Mine research shows aquifers, streams suffer
No one disputes that, once the mining industry completes the excavation of 500,000 acres of strip mining in Central Florida, the region's ecosystem will never be the same.
The phosphate mining companies, however, believe they can reconstitute the ecosystem to an acceptable facsimile.
But those downstream from the mines of Bone Valley -- and some who are next in line for mining -- fear the industry could create an environmental Frankenstein instead.
Charlotte, DeSoto and Sarasota counties are all concerned about the quality and quantity of water in the Peace River, which flows through the mining district.
The water is crucial to the health of the Charlotte Harbor estuary and provides a drinking water source for about 200,000 people.
Water flows have been reduced from mining, contaminants from mining sites have degraded water quality and radiation from mine sites may slightly increase the risk of cancer, a review to scientific studies shows.
Research backs concerns
"Phosphate mining disrupts water quality, soils, drainage patterns, and wetlands," states the 1998 Water Resources Atlas of Florida. "It also leaves mining and processing wastes, such as sand, clays and gypsum behind."
The Peace River flows through the heart of the mining district. That coupled with the sheer magnitude of mining operations suggests impacts should be studied.
Eventually, 500,000 acres in Polk, Hillsborough, Manatee, Hardee and DeSoto counties will likely be mined. The mines would include 200,000 acres of clay settling areas.
Considered the "gray gold" of Florida, phosphate is primarily used to make fertilizer. In rock form, it brings about $30 per ton. About 23 million tons worth $690 million of phosphate move out of Florida through the Port of Tampa each year, according to a recent federal survey.
The Peace River's flow has declined 37 percent in the past 30-year period and base flow has disappeared in the upper Peace during Florida's recent dry seasons.
One 1998 study by the U.S. Geological Survey concluded that excessive well pumping by phosphate mining and agriculture had dramatically lowered the level of the Floridan Aquifer, causing at least one major spring that once fed the Peace River to dry up.
Dr. John Garlanger, a consulting engineer for phosphate companies, claims the USGS's conclusions are erroneous. He claims in a study he published earlier this year that a decline in rainfall accounts for the vast majority of the reduction in flow.
Mining reduces the flow of the river some 5 percent, according to Garlanger. However, the impact is insignificant because most of the decline occurs during high flow periods, according to Garlanger.
David Moore, deputy director of the Southwest Florida Water Management District, cites anecdotal evidence to argue that phosphate mining has had little impact on stream flow. He points out that the changes in the flow of the Peace River mirror the changes in the flow of the Withlacoochee River, which has had no mining in its watershed.
That shows the Peace, which has witnessed 120 years of mining in its watershed, is holding up as well, Moore said.
Still, Moore acknowledges that the upper Peace River is in serious trouble. The water district envisions some $80 million in projects to restore the base flow of the river, including reconnecting the drainage systems of abandoned mine sites with the river.
Shallow creeks on reclaimed mine sites were found to carry more than three to six times the amount of dissolved solids than creeks in unmined areas, according to the 1993 USGS study.
The study also concluded that well water on mined sites often contains higher concentrations of ammonia, nitrogen and many trace elements than normal aquifer levels.
The quality and quantity of freshwater flowing to the Charlotte Harbor estuary is crucial for the health of the estuary, numerous studies indicate.
If salt water moves upstream, the size of the estuary will be reduced, warned Ernst Peebles, a University of South Florida researcher who studied the harbor for three years.
Estuaries are bays where freshwater mingles with saltwater. The habitats are crucial for many important marine species, especially juvenile fish, according to Peebles.
The water atlas also cites the importance of "essential nutrients of terrestrial origin" that wash down from upstream during high-flow periods.
Reclamation concerns
A primary concern with the mining process is the proliferation of clay settling areas on reclaimed mine sites. The areas form an "almost impervious seal over the land which they cover," states a 1992 BMR Regional Conceptual Plan for the phosphate mining district.
As a result, they don't readily allow rain to soak in to recharge surficial aquifers.
The clay "may present an obstacle to the restoration of hydrologic functions," said BMR environmental administrator James "Bud" Cates, who drafted the 1992 plan.
Reclaimed clay settling areas also could allow clay silt to wash into the river during storms. That concern proved true last month when stormwater washed out a dam at a 1,400-acre former mine site near Fort Meade.
The excavation of the mine pits also removes a layer of dense clay with the ore at the bottom of the strip mines. That clay often separates the uppermost aquifer from the intermediate aquifer below it, causing the two aquifers to act, according to USGS studies.
That makes the water table more prone to dropping, which could cause lakes and streams to go dry.
The practice of refilling the mine pits with purified sand left over after the ore processed also poses concerns. Water drains faster through the sand than natural soil, lowering water tables and reducing the flow of nearby streams, according to a 1993 USGS study.
The study found that water table levels and stream flows were lower on reclaimed mine sites compared to unmined areas.
Radiation concerns
Radiation levels are naturally high throughout Central and Southwest Florida. However, some studies indicate that mining brings the materials closer to the surface after reclamation.
For example, at the Tenoroc Fish Management Area near Auburndale in Polk County, a former phosphate mine that was donated to the state in 1981, a consultant hired by the EPA, found Radium 226 at high enough concentrations to warrant concern.
Such radiation levels pose no risk for short-time exposures, according to EPA administrator Brad Jackson. However, the risk from long-term exposure "needs further study," he said.
Other studies appear to reach contradictory conclusions.
People who live in Central Florida's phosphate district are twice as likely to suffer lung cancer, claims a 1985 research paper published in the Journal of the American Medical Association.
However, only three out of 1,000 people residing on reclaimed mine sites for 70 years would be likely to get cancer, according to the Florida Institute of Phosphate Research. To date, about 4,000 homes have been built on reclaimed mine sites.
James Stricker, a University of Florida extension service soil scientist, conducted a study to determine if high-value crops could be grown on clay settling areas.
He found that many crops, from citrus to corn, could thrive in the clay.
But farming on clay settling areas comes with two problems: The clay is often so soft it requires special tractors; and the crops will be tainted with the stigma of radioactivity.
Stricker found that the radium content of clay settling areas averaged 19 times that of unmined sandy soil. And crops grown on phosphatic clay were "generally higher" in Radium 226 than other crops. But the levels in the clay-grown crops posed an "insignificant health risk," according to the study.
Seepage from gyp stacks also has been found to contaminate ground water -- but only within relatively short distances from the stack, according to a 1980 USGS groundwater study. Radioactivity was higher at wells within 200 feet of gyp stacks and phosphorus contamination was high within 1,500 feet.
Gyp-stack nightmare
The fate of mountain-like gyp stacks that surround Polk County's half-dozen chemical plants also remains uncertain.
They are formed by piling up phospho-gypsum, a slightly radioactive byproduct of the process that turns phosphate into fertilizer.
Some 20 stacks have been built to date and seven more are under construction. With bases covering 600 acres each, they rise 200 feet or more. The stacks hold more than 1 billion tons of phospho-gypsum.
The phosphate industry has proposed using phospho-gypsum for purposes ranging from fertilizer for peanut farms to road base. But the U.S. Environmental Protection Agency has refused to permit the uses because of the material's low-level radioactivity.
So it must be disposed of in stacks.
When the plants shut down -- and it's certain they will eventually, once the phosphate ore supply in the region is exhausted in 25 to 50 years -- the acidic water will keep seeping, likely for decades.
The DEP doesn't know what it will do with the "gyp-stacks" after that.
Will the government be liable for 27 giant gyp stacks?
"It's a scenario that keeps people up at night," says Stephen Partney, administrator for the DEP's Bureau of Mine Reclamation. "If anybody has a reasonable solution, we'd be interested to hear it."
You can e-mail Greg Martin at gmartin@sun-herald.com
By GREG MARTIN
Staff Writer