Mercury and Our Environment

Mercury and the Environment

Mercury is released into the environment by natural sources including volcanoes, oceans, and soils, as well as manmade processes such as gold and ore mining, medical waste incineration, municipal and hazardous waste combustion, cement manufacturing, fossil fuel combustion, and pulp and paper milling. Trace amounts of mercury are present in fossil fuels, such as coal and oil. According to EPA, U.S. electric utilities released 48 tons of mercury in 1999, the latest year for which data are available. Overall, only 55% of mercury emissions are from natural sources. For more information on mercury in the environment, please click here.

Health Effects for Humans

Mercury occurs naturally in the environment, and all humans are exposed to very low levels of it. Typically, our bodies naturally eliminate this trace amount of natural mercury.

Most human intake of mercury occurs from eating fish or seafood containing a form of mercury called methylmercury. When mercury gets into waterbodies, it can be converted into methylmercury and enter the aquatic food chain, where it bioaccumulates in fish tissue. The magnitude of human exposure to methylmercury depends on the level of mercury in the fish consumed and the amount of fish consumed. Humans also are exposed to mercury when elemental mercury contained in metal mixtures, such as dental fillings, is released into the environment.

Fish consumption dominates the pathway for human and wildlife exposure to methylmercury. Bioaccumulation plays a major role in humans high exposure to methylmercury (See Diagram Above). Epidemics of mercury poisoning following high-dose exposures to methylmercury in Japan and Iraq demonstrated that neurotoxicity is the health effect of greatest concern when methylmercury exposure occurs to the developing fetus. Dietary methylmercury is almost completely absorbed into the blood and distributed to all tissues including the brain; it also readily passes through the placenta to the fetus and fetal brain.

Why Mercury is Damaging to the Environment

The pattern of mercury deposition influences which eco-regions and eco-systems will be more highly exposed. Piscivorous (fish-eating) birds and mammals are more highly exposed to mercury than any other known component of aquatic ecosystems. Adverse effects of mercury on fish, birds and mammals include death, reduced reproductive success, impaired growth and development, and behavioral abnormalities.

Within the US, Mercury contamination has been documented in the endangered Florida panther and the wood stork, as well as populations of loons, eagles, and furbearers such as mink and otter. These species are at high risk of mercury exposure and effects because they either are piscivores or eat piscivores. Concentrations of mercury in the tissues of wildlife species have been reported at levels associated with adverse health effects in laboratory studies with the same species. Modeling analyses conducted by the EPA also suggest that it is probable that individuals of some highly exposed wildlife subpopulations are experiencing adverse effects due to airborne mercury emissions.

The levels of methylmercury found in the most frequently consumed commercial fish are low, especially compared to levels that might be found in some non-commercial fish from fresh water bodies that have been affected by mercury pollution. While most U.S. consumers need not be concerned about their exposure to methylmercury, some exposures may be of concern. Those who regularly and frequently consume large amounts of fish, either marine species that typically have much higher levels of methylmercury than the rest of seafood, or freshwater fish that have been affected by mercury pollution, are more highly exposed. Because the developing fetus may be the most sensitive to the effects from methylmercury, women of childbearing age are regarded as the population of greatest interest. For more information on EPA studies of mercury in the US, click here.

Why Recycle Light Bulbs?

• Keeps mercury containing products out of inappropriate waste disposal streams (especially incineration);
• Preferred disposal method in most states for mercury-containing lamps;
• Consistent with solid waste disposal bans and partial bans in some states;
• May limit user's Superfund liability; and simplifies enforcement

Environmental Facts Relating to Mercury and Light Bulb Recycling

• Each year, an estimated 600 million fluorescent lamps are disposed of in U.S. landfills amounting to 30,000 pounds of mercury waste.
• The Environmental Protection Agency reports that 187 incinerators nationwide emit approximately 70,000 total pounds of mercury into the environment each year.
• In 1992, mercury-containing lamps were added to the United States' Environmental Protection Agency's (EPA) list of hazardous substances. (The EPA's regulatory threshold of 2 mg./liter is usually exceeded by mercury-containing lamps).
• Mercury was number three on the 1997 list of hazardous substances as outlined by the Agency for Toxic Substances and Disease Registry (ATSDR) and the EPA.
• In America one-in-six children born every year have been exposed to mercury levels so high that they are potentially at risk for learning disabilities, motor skill impairment and short-term memory loss.
• The Mercury from one fluorescent bulb can pollute 6,000 gallons of water beyond safe levels for drinking.
• In the states of California, Minnesota, Ohio, Illinois, Indiana, Michigan, and Wisconsin, it is unlawful for anyone to dispose of fluorescent bulbs as universal waste.

 
Source: Light Bulb Recycling, EPA