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<br /> OREGON WASHINGTON T N PHONE(206)285-2400
<br /> CALIFORNIA12 To FAX(206)283-8036
<br /> NEVAD
<br /> IDAHOA S 143 "E
<br /> o
<br /> 7 T65 TS 2737 WEST COMMODORE WAY SEATTLE,WA 98199-1233
<br /> PRODUCTS TTS
<br /> PO BOX 24447 SEATTLE,WA 98124-0447
<br /> TIME TESTED E
<br /> October 20, 1998
<br /> Mr Harlin Knoll
<br /> San Joaquin County Public Health Services
<br /> Environmental Health Division
<br /> P O Box 2009
<br /> Stockton, California 95201 ,
<br /> RE Submittal of Third Quarter 1998 Groundwater Monitoring Report for -
<br /> Jackpot Food Mart, 14000 E Highway 88, Lockeford, California (Property No 04-049)
<br /> Dear Mr Knoll,
<br /> At the request of the San Joaquin County Public Health Services Environmental Health Division (PHS/EHD),
<br /> an additional environmental investigation was Implemented at the subject site in December 1994 to evaluate
<br /> the extent of hydrocarbon-Impacted sods and to determine whether or not groundwater had been Impacted
<br /> A total of four groundwater monitoring wells were installed during this Investigation In July 1996, six
<br /> additional groundwater monitoring wells were Installed on and off of the subject site to assist In defining the
<br />• extent of groundwater impacts Based on the results of the Investigations, Time Oil has Implemented
<br /> groundwater monitoring
<br /> Please find enclosed Science& Engineering Analysis Corporation's (SECOR's)"Quarterly Monitoring Report,
<br /> July - September 1998" dated October 16, 1998 This document presents analytical results and field
<br /> observations collected during Third Quarter 1998 groundwater sampling activities
<br /> For your convenience a summary of previous site activities is attached
<br /> Third Quarter 1998 Groundwater Sampling Results-August 1998
<br /> On August 13, 1998, samples were collected from each of the groundwater monitoring wells (MW-1 through
<br /> MW-10) at the subject site by a representative of SECOR Pnor to purging, the depth to water in each well
<br /> was measured to evaluate elevation, flow direction, and gradient As noted In the attached report,
<br /> groundwater with a southerly flow direction and a gradient of 0 04 ft/ft was encountered In the wells at
<br /> depths of 64 32 feet to 76 85 feet below ground surface Free product was not encountered in any of the
<br /> wells The locations of the wells are identified on Figure 2 of the attached report
<br /> Since the April 1998 sampling event, groundwater elevation increased in each well by 0 81 feet to 9 54 feet,
<br /> resulting in an overall increase in groundwater elevation of 2 81 feet across the site Groundwater flow
<br /> direction also changed from southwest to south Changes in groundwater depth and flow direction are most
<br /> likely a result of seasonal variation Groundwater gradient was consistent with previously collected data
<br /> Table 1 in the attached report summarizes all groundwater elevation data collected to date
<br /> Analyses identified elevated concentrations of hydrocarbons in the samples collected from MW-1 (15,700
<br />. ppb gasoline, 380 ppb benzene, 2,500 ppb toluene, 1,130 ppb ethylbenzene, 2,480 ppb xylenes), MW-2 (250
<br /> ppb gasoline, 6 4 ppb benzene, 0 9 ppb toluene, 0 50 ppb ethylbenzene, and 51 1 ppb xylenes), MW-3 (572
<br /> ppb gasoline, 113 ppb benzene, 25 5 ppb toluene, 45 6 ppb ethylbenzene, and 60 4 ppb xylenes), MW-4 (
<br /> 229 ppb gasoline, 12 4 ppb benzene, 2 2 ppb ethylbenzene, 0 7 ppb xylenes), MW-5 (4,760 ppb gasoline,
<br /> 486 ppb benzene, 852 ppb toluene, 207 ppb ethylbenzene, and 1,050 ppb xylenes), and MW-6 (328 ppb
<br /> gasoline, 20 5 ppo benzene, 1 6 ppb toluene, 3 5 ppb ethylbenzene, 32 1 ppb xylenes) Lower
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