ARCHIVED REPORTS_XR0009331 - Laserfiche WebLink

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' TABLE 2 ANALYTICAL DATA: GROUND WATER Port of Stockton Former UST Site No 3, San Joaquin County tResults rt ported in s per billion= Well Date TPH-9 Benzene Toluene Etliylbenrene Xylenes MTBE Number Sam led EPA 8015-m EPA 8260 EPA 8260 EPA$260 EPA 8260 EPA 5260 ' MW3-1 07/09/99 610 18 302 236 79I ND 10/22/99 2,750 270 120 49 390 ND 02/08/00 1,800 12 85 30 180 N A ' 05/17/00 180 120 82 38 428 N A 09/14/00 400 11 11 60 44 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 05/17/00 790 64 174 19 181 N A- 1 09/14/00 6,600 150 660 370 530 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- 05/17/00 1,600 93 560 180 737 N A 09/14/00 6,800 1 37 1 190 1 79 1 330 1 N A �Orttng Limits 50 0 5 ND Analyte not ddeded at t sporting hmas hsW in laboratory nV ort. NA Not Anafyzod ' MeLs mµgll as follows bm=L=l,toluane=150,ethylbeuzene=700,xy1nes=1750 ' SUMMARY OF FINDINGS On September 14, 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 S 6°E along a gradient of 0 014 feet/foot (equivalent to 14 feet of dip per 1000 feet of horizontal distance) The average depth-to-water on September 14 was 115 feet below 1 the casing-tops of the three project monitoring wells Groundwater samples were collected from the monitoring wells on September 14, 2000 and analyzed ' for TPHg by EPA Modified Method 8015, and BTEX by EPA Method 8260 No gasoline as free product was or has ever been observed in any well ' Overall, concentrations of all analytes have decreased significantly in all of the wells,with the exception of this reporting quarter where TPHg in MW3-1, MW3-2 and MW3-3 have increased The change in groundwater gradient and direction are indicative of the influence of the Deep Water Channel,which is ' 1200 feet northeast of the site For MW3-1,benzene concentrations in groundwater have risen slightly from 12 µg/1 (May 17, 2000) to 11 0 µg/1 Toluene concentrations in groundwater have increased slightly from 8 2 µg/1 on May 17, 2000 to 11 0 µg/1 (Sept 14, 2000) Ethylbenzene ' concentrations in groundwater increased from 3 8 µg/1 (May 17, 2000) to 6 0 µg/1 (Sept 14, ,tet sft3 gtr5 dm 5