Schuetz, M. | 2nd Annual Western Groundwater Conference, 17-19 September, Sacramento, CA, 36 slides, 2019

Previous activities at the 90.26-acre former waste disposal facility contaminated soil and groundwater with VOC, SVOC, total petroleum hydrocarbons, heavy metals, and PCBs. After extensive remedial efforts, sampling in 2015 showed low concentrations of VOCs remained in soil gas and groundwater in limited subsurface locations where residential housing redevelopment was planned, posing a potential vapor intrusion risk. To mitigate the soil contamination, a 41-well soil vapor extraction (SVE) system was installed in two areas of the site. Within 18 months of operation, steady-state, diffusion-limited removal of VOCs was attained. Enhanced attenuation was implemented in areas with elevated groundwater VOC concentrations. Substrate materials were injected into groundwater, which accelerated natural attenuation to reduce residual VOC. Long-term groundwater monitoring is planned, and SVE monitoring will continue for >two years after treatment. Future work includes the installation of two vapor intrusion mitigation design options and a remote data monitoring system for each proposed residential building to address the potential soil vapor indoor air pathway. https://www.grac.org/media/files/files/a1e84ec6/19-3-2-c-melissa-schuetz.pdf For more information, including site documents on the SVE system, see https://www.envirostor.dtsc.ca.gov/public/profile_report.asp?global_id=19000021&mytab=activities