methylmercury.
Problems Related to Mercury:
Mercury cannot be degraded because it is one of the basic chemical elements. Therefore, once it is released, it is transported through the environment and can be found in the Earth’s soil or water bodies. It can also be transformed into a toxic pollutant. Sulfate reducing bacteria, which are commonly found in lake sediments and wetlands, can transform ionic mercury to methyl mercury.
One common form of organic mercury that microorganisms often produce is methyl mercury. Methyl mercury can be dangerous because it can accumulate in living organisms. According to the process of biomagnification, methyl mercury can reach high levels fish and marine mammals causing concentrations of methyl mercury to increase in the food chain. The biomagnification process causes relatively low concentrations in water to increase to relatively high concentrations, resulting in high exposure of methyl mercury from fish consumption. This contamination affects not only the fish, but also birds and humans who eat them as well.
Fish with elevated mercury levels develop a decrease in spawning success, an increase embryo mortality in lake trout eggs, altered schooling movements, and acute toxicity. Birds that eat contaminated fish have been found to have reduced reproductive success, decreased chick survival, spinal cord degeneration, disrupted hormone levels, and difficultly flying, walking, and standing.
Consuming methyl mercury contaminated fish can cause neurological impairment. Women of child-bearing age and children are particularly sensitive to mercury exposure. Studies have also tied the consumption of these fish to cardiovascular disease in men, increased risk of acute heart disease and death in men living in Eastern Finland, Europe and Israel.