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Use[l Environmental Site Assessment ,Heritage Square Page 3 L f These sand deposits are estimated to be more than 9,000 years old and are underlain by more than 1,000 F feet of Cenozoic alluvial sediment. The unconsolidated alluvial'sediment rests upon several thousand feet of upper Cretaceous marine sedimentary rock belonging to the Great Valley Sequence. 4.0 FIELD PROCEDURES This section includes a description of the site preparation, groundwater sampling procedures for the abandoned well, and direct push and hand auger boring and g sam lin procedures. P On May 29, June 10, and .lune 11, 2002, Condor representatives were on-site to -collect soil and groundwater samples from an abandoned well, eight direct push borings, and four hand auger borings. The hand auger boring soil samples were collected under the direction of Mr. Harlin Knoll of the EHD. Ur 4.1 SITE PREPARATION The proposed site perimeter was marked with white paint and Underground Services Alert (USA) was notified at least 72 hours in advance of the boring fieldwork to locate and identify underground utilities in and near the work area. However, because the proposed boring locations were on private property, some utilities contacted by USA did not mark their lines past property boundaries. Therefore, it was the Lresponsibility of the property owner to locate and identify underground utilities in and near the work area. EHD was notified of the fieldwork schedule in advance. 4.2 ABANDONED WELL GROUNDWATER SAMPLING PROCEDURES Condor personnel were on site on May 29, 2002 to further investigate the nature of the abandoned well. The investigation included measurement of the depth to groundwater in the well, measurement of the total well depth, and collection of one "grab" sample from the well water surface for laboratory analyses. The location of the wel I is shown ill Figure 3, Appendix A. A weighted line was lowered into the well to ascertain the total depth. The well was measured to be L approximately 322 feet deep. The water level in the well was determined to be approximately 34 feet below ground surface (bgs) by using a depth-to-water meter. One "grab" groundwater sample was collected from the well water surface with a disposable bailer and subsequently transferred to four 40- L milliliter glass vials and one 1-liter glass bottle. The sample containers were labeled, stored in a cooler chilled with Blue lee*, and delivered under chain-of-custody procedures to Argon Laboratories in Ceres, California, for analyses. The samples were analyzed using U.S. EPA and California approved methods. 4.3 DIRECT PUSH AND HAND AUGER BORING PROCEDURES L+ A Condor geologist was on site on June 10 and 11, 2002 to supervise the boring advancement work. Prior to commencement of fieldwork, a tailgate safety meeting was held and a site-specific Health and Safety Plan was discussed with, and presented to, ail field personnel for their signatures. The investigation included the advancement of eight direct push soil borings (B-1 through 13-8) to collect soil and groundwater samples from the vicinity of TK1 and TK2 using a Geoprobe direct push boring If and sampling system, and four hand auger borings (C-1 through C-4) to collect soil samples from below Lthe underground piping beneath the Heritage Square building. The boring locations are shown in Figure 3, Appendix A. Four direct push borings were advanced in the vicinity of TK1 (13-1 through B-4), four direct push borings were advanced along the property boundary adjacent to TK2 (B-5 through 13-8), and I L four hand auger borings were advanced along the segment of underground piping beneath the Heritage Square building (C-1 through C-4). The direct push borings were hydraulically advanced using a 2-inch L i is CONDOR