Adanta conducted a detailed site investigation to resolve all remaining data gaps and site characterization issues necessary to complete a Focused Feasibility Study (FS), in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act. A TRIADtype approach was utilized to allow the project team to evaluate early sample results on a “real-time” basis, in order to guide placement and quantity of follow-on sampling. An initial project planning session was held with the primary stakeholders to discuss the details of the investigative approach and implementation.
Adanta developed a project Sampling and Analysis Plan for review by stakeholders, including the Environmental Protection Agency, the U.S. Army Corps of Engineers, the Lorentz Shallow Groundwater Task Force, and the FS Contractor. A source for persistent high concentrations of 1,1dichloroethylene in groundwater downgradient from the site had not been previously identified. Adanta conducted extensive soil and groundwater sampling to identify the source(s) by investigating several possible source areas: West-northwest portion of the Lorentz Barrel and Drum (LBD) Property adjacent to treatment systems and the west fence; The Newark Property immediately west of the LBD Property; several features under East Alma Avenue including storm sewer, sanitary sewer, and former surface drainage ditches; and the sanitary sewer under South 10th Street. Additional sampling in the San Jose State University athletic field adjacent to South 10th Street was also needed to complement the data collected under the streets. In addition, Adanta evaluated the presence of polychlorinated biphenyls under the sidewalks adjacent to the LBD Property to locate the secondary source of groundwater contamination.
