OKLAHOMA CITY — Ed Kessler couldn’t believe what was happening in his pond.

A sample of fish swimming in his pond near Purcell revealed a troubling discovery - mercury.

Fish from Kessler’s pond was sampled during an Environmental Protection Agency study conducted from 2000 through 2003. The Norman resident learned fish tested from his pond had 0.558 parts per million of mercury.

The amount may seem microscopically miniscule, but it’s higher than the 0.5 ppm level that can be dangerous for pregnant women and children. It’s also nearly twice the 0.3 ppm screening value for human health - EPA lingo for high enough to warrant further study.

The fish wasn’t too toxic by EPA standards to shun altogether, but it was more than enough to make Kessler wonder. Nineteen of the 21 Oklahoma sites tested by the EPA had fish with some level of mercury, arsenic or toxic organic chemical.

“The bottom line is you don’t know if you can eat the fish or not, unless you have one of the few ponds that doesn’t have mercury or toxins,” Kessler said. “Even if the mercury is a little low, I don’t want to eat fish with mercury in it.”

Kessler also keeps tabs on the Oklahoma Department of Environmental Quality, which monitors toxins in fish in 49 of the state’s largest public reservoirs. Monty Elder, environmental program manager at DEQ, said sites are sampled every seven years, but tests become annual at places where fish have toxins that exceed a minimum limit.

For mercury, it’s 0.5 ppm, or milligrams per kilogram.

Elder said the DEQ bases its standard by the EPA’s guide for fish consumption. Pregnant women and children 6 and younger should limit fish with levels between 0.5 and 1.0 ppm to two meals per month and avoid it altogether if it’s higher. For everyone else, the EPA levels are 1 ppm for limited eating and 1.5 for none at all.

According to the EPA, microscopic organisms convert mercury and methylmercury within fish, and predator fish usually have more of it. Mercury and methylmercury damage the nervous system, especially its development within fetuses, babies and younger children.

In late 2004, Elder said, the EPA lowered its mercury advisory level for pregnant women from 1.0 to 0.5.

“Given the changes in mercury consumption levels, there are 10 lakes in Oklahoma in which sampled fish contained levels of mercury above the 0.5 mg/kg consumption advisory level,” Elder said.

“Those lakes,” she said, “are McMurtry, Zoo, Draper, Coalgate, McGee Creek, Hugo, Broken Bow, Wister, Greenleaf and Heyburn.”

McMurtry is near Stillwater, Greenleaf is south of Fort Gibson, Heyburn is 11 miles southwest of Sapulpa, and Stanley Draper and Zoo lakes are in the Oklahoma City area.

The advisory means those lakes will be tested again this year. If the readings come back high again, the DEQ will issue consumption advisories for the specific lakes.

For now, though, there are no posted warnings for fish consumed at those places. Mike Fina, an Oklahoma Tourism and Recreation Department spokesman, said public lake personnel work closely with the DEQ and they would post advisories as soon as the environmental department tells them to.

“They govern us in that regard, the level of mercury in the water and fish. In fact, we rely on them for those tests,” Fina said. “They have not directed us to do any postings. We work so close with them, we’re a conservation agency as well and also from the tourism aspect.”

The only advisory in effect for any Oklahoma lake is for catfish in the Bitter Creek Watershed near Altus due to elevated levels of pesticides DDT and toxaphene. Pregnant women and young children are advised to have no more than two servings in a month of fish caught there.

Because the state has so many untested lakes and no one knew how this year’s readings on fish in the 10 reservoirs would turn out, the DEQ last year issued a statewide advisory on mercury. The advisory says pregnant and nursing women, along with kids 15 and younger, should eat locally caught predator fish no more than once a week.

Bass, walleye, saugeye and flathead catfish are the predator fish to watch. The advisory says sunfish and channel catfish typically have less mercury.

Elder said the DEQ soon will be able to test more bodies of water quickly, thanks to a new $50,000 machine that allows testers to take out a small core of flesh and inject in the machine for a much faster reading.

Getting to more places is needed, she said, because it’s otherwise impossible to tell which lake, pond, or stream has fish with high mercury. The DEQ spends $75,000 a year on monitoring fish toxins. Its plan to expand the program would double the cost.

“Mercury is an interesting thing because the presence of mercury in the water doesn’t mean it’s in the fish,” she said. “It has to be methylated. It doesn’t occur in every lake and it depends on a lot of factors. … You can have lakes right next to each other and only one have fish with higher mercury, which means you have to sample every lake.”

The mercury warnings for fish have no bearing on recreational activities at those sites, she said. Elder said the lakes are safe for fishing, swimming, boating or anything else people would do for fun.

Fina said Greenleaf is among a number of reservoir areas getting plenty of visitors, and they remain popular for fishing.

Back in Norman, Kessler believes government agencies are responding to toxins in fish but have been slow in doing so. Establishing where the mercury comes from is vital in figuring out how to stem it.

The mercury warnings for fish don't affect municipal water supplies, often fed by area lakes, Elder said. Such water is tested for hundreds of chemicals and is always treated, Elder said, and when chemicals are present they cannot exceed EPA standards.

Given the health risks associated with mercury and other toxins, Kessler hopes environmental officials put a rush on finding the answers.

“The question is how do you handle it,” he said. “I don’t want to be like so many other false alarmists, and yet something needs to be done.”



James S. Tyree is CNHI News Service Oklahoma reporter.