|
r...� N%Wol
<br /> Confirmation Soil Vapor Survey Workplan
<br /> Moore Petroleum Bulk Plant,5491 F Street,Banta,California
<br /> Page 5
<br /> June 29,2007-Apex issued a letter to the SJCEHD suggesting that additional sampling be
<br /> performed in the area around CPT-2 to confirm the presence of weed oil 30 feet bgs. Apex also
<br /> recommended that proposed well MW-15 be installed to the original depth of 20 feet bgs.
<br /> October 31,2007-Apex advanced and sampled 13 soil vapor points at the subject site. Results
<br /> of the soil vapor survey are documented in Apex's Soil Vapor Survey Results Report, dated
<br /> December 12, 2007.
<br /> March 12, 2008-The SJCEHD issued a letter requesting a fate analysis of proposed sample
<br /> analyte list(DAP, DBP, Dino Scb). The SJCEHD also approved the installation of well MW-15
<br /> to the originally proposed depth of 20 feet bgs.
<br /> May 8, 2008-The SJCEHD issued a letter approving the Sample Reduction Request Letter
<br /> dated January 23, 2008. The SJCEHD approved the following groundwater monitoring
<br /> frequency of; quarterly sampling of MW-3, MW-7, MW-8, MW-10, MW-11, VEW-2, RW-2 and
<br /> newly installed MW-15; semi-annual sampling of MW-4A, and MW-12; and annual sampling of
<br /> MW-2, MW-5, MW-6, MW-9, MW-13, MW-14, MW-16, and MW-17.
<br /> August 18, 2008 -Apex installed monitoring well MW-15 to a total depth of 20 feet bgs. Apex
<br /> submitted the results of the installation in a results report on December 8, 2008.
<br /> April 30, 2009-Apex submitted a letter to the SJCEHD requesting that the analytical suite for
<br /> groundwater samples be reduced to include only total petroleum hydrocarbons as gasoline
<br /> (TPHg), as diesel (TPHd), as kerosene (TPHk), and as motor oil (TPHmo). The reduced
<br /> analytical suite was approved in a letter from the SJCEHD dated July 2, 2009.
<br /> June 12, 2009-Apex submitted a Monitoring Well Installation Workplan proposing to install a
<br /> deep screened well to a depth of 80 feet bgs via conductor casing to 52 feet bgs to determine the
<br /> vertical extent of contamination at the site. The workplan was approved by the SJCEHD in a
<br /> letter dated July 2, 2009, under the condition that the well be installed with 10 feet of screen.
<br /> July 2, 2009-Apex received a letter form the SJCEHD reducing the required sampling
<br /> frequency for wells at the site. Under the new sampling program, wells MW-3, MW-4A, MW-7,
<br /> MW-8, MW-10, MW-11, MW-12,RW-2,and VEW-2 will be sampled semi-annually and wells
<br /> MW-2,MW-5, MW-6, MW-9, MW-13,MW-14, MW-16, and MW-17 will be sampled
<br /> annually. The letter did not provide sampling frequencies for wells MW-1 and MW-15. The
<br /> letter recommended that the SVE system be turned off to perform rebound testing. Additionally,
<br /> the letter approved a confirmation soil vapor survey during the SVE system rebound testing to
<br /> further assess the risk posed by vapor intrusion at the site.
<br />
|