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C. VV o A S S D C I A T E S I N C evidenced by the water quality data collected from the monitoring wells subsequently installed at the site Therefore, the likelihood of any contaminants in the vadose zone reversing or threatening to reverse the mass reduction rate of groundwater pollutants is very low Criterion 2: Separate phase product has been removed to the extent practicable. Free product has never been detected at this site Criterion 3: No existing water supply wells, deeper aquifers, surface waters, or other receptors are threatened by pollutants remaining in the aquifer. According to USGS 7 5-minute topographic map titled Union Island, Calif 1978 there is one point located approximately 650 feet north of the site on Holly Drive identified as Well 26 Boring logs were not found for this well On March 19, 2001, ATC performed a site vicinity survey to try and locate this well Some piping and associated valves were observed in the vicinity where Well 26 is located on the map According to City of Tracy, Department of Engineering, this piping is not associated with a well but is associated with a concrete irrigation ditch During the survey, a domestic well was observed at 2541 Holly Drive According to the tenant who has been living at the residence for two years, the house is supplied with municipal drinking water and the property owner stated that the well is not operational Approximately 900 to 1,000 feet west of the site on Grant Line Road, the logs identify a site called "Jordan Real Estates" where there are three monitoring wells identified as MW-1, MW-2, and MW-3 Each well is 24 feet deep and screened from a depth of 4 to 24 feet These wells are located hydraulically crossgradient from the site Approximately 1,800 feet to the west of the site, well logs identify an irrigation well with a completion depth of 212 feet and a screened interval ranging from 159 to 194 feet below ground surface This well is located hydraulically crossgradient from the site and is screened in an aquifer much deeper than the impacted aquifer Based on this information, the likelihood of pollutants remaining in the aquifer threatening these potential receptors is very low Criterion 4: The total pollutant mass remaining in the groundwater is decreasing at predicted rates and neither creates, nor threatens to create, a risk to human health and safety or future beneficial use(s) of the aquifer. iWater quality data collected at the site indicates that the concentrations of petroleum hydrocarbons have significantly decreased over time to almost non detectable levels W 142034 00021dosure-addendum&c 5