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Third Quarter 1995 Monrtonng and Sarripling Report 2
<br /> The Southland Co ration 9110 Thomton Road Stockton CA October 31 1995
<br /> Based on monitoring data collected from the site-related wells,groundwater flow diverges from the site
<br /> to the northeast and southeast at a gradient of 0 006 ft/ft No SP was found in any of the monitoring
<br /> wells Groundwater levels decreased approximately 1 8 feet since the previous quarterly monitoring
<br /> event (June 6, 1995) Historical and recent groundwater monitoring data are summarized in Table 1
<br /> (Attachment 2) Field Data sheets are included in Attachment 3
<br /> Monitoring Well Sampling and Analytical Results
<br /> On September 6, 1995,the following monitoring wells were sampled MWA, MW4, MW-5, MW-7,
<br /> MW-8, MW-9, MW-13, MWA 4, MWA 5 (A, B, and C), MWA 6, MWA 7 (A, B and C), MW-18, MW-19,
<br /> MW-20, former pumping wells PWA, PW-2 and PW-3, and former recovery well RW-1 On
<br /> September 21, 1995, groundwater in wells MW-1, MW4 and MW-9 was resampled to confirm the
<br /> presence of benzene in the wells Monitoring well MW-1 1 was inaccessible and will be sampled during
<br /> the next quarterly event in December 1995 At least three well volumes of water was purged (unless
<br /> the wells were purged dry) to ensure stabilization of pH, conductivity and temperature Wells MW-2,
<br /> MW-3 and MW-10 were dry and could not be sampled Monitoring wells with sufficient water were
<br /> allowed to recharge to at least 80 percent of the initial level before sampling Samples were collected
<br /> from the monitoring wells using disposable bailers The samples were labeled, stored on tee in an
<br /> insulated container, and delivered to GTEL Environmental Laboratories in Concord, California under
<br /> chain-of-custody manifest The samples were analyzed for BTEX and TPH-G by Environmental
<br /> . Protection Agency (EPA) methods 8020/modified 8015
<br /> Purge water was contained in Department of Transportation (DOT)-approved 55-gallon drums and
<br /> stored on site pending characterization and disposal On September 21, 1995, approximately 515
<br /> gallons of purge water was pumped to the sanitary sewer in accordance with the Special Permit for
<br /> Waste Water Discharge letter, dated June 5, 1995, from the City of Stockton, Department of Municipal
<br /> Utilities
<br /> Analytical results for groundwater samples collected on September 6 and 21, 1995 are summarized in
<br /> Table 1 No TPH-G was detected in any of the monitoring wells sampled In the September 6
<br /> samples, benzene was detected only in groundwater from wells MW-1, MW4 and MW-9 at
<br /> concentrations of 2 1 parts per billion (ppb), 0 5 ppb and 1 2 ppb, respectively In the September 21
<br /> samples, benzene was detected in MW-1 and MW-9 at 0 6 ppb and 0 5 ppb, respectively A copy of
<br /> the laboratory analytical report and the chain-of-custody manifest are included in Attachment 4
<br /> The site is currently being considered for closure of environmental remedial activities through the
<br /> Regional Water Quality Control Board -Central Valley Region (RWQCB-CVR), and the San Joaquin
<br /> County Public Health Services (SJCPHS) On September 19, 1995, groundwater was collected from
<br /> domestic wells located in the vicinity of the site No dissolved petroleum hydrocarbons were detected in
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