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

ASPECT CONSULTING PROJECT NO. AS190583A-08  MAY 21, 2025 FINAL 71 direct contact exposure. The data tables include both the total cPAH (TEQ) and total cPAH (TMEQ). In accordance with MTCA (WAC 173-340-708[8][f]), multiple PCB Aroclors are assessed as a single hazardous substance by calculating the total PCB concentration for the mixture. As agreed to by Ecology,25 only detected Aroclor concentrations are included in the total PCB concentration summation. For evaluation of diesel-range and oil-range TPH data (from NWTPH-Dx analytical method), Ecology policy requires summing the diesel-range TPH (TPH-D) and oil-range TPH (TPH-O) results to represent a single petroleum product, unless it is clear that more than one product is present (Ecology, 2004). For purposes of this report, we term the summed value “TPH-D+O,” which is used for comparison against PCLs. TPH-D and TPH-O are both commonly detected in Upland Area soil samples but, in the RI groundwater data set including more than 300 samples, TPH-O is not detected except at one well (UST71-MW-102, which has high turbidity groundwater samples). Because detectable TPH-O is essentially not present in Upland Area groundwater, the TPH-D+O summation for soil and groundwater includes one-half the reporting limit (“1/2U”) for nondetected TPH-D values but only detected values for TPH-O. The chemical data maps included in this section show, for each constituent with exceedances in soil or groundwater, the combined soil and groundwater sample locations where detected concentrations in both media exceed the PCLs. On these “exceedance maps,” explorations with soil data for the constituent are depicted as a square, and explorations with groundwater data for the constituent are depicted with a circle. Explorations that had detected exceedances in soil or groundwater have the respective symbol color coded on these exceedance maps. Constituents with exceedances detected at only one location within the unit are not plotted on the maps, except in specific instances described in the text. However, all exceedances are highlighted in the data tables and are mentioned in the narrative for each unit. Because there are no total cPAH (TEQ) soil exceedances of the industrial direct contact value, the chemical data maps for cPAHs depict data for total cPAH (TMEQ) except for the Warehouse Subarea of Unit A where the total cPAH (TEQ) data for vadose zone soil is compared to the MTCA Method B soil cleanup level for direct contact and the total cPAH (TMEQ) data is compared to the soil-leaching-to-groundwater value. As discussed in Section 5.3, if results of a dissolved metals analysis are not available, a concentration of total metals less than the PCL for that dissolved metal complies with the PCL and that convention is applied in the exceedance maps. The figure numbers for the unit-specific figures include the unit designation in them for ease of reference (e.g., Figures 6-A2 through 6-A12 for Unit A, etc.). 6.3 Alkaline-pH Groundwater Produced by Crushed Material As discussed in Section 2.2.3.1, approximately 252,000 tons of CM was placed across approximately 32 acres of the Upland Area during mill demolition by the end of June 25 Andy Kallus (Ecology) email to Steve Germiat (Aspect Consulting), June 18, 2018.