Who'll stop the mercury rain?
These days your favorite fish may come with a side of toxic mercury. It's a tough reality for Lake Michigan fishing boat captain Duane Nadolski, who says that after asking, "How's the fishing?" his customers often inquire: "Are these fish safe to eat?" Now, people who do their fishing at food stores have similar fears. Swordfish, shark, and several other fish are off limits for young children and women who are pregnant, nursing, or planning to conceive. And two weeks ago, the Environmental Protection Agency and the Food and Drug Administration warned that these consumers should also cut back on some canned tuna, eating no more than one 6-ounce can of albacore per week.
There's little relief in sight. Efforts to limit mercury from the 1,100 coal-burning power plants that are the main uncontrolled source of the pollutant in the United States have slipped into a political and technical morass. Last December, the Bush administration moved to ease planned mercury regulations and extend a federal emissions deadline by 10 years. The result was an outcry--and now the EPA is rethinking the scheme. But proposals for faster reductions face other hurdles: Technologies for reducing mercury emissions from power plants have a long way to go, and even the best U.S. controls won't touch the clouds of mercury coming from natural sources and from industry abroad.
In fact, mercury pollution could get worse before new controls kick in. About half the nation's electricity already comes from burning coal, and dozens more plants may come online in the next decade. As coal burns, it releases traces of mercury that waft out of smokestacks. Much of the mercury stays airborne for up to two years and spreads around the globe. But some is emitted as a water-soluble compound formed when mercury reacts with chlorine, an element often found in coal from eastern states, says Praveen Amar, an engineer with the Northeast States for Coordinated Air Use Management.
Precipitation quickly washes this form of mercury into lakes, rivers, and oceans, where microorganisms take it up and convert it into toxic methylmercury. The mercury passes up the food chain into fish--reaching the highest levels in large predatory species like swordfish and tuna--and on into people. High levels can cause learning problems or retardation in children and neurological damage in developing fetuses. One recent study found fetus-harming levels of mercury in about 8 percent of U.S. women of childbearing age.
Backing off. After years of study, the Clinton administration announced in 2000 that it would regulate mercury as a hazardous air pollutant. Under the Clean Air Act, that designation would have forced utilities to install top-notch pollution controls on virtually all smokestacks. Current emissions were slated to fall by 90 percent over four years. But late last year, when the EPA unveiled a long-awaited plan for controlling mercury, it proposed shifting it to a more lenient section of the law. The shift would allow utilities to use a flexible pollution trading program, require an overall cut of 70 percent rather than 90 percent, and give them 15 years to do it.
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