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• In July 1996, three soil borings were drilled and two were converted to monitoring wells Contaminated soil was encountered in two of these, and one or more hydrocarbon contaminants were detected in water samples from all three, as well as in the previously drilled well (VM-1) The resulting data helped to partially define the limits of soil contamination, but the limits of groundwater contamination were not reached A soil vapor survey was conducted in March, 1998, in order to better define the extent of near- surface soil contamination This survey was followed by the drilling of two new soil borings to collect samples to confirm the vapor results The results of the investigation were presented in the Soil Assessment Report prepared by Upgradient in April, 1998 Subsequently, one of the bonngs was converted to groundwater monitor well VM-4 In May, 1999, Upgradient Environmental submitted a work plan to complete the off-site delineation of groundwater contamination to perform feasibility tests of various remedial technologies The work plan specified locations for four off-site monitor wells, one on-site vapor extraction well, one on-site air sparging well, and one on-site bacterial morulation boring Except for the bioremediation bonng,these activities were approved by PHS/EHD, and Upgradient began the process of obtaining encroachment permits from the City of Stockton to drill the off-site wells To date, these permits have not been approved However, on August 30, Upgradient mobilized V&W Drilling to the site, and the vapor extraction and air sparging wells were drilled hi October, Upgradient performed the third quarter groundwater monitoring event The procedures used in these activities are described below 3.0 PROCEDURES 3.1 Drilling and Sampling Figure 2 shows the locations of VT-1 and SW-1 Both wells were drilled with a hollow-stem auger rig VT-1 was drilled to a depth of 30 feet,and samples were collected at 5-foot intervals beginning at 15 feet SW-1 was drilled to a depth of 32 feet and also sampled at 5-foot intervals, except that it was continuously sampled from 30 to 33 feet The sampler was washed in a TSP solution between samples, and the augers were steam-cleaned between borings The auger returns were stored in 55-gallon drums pending laboratory analysis of the samples The geologist capped and sealed either the middle or bottom sleeve of each sample for laboratory analysis and placed it into a precooled ice chest The remainder of the sample was then disaggregated in a resealable plastic bag and allowed to volatilize for several minutes in the sun The geologist then inserted a portable photo-ionization detector (PTD) into the bag and screened the sample for the presence of hydrocarbon vapors The PID reading and other observations were noted on the boring logs (Appendix A) 3