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Mr. Steve Osborne - 3 - 22 February 2011 KMEP Stockton Terminal Our comments are presented below. 1. We are concerned that the failure to collect the EC, DO and ORP data hampers the evaluation of the biodegradation potential of the plume. The field parameter data are of equal importance to the electron acceptor data, so it is unclear why KMEP did not collect these parameters. KMEP needs to continue collecting field parameters during subsequent monitoring events to provide a more thorough MNA analysis. 2. KMEP's 2008 Estimated Time to Reach Water Quality Objectives included estimates for benzene and TPHg to reach WQOs, but the Annual Report did not include estimates for these chemicals. KMEP's position that benzene has many non-detects is not supported by the data listed in Table 2, which show that elevated concentrations of this chemical are emanating from the manifold area. In addition, KMEP provides no literature verifying its contention that MTBE contributes to the quantification results for TPHg. KMEP's rationale for discontinuing time estimates for these chemicals is unsubstantiated, and the estimates for them must be included in subsequent analyses to provide a more comprehensive estimate of the time by which WQOs are likely to be attained. 3. The "elevated benzene" criterion listed in Section 6.1.2 for categorizing SP/M-3, SP/M-4, and SP/M-6 as co-mingled area wells, is not supported by the historical data in Table 2, which show that benzene has never been detected in these wells, except for one minor hit in SP/M-3 in 2003. Additionally, if benzene were to show up in these so-called co-mingled wells, it is likely that it could have originated from KMEP's upgradient, manifold area wells, SP/M-1 and SP/M-9, where the source of benzene has been acknowledged as originating on KMEP property. The data do not support KMEP's rationale for concluding that pollution in these wells is co-mingled with plumes that originate off-site. The "off-site sources" criterion listed in Section 6.1.2 to designate SP/M-10 as a co- mingled well is also inconsistent with the data presented in NuStar's 30 January 2009 Vertical Investigation Results Report. This report presents grab-groundwater data collected from two borings, NS-6 and NS-13, advanced in the vicinity of SP/M-10. TPHg and benzene concentrations in NS-6, which is on the NuStar property upgradient from SP/M-10, were one to five orders of magnitude lower than concentrations in SP/M-10. TPHg and benzene concentrations observed in NS-13, which is on KMEP property downgradient from SP/M-10, were also lower than concentrations in SP/M-10. These data indicate that the source of the elevated TPHg and benzene observed in SP/M-10 originated on the KMEP property, and those concentrations are not co-mingled with groundwater pollution from off-site. 4. Although KMEP has not updated the estimate to achieve WQOs for SP/M-10, the 2008 estimate shows that benzene and TPHg concentrations were increasing at that time. KMEP concluded that there was no trend for MTBE. This indicates that biodegradation is not attenuating MTBE levels in this well. In addition, the Mann- Kendall trend analysis in Appendix D indicates a positive S statistic for 2006 to 2010 MTBE data. A positive Mann-Kendall S statistic generally indicates an increasing trend. One possible explanation for the increasing pollution levels in SP/M-10 may be the eastward, downgradient migration of the petroleum hydrocarbon plume from