Mercury
Mercury is a toxic metal that occurs naturally in rocks, sediments and soil and is particularly harmful to children.
Sources of exposure
Most people have heard of the toxic effects of mercury. Mercury poisoning, sometimes known as "Mad Hatter's Disease", served as the inspiration for the Mad Hatter character in Alice in Wonderland.
Mercury is a toxic metal that occurs naturally in rocks, sediments and soils. Above-average mercury concentrations in the environment are also often associated with volcanic activity. As mercury is naturally present in coal and oil, it is also released when fossil fuels are burned.
Mercury is used in many products such as batteries, thermometers and thermostats, and it has been used in a variety of industrial processes, especially in the chemical industry. Mercury can enter the environment through industrial processes, agricultural processes, various mercury-containing products (household, commercial and medical), wastewater and contaminated sediments. At industrial and hazardous waste sites, mercury spilled or improperly stored can also contaminate soil and groundwater.
The use of mercury increased during the industrial revolution around 1900, but has declined in recent decades due to health and environmental concerns. Mercury can be present in soil and groundwater if mercury-containing pesticides have been used in agriculture. Outdoor paints containing mercury can also contaminate soil and groundwater.
Mercury can be found in the environment in various forms, including elemental mercury (the silvery, metallic liquid most of us are familiar with), inorganic mercury and organic mercury. Inorganic mercury can dissolve in water and is derived from elemental mercury through natural or industrial oxidation processes.
Organic mercury, also known as methylmercury, is produced from inorganic mercury by certain species of bacteria. This form of mercury is known to accumulate (bioaccumulate) in fish. The fish ingest the mercury and it accumulates in the tissues of their bodies. As a result, the mercury concentration in fish can be thousands of times higher than in the environment. This mercury can then accumulate in the bodies of people who eat the fish and lead to health problems.
Possible effects on health
Exposure to high concentrations of mercury can lead to:
- Brain damage
- Developing foetuses
- Irritability, tremors, visual, hearing and memory impairment
- Kidney damage
Both inorganic and organic forms of mercury are particularly harmful to children, whose bodies can absorb mercury more easily. High mercury exposure can also damage the brain and developing foetuses. Mercury poisoning is often accompanied by irritability, tremors and impaired vision, hearing or memory.
Mercury levels above the limit can occur where mineral deposits containing mercury are present, where there is volcanic activity or where the soil or groundwater has been contaminated with mercury.
The mercury content of most drinking water is too low to significantly affect human health. Naturally occurring mercury levels in most drinking water wells are below 0.5 micrograms per litre. However, mercury levels above the limit can occur where mineral deposits containing mercury are present, where there is volcanic activity, or where the soil or groundwater has been contaminated with mercury. Long-term exposure to mercury above the MCL can cause kidney damage. Organic mercury (methylmercury) is rarely found in drinking water.
Sources:
https://www.filterwater.com/t-mercury.aspx