Chapman Patel Cleaners, Removal Action Workplan

Chapman Patel Cleaners, Removal Action Workplan

The project consists of implementing the Chapman Patel Cleaners Removal Action Workplan (RAW) to address tetrachloroethylene in soil vapor located on a 1.17-acre property located in a commercial/retail shopping center located at 3534 East Chapman Avenue in the City of Orange. The remedial activity identified in the RAW consists of installation of soil vapor extraction (SVE) wells and operation of an SVE system. Background: Based on previous reports, dry-cleaning businesses have operated at the Site since 1985, and a PCE-dry cleaning machine was utilized at the Site until 2016. The Site is currently occupied by Danny’s Cleaners, a dry-cleaning business. Adjacent businesses in the shopping center include a restaurant building to the north (Aces Bar and Grill) and adjacent tenant space to the south occupied by a United States Representative. Businesses further south include a beauty salon, a chiropractic business, and a Thai massage spa business. A fast-food restaurant (Carl’s Junior) is located on a separate parcel to the west. An additional shopping center on a separate but immediately adjacent parcel to the east contains two restaurants, a beauty salon, and a dental care business. Residential properties are on the parcels south of the shopping center, and a school is located north across Chapman Avenue. Previous Investigations: In December 2015, a Preliminary Site Investigation was conducted during which the PCE dry-cleaning machine was still onsite. Soil vapor probes were installed in shallow soil at the Site between 3 to 5 feet below ground surface (bgs). PCE was detected in soil vapor samples with the highest concentrations detected near the PCE dry-cleaning machine and boiler locations in the northeast and southeastern portion of the dry-cleaning facility. In early 2016, the PCE dry-cleaning machine was reported removed from the Site. In April and June 2018, seven soil vapor probes were installed to depths ranging between 5.5 and 19 feet bgs and PCE was detected in all soil vapor samples with the highest concentration collected at 5 feet bgs near the former dry-cleaning machine. Concentrations decreased with distance from the former dry-cleaning machine to the south and east. From June 2021 through June 2022, a series of additional assessments were conducted including indoor air sampling along with installation and sampling of soil vapor probes onsite and offsite to determine the lateral and vertical extent of impacts and to assess the presence of potential impacts to groundwater. Most recent indoor sampling air conducted in June 2023 revealed that PCE concentrations were detected in indoor air samples above regulatory screening levels (commercial scenario) with the highest concentrations detected in the bathroom in the northeast corner of the dry-cleaning business and in the western portion of the eastern adjoining dental business. Soil vapor sampling has identified the most elevated concentration of PCE present in soil vapor in the upper 40 feet, with the highest concentrations near the dry-cleaning facility and general decreasing to the west. In May 2024, SVE wells were installed to the depths of 20 and 40 feet bgs, and an SVE Pilot Test was conducted. Sustained negative pressure readings were observed during the SVE Pilot Test beneath the building immediately north of the source property, indicating the severance of PCE vapor intrusion pathway for these structures. On September 1, 2020, Chapman Commercial Investors entered into a Standard Voluntary Agreement (Docket No. HSA-FY19/20-118) with the Department of Toxic Substances Control (DTSC) for oversight of a supplemental site investigation and remediation at the Site if necessary. Project Activities: The remedial measures described in the RAW include the installation of five extraction wells and the operation of a mobile SVE system onsite. Four of the extraction wells will be located in the adjacent parking lot to the west (between the shopping center and Carl’s Junior restaurant at 3518 East Chapman Avenue) and one extraction well will be located immediately north of the Site (between Danny’s Cleaners and Aces Bar and Grill). Each well boring will be completed as a 4-inch diameter SVE well. The wells are proposed to be constructed of 4-inch diameter Schedule 40 PVC casing with factory screened slots (0.020- inch) from approximately 5 to 25 feet bgs. The annulus of the screened portions of extraction wells will be backfilled with a sand (or equivalent) filter pack from approximately 4 to 25 feet bgs and hydrated bentonite chips from 2 to 4 feet bgs. The remainder annular space to the surface in each proposed well will be filled with concrete. The wells will then be completed at the ground surface with a watertight, flush-mounted, approved traffic-rated vault set within the concrete perimeter seal. All investigative derived waste will be placed in 55- gallon drums which will be labelled with non-hazardous waste labels and temporarily stored on-Site, pending transportation and disposal to a California licensed waste disposal facility. Project-related air pollutant emissions from excavation and disposal activities are subject to compliance with all applicable or relevant and appropriate requirements including, but not limited to, South Coast Air Quality Management District (SCAQMD). The SVE system will operate under a Various Locations permit obtained from the SCAQMD (Rule 1166). Although not anticipated, in the event biological, cultural or historical resources are discovered in the course of project activities, work will be suspended while a qualified biologist, cultural or historical specialist makes an assessment of the area and arrangements are made to protect or preserve any resources that are discovered. If human remains are discovered, no further disturbance will occur in the location where the remains are found, and the County Coroner will be notified pursuant to the Health and Safety Code, Chapter 2, Section 7050.5.

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