Fishing in the Suwannee has always been a popular local pastime, and with the slowdown in the economy, some local folks have turned to catching their own bass, bream and catfish rather than buying them from a store. They may want to think again.

Recent findings by the U.S. Geological Survey raise concerns about mercury contamination in fish caught from the Suwannee and other area rivers. Currently, there are eight kinds of fish that carry mercury advisories from the Florida Department of Health in the Suwannee River system, which includes the Santa Fe, Withlacoochee and the Alapaha. (See chart, this page.)

Mercury is a neurotoxin that can damage the nervous system and cause learning disabilities in unborn babies and children 15 and younger. “Mercury is a terribly dangerous thing,” said Joan Stevens, president of Save Our Suwannee. “Not only does it affect our air, but our water too.”

In the USGS study, the most comprehensive yet of rivers and streams in the southeast, the highest levels of mercury in fish were found in the remote “blackwater” streams flowing into rivers such as the Suwannee.

The Suwannee, however, is a unique case.

“It is an interesting situation on the Suwannee,” said Ted Lange, a fisheries biologist with the Florida Fish and Wildlife Conservation Commission. “The levels are all over the place. It goes up and down. The Suwannee is the only place we see such variability.”

Lange and other researchers are not sure what causes such variations in levels of contaminants. Lange hypothesizes that when the Suwannee is dry mercury falls on the riverbed and is later soaked up in large amounts by the river when it rises. During the flooding of the Suwannee last spring, mercury levels were very high, said Lange.



Where does the mercury come from?

Mercury is a naturally occurring element. However, according to Lia Chasar, co-author of the USGS study, the main source of mercury pollution is emissions from coal-fired power plants both in the U.S. and abroad.

“Coal-fired power plants are the largest contributor,” said Chasar, a research hydrologist and ecologist. Cement manufacturing plants aren’t far behind.

“The most of the mercury in our waters come from atmospheric deposition,” Chasar said in an interview posted on the USGS Web site. “That’s mercury that gets emitted from coal-fire power plants and waste incineration as a by-product of the cement chlorine.”

Nonetheless, Lange says it is Florida’s wet climate and the high concentration of wetlands and forests surrounding these rivers, where bacteria flourish, that result in higher mercury levels in “blackwater,” or tea-colored, rivers and streams. Mercury released into the atmosphere here and overseas rains down into waterways where it mixes with certain bacteria and converts into methyl mercury, a form that allows the toxin to enter the food chain, according to Lange. Because it rains more in Florida, there is more mercury leaving the atmosphere and entering waterways. Mercury can travel from as far away as China’s many coal-fired plants and end up in the Suwannee River system, said Lange.

“It is an atmospheric problem,” Lange continued. “Mercury pollution is a global problem with local sources.”

Scientists are seeing “signs that there is a regional footprint” in mercury pollution in our area, said Chasar. However, she did not explicitly link the problem to local industry.

Tom Messer, plant manager of Suwannee American Cement in Branford, said by email that his facility was “one of the lowest mercury emitting cement plants in the U.S. and well below our permit limits, even so we are constantly working with environmental scientists and professionals in finding technologies to reduce these amount.”

Unless mercury emissions are lowered we will continue to see fishing advisories, said Lange. Already eight types of fish in the Suwannee River system have eating restrictions due to the high mercury levels. The restrictions range from a recommendation of a single six-ounce meal per week of channel catfish to just one per month of largemouth bass, bowfin and gar. Women of childbearing age and children under fifteen should only have one meal of channel catfish, largemouth bass, bowfin and gar per month. Although small fish such as bream are safest to eat, they are also included in the advisories.

The USGS study, which from 1998 to 2005 sampled fish across the nation, including bass, catfish and bream, from over 291 streams and found mercury in every fish tested. Within the southeast, Florida had the highest levels of mercury contamination in fish, with the Suwannee River system showing levels exceeding many rivers across the state and country, said Chasar. “The Suwannee is up there,” said Chasar.

Ponds and lakes also suffer mercury contamination. “We know that roughly the same amount of mercury falls from the atmosphere within a local area (North Florida); however, we find different levels of mercury in fish from various waterbodies. Much of this is dependent upon individual waterbody characteristics including characteristics of the watershed (size and types of landcover within the watershed), the waterbody itself (water chemistry and size) and the fish themselves (what species and age). So mercury levels vary considerably from lake to lake and unless we test fish (in that particular lake or pond) we really don’t know their mercury content,” said Lange by email.



Not a new problem

In 1983 an FWC study was conducted of the Chipola River after reports of contamination from a battery plant. Fish from the Chipola were compared to fish from the Santa Fe. Mercury levels in the Santa Fe proved to be significantly higher. These findings first lead researchers to believe mercury pollution was a statewide problem nearly 30 years ago.

Considering the results of these earlier studies, Chasar and Lange did not seem surprised by the findings of this most recent study, in which more than one-quarter of fish tested exceeded the EPA’s safe level of mercury consumption. Still, Chasar says scientists are not suggesting eliminating fish from diets.

“We’re not telling people not to eat fish, just to make wise choices,” said Chasar.

For example, one should closely monitor the types of fish one consumes and the amount, according to the Florida Department of Health. “Advisories are not intended to discourage anglers from eating fish but should be used to choose fish lower in mercury while limiting consumption of some species of fish from certain waters,” according to the DOH Web site. The site states that fish with long lifespans, such as largemouth bass, create the greatest potential to accumulate high levels of mercury.

Mercury contamination raises other concerns as well. For one, mercury does not affect humans alone. The toxin has been proven to harm the reproductive systems of forest animals and birds. Furthermore, while humans can eat a certain amount of fish contaminated below 0.3 parts per million, wildlife may be harmed by eating fish with anything over 0.1 parts per million, making the current condition of the Suwannee especially dangerous for local wildlife. More than two-thirds of the fish sampled across the country had a concentration that was unsafe for wildlife, according to the study. “We hope our study will call attention to the sensitivity of ecosystems here in the southeast,” Chasar said.

The recession and overall popularity of fishing locally add another dimension. “We’ve seen an increase in people fishing for food,” said Trea Reeves, of Piddlers bait and tackle shop in Branford. “We’ve seen a dramatic decrease in overall sales. There are not as many tournament fishermen since the downturn of the economy. Plastic sales have gone down. However, live bait sales have gone up.”

In Lafayette County, Mayo Bait and Tackle, which also sells fish for human consumption, reports a drastic decrease in sales of mullet and other food fish.

“People are poor around here, they’ve always fished for food,” said Randy Johns, an avid Hamilton County fisherman. Johns says he eats fish twice a week, including bass, catfish and gar. As far as mercury pollution, he says he is “not worried about it” and plans to keep fishing as usual.



Where do we go from here?

Lange says we must start with alternatives to fossil fuels and technologies, now available, that decrease emissions.

“They are expensive, but there are technologies available,” he said.

For now, the majority of fish in the Suwannee are safe to eat, but will that still be the case in 20 years? No one can say for sure.

“We put it (mercury contamination) up there, so it is conceivable that we can lower it,” said Lange.