Expert: Sinkholes may plague Stauffer
By RICHARD DANIELSON
© St. Petersburg Times, published August 19, 2000
A geological consultant for the U.S. Environmental Protection Agency has acknowledged publicly what skeptics of the proposed Stauffer Chemical cleanup have insisted all along: That the area around the Stauffer site "is prone to sinkhole formation."
Andrew Grimmke, who works for the Atlanta office of Black & Veatch, also told a citizens advisory group Thursday night that he has reviewed studies of the Stauffer area going back to the late 1980s. He said he found "numerous data gaps" about the geology and underground water characteristics of the area around the site, which is on the Pinellas-Pasco county line.
Moreover, Grimmke said measurements of a thin layer of clay and silt under the site have been "inadequate given the predilection for sinkholes" in the area. That layer separates the surface-water table from the deeper Floridan aquifer, and that layer is what keeps shallow contamination from reaching the region's main source of drinking water.
During a meeting at the Tarpon Springs public library, Grimmke said he recommends that a variety of tests are needed to understand the site, its underground characteristics and how water moves beneath it.
Tarpon Springs area residents who have distrusted the EPA's stewardship of the Stauffer site welcomed Grimmke's statements.
"It was the most important meeting we've had so far," said Carlene Hobbs, chairwoman of the recently formed Anclote Citizens Advisory Group. "We've been taking little baby steps, crawling along. This is a big, giant leap."
The Stauffer site was contaminated with radioactive elements and heavy metals such as arsenic, mercury and lead during 37 years of phosphate ore processing. The plant closed in 1981 and the property was declared a federal Superfund site in 1994.
Hobbs said the EPA's acknowledgement of the sinkhole risk at Stauffer casts new doubt on the proposed method for cleaning up the site. EPA officials have advocated piling about 300,000 cubic yards of contaminated soil at Stauffer and sealing it with a cap consisting of layers of plastic, soil and grass. Hobbs said that in a sinkhole-prone area, the weight of such a "monolith" could send contaminated earth plunging into the aquifer.
In addition, an official with the Pinellas County Health Department told the citizens group that health officials have tested water from 18 private residential and business wells, most of them within a half-mile of Stauffer. In 13 of them, there were levels of contaminants, mainly sodium, iron and manganese, that exceeded drinking water standards.
Health department environmental specialist Bonnie Bergen said Friday that the preliminary test results suggested that -- contrary to what the EPA and Stauffer have said in the past -- contaminants might have moved off the Stauffer site. She said the U.S. Geological Survey should conduct additional tests to determine if they have.
"There appears to be a potential for some off-site studies," she said.
Bergen said the elevated levels of sodium, iron and manganese are probably signs of salt water intrusion into the wells. But, she said, water from one well also contained levels of thallium and radium-226 that exceeded drinking water standards.
Bill Adams, 64, owns that well, and he said the test results came as no surprise to him. His water has "smelled bad" and he's bought drinking water for years. He is considering connecting onto the city's water system.
"I knew that there was something wrong with it for a long time," said Adams, who owns Riverview Auto Sales and Service on Savannah Avenue in Tarpon Springs. "We've got three purifiers on it, and it still doesn't come out right."
Bergen also said that a 1985 U.S. Geological Survey study done in Sarasota County indicated that salt water might cause more harmful radium-226 to be released from remnants of phosphate processing than fresh water. As a result, the kind of saltwater intrusion indicated by recent well-testing should be looked at more closely, she said.
On Friday, John Blanchard, the EPA project manager for the Stauffer cleanup, said he had not had a chance to evaluate the Health Department's test results of wells in the area. As for Grimmke's conclusions, he said "there's nothing really surprising, but he really brought out the importance of doing the sinkhole testing."
Blanchard said the EPA has intended all along to do hydrological and geological tests that prove that the mound-and-cap approach is sound. The difference now is that the EPA recently decided to do those tests sooner, rather than wait until it was doing the technical designs of the mound and cap.
"We don't want a remedy that will fail any more than the community does," Blanchard said. "If we can't show it's protective" of public health and the environment, "we'll have to do something else."
Sandy Nettles, a New Port Richey geologist who attended the meeting, said the EPA should have been thinking about the danger of sinkholes a long time ago.
Nettles showed the citizens advisory group an aerial photo of the Stauffer property from 1926, long before anything was built there. But he said the map clearly shows an old sinkhole on the western part of the property.
"It's called a relic sinkhole, which means it's something that collapsed sometime in prehistory," he said. "We don't know if it was 100 years ago or 10,000 years ago."
Nettles said he also spotted a smaller sinkhole to the north and suspects there are other sinkholes on the site. He said someone filled in about five to six acres of the relic sinkhole, which he said is at least 800 feet across. The remainder of the sinkhole forms Meyers Cove, which borders the property.
"It's there and it's unstable," he said. "It's not something that you can consider to be a stable system."
Nettles said he's followed the Stauffer cleanup plan and has told officials that the mound-and-cap method won't work. Moreover, he said, plugging the sinkholes by injecting grout into them probably won't work, either.
"The idea of sinkholes," he said. "That should have been one of the first things that came up when they started looking at methods of remediation."
- Staff writer Richard Danielson can be reached at (727) 445-4194 or firstname.lastname@example.org.
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