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Mr. Nathan Crum -2 - 28 February 2008 <br />Valley Pacific Petroleum Services, Inc. <br />57 to 60 feet bgs. Separate phase product (SPH) was present in monitoring wells MW6R, <br />MW8 and MW9R. An aggregate quantity of about 100 gallons of a free product /groundwater <br />mixture was removed from these wells between January 2007 and January 2008. <br />The highest dissolved concentrations of constituents of concern (COCs) have historically been <br />detected in MW7. The highest concentrations of BTEX and TPI -Ig were detected during <br />October 2007 and January 2008 and included 260 micrograms per liter (Ng/L), 34 pg/L, <br />7.1 pg/L, 78 pg/L and 3,600 ug/L, respectively. The highest concentration of methyl tertiary <br />butyl ether (MTBE) was detected in April 2007 at 7,100 pg/L. TPHd is no longer detected in <br />groundwater in wells without SPH. Tertiary butyl alcohol (TBA) was detected at 5,600 pg/L in <br />January 2008. Our comments are presented below. <br />1. Our 28 November 2007 letter requested the submission of a well installation report and FS <br />report by 25 January 2008. 1 contacted Mr. Joe Vasquez of GZA in January 2008, and he <br />informed that they were working on both reports. We received only a well installation <br />report. We have not received an extension request for the FS report, and it is now past <br />due. I attempted to contact Mr. Gregory Stahl, Mr. Vasquez's supervisor at GZA, by <br />telephone on 20 February to determine why the FS had not been submitted, but have not <br />received a return call as of the date of this letter. Valley Pacific may either contact <br />Regional Water Board staff with a reasonable explanation for the delay in submitting the <br />FS report and to arrange an extension, or submit the FS report by 7 March 2008. <br />Regional Water Board staff are prepared to recommend enforcement if Valley Pacific <br />does not contact us or submit the FS report by that date. <br />2. The groundwater monitoring results summarized in the Figure 4 of the Report show that <br />the lateral extent of groundwater pollution emanating from the Site is delineated to non - <br />detect (ND) by monitoring wells MW11, MW5, and MW12 to the south, west and north, <br />respectively. However, the TPI -Ig and benzene detected in the MW13 (730 pg/L and <br />8.4 pg/L, respectively) show that the plume is not delineated to the east. These <br />concentrations exceed the water quality objectives of 5 pg/L for TPI -Ig and 1 pg/L for <br />benzene. Valley Pacific has not met the objective of plume delineation to the east. Plume <br />delineation must be accomplished in order adequately assess cleanup alternatives. <br />Regional Water Board staff will continue to observe concentration trends in MW13. If the <br />concentrations continue to trend above water quality objectives, Valley Pacific will have to <br />perform additional investigation to delineate the plume to the east of MW13. <br />If you have any questions regarding this letter, you may contact me at (916) 464-4811 or <br />betaylor@waterboards.ca.gov. / <br />BRIAN TAYLOR, P.G. <br />Engineering Geologist <br />cc: Mr. Harlin Knoll, San Joaquin County Environmental Health Department, Stockton <br />Mr. Gregory Stahl, Ground Zero Analysis, Inc., Escalon <br />Mr. Patrick Riddle, Law Offices of Patrick D. Riddle, Acampo <br />Mr. John Miller, Valley Pacific Petroleum Services, Inc., Stockton <br />