Roux Associates was commissioned to conduct detailed investigations of numerous freshwater and tidal wetlands to fulfill the facility’s closure responsibilities and divest the Site so that it can be returned to beneficial use.  The Site is an approximately 440-acre tract in western Staten Island that was used as a Major Oil Storage Facility (MOSF) for petroleum products until the end of 1999.  Currently, the Site contains approximately 95 acres of wetlands, both tidal and freshwater.

Roux Associates has completed extensive wetland assessment activities to develop a detailed and comprehensive understanding of the environmental conditions within the Site wetlands.  Investigations included sediment, surface water, and groundwater sampling, data evaluation, and wetland delineation.  The investigations have developed substantial information regarding the physical, vegetative, and hydrological characteristics of the wetlands.  Dissolved COCs were not detected in any of the surface water or groundwater samples collected in the Site wetland, thus indicating COCs were bound within the wetland sediment solid phases and potentially not bioavailable to benthic communities and wildlife.

Supplemental sediment analyses were conducted to provide additional evidence to the low leachability of Site COCs in the wetland sediment.  All TCLP and SPLP results were below regulatory levels.  The low SPLP leachability of the wetland sediments, in combination with the uniform absence of dissolved COCs in the wetland surface water and groundwater, strongly indicated that the COCs were bound by one of the above mechanisms and are not bioavailable. 

Further analytical testing was conducted to characterize the COC binding capacity to the wetland sediment.  These results determined that a significant fraction (up to 30%) of the COCs were bound to the sediment organic matter, while the remaining COC were more tightly bound in residual solid phases (e.g.; metal sulfides).  These supplemental characterization studies further demonstrated the Site COCs are tightly bound within the sediment solid phase, not leachable and thus do not present any long-term threat to vegetation, fish, and wildlife. 
Subsequent activities included negotiations with state agencies to develop a remediation plan for the wetland areas that would minimize impacts to the wetlands while ensuring the stability of the Site COCs.