The Cabot Carbon/Koppers Site is located in the Northern part of Gainesville and encompasses about 170 acres. The Superfund site was originally two sites: Cabot Carbon and Koppers.
Activities at the Cabot Carbon site
The Cabot Carbon site covers 49 acres in the Southern portion of the site. In 1911, chemical industrial activities began at the Cabot Carbon site. However, it was only in 1945 that Cabot Carbon purchased that section of the site to generate pine tar and charcoal.
In 1967, industrial processes stopped at the Cabot Carbon property and the property was sold to Raymond Tassinari, a local private investor. During the same year, the impoundment walls were breached resulting in the discharge of contents into the surface ditch and eventually into Hogtown Creek. The same year, Cabot Carbon was fined $100 for polluting the Creek.
In 1977, the property was sold to Harry S. Hamilton who begun the construction of current commercial properties. These constructions have disturbed creosote deposits associated with past activities. In the same year, the Florida Department of Environmental Regulation (FDER) has conducted a biological survey in Hogtown Creek and found that the creek was devoid of life for 1.1 miles downstream. In 1979, cleanup operations were performed to remove some contaminated sediments from the ditch at the Cabot Carbon site. However, there is no documented evidence to support that claim.
Activities at the Koppers Site
The Koppers site encompasses approximately 86 acres. In 1916, industrial activities with creosote impregnation started at the Koppers Site. The South and North lagoon were active from 1943 and 1956 respectively. After these lagoons closed in the 1970s, they were covered and graded. In the 60s, creosote was progressively replaced by solutions of Chromated Copper Arsenate (CAA) and pentachlorophenol. At the beginning of the 1990s, pentachlorophenol and creosote were totally phased out. Only CAA was continued to be used to treat wood until Koppers closed in 2009.
Investigations and Remedial actions
Pre-1990 ROD Actions
Between 1979 and 1981, EPA and FDER conducted preliminary studies of the Cabot / Koppers site. At the Cabot site, the shallow groundwater was found to be contaminated; soil, surface water and sediments in ditch and Hogtown Creek.
In 1982, University of Florida conducted further evaluations on the Cabot site and found contamination of the shallow.
In 1983, the EPA has conducted further investigations. A second investigation of the Cabot and Koppers sites found soil and groundwater contamination. Macroinvertebrate sampling has confirmed contamination of the North Main Street Ditch. Surface water sampling of the Main Street Ditch showed contamination with organic compounds associated with destructive distillation and creosote wood preserving processes. Later that year, Cabot Carbon / Koppers Site was listed on the National Priorities List.
In 1984, the Florida Department of Environmental Protection (FDEP) was granted by the EPA to perform a Remedial Investigation and a Feasibility Study. A year later, two remedial actions were undertaken at the Cabot Carbon site: installation of an initial groundwater interceptor trench and a leachate collection system. The Initial Remedial Investigation (RI) was completed in 1985 but was found deficient.
In 1988, Cabot Corporation and Beazer East and Koppers Company signed an Administrative Order of Consent requiring that the two Potentially Responsible Parties (PRPs) fund the supplemental Remedial Investigation and Feasibility Study (FS).
Post ROD actions
In 1991, Cabot Carbon signs the Administrative Order on Consent (AOC) which requires implementation of the ROD-required actions (remedial design). Supplemental investigations and studies were required related to affected soils in the Northeast Lagoon; and the former Cabot production well location. The remedial actions included the installation of groundwater interceptor trench and excavation and off-site removal of contaminated soil within the Northeastern Lagoon (both completed in 1995).
In 1991, The EPA issued a UAO (Unilateral Administrative Order) to Koppers to conduct data acquisition and site characterization for remedial design. These investigations have shown that contamination at the source areas of the Koppers site was greater than at the time the ROD was issued (presence of DNAPLs below the groundwater table, greater volume of contamination). Therefore, it was important to reevaluate the selected ROD remediation strategy and technologies.
In 1994, the EPA amends the UAO by requiring Koppers to perform additional site characterization and develop a Supplemental FS that includes remedial alternatives appropriate for the expanded extent of the site impacts.
In 1995, the groundwater ‘pump and treat’ system is installed for the surficial aquifer with 17 extraction wells (extraction rate of 3 gallons per minute). It was designed to mitigate off-site migration but results are negative. In 2009, the extraction groundwater system was improved to increase the pumping capacity and the contaminated water is captured through the installation of recovery trenches.
In 1997, the supplemental FS was completed. In 1999, the revised FS was issued to incorporate comments from the EPA and FDEP. The latter FS took into account the expanded extent of the site impacts but did not considered contamination within and below the Hawthorn Group.
Investigations in 2003, 2004 and 2006 have shown the presence of dense non-aqueous phase liquids (resulting from creosote use) in the Hawthorn group. Moreover, contamination has also been observed deeper in the Upper Floridan Aquifer.
In 2001 and in 2006, the EPA has issued the 5 year reviews. The last 5 year review (2006) supports additional investigations to carry the selection of a new remedial strategy to address site impacts.
In March 2010, Beazer purchased the property from Koppers to facilitate remediation. The final Feasibility study was issued in May 2010 which developed and evaluated remedial alternatives for the Koppers site. In July 2010, the EPA has issued a Proposed Plan for Koppers. The public comment period was extended to October 15th 2010.