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Mr. Steve Osborne -4 - 22 February 2011 <br /> KMEP Stockton Terminal <br /> upgradient well SP/M-9. This is supported by the decreasing concentrations trends <br /> observed in SP/M-9. The depleted NO3 and SO4, coupled with elevated methane <br /> levels, indicate that the interior of the plume is anaerobic and the metabolic pathway <br /> for biogradation is methanogenesis. However, this metabolic pathway is extremely <br /> slow and unlikely to achieve WQOs in a reasonable time. <br /> Central Valley Water Board staff does not concur that the groundwater data support <br /> KMEP's conclusion that the WQO for MTBE will be achieved in a reasonable time <br /> by MNA because the concentrations of TPHg, TPHd, and BTEX, which originate <br /> from the manifold area, are increasing in SP/M-10 as evidenced by the 2008 time <br /> estimates. Estimates of the time required to reach the MTBE WQO have increased <br /> by 30 years in SP/M-1 and by 5 years in SP/M-9 since the estimates were first <br /> quantified in 2008. In addition, groundwater samples collected from SP/M-1 may not <br /> represent an optimal location from which WQO attainment rates can be calculated <br /> because the influence from pilot tests, including bio-sparging and bioventing in 1994 <br /> and nutrient addition in 2003, are unknown. Cleanup at the KMEP Stockton terminal <br /> is not compliant with the terms of the Central Valley Water Board's approval of the <br /> Cleanup Plan, which states, "If the hydrocarbon plume migrates or concentrations <br /> increase, KMEP will need to re-evaluate remedial alternatives for the site." <br /> Concentrations of benzene and TPHg are increasing in SP/M-10. <br /> Based on historical data, KMEP has concluded that (1) most of the contaminant mass <br /> is in the shallow fine-grained soils and (2) aerobic degradation can be enhanced by bio- <br /> sparging. However, the vertical extent of the plume remains undefined. Additional data <br /> regarding the extent of the plume will become available once SP/M-913 and SB/M-9C <br /> are sampled. After KMEP has evaluated SP/M-9B and SP/M-9C sampling results, by <br /> 1 May 2011, KMEP must submit the re-evaluation of remedial alternatives to remove all <br /> pollutants originating from the Site, as required by the Cleanup Plan approval. <br /> If you have any questions regarding this letter, you may contact me at (916) 464-4811 <br /> or by email at betaylor(LDwaterboards.ca.go <br /> -BRIAN TAYLOR, P.G. <br /> Engineering Geologist <br /> cc: Mr. Harlin Knoll, San Joaquin County Environmental Health Department, Stockton <br /> Mr. Ken Yeo, Kinder Morgan Energy Partners, Sacramento <br /> Ms. Danielle Catlin-Wright, Arcadis, Roseville <br /> Mr. Joe Aldridge, NuStar, Texas <br /> Ms. Debbie Callie, Port of Stockton, Stockton <br /> Mr. Paul Supple, BP, San Ramon <br /> Mr. Mark Chandler, Time Oil Company, Seattle, WA <br /> Mr. Jeff Baker, Tesoro Companies, Inc, Auburn, WA <br />