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Mr. Jeff Baker -4 - 31 August 2010 Stockton Terminals Technical Committee Our comments are presented below. 1. Table 8 shows that (1) compliance monitoring is not being conducted in TONT-3, (2) compliance monitoring for bromate and hexavalent chromium (Cr VI) was not performed in treatment area wells TS/4-R and TS/M-2, and (3) CR VI was detected above the water quality objective (WQO) of 21 pg/L in TS/M-2 in May 2009. Central Valley Regional Water Board and Stantec staff exchanged emails on 6 July 2010 regarding the clarification of monitoring requirements for the HPI pilot study. Since that exchange, we have observed that Title 27 Section 20415(e)(1 2)(B) states: The sampling method selected shall include collection ...from each Monitoring Point and background monitoring point ... The RWQCB shall require more frequent sampling and statistical analysis than is stated in the discharger's technical report under(e)(7) where necessary to protect human health or the environment.. This excerpt indubitably establishes that (1) compliance monitoring is required in background well TONT-3 and (2) the scope of the compliance monitoring program can be determined by Central Valley Water Board staff. As such, for the duration of monthly compliance monitoring for the HPI pilot test, Tesoro must conduct compliance monitoring inTO/T-3, TS-4R, TS/M-2, and TS-5 for bromate, chromium, and vanadium. Laboratory analysis detected Cr VI in excess of the WQO in the first baseline sampling event by laboratory analytical method EPA 7196A. Laboratory analysis of subsequent baseline samples was performed using EPA method 7199. These results showed that Cr VI was non-detect (ND). Therefore, Tesoro has discontinued monitoring for this analyte. However, in the 6 July series of emails Stantec, on behalf of Tesoro, argued that calculation of the baseline concentration for this constituent should incorporate the concentrations of the Cr VI detections. We concur with Tesoro's decision to exclude analysis for Cr VI from compliance monitoring, thereby resolving the need for any additional discussion on whether the Cr VI detections should be incorporated into the baseline concentrations. 2. We concur with STTC's request to discontinue sampling TS/MW-3D in favor of TS/MW-3DR. The wells are proximal and screened at similar depth intervals. Because MRP No. R5-2004-0823 was prepared almost six year ago, Central Valley Water Board staff will update it to more accurately reflect the state of the current monitoring program. The revised MRP will convey the removal of TS/MW-3D from the monitoring program and will be sent to STTC for comments in draft form. However, STTC may not implement any changes to this MRP until a revised MRP is issued by the Executive Officer. 3. The detection of MBAS in PS/MW-20C, OW-3CR, OW-4C, and OW-9C indicates that this contaminant may be present in all downgradient wells. As such, we will require STTC to expand the MBAS sampling program to all Port of Stockton,