KOMAN recently conducted a Pre-Design Investigation (PDI) at Site 43 in Indian Head. The purpose was to gather additional multimedia data and conduct tests to support the remedial design conceptually outlined in the Draft Feasibility Study Report. The study aimed to achieve several goals:
- Refine trichloroethene (TCE) concentrations in soil to meet the Preliminary Remediation Goal.
- Evaluate geotechnical conditions near a large blast wall that could potentially impact remedy structures.
- Assess vapor intrusion conditions in three buildings to determine the need for active or passive mitigation measures.
- Investigate potential sources of cobalt in groundwater exceeding the revised and stricter Indian Head background value and determine their connection to the site.
- Evaluate site geochemistry, maximum radial distribution, and mobile porosity for an injected emulsified vegetable oil (EVO) organic substrate to support in situ biodegradation.
The activities involved in this investigation included:
- Installation of 57 test borings and 15 new monitoring wells.
- Sampling of soil and groundwater for geochemistry analysis.
- Utilizing the Triad approach for direct push soil and groundwater sampling.
- Testing geotechnical parameters.
- Conducting microbiological analyses.
- Performing groundwater isotopic analyses.
- Mapping groundwater flow direction.
- Conducting a substrate injection test.
By carrying out these comprehensive activities, KOMAN gathered valuable data to inform the remedial design process for Site 43 at Naval Support Facility Indian Head.