Laserfiche WebLink
i <br /> P&I <br /> Stork Plan for Re-excavation May 3, 1989 <br /> Former Texaco Service Station, Manteca, California AGS 38053-1 <br /> r„ <br /> concentration of 580 ppm and total lead at a concentration of <br /> 29.5 ppm. <br /> At your request, a geologist from Applied GeoSystems visited the <br /> site on October 24 and 25, 1988, to observe drilling of three <br /> soil borings and installation of monitoring wells in the borings, <br /> collect soil samples, and evaluate the soil for subjective <br /> evidence of contamination. Subjective evidence of contamination <br /> was present in soil samples collected from the boring located <br /> north of the former product-storage tanks. The results of <br /> laborat-ory analyses of soil samples collected from the <br /> unsaturated zone in this boring indicate that contaminants are <br /> present at relatively low levels (23 and 29 ppm TPH as gasoline) . <br /> No subjective evidencp of soil contamination was present in the <br /> boring located on the southern edge adjacent to the former tank <br /> cavity. <br /> In October 1988, a geologist from Applied GeoSystems developed <br /> wells and collected ground-water samples for laboratory analyses. <br /> Analysis of ground water from each monitoring well showed <br /> concentrations of gasoline below laboratory detection limits or <br /> at relatively low levels. TPH concentrations were below <br /> detection limits in MW-1, detected at. 0.29 ppm in MW-2, and <br /> detected at 0.08 in MW-3. Laboratory analyses of samples from <br /> monitoring wells MW-2 and MW-3 showed concentrations of benzene <br /> in excess of the action level for benzene in drinking water <br /> recommended by the California Department of Health Services <br /> (0.0007-ppm) . <br /> This Work Plan presents a series of tasks selected to remove the <br /> hydrocarbon-contaminated soil from the subsurface and <br /> characterize the removed soil for appropriate treatment or <br /> disposal. specific..tasks;associatedwith the proposed work <br /> include: 1) removing the :undeirground:product-delivery lines ,and: <br /> collecting soil samples .€rom native soil beneath the former.' <br /> 1oeatzoris-of the lines;` 2)""excavating the initial tank cavity to <br /> the ground-water surface at approximately 23 feet below grade and <br /> possibly excavating beneath the removed underground product-- <br /> delivery lines; and 3) characterizing the excavated soil for <br /> subsequent treatment. If subjective evidence of soil <br /> contamination exists to the north, this soil should also be <br /> removed. A sanitary sewer line is present at the eastern edge of <br /> the former tank location, and the station building is adjacent to <br /> the western edge of the former tank location. The presence of <br /> the sewer line precludes excavating to the east, and the site <br /> building would have to be demolished to excavate to the west. <br /> Monitoring well 2W-3 is located south of the former tank cavity, <br /> APP/led Ge0SYSteMS <br />