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Mr Nathan Crum - 2 - 29 January 2009 <br /> Valley Pacific Petroleum Services <br /> Starting in the fourth quarter of 2008, biogeochemical monitoring was conducted in four wells <br /> for a year-long assessment of the baseline bioremediation potential to support the <br /> implementation of an air sparge/soil vapor extraction (AS/SVE) pilot study. Valley Pacific <br /> selected AS/SVE to remediate the contaminants in the groundwater and vadose zone based <br /> on the rationale that AS/SVE would likely enhance the biodegradation potential of the Site by <br /> increasing the dissolved oxygen (DO) levels in groundwater. From upgradient to downgradient, <br /> the wells include MW-12, MW-2, MW-6R, and MW-10. The Semi-Annual Report states that <br /> Valley Pacific will also be sampling from MW-3 for the remaining three quarters of this <br /> assessment. <br /> Our comments are presented below. <br /> 1 We are surprised to learn that property access has not yet been granted for the installation <br /> of the off-site monitoring well east of MW-13. Our 19 August 2008 letter instructed Valley <br /> Pacific to submit a lateral investigation report describing the well installation by <br /> 1 November 2008. Regional Water Board staff will contact Valley Pacific during the first <br /> week of February 2009 to provide assistance in expediting site access. In future, Valley <br /> Pacific needs to inform Regional Water Board staff when it will not meet an established <br /> deadline. <br /> 2. The objective of the biogeochemical parameter monitoring is to evaluate the whether <br /> enhancing DO levels will promote remediation. It is not clear to us how Valley Pacific can <br /> accurately accomplish this evaluation without monitoring for baseline levels of DO and <br /> other biogeochemical parameters. The quarterly analytical list of biogeochemical <br /> parameters must be expanded to include analyses for DO and oxidation reduction potential <br /> to assess the redox distribution within and outside the plume. Valley Pacific must also <br /> conduct at least one sampling event for microbial enumeration to assess the current <br /> microbial consortium. <br /> 3. We concur with Valley Pacific's proposal to incorporate MW-3 into the biogeochemical <br /> parameter assessment monitoring. <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 T''"AYLO� P.G. <br /> gmeering geologist <br /> cc Mr` Hai�i ;, Knoll. SLn Joaquin County Environmental Health Department, Stockton <br /> Mr. Gregory : ,d `-.' 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 />