On the Atlantic Coast in Wilmington, the NC State Ports Authority Superfund Site was a wood treatment facility for 51 years that left behind a number of hazardous substances. Schnabel completed a remedial investigation following an Administrative Order on Consent (AOC) with the North Carolina Department of Environment and Natural Resources (NCDENR) State Superfund Inactive Hazardous Site Branch.

Hazardous substances included creosote (PAH compounds), chromated copper arsenate (CCA), and pentachlorophenol (PCP) in diesel fuel. Dioxins and furans were also present. A sitewide and off-site sampling of soil, sediment, groundwater, surface water, fish, shellfish, and macroinvertebrates confirmed impact on each media. Contamination extended off-site in groundwater and sediments within a creek and river. The presence of dense non-aqueous phase liquid (DNAPL) was verified above semi-confining units at 14 and 46 feet below the land surface. The extent and pumpability of the DNAPL pools were defined by completing over 90 Geoprobe Macro-Core boreholes, installing DNAPL recovery wells, and performing DNAPL recovery tests. Studies confirmed impact to three aquifers, a semi-confining unit, and a confining unit. Receptor studies included an inventory of all wells, springs, and surface water intakes used as potable water sources within a 4-mile radius of the site, and the identification of environmentally sensitive areas.

Human health (HHRA) and ecological risk (ERA) assessments were completed to evaluate site risk to potential receptors and to develop the risk-based remediation goals for soil and sediment. The HHRA evaluated lifetime cancer risks and non-cancer hazards for four future sites using a range of scenarios. The ERA evaluated the potential ecological risks at the site to benthic invertebrates, fish, piscivorous birds, carnivorous birds, and piscivorous mammals. Weight-of-evidence and determination of significance and relevance of results were also performed. We prepared and submitted a voluntary consent for land use restrictions document to NCDENR for review and approval. Deed modifications were also prepared and filed.