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A Mr. Terry Lau -2- 29 June 1995 4. Page 4-7 describes MW development by bailing only. Well development is usually accomplished by surging the well with a surge block, or by pumping,jetting, etc. Bailing does not provide the surging action that is needed to remove fines in the filter pack or screen. Therefore, surging or pumping should be used to develop the MWs. 5. Page 4-9 of the work plan proposes to analyze soil samples for total lead using USEPA Method 7420 and compare the results with published data for naturally-occurring lead in California soils. Comparison of sample results with published data is unacceptable. Instead, the remedial investigation (RI) must include a water quality assessment to evaluate impacts and potential impacts of soil contaminants on ground water. A demonstration must be made to the satisfaction of the Board that any potential leaching from contaminants remaining in soil does not pose a threat to ground water quality. Contaminant concentrations found above background levels in soil could pose a threat to water quality. Potentially-contaminated site soils must be compared to background soil to evaluate if a potential threat to water quality exists. Data obtained from performing the Waste Extraction Test(WET) using de-ionized water can be used to evaluate site- specific threats to water quality using the Designated Level Methodology or some other methods such as Sesoil. The RI work plan must be modified to acknowledge that a water quality assessment will be conducted to evaluate potential impacts of soil contaminants on ground water. Enclosure 2 is a copy of our 5 November 1992 Draft Water Quality Assessment document which describes how this assessment must be conducted. 6. The ground water sample for total lead described on Page 4-10 should be filtered and compared with the background total lead in ground water from filtered samples. 7. Page 4-10 of the work plan proposes to dispose of purge water onsite if constituent concentrations in the water are below the maximum contaminant levels (MCLS). The presence of organic chemicals, which are not naturally occurring, in ground water is an indication of pollution. Therefore, the discharge of such water is a waste discharge. The Porter-Cologne Water Quality Control Act requires any person to file a report of waste discharge (RWD) with the Board prior to the discharge of waste. Therefore, if you wish to discharge purge water onsite you must file an RWD with the Board. The discharge will be allowed under General Order No. 91-25000 which prescribes waste discharge requirements for the land disposal of treated ground water from the investigation and cleanup of ground water polluted with petroleum fuels. Enclosure 3 is a copy of General Order No. 91-25000 with the application requirements attached. Although the Board can allow onsite discharge of purge water from this investigation, the Navy should consider discharging to the City of Stockton wastewater treatment plant as this may be a more cost-effective and efficient disposal option. 8. Table 2 on Page 4-11 shows the analytical methods and target detection limits for soil and ground water analyses. The target detection limits for all soil analyses and total petroleum hydrocarbons as diesel and gasoline and BTEX for ground water are acceptable. The detection limits for total lead, volatile organic compounds (VOCs), and polychlorinated biphenyls (PCBs) in ground water are too high. Total lead should be analyzed using atomic adsorption instead of inductively coupled plasma to get a lower detection limit. The Board's contract labs are able to achieve a