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Mr.Nuel Henderson,P.G., SJCEHD September 21,2005 <br /> ARCO Station 6100,Tracy,California Project No.U6100-15-1 <br /> Additional Site Assessment Work Plan <br /> Page 10 <br /> the top of the bentonite seal to surface grade. A watertight locking cap will be installed <br /> over the top of the well casing and a traffic rated vault box will be mounted over the well. <br /> Well Development and Sampling <br /> Newly installed monitoring wells MW-16 through MW-20 will be allowed to stand a <br /> minimum of 72 hours after installation. Stratus personnel will develop wells MW-16 <br /> through MW-20 by surging and bailing, followed by groundwater pumping. Prior to <br /> development, Stratus will utilize an interface probe to monitor for the presence of free <br /> product. In the event that free product is detected, groundwater pumping will not be <br /> completed on the impacted well. Development will continue, to the extent practical, until <br /> the development water runs clean and pH and conductivity measurements stabilize. After <br /> well development and stabilization of the water levels, water levels and the quantity of well <br /> volumes removed from the well will be recorded. <br /> A minimum of 48 hours after the monitoring wells are developed, the newly installed wells <br /> will be purged and a groundwater sample will be collected. Samples will be collected <br /> using a disposable bailer, transferred to laboratory supplied glass vials, and placed in an <br /> ice-chilled cooler. Samples will be forwarded to a California state-certified analytical <br /> laboratory for chemical analysis. Strict chain-of-custody procedures will be followed from <br /> the time the sample is collected until the time the sample is relinquished to the laboratory. <br /> Waste Management <br /> Drilling mud, soil cuttings, and decontamination wastewater will be placed in roll-off steel <br /> bins and stored at the site pending disposal. A sample of the soil cuttings will be <br /> chemically analyzed to determine an appropriate storage facility. Dillard Trucking <br /> Company of Byron, California, will transport material stored in the soil bins to an <br /> appropriate facility for disposal. Stratus personnel will transport well purge water to a <br /> licensed facility for disposal. <br /> Surveying <br /> A California-licensed land surveyor will be retained to survey the location and elevation of <br /> each newly completed soil boring and monitoring well. The elevation of the top of each <br /> well casing will be surveyed to the nearest 0.01 vertical feet and tied to the previous survey <br /> completed at the site. Well survey data will be forwarded to the State Water Resources <br /> Control Board as required by Senate Bill AB2886 (Geotracker). <br /> Task 3: LABORATORY ANALYSIS <br /> Soil and groundwater samples will be forwarded to a state-certified analytical laboratory <br /> for chemical analysis. The samples will be analyzed for GRO using USEPA Method <br /> KABp-Arco for URS\6100\Work PlansWco610o-workplan 09-2005.doc <br />