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PHASE II ENVIRONMENTAL SITE ASSESSMENT INVESTIGATION WORK PLAN 2222 & 2244 S.Airport Wap Stockton,California 1.0 INTRODUCTION This work plan was prepared by Condor Earth (Condor) to describe proposed Phase II Environmental Site Assessment (ESA) investigation activities at 2222 & 2244 S. Airport Way (Site) in Stockton, California (Figures 1, 2, and 3, Appendix A). The purpose of the work is to investigate the potential presence chlorinated solvents from a former dry cleaning operation previously located on Site and for petroleum hydrocarbons from former gas stations surrounding the Site. The Phase II ESA Investigation Work Plan will be conducted for the City of Stockton (Client) in advance of potential development by STAND Affordable Housing.The Site is owned by The City of Stockton. The proposed work includes advancing four temporary soil gas probes and four hollow stem soil borings to evaluate the impact of the former dry cleaner and historical gas stations near the Site, inspect soil and groundwater, and collect soil and groundwater samples for laboratory analyses. After soil samples are collected from the four soil borings, the borings will be converted to groundwater monitoring wells by installing well casing, filter pack, annular sealing material, and a protective well box. All work conducted by Condor will be performed under the supervision of a State of California licensed Professional Geologist. 2.0 PROJECT BACKGROUND The Site was used as an agricultural field the early 20' Century until the early 1950s. The Site was developed in the early 1950s with four buildings on the northern portion of the Site and asphalt surrounding the buildings in a mixed residential and commercial neighborhood. The shops operating on the Site included a drug store (2202), variety store (2222 and 2226), grocery (2222 and 2244), and various service-related and retail shops. A dry cleaning shop operated at 2230 Sharps Lane(Airport Way) from 1950 until the early 1970s which corresponds to the small shop immediately north of the large market (southernmost building) at 2244 Airport Way. The buildings were removed sometime between 2010 and 2012 with the asphalt driveways and parking lots remaining. Electric and telephone lines are located on the northwestern portion of the Site and terminate at a pole. There are a total of six former fueling stations within 600 feet of the Site. Two have been investigated and remediated under regulatory oversight. The other four have no public record of investigation. The depth to groundwater in the area is expected to occur at a depth of approximately 27 to 29 feet below ground surface (bgs) and the groundwater gradient direction is predominantly to the east-northeast. Two former fuel stations are directly upgradient with respect to the Site. Three monitoring wells were present adjacent to the southwestern margin of the Site associated with the former gas station at 2255 S. Airport Way. Gasoline was detected in groundwater immediately adjacent to the Site at concentrations ranging from 55 micrograms per liter (gg/L) to 450 µg/L in monitoring well MW-6. Concentrations of contaminants in MW-6 appeared to be increasing slightly starting in 2008 until 2012 when monitoring ceased and slight odor/sheen was noted in two of the last three monitoring events, where no odor or sheen had been noted in earlier events. Based on review of publically available information, groundwater beneath the Site may be impacted by petroleum hydrocarbons. i� CONDOR