Historically, the Brothers Discount property operated as a retail gasoline and convenience store under various owners and facility names until abandoned after Hurricane Katrina in 2005. The facility dispensed gasoline fuel from three gasoline underground storage tanks (USTs), which were installed prior to 1988. After many attempts to serve numerous enforcement actions to current and past owners, the property was accepted in the UST Abandoned Tank Program in 2018 to close the UST system and assess the property contaminated by the abandoned tanks. On or about June 19, 2018, the Secretary of the Department declared the property abandoned. The UST system was permanently closed and removed in May 2020 under the provisions of the abandoned tank program removal contract.
The facility owners detected a release of gasoline on or about March 8, 1988. The source of the release was identified as a failed regular grade gasoline product line. It was estimated that 3,600 gallons of gasoline product was released. Various environmental consultants installed twelve monitoring/recovery wells for free phase product recovery and quarterly groundwater monitoring. From 1988 to 1995, interim measures to aid in the product recovery efforts included daily handbailing and passive product skimmers. An automatic product skimmer and recovery system with a vacuum unit was installed on the site in July 1996. The system operated until December 1996, when the recovery system was replaced with an automatic, air compressor driven recovery system to recover product. The air compressor system operated until December 1998. From 1998 to 2002, interim measures for product recovery and groundwater treatment included the use of absorbent materials in select monitoring wells and frequent mobile enhanced dual phase vacuum extraction events. According to quarterly groundwater monitoring reports, free phase product was not detected on site since December 2000.
Investigation
Under the provisions of the abandoned tank program remediation contract, Leaaf Environmental completed a comprehensive site investigation in December 2020 to characterize the site and further evaluate the impacts from the gasoline release.
Subsurface soils were identified and described by Leaaf geologists using the Unified Soil Classification System (USCS). In general, stratigraphic lithology observed during drilling activities at the Site consisted of either a 2 to 6 inch black topsoil layer or a 4 inch layer of concrete depending on the soil boring location followed by a fill layer consisting of tan to black river sands, rock, shells, and glass which terminated between 1 and 5 feet below ground surface (ft bgs). Native soils below this fill layer were generally a medium plasticity Gray/Black clay (CH) to a maximum depth of 10 ft bgs. This CH layer is followed by a low plasticity gray silty clay (CL) increasing in silt concentrations downward to a maximum depth of 13 ft bgs followed by a gray clayey sand (SC) to total depth (TD) of 15 ft bgs.
The first encountered groundwater during soil boring/monitoring well installation was approximately 6.5 to 7 ft bgs. Groundwater elevation measurements taken of the Sites permanent monitoring wells during the December 16, 2020, Site Investigation and the February 8, 2021, elevation survey/soil drum disposal indicate the shallow groundwater generally flows towards the northwest.
The investigation identified concentrations of Benzene, Ethylbenzene, Methyl tert-Butyl Ether (MTBE), Total Petroleum Hydrocarbons (TPH)Gasoline, and Volatile Petroleum Hydrocarbon (VPH) Fractions in soil and/or groundwater above the Risk Evaluation / Corrective Action Program (RECAP) Table 1 screening option standards. The evaluation identified two Areas of Interest (AOIs), which included the surface soil (0-15 ft) and the groundwater 3 non-drinking water zone of concern (GW3ndw).
Corrective Action
Remedial standards (site specific limiting RECAP standards) were developed for this property using Louisiana Department of Environmental Quality (LDEQ) RECAP Screening Option and Management Option (MO)-1 for non-industrial land use standards. Land use at this site is currently commercial and is expected to remain commercial in the future. Adjacent land use in the area is predominantly commercial with a mix of residential properties. The groundwater zone of concern was designated as GW3ndw based on aquifer data obtained from a site (AI #22941) located at 7000 Crowder Blvd., New Orleans, which was considered to be representative of conditions at the site. The designated POE was the Lawrence Canal located over 2,000 feet northwest of the Point of Compliance (POC). Based on the groundwater classification and distance to the POE, the Appendix H dilution factor (DF3) of 220 was used for the calculation of RECAP standards. A registered water well survey of active wells was obtained from the Louisiana Department of Natural Resources (LDNR) to evaluate groundwater use. The report identified 16 monitoring wells, 3 industrial wells, 3 dewatering wells, and 1 piezometer well.
Soil and groundwater sampling have confirmed that constituents of concern (COC) concentrations do not exceed the established site-specific remediation standards; therefore, no remedial action was required.
An inspection of the site was performed on August 13, 2021, confirming that no investigation derived waste remains on site. Nine monitoring wells were plugged and abandoned on August 13, 2021. Three monitoring wells were either damaged or destroyed and could not be located. The well plug and abandonment activities were summarized in the report dated September 14, 2021. Soil removed from the AOI shall comply with Louisiana Administrative Code (LAC) 33 Chapter 11, Solid Waste Beneficial Use and Soil Reuse, or shall be disposed at a permitted disposal facility.
The impacted media, constituents of concern, remaining constituent concentration (represented in soil by the Area of Investigation Concentration (AOIC) – the lower of the 95% upper confidence limit of the mean (95% UCL) concentration or the maximum concentration and in groundwater by the Compliance Concentration (maximum concentration)), and site-specific limiting RECAP standards established for this site.
LDEQ issued a No Further Action Letter on December 8, 2021.
In addition, Leaaf removed the liquid contents of a 300-gallon portable storage tank previously associated with a historic onsite remediation system with a 70-barrel (bbl) vacuum truck and pressure washer. The portable tank was cleaned, and ports were sealed with the exception of the vent line.
Summary of Project Results
Leaaf effectively managed the closure of the former retail gasoline and convenience store property abandoned after Hurricane Katrina. Accepted into the UST Abandoned Tank Program in 2018, the property underwent extensive assessment and remediation, resulting in the permanent closure and removal of the UST system in May 2020.
Leaaf was brought on to confirm remediation was complete and update the RECAP Proactive measures included a comprehensive site investigation in December 2020 to evaluate the impacts of historic gasoline releases. Subsurface soils and groundwater were thoroughly characterized, identifying two areas of interest with contaminant concentrations above RECAP standards. Despite this, soil and groundwater sampling confirmed that constituent concentrations did not exceed site-specific remediation standards, eliminating the need for further remedial action. The site was inspected, monitoring wells were plugged and abandoned, and the liquid contents of a historic remediation system’s portable storage tank were removed and cleaned. LDEQ issued a No Further Action Letter on December 8, 2021, marking the successful completion of the project.
Issues Encountered
During the project, Leaaf successfully addressed several challenges, including the removal of the previous system, updating the RECAP evaluation, and locating all monitoring wells at the abandoned site. These actions ensured thorough site characterization and compliance with regulatory requirements. The site was inspected, monitoring wells were plugged and abandoned, and the liquid contents of a historic remediation system’s portable storage tank were removed and cleaned. LDEQ issued a No Further Action Letter on December 8, 2021, marking the successful completion of the project.
Current Site Status
The site received an NFA following investigation and RECAP evaluation on December 8, 2021. All soils and groundwater concentrations at the site were below the RECAP limiting screening standards (LSS) and MO-1 limiting RECAP standards (LRS) for both non-industrial and industrial exposure. The property is currently in the process of redevelopment.
