3815_PGSF WMVD Pkg 2_Vol 4-2_03.03.2026_BXWA_Certified

ASPECT CONSULTING 66 FINAL PROJECT NO. AS190583A-08  MAY 21, 2025 6 Remedial Investigation Results 6.1 Data Set Used for Remedial Investigation Site characterization activities supporting the RI/FS were conducted as described in Section 4. Data used in the RI/FS include those collected during numerous phases of investigation as well as planning for and/or implementation of three IAs, as described in Section 4, between February 2012 and early 2021. The data used in the RI/FS represent current conditions for the Upland Area, following the IAs and removal of the crushed material (CM). Soil and groundwater samples from locations that were subsequently excavated during the IAs are not included in the data set used in the RI/FS. Likewise, because all CM has been removed from the Site, data characterizing the chemical composition of the CM are not included in the RI/FS data set; however, the RI Data Report (Aspect, 2014f) presents those data. Therefore, the RI/FS data set provided and discussed herein includes the following approximate numbers of samples and chemical analyses by media:  1,486 samples and 10,705 analyses for soil  626 samples and 4,155 analyses for groundwater  46 samples and 142 analyses for intertidal porewater/seeps and surface water  14 samples and 48 analyses for air 6.2 Site Units for Remedial Investigation As detailed in the RI/FS Work Plan (Aspect, 2013c), the site characterization activities supporting the RI/FS were conducted based on the potential for hazardous substances to be present within the historical operational areas of the Upland Area. Because of the proximity of many of the historical operational areas, the site characterization explorations targeting some areas often overlap with other areas; therefore, some explorations provide useful information for the assessment of more than one operational area, particularly for monitoring groundwater quality. Hence, for the purposes of compiling, depicting, and evaluating data in the RI, the Upland Area has been divided into five site units (A through E, from south to north) based primarily on historical operations and site conditions. Unit A has further been segregated to discuss data collected from within the Warehouse Subarea (commercial land use) separately from the rest of Unit A (industrial land use), and Unit C has further been segregated to discuss subsurface conditions and data collected inside of the Former Log Pond separately from the rest of Unit C. The unit boundaries and the extent of the Warehouse Subarea are depicted on Figure 2-4. The unit boundaries and the extent of the Former Log Pond are also depicted on Figure 2-4. As described in Section 2.4.4, groundwater within the Upland Area flows generally from east to west and discharges to the East Waterway. Each unit spans the east to west extent of the Upland Area (i.e., the upgradient to downgradient extent), facilitating an assessment of potential groundwater