Summertime, a Time to Watch the Mercury
Summertime, a Time to Watch the Mercury
It's summertime, time to head to your favorite fishing hole, and time to read your state's fish consumption advisory.
West Virginia, Virginia, District of Columbia, Maryland, Pennsylvania, Delaware and New York are among 46 states across the nation that warn anglers on consumption of mercury-laden sport fish from rivers, lakes and ponds.
Here, and nationwide, the main mercury-polluting culprits are local coal-fired electric power plants. In 2005, the Environmental Protection Agency (EPA) dramatically changed its policy on mercury. It began to treat mercury as a run-of-the-mill pollutant instead of a hazardous toxin and announced a cap-and-trade program. Critics charge that the scheme allows even the dirtiest plants to continue spewing mercury into the atmosphere by buying pollution credits from places as faraway as Alaska or Hawaii, creating toxic hotspots and delaying cleanup for decades.
The so-called "Clean Air Mercury Rule" has drawn public outcry and sparked a federal lawsuit by 16 states including New York, Pennsylvania, Delaware and Maryland, several cities and a plethora of American Indian tribes, environmental and public health groups. The suit contends that under the Clean Air Act toxic substances must be regulated, not traded.
In 2000, under President Clinton, the proposed EPA plan mandated that the country's 460-plus coal-fired power plants install controls by 2007 that would reduce mercury emissions by 90 percent. But in 2005, under the Bush administration's new rule, the EPA projects emissions will be cut just 59 percent by 2025.
Yet the dangers from mercury have not been reduced, in fact "quicksilver's" danger is well documented. Mercury was recognized as a potent neurotoxin in the early 20th century, when its use in the felt industry caused "Mad Hatters' Disease," or mercury poisoning, in workers.
In the 1950s, researchers realized that when women consumed mercury-tainted fish, their children risked permanent nervous system damage that could cause retardation, learning disabilities and other serious problems.
One in 17 women of childbearing age now carries enough mercury in her blood to harm a developing fetus, according to a 2005 Centers for Disease Control and Prevention study.
But it's not just humans that are affected. About 30 years ago, biologists noted dwindling numbers of common loons in the northeastern United States. Tests on blood and feathers revealed high concentrations of methylmercury, the form of mercury most toxic to living things. The birds had been poisoned by eating contaminated fish.
For decades, scientists believed that fish-eating species, like waterbirds and seabirds were most at risk. Then they discovered that aquatic mammals, like walruses, seals and whales were also mercury-laden. Recently, research has documented high mercury exposure in all parts of the food web - including plants, insects, birds, mammals, amphibians and reptiles.
Even at low levels, mercury impairs the vision and muscle coordination of seabirds, says Joanna Burger, an ecologist at Rutgers University. Those birds lay smaller clutches of eggs and have difficulty caring for the few chicks that hatch. The hatchlings are slow to develop in ways that may endanger their lives.
Lab studies show that mercury also weakens immunity, making animals susceptible to disease. Fish have difficulty schooling, making them easy prey. Mammals' impaired motor skills make it difficult for them to hunt and forage for food.
These findings trouble wildlife biologists. Wildlife habitats and food sources across the country are mercury-polluted, and since the toxic load grows with each step up the food chain, predatory species are most at risk.
More than 100 tons of mercury pollution enters our skies each year. Much of that falls back to earth near its emission source in snow, rain and dust particles and eventually washes into waterways.
An EPA-funded study showed that almost 70 percent of the mercury in Ohio Valley rainwater came from nearby coal-fired power plants-a number that has been mirrored in the Chesapeake region. These findings refute statements from the Bush administration and industry that most U.S. mercury pollution is blown in on wind currents from abroad.
Across the US, an estimated 30 percent of lakes, estuaries and wetlands are contaminated, according to the Natural Resources Defense Council. Many waterways have never been tested. At least 20 states have issued statewide warnings.
We understand the dangers of mercury exposure to living things. We have the technology to cut atmospheric emissions by more than 90 percent at a cost of less than one percent of industry profits - but we've allowed politics to run roughshod over policy. We need to change our regulatory and industrial practices to drastically cut our mercury output - including the smaller amounts produced by incinerators and consumer products - and we need to clean up legacy contamination from Superfund sites.
But our mercury-contaminated landscape is really a consequence of our dependence on coal-generated electricity. In the long run, to protect our health, our waters and our wildlife, we need cleaner, safer energy sources.
(ITALIS)Sharon Guynup released her first book last year, State of the Wild 2006: A Global Portrait of Wildlife, Wildlands, and Oceans. She writes on science and the environment for national magazines and websites.
Distributed by Bay Journal News Service