Radium taints life in Round Lake

Radioactivity in the lake's freshwater mussels, above, may be high because the lake depends on water pumped from the Floridan Aquifer. Traces of radium are found in lakes throughout Florida.

[Times photos: Mike Pease] A University of Florida professor says Round Lake has higher levels of radium in its sediments than any of about 60 lakes he has tested in Florida.

By DAVID PEDREIRA

© St. Petersburg Times, published April 19, 2000

TAMPA -- Round Lake wouldn't exist without a daily transfusion of about 250,000 gallons of water from the Floridan Aquifer.

Like dozens of other Tampa Bay area lakes and wetlands damaged by overpumping, it is on life support, hooked up to a pipe that pumps water into it from a well 480 feet deep.

But this so-called augmentation appears to be having an unintended side effect: radioactivity.

The amount of radioactivity in freshwater mussels in Round Lake has been described as "incredibly" high.

Scientists from the University of Florida discovered elevated levels of Radium 226 in Round Lake last year while studying how augmentation, ongoing for 30 years, is changing its chemistry and biology.

Although the radium levels in the water are well below federal safety standards, the amount of radioactivity in freshwater mussels in Round Lake was "incredibly" high, leading one scientist to describe the mollusks as "hot" in a memo to water managers.

Smaller levels of radiation were found in the bones of several fish species and in plants and sediments in the 11-acre lake, nestled in a forested patch of northwest Hillsborough County.

Radium 226 is a natural element found in central Florida's limestone underbelly. Traces of the known carcinogen, which takes more than 1,000 years to decay, have turned up in lakes throughout the state, and even in sediments of Tampa Bay.

Any deep well that taps into the aquifer near "hot zones" rich with phosphorus could draw water with elevated radiation levels, said Mark Brenner, a professor with the University of Florida's fisheries and aquatic sciences department.

That is apparently what happened at Round Lake, which has higher levels of radium in its sediments than any of the roughly 60 lakes he has tested in Florida, Brenner said.

"Augmentation is adding this to the lake," Brenner said, noting that radium levels in the groundwater pumped into Round Lake are higher than the levels in the lake itself. "Obviously, this is a cause for concern."

Scientists at the Southwest Florida Water Management District, which commissioned the study done by Brenner and three other scientists, say it is too early to determine whether augmentation is causing Round Lake's higher radiation levels.

"We don't think we have enough information to say where it is coming from," said Dave Moore, deputy director of the agency, known as Swiftmud. "We feel it's not appropriate at this time to speculate."

But the discovery, which will be published in the scientific journal Limnology & Oceanography next month, has kicked off a flurry of activity among water management officials.

Swiftmud approved spending $238,000 to investigate whether augmentation is elevating radiation in other west central Florida lakes.

Early data show that it has, said Joseph Smoak, a geochemist at the University of Florida who co-wrote the Round Lake study.

Swiftmud also has retained the Tampa law firm of Bavol, Bush and Sisco to study whether the radium in Round Lake could increase cancer risks for residents living around it. More than 20 homes, some worth more than $300,000, line Round Lake.

A research firm in Tallahassee hired for the task determined the water and fish in Round Lake posed no threat to humans. But they noted the mussels, if ingested regularly, would increase cancer risks beyond acceptable levels.

They also found the levels of radium in the lake sediment "exceed the cleanup standard for surface soils at uranium processing sites."

Woody Dame, who bought a home on Round Lake in 1974, said he wasn't too concerned. Without augmentation, Dame said, the lake would dry up and his property value would plummet.

"I fish out there, but I turn them loose," said Dame. "I guess it's a sign of the times. Everything's getting messed up."

Swiftmud met with more than a dozen Round Lake residents last week, outlining the data collected so far and discussing plans for further study.

Roger Schatzel, president of the Round Lake Association, is satisfied there's no health threat: "I'm not getting real spun up about it, but I'd like to see more research into what's going on."

The research could have far-reaching effects. Swiftmud oversees the augmentation of more than 60 lakes and wetlands in its jurisdiction. Most of the lakes are in Hillsborough.

Depleted by pumping from nearby drinking water well fields, the lakes and wetlands need daily doses of well water to keep from drying up.

The process is highly controversial. Environmentalists say augmentation is like covering a bounced check by writing another from the same account. The water is from the same depleted source, they argue.

Some of the new water evaporates, and much of it seeps into the ground. Indeed, more water is pumped into Round Lake than it can hold. Last year, about 59-million gallons were pumped into Round Lake, which holds 31-million gallons.

Meanwhile, the chemistry of augmented lakes changes because aquifer water is "harder" than surface water.

Round Lake, across N Dale Mabry Highway from the Section 21 Wellfield, has been augmented since the mid-1960s, when it almost immediately dried up after the well field pumps were turned on. St. Petersburg built Section 21 to supply its residents with water. The well field recently was turned over to Tampa Bay Water under a regional master water plan.

As Dame stood on his dock last week, ducks foraged for food in a field of lily pads while two largemouth bass cruised the shallows amid scurrying baitfish.

"If Y2K was real, we'd be out here netting mussels and glowing in the dark," Dame said. "But I'd rather not lose the lake. It's a pretty big investment."

- David Pedreira can be reached at (813) 226-3463 or pedreira@sptimes.com.

© St. Petersburg Times. All rights reserved.