A recent study conducted by the U.S. Geological Survey reveals mercury contamination is pervasive in rivers and streams all across the nation.

A Southeast Georgia environmental advocate says the Satilla River, which rises near Douglas and empties into the Atlantic near Woodbine, could be the "poster child" for that study.

"The Satilla exemplifies everything in that study," Satilla Riverkeeper Gordon Rogers said after the results of the study were released Wednesday. "It's a blackwater stream that's heavily contaminated with mercury, and the mercury is poisoning the fish to the point that they're inedible."

USGS scientists who tested fish from 291 streams found mercury contamination in all of them. According to the study, the highest levels of mercury were found in blackwater streams, such as the Satilla and similar rivers in the southeastern United States.

Blackwater river systems are far more efficient at transferring mercury to fish than are alluvial systems like the Altamaha River, Rogers said. Fish species, such as catfish, redbreast and largemouth bass, ingest mercury when they feed on plants and insects.

The mercury goes up through the food chain, Rogers said, concentrating in larger fish, such as the nonnative flathead catfish in the Satilla.

While flatheads are prized by fishermen for their size and taste, they are decimating native fish populations in the Satilla and are the target of a DNR eradication effort. Over the past three years, thousands of pounds of flatheads have been caught and removed.

Partly because of their mercury content, those fish are dumped in a landfill instead of being donated to a food bank or other charitable organization, said DNR Fisheries Regional Supervisor Bert Deener .

Because of the volume of flatheads the DNR catches, it's not possible to keep them all iced down to prevent the flesh from spoiling, Deener said.

"But we don't want people eating them either," Deener said. "There are certain kinds of fish and certain sizes that you want to stay away from."

The source of the mercury

While there are some who claim the mercury is naturally occurring, Rogers contends the source for most of it is coal-fired power plants.

"The science is overwhelming about where the stuff is coming from and how toxic it is," he said.

According to Rogers, mercury is emitted from power plant smokestacks when coal is burned. It lofts into the atmosphere, and eventually settles to earth, ironically using nature as a very efficient distribution system.

The lack of a coal-fired power plant in the region obviously is no safeguard to mercury pollution, Rogers points out.

"There's no coal-fired plant in the Satilla watershed," he said, "and what I mean by that is we are paying for other people's sins."

A neurotoxin, mercury is dangerous when ingested, particularly to pregnant women and children. It accumulates in the bloodstream and is expelled naturally, although very slowly, and can reach dangerous levels if too much contaminated fish is eaten.

The Environmental Protection Division of the Georgia Department of Natural Resources issues advisories on how much fish can be consumed safely. On the blackwater Satilla, it advises that flatheads 30 inches long and smaller may be eaten once a month. That's a 6-ounce serving. Flatheads longer than 30 inches should not be eaten at all.

Other fish can contain dangerous levels of mercury, too. Redbreast sunfish from the lower reaches of the Satilla, for example, also are restricted to once a month. Upstream near Waycross, it's safe to eat redbreasts once a week.

On the alluvial Altamaha, it's safe to eat flatheads of any size once a week, according to the EPD advisories.

The fact that the advisories are necessary at all incenses Rogers.

"We've known for a long time that this stuff is bad news," he said. "We shouldn't have to be talking about this at all. We need this off our plate. We need to solve this and move on."

Power companies are spending billions of dollars to cut emissions from plants that burn coal.

Georgia Power is spending $5 billion to improve its anti-pollution equipment at its larger plants in the state to meet the requirements of the Clean Air Act.

"This is the largest construction project in our company's history," company spokesman Jeff Wilson said.

The scrubbers that are being installed will bring about significant reductions of three main pollutants - mercury, sulphur dioxide and nitrogen oxide.

But Rogers contends any mercury is too much, especially if it finds its way to a blackwater river system.

"It takes just 10 pounds to contaminate the entire Satilla River system," he said.

A new state-of-the-art coal-fired plant, the Longleaf Plant, planned for rural Early County in Southwest Georgia would emit 158 pounds annually.

That project is tied up in court, but if it's built, the Satilla will suffer from the fallout, Rogers said.

"We don't need to be putting any more coal-fired plants anywhere they can reach a blackwater river," he said. "There are alternatives to coal."