Awful Fishy

For Broward's canal fisherman, potentially toxic levels of mercury are a part of the catch of the day

No one considers what its flesh might contain.

To reach his fishing spot from the unwavering urban sprawl of his city neighborhood, Keys drove west on I595 to the last exit before the toll booths that greet travelers entering Alligator Alley. Then he abandoned the interstate in a northern turn onto U.S. Highway 27, following a long curve that carries travelers almost immediately past a pull-off beside a wide canal. Several more pull-offs exist in the 13-mile stretch to the Palm Beach County line.

A young girl fishes a canal in western Broward County where larger fish carry mercury in quantities that put women and children at the greatest risk
Joshua Prezant
A young girl fishes a canal in western Broward County where larger fish carry mercury in quantities that put women and children at the greatest risk
U.S. Geological Survey scientist Bill Orem literally followed his nose to the sulfur problem
David S. Holloway
U.S. Geological Survey scientist Bill Orem literally followed his nose to the sulfur problem

Anglers along the canals range in style and sophistication from cane-pole users to bass-boat techies equipped with fish finders and expensive gear. For Keys part of the pleasure of fishing is education for his children -- their chance to see things they normally can't. Scanning the scene he spots ibis floating overhead and a single alligator drifting midcanal, all part of the natural food chain of predators that rely on fish. He shouts and points when something catches his interest.

There's another plus: a chance for the family to catch supper, just as he did as a boy in North Florida, he recalls. Others have the same thing in mind, apparently. Not far up the road from Keys, a man appears headed for his car, carrying a stringer filled with fish. North and south of the spot lie miles of freshwater canals and tributaries, where the state has provided convenient parking areas for the food- and sports-minded. On any given day several hundred people may park to fish the canals, where occasional signs note the supervision of the Southwest Florida Water Management District or the FWC.

In the official jargon of state agencies, the anglers are fishing Water Conservation Area (WCA) 2. Along with WCA 3 to the south, the area includes some 1200 square miles of eastern Everglades habitat, stretching across western Palm Beach, Broward, and Miami-Dade counties. Together WCA 2 and 3 contain more than 50 miles of canals, and many more backcountry fishing spots, according to state descriptions. The area is roughly bordered by the Palm Beach County line on the north, U.S. Highway 41 in Miami-Dade County on the south, Florida's Turnpike on the east, and the Collier County line on the west.

Collected from rainwater runoff and some underground springs, canal water in WCA 2 and 3 flows gently south and east past banks crowded with exotic low growth. Cattails and yellow-flowered Spanish needles cluster near small native cypress trees, red bay trees, and an occasional pond apple tree. For miles along the western canals of Palm Beach County, the dead trunks of Brazilian pepper trees line the banks.

Throughout that system fish exist as both predators and prey: bluegill, redear sunfish, pickerel, oscar, and the imported Mayan cichlid flourish. Hunting those species are larger predators: gar, bowfin, and largemouth bass, the most sought-after freshwater game fish. Bass in WCA 2 and 3 provide anglers with some of the "highest catch rates in the state," declare Fish and Wildlife brochures. And the bigger a fish is, the more likely it harbors dangerous levels of mercury.

Although Arthur Keys does not know that, scientists and administrators in the state Department of Health and the DEP do: They are all too familiar with WCA 2 and 3. Their written warnings to anglers -- not posted on public signs -- include the following recommendations:

• Never consume bass, bowfin, or gar caught in WCA 2 and 3.

• Eat no more than one eight-ounce helping of other fish per month, unless you're a full-grown male. Then you can eat one per week.

The need for such extreme rationing grew with the 20th Century. For 100 years mercury has been slipping into the South Florida environment like an invisible enemy, impossible to track accurately to its source, says Tom Atkeson, the bureau chief of the mercury program at the DEP. A metal sometimes known as quicksilver, it arrives by air, reaching the soil in the abundant wash of South Florida's rain. Once on the ground, an unusual bacteria converts the metal to its organic form, methylmercury. The organic form -- odorless and invisible -- can be deadly if consumed in abundance. Atkeson's job is to organize and direct research that ultimately might identify the causes of mercury pollution and propose ways to stop them.

Neither Atkeson nor any other researcher in state and federal government has identified just how much mercury comes from local sources and how much originates from "worldwide use," but they can cite some major contributors: mercury batteries, paints containing mercury, phosphorescent lights. Pollutants from vehicles and other sources in the vast urban sprawl stretched along the eastern coast of Florida are also part of the problem.

"How much a part of the problem?" Atkeson asks. "We don't know. But we do know that since 1900, mercury in the Everglades region has increased fivefold."

Among the biggest contributors of airborne mercury, he says, may be the emissions from medical-waste incinerators and municipal solid-waste plants. Once mercury has arrived, it remains planted in the environment for years -- and in South Florida it becomes converted to methylmercury.

"This is the stuff that can kill," says Bill Orem, a career scientist for the U.S. Geological Survey in Washington, D.C. Like Atkeson, the 47-year-old Orem is a midcareer scientist. Unlike Atkeson, he is not an office scientist or a bureaucrat. Orem travels regularly from his office in Reston, Virginia, to South Florida to study mercury accumulation and its effects here. A calm, articulate admirer of the vast Everglades region, Orem explains that methylmercury, the organic form of the metal, springs from a bacterium that does not require oxygen to live. Found in underwater peat sediment or mats of algae, the bacteria use sulfur to respire, using it as other organisms use oxygen.

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