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' Groundwater Investigation,Monitor Well Destruction and Installation and Interim Remediation u b Gon P mp Test Report Boyett Petroleum,419 S.Main St,Manteca,CA ' January 30,2004 3 3 ' On May 15, 2003, a Condor representative met with SJCEHD representatives to discuss Condor's recommendations presented in the quarterly monitoring reports for the third and fourth quarters of 2002 and the first quarter of 2003, and to address concerns the SJCEHD had regarding the site. In a letter dated May 29, 2003, the SJCEHD directed the submittal of a work plan to install, test, and operate an interim remediation system and a work plan to adequately define the lateral and vertical extent of the contaminant plume at the site. The SJCEHD also agreed with Condor's recommendation to destroy damaged monitoring wells MW-4 and MW-5, and to install a monitoring well to replace MW-4. Condor submitted an Additional Groundwater Investigation Work Plan, dated June 25, 2003, and an Interim Remediation Work Plan, dated June 25, 2003, to the SJCEHD and CRWQCB. The Additional ' Groundwater Investigation Work Plan was prepared to describe proposed groundwater investigation activities to evaluate the lateral and vertical extent of petroleum hydrocarbon contamination in groundwater up-gradient and down-gradient of the UST area using direct push boring methods. The ' Interim Remediation Work Plan addressed the installation of a pump and treat system for interim remediation, including installation of a 4-inch extraction well, and the destruction of MW-4 and MW-5 and the installation of a replacement monitoring well for MW-4. In two letters dated August 25, 2003, ' Mr. Wong of the SJCEHD approved both work plans. Detailed site background information and historic groundwater monitoring data are included in Appendix D. 3.0 ADDITIONAL GROUNDWATER INVESTIGATION ' 3.1 CPT AND DIRECT PUSH BORING FIELD PROCEDURES CE URES ' On October 20 through 23, 2003, Condor conducted a groundwater investigation using direct push boring methods. Condor supervised the completion of four deep CPT boring pairs (CPT-3 through CPT-6) and five shallow hydropunch borings (HP-1 through HP-5). The boring locations are shown in Figure 3, Appendix A. At each deep boring pair location, the first boring was advanced to provide a near- continuous geologic log of the subsurface soil profile. The second boring at each pair location was advanced next to the first boring to collect a discrete groundwater sample from saturated horizons identified in the geologic log from the first boring. Five Hydropunch® borings were advanced to collect ' groundwater grab samples to investigate the lateral extent of contamination in shallow groundwater cross- and down-gradient of the site. ' This section includes a description of the site preparation, direct push boring procedures, and groundwater sample laboratory analyses. The borings were advanced by Gregg In Situ, Inc. of Martinez, California. A detailed presentation of the cone penetration test data and field equipment and procedures is provided in ' Appendix E. 3.2 SITE PREPARATION ' Condor received drilling permits from the SJCEHD and an encroachment permit from the City of Manteca for the proposed CPT and direct push borings prior to initiating any fieldwork. The proposed boring locations were marked with white paint and Underground Service Alert (USA) was notified 72 hours in advance of the fieldwork to locate and identify underground utilities in and neax the work area. Because three of the CPT boring pair locations were on private property, however, some utilities contacted by USA did not mark their lines past property boundaries and on to the site. Condor contracted ! Cruz Brothers Locators (Cruz Brothers) of.Crr.ttc Vallp�, r' +., ,.,,-A,...r_A .« ... a .,�u._. u_.., r..__ __._ ' , ___1 -- ---- • ----J, .. 1 — vv,aµu�.t u11µy,�i VLll1LL U"11Ly 1111k. iui att Vl! and identification services in and near the work area on October 17, 2003. The SJCEHD was notified of the fieldwork schedule 72 hours in advance. ' �1� CONDOR