COGENUJ36 - Laserfiche WebLink

Home Browse Search

Transformer Oil Release Clean-up and Closure Report 1049 South Wilson Way, Stockton California 2.5 Phase 4 2.5.1 Phase 4 Excavation and Restoration March 23, 2022— PG&E and Arrow Construction poured concrete for the new driveway, sidewalk, and gutters along South Wilson Way. PG&E marked the area around the storm drain for Underground Services Alert (USA) and called in a USA ticket. March 30 and 31, 2022. PG&E conducted excavation of the storm drain inlet and the concrete catch basin below the drain. PCBs were detected within the storm drain during the previous Phase 1 and 2 sampling events (Sections 2.2.2 and 2.3.2), in wipe samples W1 and W2 and concrete sample SDI. The excavation area was approximately 4 feet deep. The concrete area around the drain was a round pour, measuring approximately 2.7 feet by 2.7 feet in area and approximately 0.6 feet thick. No evidence of oil outside the storm drain was observed during the excavation. All excavated soil and concrete debris were placed into a roll-off soil bin. 2.5.2 Phase 4 Excavation and Restoration March 31, 2022. PG&E collected an additional verification sample at the base of the storm drain excavation. One soil sample, designated as 1049 Wilson Way, was collected from the bottom of the excavation directly under the storm drain sump, at a depth of approximately 4 ft bgs. The soil sample was placed in an ice-chilled cooler and transported under proper chain of custody protocol to Castle for PCB analysis by USEPA Method 8082. The analytical results are summarized in Table 1. No PCBs were detected in the Phase 4 verification soil sample. 2.6 Waste Disposal Soil and concrete debris generated from the excavation and cleanup activities were stored in Department of Transportation-approved 20 cubic yard soil bins. The PCB-contaminated waste was characterized and transported on August 28, 2021, and March 31, 2022, for proper disposal at the US Ecology Nevada facility located in Beatty, Nevada. The waste manifests (023134172JJK and 023135757JJK) are included as Appendix D. 3 Conclusions Following release of the transformer oil at the site on July 27, 2021, excavation clean-up, verification sampling, and site restoration activities were conducted between July 27 and March 31, 2022, by PG&E and its subcontractors. A total of 53 verification samples (including 15 primary asphalt samples, 3 primary concrete samples, 24 primary soil samples, two primary wipe samples, and nine duplicate samples) were collected from the excavated areas and potentially affected surrounding areas. arcadis.corn Stockton Release Closure Report_07062022 6