Mercury, also known as quicksilver, is an element that does not break down. It occurs naturally and is found in very small amounts in oceans, rocks and soil.

Mercury is an element that conducts electricity well, making it practical to use for thermometers and thermostats. It is also used in fluorescent lights, pressure gauges, button batteries, old alkaline batteries, old paint, dental fillings and novelty items such as lighted tennis shoes.

Mercury is a toxic heavy metal that affects the human brain, spinal cord, kidneys and liver. It affects the ability to feel, see, taste and move. Symptoms include tingling sensations in the fingers and toes, a numb sensation around the mouth and tunnel vision. Long-term exposure can lead to personality changes, stupor and coma. Pregnant women and young children are the most susceptible to mercury poisoning. The most likely route of exposure is by eating mercury-contaminated fish. A mercury fever thermometer, like those used in the home, contains enough mercury to potentially contaminate 9,000 cans of tuna fish.

The most toxic form of mercury to humans and the environment is methyl mercury. Methyl mercury is a form of mercury that is converted by bacteria and organic materials. Mercury that gets into the Bay is often converted into methyl mercury in the shallow waters and ends up being ingested by plankton, microscopic animal and plant life used as food by nearly all aquatic animals. Larger fish feed on the plankton and methyl mercury becomes concentrated in predatory fish’s flesh through a process of bioaccumulation.