ARCHIVED REPORTS XR0006030 - Laserfiche WebLink

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l T , L LYmlted Hydrogeolci4c Assessmerd Workplan 1399 E Yosemite Avenue Manteca California Drilling and sod sampling equipment will be either steam cleaned or washed prior to first use, and between borings, to reduce the possibility of cross-contamination Rinsewater will be stored temporarily on site in U S Department of Transportation (DOT)-approved 55-gallon drums, pending laboratory analysis of the boring samples Following receipt of the laboratory results, the rinsewater will be transported from the site to an appropriate disposal facility The selected sod samples will be analyzed for concentrations of a) total petroleum hydrocarbons (TPH), as gasoline, by GC/FID Method 5030, TPH, as diesel, by GC/FID Method 3550, and c), benzene, toluene, ethylbenzene, and total xylenes (BTEX) by EPA Method 8020 In addition, the soil sample from each boring with the highest TPH concentration will be analyzed for total lead by EPA Method 7421 In each boring, a maximum of two samples, one from above and one from below the air-water interface, will be collected for possible analysis of petrophysical properties, including air or water permeability, porosity, and grain-size distribution All drill cuttings will be stored temporarily on site, on and under plastic sheeting, pending laboratory analysis of either the boring samples or additional samples collected from the stockpile that may be required in order to determine proper disposal Following receipt of the laboratory results, the drill cuttings will be transported, by a licensed hauler, from the site to an appropriate disposal facility Groundwater Monitoring Well Installation Sampling, and Surveying , Four-inch-diameter groundwater monitoring wells MW-3A and MW-6 will be installed in each of the locations indicated on Figure 2 A diagram of typical groundwater monitoring well construction details is included as Figure 3 At a minimum, each of the wells will be constructed according to the standards found in the California Code of Regulations, Title 23, Sections 2647 and 2648, and California Department of Water Resources Bulletins 74-81 and 74-90 Water sampling equipment will be either steam cleaned or washed prior to first use Separate sampling equipment will be dedicated to each well to reduce the possibility of cross-contamination The wells will be completed as indicated on Figure 3, with perforated casing extending, where possible, from 5 feet above the highest anticipated level of groundwater to 10 feet into the zone of first water Each of the wells will be capped with a locking wellhead cap and secured by a water-tight, traffic-rated wellhead vault The top-of-casing elevation above mean sea level of each well will be surveyed, using an established bench mark, by a licensed surveyor Depth-to-water measurements in each well will be adjusted to this new datum 10 90-098A WPP 5