Laserfiche WebLink
OU 9: Work Plan <br />Spot <br />Check <br />Slide <br />Hammer <br />Passive <br />Soil Gas <br />Survey <br />Soil Vapor Soil Hydropunch <br />Explorations <br />12 <br />(Installed <br />for 0U8) <br />0U9_13-12-HP <br />And 0U8_MW-18 <br />(Already drilled for MW-8) <br />Samples 4 2 <br />Analyses 4,4'-DDE, <br />4,4'-DDT <br />Pesticides/ <br />herbicides <br />Pesticides/ <br />herbicides <br />Prior to subsurface investigation, Kleinfelder will perform a Passive Soil Gas Survey (PSGS) with <br />the 12 Amplified Geochemical Imaging® (AGI, formerly known as the GORE-SORBERTM) <br />modules already installed for OU 8 (Figure 0U9-1). These modules produce chemical mass <br />values that correlate with concentrations. These mass value data will be used to qualitatively <br />assess relative differences in subsurface conditions prior to subsurface investigation. OU 9 <br />exploration and PSGS pesticide data will be combined with similar OU 11 pesticide data to <br />develop a regression model to estimate potential pesticide concentrations in OU 9 soil and <br />groundwater. <br />To assess groundwater conditions, Kleinfelder will collect groundwater samples from locations <br />where pesticide/herbicide concentrations were detected in Phase II soil. Kleinfelder will collect <br />soil and groundwater samples at 13-11, where 4,4'-DDE was detected at 68 ug/mg, and 13-12, <br />where 2,4-DB was detected at 50 ug/mg (Figure 0U9-1, explorations 0U8 MW-18 and OU9_13- <br />12-HP). Kleinfelder will advance a pushprobe exploration at 13-12 and collect soil samples at <br />depths of 5 and 10 feet bgs and a Hydropunch. Phase II maps indicate that the 13-11 location is <br />within approximately 5 feet of 0U8_MW-18; therefore, 0U8 MW-18 soil and Hydropunch <br />samples will be analyzed for pesticides and herbicides. <br />Based on proposed industrial use, depth of contaminated soil, and the concrete cap that will be <br />installed as part of the Site construction, Kleinfelder will base further recommendations on <br />groundwater data. These data will indicate either: <br />Pesticide/herbicide concentrations below EPA Tap Water and Tier 1 Groundwate ESLs. <br />If groundwater data are below applicable levels, Kleinfelder will recommend no further <br />action. <br />Pesticide/herbicide concentrations above EPA Tap Water and Tier 1 Groundwater ESLs. <br />If Kleinfelder finds groundwater concentrations above applicable levels, Kleinfelder will <br />use past data collected from this closure work plan and existing Phase ll data to define <br />contamination extent and conduct a soil removal action. <br />20173951.001A/SAC17R68420 Page 18 of 26 November 2, 2017 <br />© 2017 Kleinfelder www.kleinfelder.com <br />KLEINFELDER 2882 Prospect Park Dr., Suite 200, Rancho Cordova. CA 95670 p I 916.366-1701 f I 916.366-7013