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On December 19 and 22, 1997, Ramage Environmental collected soil and groundwater-grab <br /> • samples from eleven locations using a Geoprobe` 5400 Direct-Push Technology (Geoprobe) ng, <br /> operated by Fisch Environmental of Valley Springs, California Field observation and analytical <br /> laboratory results indicated that diesel and gasoline hydrocarbons had impacted soil and <br /> groundwater beneath the site, the city of Tracy right-of-way (Hamilton Alley) and other private <br /> property parcels to the north and east of the site <br />' Soil samples collected by the Geoprobe from soil borings located within and in close proximity to <br /> the former UST excavation contained the highest concentrations of diesel and gasoline <br /> hydrocarbons Petroleum hydrocarbons were detected in soil samples collected at 10 feet bgs at <br /> concentrations as high as 1,800 ppm of Total Petroleum Hydrocarbons (TPH)-as-diesel, 400 ppm <br /> of TPH-as-gasoline and 5 4 ppm of benzene Methyl tertiary butyl ether(MTBE) was not detected <br />' in any of the soil samples analyzed Vertically, the extent of impacted soil is defined to less than <br /> 15 feet bgs The most heavily impacted soil is present from lust above the current groundwater <br /> table at approximately 7 feet bgs to a depth of approximately 12 feet bgs Laterally, impacted soil <br /> extends to the north of the site beneath Hamilton Alley and the private property parcels east and <br /> north of the site The lateral extent of impacted soil to the north and east of the site is not fully <br />' defined The analytical results of the soil sampling are also summarized in Table 1 <br /> Groundwater-grab samples collected from 01 eleve of the sample locations contained detectable <br /> concentrations of diesel and gasoline hydroc s Petroleum hydrocarbons were detected in <br /> close proximity to the former UST excavation at concentrations of 1,300,000 ppb of TPH-as- <br /> diesel, 140,000 ppb of TPH-as-gasoline, 11,000 ppb of benzene and 400 ppb of MTBE Two <br /> groundwater-grab samples analyzed by EPA Method 8260 did not contain alcohol- or ether-based <br />' oxygenate compounds Some free product was observed during the soil and groundwater <br /> sampling in and around the former UST excavation Laterally, impacted groundwater extends to <br /> the north and east of the site under Hamilton Alley and private property The lateral extent of <br />' impacted groundwater is not defined The analytical results of the groundwater-grab sampling are <br /> summarized in Table 2 <br /> 5 <br />