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tfy <br /> UARTERI.Y rvlON1TORING REPORT 1111RD( 11AR'ft10 t't99i <br /> 7910 Lower Sacramento Road,Stockton,California <br /> Shell WIC No.204-752440808 <br /> Della Project No.40 88-147 <br /> rage 2 <br /> nstitUCTILS in <br /> e soil and ground <br /> " Previous work performed by Della includes investigation eorrpetroleum <br /> adlst storage tanks,quarterly water elevation <br /> water at the site,assisting in the replacement of the un & <br /> � measurements, and quarterly sampling of ground water far laboratory analysis. The: previous activities <br /> performed at the site and results obtained are presented in the following reports prepared by Delta: <br /> Date <br /> Re xt <br /> April 19, 1988 <br /> Proposed Work Plan March 31, 1989 <br /> Phase I Hydrogeologic Assessment lirork Plan April 6, 1989 <br /> Tank Closure Report October 20, 1989 <br /> Phase I H;drogeologic Assessment Report October 15, 1990 <br /> Problem Assessment Report December 26, 1990 <br /> Quarterly Monitoring Report, Fourth Quarter 1990 <br /> Quarterly Monitorwrg Report, First Quarter 1991 April , 199119911 <br /> Quarterly Monitoring Report, Second Quarter 1991 July 3, <br /> 3.0 PRO ECC R SUI T5 <br /> 3.1 Ground Water Elevation pata monitoring and MW-3 on August 20,1991. <br /> Depths to ground water were measured atable1. Using ground water elevation data collected during <br /> MW <br /> i. <br /> Ground water elevations are summart m <br /> the August 20, 1991, sampling event, the ground water flow direction was towards the northeast at a <br /> hydraulic gradient of approximately 0.001. A ground water contour map based on measurements collected <br /> on August 20,1991,is illustrated in Figure 3. <br /> 3.2 Ground Water Chemist <br /> Ground water samples were collected from monitoring wells MW-1,MW-2,and MW 3 ,e y lbenzene,anon August d <br /> and were submitted to a California-cestifed laboratory for analysis of benzene,toluene, <br /> Xylenes;(BTEX),and total petroleum hydrocarbons(TPH). Monitoring well locations areshown <br /> s P in <br /> Figure <br /> g re 2. <br /> cted <br /> and the chemic:al.results_are praentt,d in Table 2. Chemical results of the,gr t _- <br /> on August 20, 1991, indicated that BTEX and TPH concentratans were below the analytical met o <br /> ring wells.. Copies of certified laboratory reports are presented in <br /> detection limits in all three monito <br /> Appendix A Ground water samples will again be collected for chemical analysis of BTEX and TPH in <br /> November 1991: <br /> Ell <br /> r f <br />