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Soil Remediation Plan <br />Thornton, California <br />July 22, 1992 <br />Page 2 <br />On November 1, 1990, RESNA Industries/WaterWork Corp. (RESNA) personnel advanced <br />three soil borings (MW1, MW2, MW3) to depths ranging from 27 to 28 feet below grade to <br />characterize subsurface conditions at the site. These borings were subsequently converted to <br />groundwater monitoring wells. The boring/well locations are plotted in Figure 2. <br />On October 28, 1991, RESNA personnel advanced three additional soil borings (MW4, MWS, <br />MW6) to depths ranging from 27 to 30 feet below grade at the project site to further define the <br />lateral and vertical extent of the petroleum hydrocarbon soil and groundwater contamination. <br />The borings were subsequently converted to groundwater monitoring wells (Figure 2). <br />Field observations and laboratory analysis indicates soil and groundwater impaction by petroleum <br />hydrocarbons is limited to a relatively small area in the vicinity of the former tanks. However, <br />site conditions suggest that an additional off-site contaminant source may exist northeast of the <br />site near MW4. <br />A detailed discussion of field activities conducted to date and analytical results are included in <br />RESNA's January 13, 1992 Interim Problem Assessment Report. <br />In correspondence dated, May 27, 1992, San Joaquin County Public Health Services, <br />Environmental Health Division (PHS/EHD) requested further work be done to address <br />documented residual soil contamination. <br />To reduce the continued threat to groundwater posed by the contaminated soil remaining in place <br />near the location of the former tanks, it is proposed that approximately 200 cubic yards of <br />hydrocarbon impacted soil will be excavated and subsequently remediated. <br />GPLR0792.TJL <br />