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While groundwater samples from developed wells MW-1 and MW-3 were free of TPH-D and HVOs, TPH-G and BTEX were present. The similar concentrations of these contaminants ( 780-910 ppb TPH-G and 6 . 8-8.2 ppb benzene) may indicate a uniform distribution of these contaminants across much of the site. No contaminants were detected in the groundwater sample from MW-2 . Given the high concentrations of TPH-G and TPH-D detected in soil within borings EB-8 and EB-11 , and in consideration of ' the porosities of sands encountered at the site ( see Appendix A- soil boring logs ) , Uriah proposes the following: 1 ) The installation of two additional soil borings at the locations specified in Figure 2. These will be installed and sampled in the same manner as previous borings . 2 ) On-site testing of soil vapor extraction (SVE) tech- nology, the probable remediation technology of choice. An overview of SVE technology is presented below. Soil Vapor Extraction and Bioventing Technology Overview Soil Vapor Extraction ( SVE) of organic contaminants in vadose soils is a process that embraces the principle that many anthro- pogenic organic hydrocarbons, including those which comprise gasoline, will volatilize at ambient soil temperatures. Upon partitioning from the liquid to the gaseous phase, these ' contaminants will enter the pore spaces between soil particles until an equilibrium is achieved. This partitioning is described by Raoult ' s Law. Partitioning into the vapor phase is determined by the volatility of a contaminant, its solubility in water, ' and the degree to which it will adsorb to soil and other particulate matter. Henry ' s Law and vapor pressure are used to determine appropriate volatility for SVE. Henry ' s Law constants above 0 .01 (dimensionless ) tend to move from aqueous to gaseous phase. Contaminants with vapor pressures greater than 25 mm/Hg are generally considered as good candidates for SVE, with vapor pressures as low as 1 mm/Hg acceptable. The vapor pressure of gasoline is between 37 and 260 mm/Hg depending upon the degree of weathering (degradation) . The solubility of gasoline is appropriate to SVE parameters and, while gasoline may adsorb onto soil and other (organic) particles within the soil matrix, sorption is generally not 1 so strong as to preclude efficient SVE remediation. In fact, 2-5% water vapor is considered necessary to avoid drying of the soil which would lead to a reduction in contaminant vapor extraction efficiency. 8.