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ARCADIS Mr. Perry Myers <br /> 11 July 2008 <br /> Analytical Program <br /> Groundwater samples will be analyzed for dissolved lead by EPA Method 6020 series, <br /> which has a reporting limit(RL)of 1 microgram/liter(pg/L). The Groundwater samples <br /> will be collected in two non-preserved 500-milliliter poly containers. The samples will <br /> be labeled, placed on ice and delivered under chain of custody protocol to Curtis & <br /> Tompkins (C&T), Ltd. of Berkeley, California. Samples will be filtered in the laboratory <br /> with a 0.45 micron filter and with a 0.10 micron filter. Both samples will be analyzed for <br /> lead. Samples will be analyzed on a 24 hour turnaround time(TAT). <br /> Monitoring Wells <br /> Because the grab groundwater samples collected from the temporary wells may be <br /> high in silt content, the analytical results may indicate erroneous elevated <br /> concentrations of dissolved lead. The elevated concentrations would likely be a result <br /> of the silt and not dissolved lead in groundwater. If elevated concentrations are <br /> detected, then a permanent monitoring well will be installed on the southwestern side <br /> of OU-4 as shown on Figure 1. <br /> The well will be installed in an 8-inch diameter borehole reamed with a hollow-stem <br /> auger drill rig. Soil samples will be collected at five-foot intervals with a California- <br /> Modified split spoon sampler. A field geologist, under the supervision of a California <br /> Professional Geologist, will record the lithology of the subsurface strata in accordance <br /> with the Unified Soil Classification System (USCS). <br /> The well will be installed to a depth of approximately 25 feet bgs, with polyvinyl <br /> chloride(PVC)blank and up to 20 feet 0.010 PVC slotted screen. The depth and <br /> amount of screen will be based on lithology encountered during drilling. A sand filter <br /> pack (#1/20)will be placed from bottom of the borehole to approximately 2 feet above <br /> the top of the screen. An approximate 2-foot bentonite seal will be placed above the <br /> filter pack.After the bentonite seal has set for approximately 30 minutes, the <br /> remaining annular space will be backfilled with neat cement. The well will be <br /> completed with a stove pipe stick-up until the City of Tracy completes construction of <br /> the multimodal facility. Following construction, the well will be completed with a traffic- <br /> rated flush-mounted well box, if required by the City. <br /> A minimum of 72 hours after installation, the new monitoring well will be developed <br /> using a bailer, surge block, and pump combination to remove entrained fine particles. <br /> Approximately ten casing volumes of groundwater will be purged from the well prior to <br /> groundwater monitoring. Temperature, pH, specific conductivity, and turbidity will be <br /> measured during development. The wells will be considered developed when <br /> groundwater parameter measurements vary±10 percent or less. <br /> The well will be sampled using low-flow sampling techniques. The sample will be <br /> analyzed for dissolved lead by EPA Method 6020, which has a reporting limit(RL)of 1 <br /> Page: <br /> cv�«r.-klweWPRMT­yFamenmy,MvcnwpMs�Yknne VGwProbawUPRtteay CALenaroorscRcpG+ecw!r,*s daft_ V opl.dc 2/3 <br />