Rig will dig into Stauffer plant site

Probing 80 to 100 feet below the surface may reveal whether capping pollutants at the site might create a sinkhole and pollute the water supply.

By ROBERT FARLEY, Times Staff Writer
© St. Petersburg Times
published October 26, 2002

TARPON SPRINGS -- A truck with a 30-foot mast that looks like a well-drilling apparatus will be boring holes to test the ground under the Stauffer Superfund site over the next two weeks.

The 3-inch-wide borings, which will reach 80 to 100 feet deep, are the final step of field work in a study designed to answer whether the ground beneath the former phosphorus processing plant is prone to sinkholes.

The tests were commissioned after former U.S. Environmental Protection Agency ombudsman Robert Martin raised concerns about moving forward with plans to mound and cap contaminated soil on the 130-acre site without first determining whether such a mound might trigger a sinkhole and send pollutants directly into the drinking water supply.

At the direction of the EPA, Stauffer Management has used a handful of techniques such as ground-penetrating radar and electromagnetics to study the ground beneath the site. Those methods, however, did not include actually digging into the soil, said Stauffer site manager Frank McNeice.

Draft reports on the geophysical study, as well as a groundwater study, are expected to be completed by the end of the year, McNeice said. Stauffer is paying for the test.

Studies in 1989 and 1991 concluded the surficial aquifer, which is not used for drinking water, was highly contaminated. The groundwater study, based on samples from monitor wells, should determine how much of that contaminated water has leached into the deeper, drinking water aquifer.

A thin layer of clay that separates the two aquifers is described as "semipermeable" -- meaning water likely passes on a limited basis between the two water supplies. The soil borings will determine how thick the clay layer is between the two aquifers.

"We will be able to pull up a whole sample of soil and see how deep the clay is, and how thick," McNeice said.

In July, the company performed three other soil borings on the north side of the 130-acre site. Those holes went down about 120 feet, McNeice said. The five to 10 borings to be done over the next two weeks will go down 80 to 100 feet. Tests done in years past have gone down to only 20 feet, McNeice said.

Stauffer officials on Friday issued a news release about the upcoming work, McNeice said, because it will be very visible to passers-by.

A third study, to determine the long-term effectiveness of the plan to stabilize contaminated soil, still awaits EPA approval to begin. That study may take months, but the geophysical and groundwater studies will go a long way toward determining whether the controversial mound-and-cap cleanup plan is workable, McNeice said.

EPA project manager Nestor Young could not be reached for comment.

Stauffer was a phosphorus processing plant operating on the site from 1947 until the early 1980s. Hazardous waste byproducts left behind include arsenic, antimony, beryllium, thallium, elemental phosphorus, radium-226, radon and carcinogenic polyaromatic hydrocarbons.

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