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Union Pacific Railroad Company - 3 - 14 July 2023 Former Bunker C Vaults its contents. Antea Group also collected a composite soil sample from four soil borings surrounding (not beneath) the UST and sump at approximately 5.5 feet below ground surfaces (bgs). Additionally, Antea Group investigated soil impacts near the oil water separator (OWS) by collecting a composite sample from four soil borings around the perimeter of OWS and from one boring within the OWS location. Soil samples were collected from these borings at approximately 6.5 feet bgs. Following the sample collection, Antea Group oversaw the excavation and removal of the UST and the destruction and abandonment of the concrete sump and OWS. Antea Group analyzed all samples for gasoline range organics as volatile fuel hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) as semi-volatile organic compounds, diesel range organics, oil range organics, and metals. This analysis did not include BTEX compounds. While the composite soil samples did not contain PAHs above regulatory levels, they did contain 320 micrograms per kilogram (pg/kg) of volatile fuel hydrocarbons, which show that a release occurred in the area of the former UST. Consequently, an additional soil analysis is needed to determine if BTEX concentrations in the soil pose a direct contact risk for human exposure. Additionally, Antea Group did not collect grab groundwater samples from near the UST or OWS during the site investigation. Central Valley Water Board staff does not agree with Antea Group's recommendation for no further action. An assessment of potential impacts to groundwater at these locations is also needed to determine if the site poses a risk to human health and safety and to the environment. Barber Site (GeoTracker ID: T10000021210) At the Barber site, Antea Group investigated two subsurface structures during the previous site assessment. Antea Group collected soil samples from around the outside corners of the northern structure (not beneath) at a depth of 8 feet bgs. Antea Group also collected a soil sample and a liquid sample from the sump in the interior of the northern structure but did not report the analytical results for the liquid sample. The only soil sample that Antea Group analyzed from the northern structure was the sample taken from within the interior sump. For the southern structure, Antea Group collected soil samples from near the outside corners (not beneath) at five feet bgs, as well as one soil sample from inside the sump. Diesel range organics detected in the soil samples collected from the within the southern structure and from outside the north corner of the southern structure contained 3,800 and 1,900 milligrams per kilogram (mg/kg), respectively. Both of these values exceed the San Francisco Bay Regional Water Quality Control Board's Environmental Screening Levels (ESLs) for leaching to groundwater and direct contact in commercial settings. Naphthalene concentrations of 72 pg/kg and 110 pg/kg were detected in soil samples collected from outside of the east and west corners of the southern structure, respectively. While the naphthalene concentrations were denoted as laboratory estimates in the Report, they are above the ESL associated with a risk for leaching to groundwater. Antea Group did not remove the underground structures on site and concluded that no further action is needed based on the current usage and location of the property.