CUPA-2020 Session Details

Post-Remediation HRSC; Successful Large-Scale VI Investigation
Thu, Feb 6    8am - 9:45am    66 of 100 seats available
TH-F1   Cleanup
Location   SANDPEBBLE-DE
Credits      REHS: 2
   Objective
A remediation case study demonstrating the use of advanced site characterization technologies to identify a remaining source area and help design a more effective remedial approach; Discuss lessons learned from collaborative communications with the affected communities, RP, and consultant for efficient and successful VI assessment
   Description
This presentation will provide a case study of high-resolution site characterization for a release of VOCs at a former circuit board manufacturing facility in Orange County, California. The source area was remediated by excavation and the case was closed in 2006, but the case was reopened in 2017 when a downgradient groundwater monitoring well indicated increasing concentrations of trichloroethene in groundwater. A high-resolution site characterization using MIP and HPT technologies combined with conventional soil and groundwater sampling was performed during 2017 and 2018. The investigation resulted in the discovery of a remaining source area that had not been detected during previous investigations or remedial excavation activities. The results of the investigation will be used to determine appropriate interim and final remedies for soil and groundwater; A former aeronautics & electronics R&D & production facility in Orange County operated from 1957-1993. The site was demolished, remediated & rezoned for residential use. The 2017 CSM update identified the data gaps in soil vapor which required further assessment. The primary COC is TCE.
   Speakers
Maile Gee
Santa Ana Regional Water Quality Control Board
maile.gee@waterboards.ca.gov

Jessica Law, Santa Ana RWQCB, Jessica.law@waterboards.ca.gov

   Presentation
Post-Remediation High Resolution Site Characterization
A case study for the use high resolution site characterization techniques to locate a residual source of TCE contamination at a legacy chlorinated solvent cleanup site located in Orange County, California.
Successful Large-Scale Vapor Intrusion Investigation
A former aeronautics and electronics research, development, and production facility operated on 98 acres in Orange County from 1957 until 1993. The former facility was demolished and remediated in the 1990s and rezoned for residential use after receiving a soil closure from the LOP. Two TCE soil gas plumes have been identified that require the need for indoor air evaluation. The larger of the two TCE soil gas plumes is over 1.5 miles in length and over 0.5 miles wide. To date, over 500 homes and 3 commercial businesses have been identified to have their indoor air evaluated for potential vapor intrusion. This presentation will elaborate on the lessons learned from collaborative communications with the affected communities, the responsible party, and their consultant for the efficient and successful vapor intrusion assessment.