Mercury

Health concerns

Exposure to mercury, even at low levels, can cause neurological damage, memory and learning problems, and delays in speech and reading ability in children.

Where it is found

The most common source of human  mercury exposure is through eating fish contaminated with methylmecury, an organic—and highly toxic—form of the heavy metal resulting from interactions with bacteria. Airborne mercury pollution emitted from coal-fired power plants, waste incineration, cement kilns, petroleum refineries, chlor-alkali plants, smelting and mining operations is carried by precipitation into waterways. There it is absorbed by plants and aquatic life and converted to methylmercury, and as bigger fish eat contaminated smaller fish, it concentrates in their flesh. The largest predatory fish at the top of the food chain, such as swordfish, bigeye tuna and ahi tuna, tend to have higher amounts of methylmercury in their bodies—enough to be a health concern for young children and pregnant women in particular.

Mercury can also be found in silver amalgam dental fillings, button batteries (the kind used in watches, calculators, pacemakers, etc.), thermostats, swtiches, compact fluorescent lighting and in some cosmetic skin-lightening and acne creams sold outside the United States. Mercury is used to manufacture chlorine for bleach and other industrial products, and to make hard plastics in China. It is widely used in small-scale gold mining throughout the developing world.  Mercury pollution travels great distances in the air, making it a global environmental problem.

Stay safe
Eat fish low in mercury. Use NRDC’s Consumer Guide to Mercury in Fish to find out what’s safe to eat.

Avoid silver dental fillings. If you already have them, do not rush to remove them—drilling vaporizes mercury, increasing your risk of exposure.

Don't use skin-lightening or acne creams purchased abroad, as they may contain mercury.

Note: Most routine childhood immunizations do not contain mercury. Thimerosal, a preservative containing mercury, was removed from children’s vaccines in the early 1990s. Some flu vaccines may still contain thimerosal, but parents can request a thimerosal-free version. 

Compact fluorescent light (CFL) bulbs contain a small amount of mercury. Broken bulbs may release this mercury, so follow the disposal instructions listed in Compact Fluorescent Lights: The Mercury Matter. Although CFLs contain some mercury, they consume less power than inefficient incandescent bulbs, and thus help to reduce the demand on power plants that emit airborne mercury pollution.

The big picture
You can take precautions to limit your mercury exposure, but stopping mercury pollution at its source is the best way to protect our health. NRDC and other groups are fighting to clean up power plant pollution and pushing for clean, green energy. Our health team is working to clean up or shut down the last mercury chlor-alkali plants in the country, and pushing the EPA to set tough standards on pollution from cement kilns.

We also need to get mercury out of consumer products – NRDC has already helped eliminate the mercury fever thermometer, and mercury is being phased out of many batteries manufactured in the United States.

In 2008, the United States banned the export of mercury, reducing the amount of this dangerous metal on the world market. But other countries still use mercury in their industries, tainting the air and waters across the planet. NRDC is helping lead the way in forging an international treaty to slash mercury pollution worldwide.