SITE INFORMATION AND CORRESPONDENCE

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AWN page 3, 16 Harding Way 5. Task ID#15, Notify USA. How does this task differ from scheduling a Utility Locator? The duration for this task was listed as five days. Please explain why this task takes so long. SJC/EHD does not approve the proposed Project Schedule-Site Assessment. SJC/EHD considers a reasonable schedule to be that all site assessment fieldwork will be completed before the end of June 2002, and that a report of findings will be submitted before the end of August 2002. The Project Schedule-Remedial Well Installation and Aquifer Testing was more reasonable, though SJC/EHD has the same comments concerning the duration of times for receiving a drilling permit and scheduling the utility clearance and drilling. Also, the duration for task ID#16, Aquifer testing was listed at 20 days, while the work plan proposes a 3 day test. Adjusting the project schedule by 15 days moves the report submittal deadline for the feasibility testing assessment report to June 10, 2002. A work plan for interim remediation was proposed to reduce the concentration of methyl tertiary butyl ether (MtBE) in groundwater at the site. The proposal is to pump groundwater from monitoring well MW-4, vapor well SVE-1 and the proposed groundwater extraction well on a schedule of once a month using a vacuum truck. SECOR did not list a target quantity of groundwater for removal at each event. Considering the current depth to groundwater and the fact that the pumping test performed during the MPE test showed that MW-4 could sustain only a very low pumping rate, SJC/EHD questions that this will be an effective interim remedial alternative. In addition, Step 3 of the State Water Resources Control Board Guidelines for Investigation and Clean up of MtBE and other Oxygenates final draft dated March 30, 2000 states that sites with persistent concentrations of MtBE of 10,000 micrograms per liter (µg/I) should perform interim remediation to reduce the concentrations and mass before the plume can spread. The subject site has concentrations of MtBE on-site in MW-4 consistently over 300,000 µg/I, and off-site in MW-6 consistently over 60,000 µg/l. Interim remediation should be extended to include the area of MW-6. Installation of additional extraction wells may be necessary. In summary: The work plan for site assessment activities is approved with the condition that all field work is completed by June 28, 2002 and that a report of findings is submitted to SJC/EHD by August 30, 2002. The work plan for feasibility testing is approved with the condition that all work is completed and a report of findings is submitted to SJC/EHD by June 10, 2002. Interim remediation must begin immediately, and must be extended to include all known areas of the plume with contaminant concentrations greater that 10,000 µg/l. If groundwater extraction proves to bean ineffective or unfeasible interim remediation method for this site, an addendum must be submitted to SJC/EHD proposing an alternative method. Donna Heran, REHS, Director Environmental Health Department Lori Duncan, Senior REHS Margareagorio, Supervising REHS LOP/Site Mitigation Unit IV LOP/Site Mitigation Unit IV cc: Marty Hartzell, CVRWQC13 Clint Harms, SECOR