Site 43 Pre-Design Investigation at Naval Support Facility Indian Head, Indian Head, MD – NAVFAC Washington
KGS conducted a Pre-Design Investigation (PDI) on Site 43 at Indian Head collecting additional multimedia data and testing to support the remedial design developed conceptually in the Draft Feasibility Study Report. Study goals were to refine trichloroethene (TCE) concentrations in soil above the Preliminary Remediation Goal; evaluate geotechnical conditions near a large blast wall potentially affecting remedy structures; evaluate vapor intrusion conditions in three buildings to determine whether active or passive mitigation measures are needed; investigate potential sources of cobalt in groundwater above the revised and more stringent Indian Head background value and determine if they are site related; and evaluate site geochemistry, maximum radial distribution and mobile porosity for an injected emulsified vegetable oil (EVO) organic substrate to support in situ biodegradation. Activities included installation of 57 test borings and 15 new monitoring wells; soil and groundwater geochemistry sampling; direct push soil and groundwater sampling (Triad approach); geotechnical parameter testing; microbiological analyses; groundwater isotopic analyses; groundwater flow direction mapping; and a substrate injection test.