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PHONE 285 2400 CABLE ADDRESS TIMOIL SEATTLE T (FAX) 206 283 8036 TACOMA EN — r tr •I 1 PORTLAND STOCKTON T LOSANGd 112 i 2 N TIME of -c�o LOS ANGELES 9 ; g' q � � 11, b 5 TS T 2737 WEST COMMODORE WAY SEATTLE,WA 98199 1233 PRODUCTS P O BOX 24447 SEATTLE WA 98124 0447 TIME TESTED ^^ E February 13, 1996 Mr Harlan Knoll San Joaquin County Public Health Services Environmental Health Division P O Box 2009 Stockton, California 95201 RE Submittal of Groundwater Monitoring Report - Fourth Quarter 1995 for Jackpot Food Mart, 1434 W Yosemite Ave , Manteca, CA (Property No 04-167) Dear Mr Knoll, On June 20, 1994, the San Joaquin County Public Health Services Environmental Health Division (PHSIEHD) requested that Time Oil conduct groundwater monitoring until cleanup of the above- referenced site has been achieved Accordingly, please find enclosed Science & Engineering Analysis Corporation's (SECOR) "Quarterly Monitoring Report, December 1995" dated February 5, 1996 This report presents analytical results and field observations collected during Fourth Quarter 1995 groundwater sampling activities For your convenience a summary of previous site activities is attached Fourth Quarter 1995 Groundwater Sampling Results - December 1995 On December 5, 1995, samples were collected from each of the groundwater monitoring wells (W-3 and W-5 through W-7) at the subject site by a representative of SECOR Prior to purging, the depth to water in each well was measured to evaluate elevation, flow direction, and gradient As noted in the attached report, groundwater with a southwesterly flow at a rate of 0 001 ft /ft was encountered in the wells at depths of 15 10 feet to 16 12 feet below ground surface The location of the wells is identified on Figure 2 of the attached report Since the previous sampling event, groundwater elevation increased in each of the wells by 0 90 feet to 1 24 feet, or an overall average Increase in groundwater elevation of 1 08 feet across the site Groundwater flow direction changed from northeast to southwest, however, gradient remained consistent with previously collected data The variations in groundwater elevation and direction are most likely due to seasonal variation Table 1 in the attached report summarizes all groundwater elevation data collected to date Analyses did not indicate presence of hydrocarbons in any of the samples collected from the wells Table 2 in the attached report summarizes historical analytical data, and the laboratory reports for the most recent sampling event are included as Attachment 1 Conclusions Because groundwater at the subject site has not been impacted, and soil impacts appear to be only residual, Time recently contacted the PHSIEHD to discuss the need for active site remediation and potential changes to the current quarterly groundwater monitoring program Based on that telephone conversation, it is Time's understanding that semi-annual groundwater sampling (rather than quarterly groundwater sampling) may be conducted until closure of the site has been granted SECOR will conduct the next groundwater sampling event during the Second Quarter of 1996 i