SITE INFORMATION AND CORRESPONDENCE

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.rte V INTERNATIONAL.TECHNOLOGY CORPORATION Ms. Mary Meays 2 January 25, 1995 3. _ (paragraph 1; page 2): "Please b aware that for verification sampling of the excavation, soil samples should be collected for analysis every 20 feet and therefore, it may be necessary to collect more than five soil samples as proposed by the plan." RRA 3: The rate of verification sampling has been estimated by IT in our: "Interim Corrective Action Plan," however, if the size of the actual excavation and/or field conditions warrant the collection of additional samples, the appropriate samples will be collected. 4; to 'aph 2; page 2): "It is unclear how the annular space will be filled with an approved bentonite grout mixture. Please submit a permit application completed by a C-57 California contractor, $99 permit fee, and a description of how the vapor well will be sealed." Response 4: The vapor observation point will consist of a slotted PVC screen, laid horizontally across the base of the excavation on a bed of gravel. The horizontal well will be attached to a vertical stand pipe, extended to six inches below grade. The excavation will be backfilled around the vapor observation standpipe. The well head (approximately one foot of standpipe) will be contained in a traffic rated well box. The well box will be cemented into place during resurfacing of the excavated area. The annular space surrounding the well will not.be filled with bentonite but will be sealed only with the envelope of geotextile fabric, the overlying pavement surface and cement at the base of the well box. A permit application, fees, and a description of the well installation procedures and specifications, will be submitted to the PHS/EHD prior to initiation of field activities. 5. Comments 5 (paragraph 3; page 2): '"The plan indicated that the vapor well would be used to monitor volatile petroleum hydrocarbons. As PHS/EHD indicated, the major contaminant does-not readily emit volatile constituents which may be detected" Response 5: The vapor observation point will be utilized to monitor volatile petroleum hydrocarbons (if any) which remain in native soil following overexcavation activities. This monitoring point will be located so as to be incorporated into a future soil remediation system as conditions warrant. It is possible that no detectable volatile petroleum hydrocarbons will be encountered.