WA State Dept of Ecology 9/18/2023

Joel Haack January 6, 2023 Page 16 Soil sampling in accordance with Ecology's residential sampling requirements for properties within the Everett Smelter Cleanup area was conducted in January 2021.Ten direct-push borings were advanced in each lot to 10 feet bgs for a total of 60 borings at the Property (B-1 through B-60, Figure 3). Up to two samples were collected from fill material from 0.5 to 5 feet bgs. Two samples of native material were also collected from each boring at 0 to 6 inches and 18 to 24 inches below the contact with fill material. Soil samples collected from borings B-1, B- 11, B-14, B-15, B-19, B-21, B-24, B-25, B-41, and B-56 contained contaminants above their respective cleanup levels (Figure 3). Results of soil samples collected from the Property are further summarized in Table 1. Remedial Actions: Based on the results of sampling activities in January 2021, six excavation areas for soils contaminated with lead, arsenic and cadmium were identified at the Property (Excavation Area 1 to Excavation Area 6, Figure 3). A total of 805 tons of known and potentially contaminated soil from the six excavation areas was excavated and removed from the Property in October 2021 for disposal at a permitted facility.Table 2 summarizes the extents of the excavations and location of confirmation soil samples. The extent of the excavations and locations of confirmation soil samples are shown on Figure 5 through Figure 10. With the exception of B21SW-E:3 (Excavation Area 3;Table 2; Figure 7), all confirmation soil samples did not contain arsenic, lead, or cadmium above the Method A cleanup levels. Sample B21SW-E:3 was collected from the eastern sidewall of Excavation Area 3 along the eastern Property boundary with the LMGC.