ARCHIVED REPORTS - GROUNDWATER MONITORING WELL INSTALLATION AND LIMITED SOIL SAMPLING

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KLEINFELDER 1 EXECUTIVE SUMMARY ' Kleinfelder prepared a workplan for First Service Properties in response to the request of Mr. Vemell Hill, Jr. for the limited characterization of groundwater and shallow soils at the former ' Elks Lodge Property located near the northwest comer of Sonora Street and Center Street in Stockton, California. Kleinfelder installed and developed three monitoring wells on the site. Groundwater elevations at the site ranged from -11.43 feet above mean sea level (msl) to -12.22 feet msl. Depth to groundwater was measured between approximately 23 to 24 feet below ground surface (bgs). The ' groundwater flow direction was calculated to be towards the east/southeast, with an overall gradient of 0.003 feet/foot. The 3 wells were developed and sampled in accordance with the approved Kleinfelder workplan(Revised Workplan dated March 30, 2004) Soil samples were collected during the advancement of the soil borings for the monitoring wells for lithologic classification and possible laboratory analysis. Two soil samples from each boring L were submitted for laboratory analysis. The soil samples were collected from the 15 foot and 25 foot intervals in each boring. The soil samples were analyzed for Total Threshold Limit Concentrations (TTLCs) for Lead, California Assessment Manual (CAM-17) metals, volatile ' organic compounds, total extractable petroleum hydrocarbons as diesel (TPH-d) and motor oil (mo), and total purgeable petroleum hydrocarbons as gasoline (TPH-g). ' Additional soil samples were collected from shallow borings advanced by hand auger. Six of the shallow soil borings were located near the concrete pad located near the southern portion of the ' site where previously reported lead concentrations occurred, while twelve additional boring locations were advanced at stepped-out locations around the perimeter of the site. A total of 24 shallow soil samples were analyzed. The shallow soil samples were analyzed for TTLC-Lead concentrations. The soil samples collected from the soil borings advanced during the installation of the groundwater monitoring wells showed detectable concentrations of barium, chromium, cobalt, copper, nickel, vanadium, and zinc. Each of the noted detected concentrations were below the U.S.E.P.A. Region IX Preliminary Remediation Goals (PRGs) for Residential as well as Industrial ' Sites, and may be considered to be naturally occurring background concentrations. The soil samples collected and analyzed from across the site showed relatively higher concentrations of lead on the eastern half of the site versus the western half of the site. It appears that the bulk of the lead contamination is contained to the eastern portion of the site, although as, stated above there is a location within parcel 16 which exhibits a high concentration of lead. ' The soil samples collected and analyzed from near the concrete pad appeared to show decreasing concentrations of lead with depth in 5 out of the 6 sample locations with concentrations 42162.E01 /STO4R854 Page 1 of 22 Copyright 2004,Kleinfelder,Inc. July 1,2004