ARCHIVED REPORTS XR0012562 - Laserfiche WebLink

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rM; ti 1 01 ON Mr. David Heinrich November 10, 196F, Page Following the initial soil sampling, the immediate area beneath pump two was excavated to a depth of 15 feet and five represent- ative samples (A-E) were taken from the sides and bottom of the pit. rhe results of this soil sampling are presented in Table 1 and Appendix I. In order to further define the vertical and lateral extent of hydrocarbon constituents in soil and determine if groundwater was impacted at the site, the following work steps are recommended: - Fill the existing excavation to grade with imported clean soil in order to continue construction of the Food mart building on site. - Install slotted PVC pipe beneath the foundation Of the proposed food mart in the event that p. soil vent system is needed in the future (Figure 3) . The slotted pipe would be used to abate hydrocarbon vapors if the building becomes impacted. Vapors would be evacuated from beneath the building through the pipe via a high vacuum blower. The evacuated vapors would be treated If necessary to meet acceptable air quality levels, - Drill and sample three soil borings in the vicinity Of the remo,.,d product dispensers to define the areal and vertical extent of adsorbed hydrocarbons (Figure 4) . The borings word be terminated 10 feet below the last hydrocarbon impacted sample, using field inspection methods to indicate levels of contamination. - Drill three borings and install monitoring wells around the pump island canopy (Figure 4) . The borings would be drilled fifteen feet b�lcw where groundwater is encountered (approximately 30 feet) . ' Eaih well would be constructed with 4-inch diameter, .020,.inch machine slotted PVC well screen and 4-Inch diameter blank PVC casing. A well pack consisting Of No. 2 Monterey sand would be placed in the annulus between the borehole and the well screen from the bottom of the borehole to approximately 1 foot above the screened interval in each well. The completed wells would have a two foot bentonite seal and cement or concrete seal to the surface. A traffic-rated street box and locking well cap would be installed for access to each well. Well construction details are shown in Appendix II.