Mercury

Mercury is a potent neurotoxin. It has been linked to all sorts of serious physical and central nervous system disorders, including mental retardation, sexual dysfunction, and even death. In adults, even at very low doses, it causes neurological dysfunctions, circulatory and immune system deficiencies. But mercury is even most dangerous to a child's developing brain. During pregnancy, a woman eating contaminated fish will pass some of that mercury on to her child through prenatal blood transfer and, later, through breast milk to a nursing infant. In fact, studies indicate that the fetus will have a larger amount of mercury in its blood than the mother because mercury concentration in umbilical cord blood is almost twice as high as found in the mother's bloodstream.

In January 2003 the Centers for Disease Control and Prevention found that nearly 1 in 12 women of child bearing age (16 to 49) are currently exposed to levels of mercury that exceed U.S. Environmental Protection Agency (EPA) safe levels, putting more than 300,000 fetuses at risk from the harmful effects of mercury poisoning. We now know that that number was grossly underestimated. EPA scientists recently raised that estimate to 1 in 6 women based on evidence that mercury concentrations in umbilical cord blood is significantly higher than the mother's blood concentration. Using 2000 census figures, EPA determined that as many as 630,000 newborns are now at risk of serious congenital neurological and development impairment.

The largest source of airborne mercury in America are the nation's 1,100 coal-fired power plants that release more than 50 tons of deadly mercury into the air every year. Gravity pulls much of this mercury down to the ground, where it eventually ends up in our waterways. Bacteria and chemicals transform this mercury into METHYLMERCURY, which is extremely toxic. Methylmercury is dangerous because it bioaccumulates -- it builds up in living things because organisms, including people, absorb it at a faster rate than they can get rid of it. Fish absorb methylmercury as water runs over their gills, but the bigger problem lies in the food chain. When a large fish eats a smaller fish it absorbs the mercury that was in the prey's body. Over the fish's lifespan, methylmercury accumulates to dangerous levels. The larger and older the fish, the higher the potential for high levels of this potent neurotoxin. We humans, at the top of this food chain, are exposed to methylmercury when we eat the mercury-laden, larger predatory fish like tuna and swordfish.

Mercury is highly toxic. One study found that 1/70 of a teaspoon of pure mercury is enough to contaminate a 25-acre lake. In 1993, 27 states had issued advisories warning people of the dangerous levels of mercury in some fish. By 2003, 45 states and the District of Columbia had mercury fish advisories.

Alabama Power's Miller Steam Plant on the Locust Fork of the Black Warrior River discharges over 1,500 pounds of mercury per year -- Fourth-worst in America in 2003, according to the EPA.

For human consumption guidelines of mercury levels in different species of fish, please click here.

Citizen fishing on Village Creek near Alabama Power's (Southern Co.) Miller Steam Plant (Jefferson Co.) © David Whiteside, 2002

Miller Steam Plant (Jefferson Co.)