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• i i.. Cleo(oica(Eecknicr 2m, k.11Page 2 Soil Boring and Monitoring Well Installation Work Plan Former Moresco Property Project No.251.2 November 4, 1998 data and a discussion may be found in Geological Technics Inc. Remedial Action Report L. dated February 6, 1998. In October of 1998 Mr. Ron Rowe of SJC PHSIEHD started discussing the need for further site assessment work. During a phone conversation on November 2, 1998 he requested that a groundwater monitoring well be installed at the site to determine if contaminants, particularly MTBE had migrated to the groundwater. L. 2.0 PROPOSED INVESTIGATION The goal for this investigation is as follows: I. Determine the residual concentration of MTBE and other gasoline hydrocarbon compounds left in the soil through the zone of soil remediation. L. 2. Determine if MTBE has migrated in the soil to a depth greater then previously investigated. 3. Determine if groundwater has been impacted with MTBE and other gasoline range petroleum hydrocarbons. LO To accomplish these goals, Geological Technics Inc. proposes to install one monitoring well to 1120 feet below grade, to be named MW-1. MW-1 will be drilled through the former tank L, pit. See Figure 2: Site Map for well location. 2.1 Monitoring Well Installation L' Soil boring permits will be secured as necessary and the local regulatory agency will be notified 48 hours prior to commencing work. The subsurface will be cleared of underground utilities by notifying Underground Service Alert. The well borehole will be drilled using a 10.25-inch outside diameter continuous flight hollow stem auger owned and operated by V&W Drilling (C57# 720904). The expected depth to groundwater is approximately 110 feet below ground surface, based on data from the San Joaquin County Flood Control District. 2.1.1 Soil Sampling Procedure L- Soil samples will be collected for geological and analytical evaluation at five-foot intervals. A professional geologist working under the supervision of a registered geologist will maintain a borehole-drilling log providing sediment description using the USCS and field observations. Soil samples will be collected in 6.0-inch brass liners using a 2.0 inch modified California split spoon sampler. All soil samples will be sealed with Teflon, capped v with Teflon end caps, labeled and placed in a cooler at 4° Celsius for transport to the laboratory following Chain of Custody protocol. Because every soil sample collected will not be submitted for laboratory analysis, a screening process will be used to gather additional information through field observation noting: L- 0 sediment type, especially grain size and clay content; 0 moisture content; • visible evidence of contamination, i.e., color change due to reduction of iron or L. discoloration from hydrocarbons and other pollutants, + readings above background on a organic vapor meter (OVM)