So What is Mercury?
Mecury is an ancient element, found in many Egyptian tombs that date back 3500 years ago. Mercury, elemental symbol Hg, is also known as quicksilver from its Greek name hydrargyrum. Mercury is an elemental metal on the periodic table, element 80. Mercury is a unique metal due to its common form being a “metal liquid at ordinary temperatures” as well as normal pressures (Winter, Mark). In addition, Mercury, as well as all of its compounds, is highly toxic (Helmenstine, Anne M.). There are three different forms of mercury:
“elemental mercury, inorganic mercury compounds (primarily
mercuric chloride), and organic mercury compounds (primarily methyl mercury)” (EPA). Methyl mercury is considered especially dangerous because of how humans are exposed to it and its effects on people-acute, chronic, reproductive/developmental, and carcinogenic.
Biaccumulation and how it Applies to Methyl Mercury
An important concept that explains how humans are exposed to methyl mercury is bioaccumulation. Bioaccumulation is the “increase in concentration of a pollutant from the environment to the first organism in a food chain” (Bioaccumulation). In other words, bioaccumulation occurs when pollutants start to add up in the food chain . “Mercury occurs naturally in the environment and cycles among the atmosphere, water, and sediments " ( USGS), but human activities such as burning coal tend to increase the amount of methyl
mercury in the environment. Methyl mercury “forms when mercury binds with organic molecules in the environment” (Finch, Bill) specifically carbon and hydrogen.
“This usually happens when mercury is released into the atmosphere through burning and settles into wetlands or streams” (Finch, Bill). With the increased amount of methyl mercury, aquatic life, such as fish, get contaminated. According to the Office of Environmental Health Hazard Assessment (OEHHA), methyl mercury can be found in fresh and saltwater fish (OEHHA). This is dangerous since many people eat fish. This is how toxic chemicals such as methyl mercury get to humans, and causes many harmful effects. (EPA) People get exposed to methyl mercury in two different ways. The first is through inhalation, which is normal. The second way humans get exposed is through consumption of fish. This adds to the already present methyl mercury in humans.
Acute Effects
The inhalation of high levels of methyl mercury, which is rare, can cause many serious central nervous system (CNS) effects. These effects include blindness, deafness, and impared levels of consciousness. Similar to these acute effects, the most common effects from constant exposure to methyl mercury in humans is damage to the CNS.The symptoms of chronic exposure are put into separate categories: early and late syptoms.The earlier symptoms include paresthesia—which would be burning felt in the hands, arms, legs, or feet (NINDS), blurred vision, malaise which is a feeling of discomfort, or illness (MedlinePlus). The later effects of chronic exposure to methyl mercury are pretty much the same as the acute effects, including deafness, speech difficulties, and a lessened visual field (EPA).
Mercury Poisoning: Metal Mercury and Biaccumulation
By: Emily Sturm
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