ARCHIVED REPORTS_XR0009334 - Laserfiche WebLink

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1 TABLE 2 ANALYTICAL DATA: GROUND WATER F' Port of Stockton Former UST Site No 3, San Joaquin County ' Results reported inµg/1 (Parts per billion=ppb) F Date TPH-g Benzene Toluene Ethylbenzene Xylenes MTBE Sampled EPA 8015-m EPA 8260 EPA 8260 EPA 8260 EPA 8260 EPA 8260 07/09/99 610 18 302 236 791 N D 10/22/99 2,750 270 120 49 390 N D 02/08/00 1,800 12 85 30 180 N A ' MW3-2 07/09/99 640 119 296 219 666 N D 10/22/99 4,100 49 270 50 320 N D 02/08/00 3,200 153 380 122 200 N A ' MW3-3 07/09/99 8,420 113 2,506 886 1,772 N D 10/22/99 7,220 207 680 221 1,360 N D 02/08/00 4,500 150 460 180 880 N A ' Reporting Limits 50 gg/l 0 5 µg/1 ND Analyte not detected at reporting limds listed m laboratory report ' N A Not Analyzed MCLS m gg/1 as follows benzene�1,toluene-150,ethylbenzene=700,xylenes—1750 SUMMARY OF FINDINGS On February 8, 2000, field personnel sounded and sampled the Port's former UST Site No 3 ' monitoring wells MW3-1 through MW3-3 At that time, the local direction of groundwater flow was calculated at approximately NWE along a gradient of 0 008 feet/foot (equivalent to 8 feet of dip per 1000 feet of horizontal distance) The average depth-to-water on February 8 was 10 70 feet below the ' casmg-tops of the three project monitoring wells Groundwater samples were collected from the monitoring wells on February 8, 2000 and analyzed for ' Total Petroleum Hydrocarbons as gasoline (TPH-g) by EPA Modified Method 8015, volatile aromatics benzene, toluene, ethylbenzene, and total xylenes (BTEX) by EPA Method 8260 No gasoline as free product was observed in any well ' Overall, concentrations of all analytes have decreased significantly in all of the wells For MW3-1, benzene concentrations in groundwater dropped from 2 70 µg/1 on October 22, 1999 to 1 2 µg/l on February 8, 2000 Toluene concentrations in groundwater decreased from 120 µg/1 on October 22, 1999 to 85 µg/l on February 8, 2000 Ethylbenzene concentrations in groundwater decreased from 49 µg/l on October 22, 1999 to 30 µg/1 on February 8, 2000 Xylenes also exhibited a decrease from 390 µg/l on October 22, 1999 to 180 µg/1 on February 8, 2000 TPG-g also decreased from 2,750 µg/1 on October 22, 1999 to 1,800 µg/1 on February 8, 2000 The same decreasing trend was observed for TPH-g and BTEX concentrations in MW3-2 and MW3-3 ' Per SJCEHD's concurrence MTBE compounds were not analyzed this quarter from the well p yz q e s MTBE has not been detected in any soil or groundwater samples collected at this site 1 ua!MW gtr3 doe 5 1