Laserfiche WebLink
M. Scott Mansholt - 6 - 11 March 2008 <br /> TAOC Tracy Gravel Pits <br /> Low concentrations of metals reported in the soil samples obtained next to the rail spur, <br /> indicated the results are within the range(s) expected for naturally occurring background <br /> values. <br /> The lateral extent of affected soil has not been defined in the northwest and southeast ends of <br /> the gravel pit excavation and the area north of the adjacent residence in the southeast corner <br /> of the site; additional characterization is needed. <br /> Currently, Chevron and UPRR are evaluating alternative reuse options for the site and <br /> considering a human health risk assessment in the future after reuse options are evaluated. <br /> CONCLUSIONS <br /> Affected groundwater is limited in extent and appears to be generally delineated onsite; the <br /> offsite downgradient sampling results were ND for TPH compounds. <br /> Based on the review, I concur that the investigative trench findings supports earlier results and <br /> provides better definition for the areas of affected soil. The southwest portion of the site, <br /> south of the gravel excavation has been adequately delineated and additional investigations <br /> are not needed for this portion of the site. <br /> Additional trench excavations are needed at the northwest and southeast ends of the gravel <br /> excavation to define the lateral extent of affected soil and to determine if it extends to adjacent <br /> offsite properties. Similarly, exploration trenches are needed in the southeast corner of the <br /> site, north of the adjacent residence to evaluate the lateral extent of impacted soil at that <br /> location and to determine if it extends offsite to adjacent properties. <br /> C DH/R\ChevOVP\GravlpitsrpVMar08 <br />