Arkla Terra Property
Site Summary ProfileEPA ID: FLSFN0406909
Location: Thonotosassa, Hillsborough County, FL
Lat/Long: 28.056442, -082.318435
Congressional District: 09/12
NPL Status: Proposed: 08/26/2008; Final: 04/08/2009
Affected Media: Ground water, Soil
Cleanup Status: Removal action underway; remedial investigation/feasibility study underway
Human Exposure Under Control: Yes
Ground water Migration Under Control: There is insufficient data to determine
Sitewide Ready for Anticipated Use: No
Site Reuse/Redevelopment: In continued use – commercial land uses are located on site
Site Manager: Beth Walden (firstname.lastname@example.org)
Current Site Status
The Arkla Terra Property site includes an area where companies operated an underground storage tank refurbishment facility from 1976 until 2006. EPA placed the site on the National Priorities List (NPL) in 2009 because of contaminated ground water and soil resulting from facility operations. Ground water contamination has affected private water wells. EPA, the Florida Department of Environmental Protection (FDEP), and the Hillsborough County Health Department have investigated site conditions and taken steps to clean up the site in order to protect people and the environment from contamination. Hillsborough County has connected properties with contaminated wells to the public water system.
EPA continues to sample private drinking water wells on and around the site regularly. In February 2013, EPA completed a short-term cleanup, referred to as a removal action. The removal action consisted of in-situ thermal treatment of PCE-contaminated soils. The contaminated soils were the source of on site and off site ground water,. EPA is also continuing site investigations to evaluate the need for more cleanup activities. Through monitoring, investigations and ongoing cleanup actions, EPA, FDEP and Hillsborough County continue to protect people and the environment from site contamination.
Site Location and Background
The 8-acre site is located at 11706 U.S. Highway 301 in Thonotosassa, Florida, 16 miles northeast of Tampa. Site surroundings include residential areas to the west and south, agricultural lands to the north, and a bus refurbishing business to the east.
From 1976 to 2006, several private companies, including Arkla Terra Inc., used the site as an underground storage tank refurbishing facility. Operators stored over 500 storage tanks on the site property at one time, along with other types of containers. Operators used solvents, including tetrachloroethylene (also known as PCE or PERC), to clean the tanks prior to their repair.
In 2009, EPA listed the site on the NPL. Several businesses currently operate on site, including an accounting company, an environmental consulting firm, a concrete cutting business, an automotive store and a landscaping business.
In April 2012, EPA began construction, startup, and operation of a thermal treatment system. The system was a multi-phase extraction system, which included soil vapor and groundwater extraction. The total treatment area was approximately 2,301 square feet and the approximate treatment volume was 4,770 cubic yards.
Site investigations found contamination in ground water and soil affecting private drinking water wells that could potentially harm people in the area. Contamination resulted from activities at the site. Potential contaminants of concern include PCE.
EPA and its contractor have been collecting residential well water samples since 2009 between Ohio Avenue to the north and Joe Roberts Road to the south. Sampling has identified contamination in some wells. In coordination with the county health department and FDEP, EPA has provided filtration systems for these wells. Hillsborough County has also extended municipal water lines into affected areas to connect residences to the public water supply. Not all residents chose to connect to the public water system.
EPA continues to coordinate with residents in the area of interest to request permission to sample private wells. If EPA has selected your property for sampling, the Agency has already contacted you for your permission. If EPA has not contacted you regarding the need to sample your well, then the Agency does not need to sample your well at this time. For more information, contact the site’s Remedial Project Manager Beth Walden (email@example.com).
Investigation and Cleanup Responsibility / Oversight
EPA leads site investigation and cleanup activities in cooperation with FDEP.
Site Cleanup Plan
In February 2013, EPA completed the removal action which consisted of removing 1,491 pounds of PCE from the subsurface. The multi-phase extraction system was intended to quickly recover non-aqueous phase liquid (NAPL) and concentrated sorbed and dissolved PCE by raising the subsurface temperature to the azeotropic boiling point of PCE and water. 27 buried electrodes in 9 boreholes (three depth zones) were installed as part of the system. The electrodes passed electrical current through the soil, directly raising the soil temperature through resistance heating. Conduction and water convection effects act to distribute heat through the soil between electrodes. PCE is driven by the increased temperature from the pure, sorbed, and dissolved phases to the vapor phase, where recovery of contaminants is most efficient.
The system was operated through the end of January 2013. The vendor removed all the vapor and groundwater extraction and treatment equipment. Currently, the asphalt pad and wells remain for potential future use in remedial efforts. The electrode wells have been left as originally constructed, while surface well vaults have been installed on the extraction, temperature sensor, and temperature/pressure/vacuum sensor wells.
EPA is finishing the remedial investigation and feasibility study in the fall of 2013. EPA is planning a Record of Decision for Summer of 2014.
In February 2013, EPA finished the non-time critical removal action.
EPA is currently finishing the remedial investigation/feasibility study to evaluate whether the Agency will need to undertake more work to clean up any contamination that was not addressed by the removal action. As part of this investigation, EPA continues to sample on-site monitoring wells and select off-site private wells to assess ground water quality in the area.
EPA has funded the cost of the removal action. EPA will later seek reimbursement from responsible parties.
Community engagement and public outreach are core components of EPA program activities. EPA is working with the community and its state partner to develop a long-term cleanup plan for the site, reflecting the Agency’s commitment to safe, healthy communities and environmental protection.
EPA is conducting a range of community involvement activities to solicit community input and to make sure the public remains informed about site activities throughout the cleanup process. Outreach efforts have included fact sheets, public notices and public meetings.
In February 2010, EPA held a meeting to explain the residential ground water sampling process and the ongoing site investigation. EPA also held a meeting in summer 2011 to inform residents about the upcoming removal action.
EPA continues to sample on-site monitoring wells and select off-site private wells to assess ground water quality in the area. These activities are part of EPA’s ongoing remedial investigation/feasibility study.
EPA keeps additional site documents and information in a site information repository at the location below. EPA also posts site documents, when available, on EPA’s CERCLIS Site Profile page. For documents not available on the website, please contact the Region 4 Freedom of Information Office.
EPA has established an information repository at the Region 4 offices and locally at the following location:
Thonotosassa Branch Library
10715 Main Street
Thonotosassa, FL 33592