Vapor Intrusion Sampling & Groundwater Remediation at Former Dry Cleaning Site
KERAMIDA was retained to investigate the extent of impacts related to the historic operation of a dry cleaner, develop a remedial strategy to address PCE-impacted soil, groundwater, and indoor air, and implement the remedial strategy. Previous remedial actions performed by others involved soil excavation and in-situ chemical oxidation, which reduced the PCE concentrations but not to the point where closure was possible. A supplemental remedial strategy was developed that involved enhanced reductive dechlorination (ERD) of one small area of on-site impacted groundwater via injection of electron donor chemicals and anaerobic bacteria into the impacted areas. A Remediation Work Plan (RWP) Addendum was developed, submitted to the Indiana Department of Environmental Management (IDEM), and approved. The initial injection took place in June 2012 and a supplemental injection occurred in June 2015. Monitoring is ongoing and residual VOC concentrations in the groundwater have been eliminated.
Based on significant impacts remaining in one other isolated deep well, and the presence of potable water supply wells on one adjacent and one nearby, downgradient property, IDEM asked that vapor intrusion (VI) sampling be performed on the adjacent property and that the owners of both properties be approached with an offer to connect them to the municipal water supply. After lengthy discussions, both property owners agreed to be connected to the municipal water supply, and this work was completed in early 2017.
Vapor intrusion (VI) sampling was also performed in multiple locations at the adjacent property and elevated vinyl chloride (VC) concentrations were identified in sub-slab samples (but not indoor air) of the office building. A VI mitigation system was subsequently installed on the office building in early 2016.
KERAMIDA continued quarterly groundwater monitoring at the Site in the source area through the second quarter of 2017. KERAMIDA received restricted closure on the Site in late 2017 following submission of a NFA letter.