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Mr. Nuel Henderson, Jr. , SJCEHD June 27, 2005 Former Apache Plastics Facility, Stockton; CA Project No. 2005-2050-01 Well Installation and Destruction Letter Report Page 4 Analytical Methods Soil and groundwater samples were forwarded to Alpha Analytical, Inc., a California state- certified laboratory (ELAP #2019), for chemical analysis under strict chain-of-custody procedures. Soil and groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHG) using USEPA Method SW8015B DHS/LUFT Manual, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX), methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), di-isopropyl ether (DIPE), tertiary amyl methyl ether (TAME), tertiary butyl alcohol (TBA), 1 ,2-dichloroethane ( 1 ,2-DCA), and 1 ,2-dibromoethane (EDB), using USEPA Method SW8260B . Soil analytical results are presented in Table 1 and groundwater analytical results are presented in Table 2. Certified Analytical Reports with chain-of-custody records are presented in Appendix C. Analytical Results Petroleum hydrocarbons were not detected in any of the soil samples collected from well borings MW- 15 , MW- 16, or MW47. Four groundwater sampling events have been completed using wells MW45 through MW- 18 . TPHG has been reported at maximum concentrations of 90 micrograms per liter (ltg/L) (well MW- 15), 490 µg/L (well MW46), and 450 µg/L (well MW-18). Benzene has been reported at maximum concentrations of 0. 73 µg/L (well MW- 16), 0. 84 ltg/L (well MW- 17), and 19 ltg/L (well MW48). TBA has also been reported in samples collected from wells MW- 16 through MW-18, at concentrations ranging from 13 µg/l, to 110 µg/L. 1 ,2- DCA has been detected in samples collected from each of the newly installed wells, at concentrations ranging from 1 .7 µg/L to 210 µg/L). LIMITATIONS This report was prepared in general accordance with accepted standards of care that existed at the time this work was performed. No other warranty, expressed or implied, is made. Conclusions and recommendations are based on field observations and data obtained from this work and previous investigations. It should be recognized that definition and evaluation of geologic conditions is a difficult and inexact art. Judgments leading to conclusions and recommendations are generally made with an incomplete knowledge of the subsurface conditions present. More extensive studies may be performed to reduce uncertainties. This report is solely for the use and information of our client unless otherwise noted. K:\Apache Plastics\Reportx\Apache-well-install-destruct-letter report.doc