Potter's Septic Tank Service Pits

• Site Profile
• Administrative Record Index (All PDF: OU1 (24 pp., 1.0M), ROD Amend (1 pp., 37K), ROD ESD (1 pp., 24K)
• Additional Site Documents including Five Year Reviews, Records of Decisions (ROD) and Explanation of Significant Differences (ESD).
• For documents not available on the website, please contact the Region 4 Freedom of Information Office (http://www.epa.gov/region4/foiapgs/submit.htm).

Site Background:
The Potter's Septic Tank Service Pits site located in Sandy Creek, Brunswick County, North Carolina is a 5 acres site. In 1976, the U.S. Coast Guard was notified of an oil spill in Rattlesnake Branch Creek. The Coast Guard and the North Carolina Department of Natural and Economic Resources traced the oil spill to one of the four disposal pits at the site. In 1983, the present owner informed the North Carolina Department of Human Resources that he had uncovered sludge in his front yard. The State found contaminants in his well and shut it down. The EPA found contaminants in the soil and groundwater on the site. Approximately 1,800 people obtain drinking water from private wells within 3 miles of the site. The groundwater is contaminated with volatile organic compounds (VOCs) including benzene and xylene, phenols, and other petroleum compounds. The soil in contaminated with heavy metals, chloroform, phenols. VOCs and other petroleum compounds. People who use contaminated well water may be at risk. Direct contact with contaminated soil was a health threat, especially to children playing in the area, before the removal of contaminated soil and sludge.

Cleanup Progress: Construction Completed
The U.S. Coast Guard and the North Carolina Department of Natural and Economic Resources removed 40,000 gallons of oil from the creek and the disposal pits, as well as 150 truckloads of oil sludge and oil-stained soil. Thick oil sludge that could not be removed was mixed with sand and buried on the site. In 1984, the EPA removed approximately 3 million pounds of contaminated soil from the site and transported it to a federally-approved hazardous waste facility.

The EPA completed an investigation into the nature and extent of contamination at the site in 1992. In the summer of 1992, the EPA issued a Record of Decision and selected a remedy which provides for cleanup of soil and groundwater at the site. The remedy includes: Extracting groundwater and on-site treatment using above-ground precipitation, flocculation, and filtration to remove metals; air stripping to remove VOCs with discharge of the treated water to Chinnis Branch; on-site contaminated soil treatment using a low temperature thermal desorption unit, testing to determine whether concentrations of heavy metals exceed cleanup standards and, if so, stabilizing the soil using off-site soil treatment. The EPA began cleanup actions in late 1994 and soils cleanup has been completed. EPA remediated approximately 32,000cu/yds of contaminated soils. Based upon other requirements of the ROD and RD, it was determined that the performance standards were met.

The soil remedial action removed a very large mass of the contaminant mass that was once present at the site. EPA obtained additional groundwater quality data from the Potter's site in June 2000. The data clearly showed inorganic and organic contaminants decreasing over time to concentration below the ROD-specified clean-up goals. Therefore EPA amended the original remedy selected in the 1992 ROD on September 27, 2000. The new selected remedy is Monitoring Natural Attenuation and Institutional Controls. The Site was categorized as "construction completed" on September 27, 2000. The Groundwater remedial action started in September 2001. Activities included all actions necessary to evaluate the extent of migration of a contaminated plume from the Potter's Pits site including : the collection of groundwater samples from drinking water; the installation and sampling of groundwater wells and the monitoring of groundwater contaminants. As of January 1, 2008, 5 quarters of groundwater sampling was completed and 3 more quarters of groundwater monitoring data is needed to evaluate that the monitored natural attenuation of the Site is effective in groundwater remediation.  Black & Veatch will conduct another round of groundwater sampling the Fall of 2008.