Publication Details (including relevant citation information):
Domonkos Feher, Robert Chong, Joseph Shacat, Tenth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 22-26 2016, Palm Springs, CA
Background/Objectives. The Grace Pacific Lower Makakilo Facility is located on the Waianae Range of Oahu, Hawai'i, at a surface elevation of approximately 120 feet amsl. The property occupies approximately 54 acres and was formerly used as an aggregate processing facility from the mid-1970s to 2012, at which point industrial operations were shut down. Site characterization in the framework of the Hawai'i Department of Health [DOH] Hazard Evaluation and Emergency Response [HEER] Office’s Voluntary Response Program [VRP] is ongoing. During demolition activities associated with the shutdown in 2012, there was an accidental spill of PCB contaminated capacitor oil. Subsequent release response assessment and remediation were conducted by ESI. The objectives of the release response and remedial actions were to (1) assess and delineate the extent of PCB contaminated soil, and to (2) remediate and properly manage and dispose of PCB waste. The investigation was designed to comply with both, the sampling strategies promulgated in the Toxic Substances Control Act [TSCA], and the Technical Guidance Manual [TGM] issued by the DOH HEER Office. The DOH has been a long-time proponent of more representative and statistically sound, "incremental" sampling methods as a means for obtaining reproducible and technically defensible data and encourages responsible parties to include these methods into their sampling design whenever possible. Thus, traditional discrete soil sampling methodology and the Multi-Increment® Sampling [MIS] approach were used simultaneously to probe whether the two methods would lead to similar decisions at comparable costs.
Approach/Activities. Discrete soil sampling in connection with rapid real-time field analysis (ELISA) of PCBs and MIS® methodology were explored as two efficient tools to investigate the extent of PCB contamination at the spill site (80’x90’). Laboratory data for MIS® were used for compliance with the DOH HEER Office TGM guidance. Simultaneously, EPA regulatory requirements were satisfied by confirmation sampling according to TSCA PCB clean-up procedures (40 CFR 761). Contaminated soil was removed in a targeted manner in small portions. To decrease the overall cost of soil removal and to minimize the need for off-island disposal, multiple iterations of removal and confirmation sampling according to both methods (TSCA discrete sampling and MIS®) were utilized.
Results/Lessons Learned. MIS® methodology provided data required to delineate the extent of a PCB contaminated capacitor oil spill and demonstrated that the removal action was sufficiently protective of human health and the environment. Although sampling guidance referenced under TSCA (based on discrete sampling) can provide valuable data to aid with the delineation of the extent of a PCB spill and the confirmation of complete removal, in the present case, the MIS® approach resulted in comparable decisions in a more efficient manner with substantial cost savings and better, more reliable data than the traditional approach using discrete sampling.