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1 <br />The techniques available for obtaining soil -pore liquid have been <br />evaluated with consideration of standard chemical analytical proce- <br />dures. Based on this evaluation the following analytical plan is <br />proposed to satisfy the requirements of Section 13273 of the Califor- <br />nia Water Code. This plan recognizes the following: <br />• Man-made compounds are unambiguous indicators of site <br />leakage, whereas naturally occurring compounds are not <br />necessarily unambiguous indicators. <br />• Some of the most mobile contaminants are man-made. <br />Both laboratory and field techniques for extracting <br />soil -pore liquid alter the distribution of certain chemi- <br />cal parameters. <br />• The volume of liquid that can be extracted from soils <br />using either laboratory or field techniques will often be <br />insufficient to perform chemical analyses that achieve <br />generally accepted detection limits. <br />Analysis of a soil sample with its soil -pore liquid for <br />man-made compounds provides a more conservative determi- <br />nation of potential site leakage than analysis of only the <br />soil -pore liquid. <br />In view of these considerations, EMCON proposes to obtain soil samples <br />from the unsaturated zone to be analyzed in total for the following <br />man-made compounds: <br />• Volatile organic compounds using EPA Method 8240 <br />• Semivolatile organic compounds using EPA Method 8270 <br />• Chlorinated pesticides and PCBs using EPA Method 8080 <br />Procedures and techniques for sample collection, preservation, and <br />shipment, chain -of -custody control, and chemical analyses are present- <br />ed in Appendix B. <br />15 <br />Emcon Associates <br />