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' page 3, 16 Harding Way <br /> ' S Task ID#15, Notify USA How does this task differ from scheduling a Utility <br /> Locator? The duration for this task was listed as five days Please explain <br /> why this task takes so long <br /> SJCIEHD does not approve the proposed Project Schedule-Site Assessment SJCIEHD <br /> considers a reasonable schedule to be that all site assessment fieldwork will be <br /> completed before the end of June 2002, and that a report of findings will be submitted <br /> Ibefore the end of August 2002 <br /> The Project Schedule-Remedial Well Installation and Aquifer Testing was more <br /> ' reasonable,though SJCIEHD has the same comments concerning the duration of times <br /> for receiving a drilling permit and scheduling the utility clearance and drilling Also, the <br /> duration for task ID #16, Aquifer testing was listed at 20 days, while the work plan <br /> 1 proposes a 3 day test Adjusting the project schedule by 15 days moves the report <br /> submittal deadline for the feasibility testing assessment report to June 10, 2002 <br /> A work plan for interim remediation was proposed to reduce the concentration of methyl <br /> ' tertiary butyl ether(MtBE) in groundwater at the site The proposal is to pump <br /> groundwater from monitoring well MW-4, vapor well SVE-1 and the proposed groundwater <br /> extraction well on a schedule of once a month using a vacuum truck SECOR did not list <br /> ' a target quantity of groundwater for removal at each event Considering the current depth <br /> to groundwater and the fact that the pumping test performed during the MPE test showed <br /> that MW-4 could sustain only a very low pumping rate, SJCIEHD questions that this will <br /> be an effective interim remedial alternative In addition, Step 3 of the State Water <br /> Resources Control Board Guidelines for Investigation and Clean up of MtBE and other <br /> Oxygenates final draft dated March 30, 2000 states that sites with persistent <br /> concentrations of MtBE of 10,000 micrograms per liter (µg11)should perform interim <br /> ' remediation to reduce the concentrations and mass before the plume can spread The <br /> subject site has concentrations of MtBE on-site in MW-4 consistently over 300,000 µg11, <br /> and off-site in MW-6 consistently over 60,000µg11 Interim remediation should be <br /> ' extended to include the area of MW-6 Installation of additional extraction wells may be <br /> necessary <br /> In summary The work plan for site assessment activities is approved with the condition <br /> that all field work is completed by June 28, 2002 and that a report of findings is submitted <br /> to SJCIEHD by August 30, 2002 The work plan for feasibility testing is approved with the <br /> condition that all work Is completed and a report of findings is submitted to SJCIEHD by <br /> June 10, 2002 Interim remediation must begin immediately, and must be extended to <br /> include all known areas of the plume with contaminant concentrations greater that 10,000 <br /> µg11 If groundwater extraction proves to be an ineffective or unfeasible interim <br /> remediation method for this site, an addendum must be submitted to SJCIEHD proposing <br /> an alternative method <br /> ' Donna Heran, RENS, Director . <br /> Enffvi__ronmental Health Department <br /> l,"a <br /> Lon Duncan, Senior REHS Margare agono, Supervising REHS <br /> LOP/Site Mitigation Unit IV LOP/Site Mitigation Unit IV <br /> ' cc ARarty Hartzell, CVRWQCB <br /> ✓Clint Harms, SECOR <br />