WORK PLANS - Laserfiche WebLink

Home Browse Search

Existing data indicate potential natural attenuation over the previous observation period, but they do not clearly demonstrate it (Chart 0U8-P). Petroleum-related compounds naturally attenuate. Kleinfelder therefore generally anticipates that exploration should indicate natural attenuation; however, there is potential for unanticipated results, including TPHueh that may be more resistant to biodegradation-caused natural attenuation, or solvent contamination that may pose soil vapor health risks. OU 8: Work Plan Spot Check Slide Hammer Passive Soil Gas Survey Soil Vapor Soil Hydropunch Explorations OU8 SG-01 through 0U8 SG-29 0U8 SV-01 and 0U8 SV- 01 OU8_MW-16 through 0U8 MW-20, 0U8 SV-01 and OU8 SV-01 Samples 29 2 6 7 Analyses TPH, Chlorinated Solvents TPH, Chlorinated Solvents TPH, Chlorinated Solvents Prior to subsurface investigation, Kleinfelder will perform a Passive Soil Gas Survey (PSGS) with 29 Amplified Geochemical Imaging® (AGI, formerly known as the GORE-SORBERTM) modules (Figure 0U8-1, 0U8_SG-01 through OU_SG-29). These modules produce chemical mass values that correlate with concentrations. These mass value data will be used to qualitatively assess relative differences in subsurface conditions prior to subsurface investigation. This will allow Kleinfelder to collect data representing the highest concentrations to better define concentration extents, avoid potential subsequent sampling, and guide potential remedial actions. To assess expected ongoing natural attenuation, Kleinfelder will collect groundwater samples from locations where previous timeseries concentration data were collected. Kleinfelder will advance pushprobe explorations and collect Hydropunch samples at the locations of past monitoring wells installed for this Operable Unit (Figure 0U8-1, 0U8_MW-16-HP through 0U8 MW-20-HP). To define lateral and vertical contamination, Kleinfelder will also advance one pushprobe exploration where the PSGS indicates the highest contamination concentrations and one where PSGS indicates lowest contamination concentrations. Soil samples will be collected from these locations at depths of 10, 15, 20, and 25 feet bgs. Hydropunch groundwater samples will also be collected from these locations, and soil vapor monitoring wells will be installed at two depths: One approximately 3 to 5 feet above the water table and one approximately 5 feet bgs. These data will be combined with similar data collected from OU 5 explorations, and a regression model will be developed to calculate soil, groundwater, and soil vapor concentrations from the PSGS mass values. These PSGS-based explorations are subject to change after PSGS results are available for analysis. 20173951.001A/SAC17R68420 Page 16 of 26 November 2, 2017 C) 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