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<br /> Site History& Background Flag City She[!#1003
<br /> ' New West Stations 6437 West Banner Street, Lodi, California
<br /> under General Order# 5-00-119,NPDES# CAG915001.
<br /> ' ENVIRONMENTAL CHRONOLOGY
<br /> In March 2005, an Underground Storage Tank (UST) Unauthorized Release Form was prepared by the
<br /> San Joaquin County Environmental Health Department (SJCEHD) for the Site. Additionally the
<br /> SJCEHD issued a letter requesting that New West perform a subsurface investigation at the Site.
<br /> ' In July 2005, Apex Envirotech, Inc. (Apex) submitted a work plan proposing the installation of four first
<br /> zone wells and two second zone wells on and off Site. The SJCEHD accepted the work plan.
<br /> On August 1, 3, and 11, 2005,Apex personnel supervised the installation of six groundwater monitoring
<br /> wells (MW-1, MW-2, MW-3A, MW-313, MW-4A and MW-413). Elevated concentrations of MTBE were
<br /> ' detected in soil and groundwater. MTBE was detected in soil samples MW-3A-10 and MW-3B-32.5 at
<br /> concentrations of 210 mg/kg and 750 mg/kg, respectively. Dissolved concentrations of MTBE were
<br /> ' detected in wells MW-1, MW-3A, MW-313, and MW-413 at concentrations of 1.2 ug/L, 56,000 ug/L,
<br /> 7,400 ug/L, and 360 ug/L, respectively. No other constituents of concern were reported above their
<br /> respective laboratory reporting limits. Results are documented in the report Groundwater Monitoring Well
<br /> ' Installations Results Report, dated September 22, 2005.
<br /> In September 2005, the SJCEHD requested additional monitoring wells to define the lateral and vertical
<br /> ' of the groundwater plume and the installation of an interim remediation system.
<br /> In October 2005, Apex commenced sampling the two municipal drinking water wells located along De
<br /> ' Broggi Road (CSA-31-1 and CSA-31-2). Samples collected did not contain concentrations of petroleum
<br /> hydrocarbons above laboratory detection limits.
<br /> ' In October 2005, Apex submitted Work plan for Monitoring Well Installations and Interim Remedial
<br /> Action, proposing batch extraction activities, monitoring well installations and a remediation system
<br /> ' proposal. The work plan was approved by the SJCEHD.
<br /> In November 2005, Apex, Mr. Moore, SJCEHD, and the RWQCB-CVR met to discuss the current Site
<br /> status, environmental concerns, and future environmental work.
<br /> During November 2005,Apex sampled monitoring wells MW-4A and MW-413 on a weekly basis.
<br /> ' On October 27 and 28 and November 30, 2005, Apex personnel supervised the drilling, sampling and
<br /> installation of five extraction wells (EW-1, EW-2, EW-3, EW-4, and EW-5) and November 9 through 11,
<br /> ' 2005, Apex personnel supervised drilling, sampling and the installation of four off-Site groundwater
<br /> monitoring wells (MW-5A, MW-513, MW-6B, and MW-6C). All soil samples were below detection
<br /> limits except for MTBE in the extraction well samples collected at the 25 and 25.5-foot intervals, which
<br /> ' were collected below the groundwater level. The sample collected at well EW-4 at the 15.5-foot interval
<br /> also had a detection of MTBE, also collected below the groundwater level. Quarterly groundwater
<br /> ' samples showed MTBE detected at all first zone wells except wells MW-1 and MW-5A. MTBE was
<br /> detected at second zone wells MW-3B and MW-4B but was non- detect at wells MW-513 and MW-613. A
<br /> ' Page 2 of 7 Closure Solutions, Inc.
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