WORK PLANS - Laserfiche WebLink

Home Browse Search

Since applying to the Board for Regulatory Oversight, Kleinfelder has frequently coordinated with and sought direction from Ms. Amy Ha. Kleinfelder recently reviewed its closure plan with Ms. Ha and regulator Mr. Steve Meeks. Kleinfelder would like to present this closure work and provide electronic and paper-copy tabulated source data to expedite review. Existing data, general recommendations, and detailed work plans for Operable Units 1 through 11 are summarized below. OPERABLE UNIT 1 OU 1 Description OU 1 Corresponds to Sub-Recommendation 7-2, which concerns septic tanks and leach lines associated with former Spreckels operations'. The Phase I identified potential for soil contamination via improper disposal of compounds. Phase ll samples were collected and analyzed for metals and petroleum/solvent-related compounds (Figure OU1-1). It is unclear exactly where these septic systems were located. Based on Phase I and Phase II maps, it appears one was located immediately north of the Site and one was located immediately south. Two borings, however, were drilled within the Site. The northern boring (5-7), was drilled between apparent locations of the two septic systems and therefore appears to have been drilled to assess conditions between both. The southern boring (5-1) is located along the southern Site border and therefore appears to have been drilled to explore northern extent of the septic system located immediately south of the Site. Metals: Existing Data Four soil samples were collected and analyzed for CAM 17 metals (Table OU1-M, borings 5-1 and 5-7). Concentrations are all below the lowest applicable industrial soil ESL (Industrial Threshold)2, but arsenic laboratory reporting limits exceed the industrial threshold. Moreover, cobalt and mercury results and arsenic and thallium laboratory reporting limits exceed Protection of Groundwater Site Screening Levels (SSLs). Kleinfelder has analyzed these metal concentrations against those from OU 7 (Table OU7-M, soil samples 12-8 through 12-16) and OU 11 (Table OU11-M, soil samples 6-6 through 6-13). CAM 17 metal concentration distributions from OU 1 and OU 7 are very similar, despite samples being collected from two separate areas to assess potential for two separate means of potential contamination. This indicates OU 1 metal concentrations represent natural background concentrations. Moreover, additional sampling was conducted during installation of monitoring well MW-13, which was located approximately 30 feet northwest of an OU 11 rail spur (Table OU11-M, soil sample MW-13). Soil samples were collected at depths of 10 and 15 feet below ground surface (bgs) and analyzed for CAM 17 metals. Most results are ND, except for barium, chromium, copper, nickel, vanadium, and zinc. Concentrations are similar to OU 1 and OU 7 concentrations. These data further indicate that OU 1 and OU 7 metal concentration represent natural background conditions. Previous correspondence referenced two sub-Recommendations: 7.1 — Near the Administration Building; and 7.2 — Near the Can Slab. These sub-Recommendations were based on then-estimated Site boundaries and previous exploration locations. Kleinfelder has since georeferenced the initial Phase I and Phase II maps against current aerial photography and determined that sub-Recommendation 7.1 is actually associated with a building located north of the Site. 2 Soil concentrations were evaluated against EPA industrial soil RSLs and DTSC industrial cancer and non-cancer endpoints. For each analyte, the lowest of these industrial ESLs is referred to the "Industrial Threshold" in this letter. 20173951.001A/SAC17R68420 Page 2 of 26 November 2, 2017 © 2017 Kleinfelder www.kleinfelder.com KLEINFELDER 2882 Prospect Park Dr., Suite 200, Rancho Cordova, CA 95670 p I 916.366-1701 f I 916.366-7013