Everglades Cleanup Offers Path for Nation, Scientists Say

By Elizabeth Shogren

Dec. 15, 2003 12 AM PT

Times Staff Writer

EVERGLADES NATIONAL PARK, Fla. — Two decades ago, residents of two Florida Panhandle towns were so concerned about a hazardous waste site near the Chipola River that state officials agreed to monitor the fish there for five years.

They did not detect any hazardous waste contamination in the fish, but they did find mysteriously high levels of mercury.

Intrigued, they kept looking.

Even higher levels of mercury turned up farther south, in the pristine reaches of the Everglades, the subtropical wilderness that sprawls across more than 2 million acres of central and south Florida.

Eventually, scientists traced the source of the mercury not to toxic discharges into the groundwater but to emissions in the air -- a problem since documented in all but six states.

The cleanup of mercury emissions is an issue that the Bush administration is required to address no later than today, which makes the success Florida officials believe they have had in reversing the trend all the more significant.

Thanks to tough state regulations controlling air pollution from waste incinerators, the main source of mercury emissions in Florida, levels of the toxin in largemouth bass and wading birds in the Everglades have dropped more than 60% since their peak in the mid-1990s.

That improvement has come far faster than anyone had predicted, said Tom Atkeson, one of the original scientists on the Florida project and now the program administrator for the mercury and applied science division of the state’s Department of Environmental Protection.

Forty-four states, including California, have detected levels of mercury in fish high enough that health officials warn against eating certain species from specific bodies of water and advise limiting consumption of others.

Under the terms of a 1998 lawsuit settlement between environmentalists and the Environmental Protection Agency, the federal government must announce by today its proposals for regulating mercury emissions from the largest remaining source of such pollution -- coal-fired power plants.

State regulators, public health professionals and environmental activists say that Florida’s positive experience cleaning up mercury in the Everglades makes a strong case for forceful federal action.

But the Bush administration favors a more gradual approach that would not require deep cuts in mercury emissions until 2018, said EPA Administrator Michael O. Leavitt. The administration would use a market-based trading system to allow companies that reduced emissions below their cap to trade pollution credits with companies that clean up more slowly.

And the electric generating industry says that requiring rapid reductions in mercury emissions could cause some utilities to switch from coal to natural gas and to increase electricity prices -- without significant gains for public health.

Mercury is a naturally occurring substance that can be released into the atmosphere from a variety of sources, including volcanoes, forest fires, incinerators and coal combustion.

A small percentage of the mercury particles and gases emitted as air pollution are transformed into methylmercury, a particularly toxic form, after they fall into waterways. Methylmercury “bioaccumulates” in fish, and its concentration increases as it passes up the food chain.

Developing fetuses, infants and young children are highly sensitive to methylmercury exposure, which can cause significant neurological and developmental damage, such as cerebral palsy, mental retardation and delays in walking and talking.

The Centers for Disease Control and Prevention this year reported that 8% of women of childbearing age had levels of mercury in their blood exceeding the precautionary standard set by the EPA. As a result, the CDC said, more than 300,000 newborns may have been exposed before birth to mercury concentrations high enough to increase the risk of neurological problems.

“Even small increases in mercury exposure are causing deficits in brain function,” said Philippe Grandjean, a professor at Harvard University’s school of public health.

“The brain is a unique resource,” he added. “We don’t want to lose any brain capacity on behalf of some pollution that can be prevented.”

Officials in Florida were inspired to take action after high levels of mercury showed up in largemouth bass, an Everglades’ signature fish and a lure for local anglers and tourists.

They were also concerned that mercury posed risks for wildlife that feed on the fish, among them the Florida panther, which is on the federal endangered species list, and many varieties of wading birds.

In 1989, Atkeson, the mercury coordinator for Florida who was then working for the state Health Department, and colleagues from other agencies received funding to test fish in the Everglades. They found mercury levels higher than 2 parts per million, several times higher than the 0.3 parts per million the EPA considers safe for eating.

“That’s when we felt something was real,” Atkeson said.

Multiple fish were then taken from 10 sites, including three popular fishing locations. They were tested by three different labs to ensure that the findings were accurate. The results prompted the initial advisory on fish consumption.

In 1990, a state regulation adopted to control other types of pollution from incinerators caused some decline in mercury emissions. In 1993, Florida was the first state to adopt a rule directly addressing mercury emissions from municipal waste incinerators, and the federal government followed with a similar regulation.

Applauding Florida’s progress, Grandjean, the Harvard professor, urged national policymakers to take aggressive action in reducing mercury emissions. “Quite clearly, what has been achieved in Florida is the right thing to do,” he said.

Whether the nation can replicate Florida’s success is open to question, since the state has unique characteristics that contributed both to the high levels of mercury in the fish and to the rapid dissipation of the problem.

For instance, the expansive sea of saw grass, the sharp-edged sedge that stands in shallow water or on damp soil covering millions of acres in south Florida, is partly responsible for the high mercury levels.

On dry days, mercury gases and particles are caught by the tall blades of the saw grass and other wetland vegetation. Eventually, the mercury drops into the water and settles into the sediment, where a small portion of it turns into methylmercury and moves into the food chain.

The shallowness and the temperature of water in the Everglades also increase the rate of mercury’s transformation into its more toxic form.

In addition, south Florida’s primary local sources of mercury air emissions were waste incinerators, not coal-fired power plants. Mercury emissions from these incinerators declined 92% between 1991 and 1999 because of pollution control efforts -- including the removal of batteries and other mercury-containing trash.

Atkeson says the state is convinced that, despite the distinct ecology of the Everglades and the sources of its mercury pollution, its success in decreasing contamination has broad applications. “The science is universal,” he said.

But Leonard Levin, who heads the mercury work at the utility-industry-funded Electric Power Research Institute, said it would be wrong to assume that Florida’s experience means that slashing mercury pollution from power plants elsewhere would quickly reduce mercury in fish.

“I don’t feel that case has been made,” Levin said. “I’m skeptical that you’ll see the same impact on a national scale that you saw in Florida.”

One reason, he said, is that power plants emit a smaller portion of the kind of mercury that tends to drop relatively close to the source.

On average, about 60% of the mercury emissions from power plants is elemental mercury, which tends to stay in the atmosphere longer and could fall to earth anywhere around the globe, he added.

“Our modeling has shown that for most of the country, more than 90% of the land area, there is a very small change in deposition for a big change in emissions,” Levin said.

Atkeson says that 20 years of data collection has given Florida something better than just modeling -- scientific evidence. Officials regularly have sampled largemouth bass from several spots around the state. They also have analyzed the sediment that makes up the floor of the vast marsh.

These data, they say, provide ample evidence that air pollution is the prime cause of mercury contamination in fish and that stringent emission regulations are tackling the problem.

One of the scientists researching mercury in the Everglades, David Krabbenhoft of the U.S. Geological Survey, said that although Florida’s experience confirms that reducing mercury air pollution will decrease fish contamination, “it is very difficult to anticipate the recovery time of a lake, stream or wetland in a different part of the world.”

But his research has shown that new mercury deposits are much more reactive -- and therefore much more likely -- to turn into methylmercury than mercury that dropped into waterways months or years ago. So “if we turn off the source of the new mercury, it’s not just a linear decrease in the impact; it should have a greater than one-to-one correspondence,” he said.

Despite the progress in Florida, the state’s advisory on fish consumption still warns people not to eat largemouth bass, bowfin or gar caught in Everglades National Park.

In the Everglades Water Conservation Areas, state land just north of the park, people are warned not to eat any of those fish, with the exception of largemouth bass under 14 inches in length. In addition, women of childbearing age and children under 10 are urged to keep their consumption of the smaller bass to only 8 ounces or less over a four-week period.

“We have more work cut out for us,” Atkeson said. If necessary, he said, “we may have to come back and push for another round of regulations.”