Most people are familiar with mercury in its most common form, the household thermometer. The truth is, most thermometers now use pigmented alcohol instead of mercury. Mercury in its most natural form is slightly toxic, but its vapor, compounds and salts are highly toxic. This toxicity causes brain and liver damage when ingested, inhaled or contacted. This is due to the fact that mercury is a bioaccumulative toxin that is easily absorbed through the skin, respiratory and gastrointestinal tissues.
Minamata disease, named after a tragic long-term mercury exposure in Japan, is a form of mercury poisoning. Minamata disease attacks the central nervous system and endocrine system and damages the mouth, gums, and teeth. High exposure over long periods of time will result in brain damage and ultimately death. In addition, if a pregnant woman is exposed to mercury, it can pose a major health risk to the unborn fetus.
Regulation of Mercury
The federal government has been monitoring mercury since the passage of The Clean Air Act in 1990. The Clean Air Act placed mercury on the list of toxic pollutants which require the greatest possible control and monitoring. Fifteen years later, the EPA passed a rule which took power plants off the list of sources which must reduce mercury to the maximum extent. Now power plants are not required to address the reduction of their mercury pollution until the year 2018. That EPA rule has completely undermined the purposes of The Clean Air Act and is currently being challenged by at least 13 states in court.
Mercury in the Environment
- Volcanic eruptions can increase the atmospheric source of Mercury by 4-6 times.
- Methylmercury in the environment works its way up the food chain, reaching high concentrations among populations of some species such as tuna.
- Mercury poisoning in humans will result from persistent consumption of tainted foodstuffs.
- Larger species of fish, such as tuna or swordfish, are usually of greater concern than smaller species, since the mercury accumulates up the food chain.
- Methylmercury related death has been known to occur from contaminated fish which has caused governments to issue warnings against consuming excess quantities of certain fish.
- Mercury contaminated fish is especially dangerous to pregnant women.
- Watersheds concentrate mercury through erosion of mineral deposits and atmospheric deposition.
- Plant and sedimentary deposits in coal contain various levels of mercury.
Commercial Mercury Exposure
In addition to power plants, many other industries emit dangerous amounts of mercury toxins. Coal-fired power plants are the largest source of mercury emissions. But there are others:
- Industrial processes
- Chlorine production
- Steel production
- Phosphate production
- Gold production
- Metal smelting
- Manufacture & repair of mercury containing weather and electronic devices
- Disposal of products containing mercury:
- Auto parts
- Fluorescent bulbs
- Medical products
Mercury exposure can also occur in less industrial settings, like:
- Cosmetic industries
- Laboratory work involving mercury or sulfur compounds