ARCHIVED REPORTS_REPORT SUMMARIZING INSTALL OF MONITORING WELLS MW4,MW5,MW7,MW8 & SOIL BORING RDM1 & 4TH QTR 2013 GROUNDWATER SAMPLING

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Ms. Angela Lee Humbrook Holdings, LLC February 12, 2014 Page 6 • Soil Sampling-MW-4,MW-6,MW-7 and MW-8 • Soil samples were collected at 5-foot intervals in each of the borings for the monitoring wells. A portion of each soil sample was placed in a re-sealable plastic bag and field screened for the presence of petroleum hydrocarbons. After the vapors in the soil samples were allowed to equilibrate with the air in the headspace of the bag, the organic vapors within the headspace were measured using a PID equipped with a 10.6 electron volt lamp. The field PID readings were recorded on the boring logs. Soil samples collected from the borings were classified using the Unified Soil Classification System visual manual method and the data was recorded on the soil boring logs. Copies of the boring logs are included in Enclosure F. The lithology encountered onsite generally consists of silt (ML) and clay (CL) to a depth of approximately 55 fogs and interbedded silt (ML) and silty sand (SM) to the total depth drilled (65 fbgs). Shallower layers of silty sand were encountered in MW-4 (approximately 45 to 45.5 fbgs), MW-6 (approximately 7.5 to 10.5 fogs and 27 to 31 fbgs), MW-7 (approximately 27.5 to 31.5 fogs), and MW-8 (approximately 10 to 10.5 fogs) and appear to be discontinuous across the investigation area. Groundwater was first encountered at a depth of approximately 55 fbgs in the borings for monitoring wells, but rose to a static depth of approximately 48 fbgs in the completed monitoring wells prior to well development on October 16,2013. Eight soil samples (two from each borehole) collected at depths of approximately 16 and 46-fogs from the boreholes for monitoring wells MW-4, MW-6, MW-7, and MW-8 were submitted for laboratory • analysis. The samples were submitted to Kiff Analytical laboratory (California-certified NELAP #08263CA), in Davis,California,for analysis of. • BTEX, TPHg, fuel oxygenates (MTBE, TAME, DIPE, TBA, and ETBE), lead scavengers (1,2 DCA and EDB), naphthalene, and chlorinated VOCs (full list) by EPA Method 8260 B; • and, TPHd by EPA Method 8015 Modified with and without silica gel cleanup (if TPHd was reported in initial sample); silica gel cleanup was performed using EPA Method 3630C Modified. The soil sample laboratory analytical results are summarized in Table 1 and a copy of the laboratory analytical report with chain-of-custody documentation is included in Enclosure G. The soil samples collected from MW-4,MW-6, MW-7 and MW-8 were non-detect for all analytes with the exception of TPHd which was reported at a low concentration of 1.6 milligrams per kilogram (mg/kg) in the sample collected from MW-6 at 46 fbgs. The laboratory also noted that the TPHd reported were higher boiling point than typical diesel. i The Workplan had proposed submitting four to six soil samples to Sierra Testing Laboratory in El Dorado Hills, California, for geotechnical analysis of the following physical properties;however, based on review of the most recent soil and groundwater data, it's RDM's opinion that these analyses may not be necessary to get closure under the LTCP and the budget would be better spent performing •