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NAVCOMSTA 2 19 August 1992 <br /> 2. At the present time 10 shallow monitoring wells and 3 intermediate depth wells <br /> have been installed in this area. High levels of trichloroethane (up to 7,400 <br /> ppb) and methylene chloride (up to 6,000 ppb) have been found in the shallow <br /> ground water in this area. High levels of PCB's, pesticides and diesel <br /> contamination have been found in the soils and high levels of metal <br /> contamination are found in the soils and sludge associated with the Waste Water <br /> Treatment Plant also located in this area. <br /> 3. PRC proposes to install an additional 15 shallow and 9 intermediate depth <br /> monitoring wells adjacent to areas previously identified as posing a threat to <br /> the environment (i .e. disposal trenches, landfill areas, waste water treatment <br /> plant, burn areas, railroad yard, pesticide storage and oiled dirt road) . <br /> 4. Of major concern in the Landfill Area is migration of contaminants into the <br /> surface waters i .e Burns Cutoff. Additional monitoring should be utilized to <br /> evaluate this condition. It is recommended that the following be performed; (1) <br /> utilize existing staff gauges and tie into ground water level measurements to <br /> demonstrate hydraulic gradients onto and off the island i .e. tidal fluctuations <br /> and (2) collect ground water samples from the existing piezometers located <br /> along the edge of the island between source areas and Burns Cut Off, and (3) <br /> sample storm water runoff at the drainage into Burns Cut Off. <br /> 5. Since IAS-8 is reported to have been the location for disposal of radioactive <br /> clothing, in addition to the priority pollutant scan proposed for sample <br /> analysis in this area it will be necessary to analyze ground water in the <br /> clothing disposal pit area for gross alpha and gross beta particles per EPA <br /> Method 9310. <br /> 6. PRC plans to collect soil samples at various locations relative to the trench <br /> and landfill sites in this area. These hand samples are proposed to be taken <br /> from 0.5- to 1.0 foot depths. Soil samples taken at this depth would <br /> presumably, represent soils used as final cover of the particular landfill <br /> structure and would not be representative or diagnostic of the materials <br /> contributing to the pollution problems. Additional soil samples are proposed <br /> for collection during the CPT sounding, however, the locations for CPT <br /> soundings are not yet specified. I am concerned that samples are not being <br /> collected from the materials which are actually causing the contamination <br /> problems. Samples should be taken from the landfill materials themselves for <br /> evaluation nf future r1panun requirements_ The CPT sampling plan including <br /> locations need to be submitted. <br /> 7. The California Code of Regulations, Title 23, Division 3, Chapter 15 govern <br /> discharges of waste to land (i .e. landfills) . Article 5 prescribes <br /> methodologies for establishing cleanup standards and undertaking corrective <br /> actions. <br /> Administrative Area <br /> 1 . Formerly the Battery Acid Disposal Area, where three monitoring wells are <br /> stated to have been destroyed. These wells should be located and abandoned per <br /> San Joaquin County Ordinance and Department of Water Resources Bulletin 74-81 . <br /> 2. The additional monitoring wells proposed to be installed adjacent to the Shell <br /> and BP Bulk Fuel Facilities may not be necessary at this time. It is our <br />