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aC" MW <br /> Wim' _ :ice r l F13 '`' `+° f�5-%. •moi d K ,' uxa��M <br /> r - <br /> fi <br /> ti ��affiR � `� - <br /> T" Y� <br /> 3 w <br /> � rvrk <br /> .. s <br /> ROME MOME'd <br /> Fig 2 <br /> 7 <br /> If hydrocarbon odors or signs of hydrocarbon are detected in a <br /> soil sample, selected soil samples will be ahalyzed For benzene, <br /> toluene xylene+ Y (BTX) by U.S. Environmental Protection Agency (EPA) <br /> Method 8020, total petroleum fuel hydrocarbons (modified EPA 8015) , <br /> tt and total lead. The samples will be delivered to SC's analytical <br /> f laboratory in Emeryville within 48 hours of collection. <br /> e Groundwater Monitoring Wells <br /> During monitoring well installation, development, and sampling, <br /> the following, procedures will be used. These methods will ensure the <br /> proper identification of groundwater quality beneath the site. <br /> Groundwater Monitorin Well Installation. At least three <br /> groundwater monitoring wells will be installed. A total of three <br /> groundwater monitoring wells is required to determine groundwater <br /> gradient and flow direction. <br /> i <br /> The wells will be completed with 2-inch-diameter polyvinyl <br /> chloride (FVC) flush-threaded casing and will be screened with <br /> 0.020-inch slotted casing from 10 feet below the groundwater surface <br /> to 2 feet above the groundwater surface. Blank casing will extend <br /> from the top of the perforated section to <br /> ground surface. Actual <br /> depths of the boreholes and screened intervals will depend on the <br /> conditions encountered during drilling. <br /> The wells will be <br /> the screen to approximately <br /> with No. 20/40 sand from the bottom of <br /> pproximately 2 feet above. the top of the screen. A <br /> 2-foot seal of bentonite pellets will be placed on the top of the <br /> sand pack. The wells will berouted <br /> 9 with bentonite-cement slurry or <br /> YJ neat cement from the top of the bentonite seal to the surface. The <br /> wells will be completed below grade, fitted with tap and bottom PVC } <br /> s' 11 caps, and have water-tight locking covers installed. Typical <br /> construction is illustrated on Figure 1. YP-cal well <br /> - <br /> The monftozing wells will not be completed opposite significant <br /> clay zones nir will monitoring wells penetrate significant clay zones <br /> that might allow for downward migration of contamination into lower <br /> aquifers. <br /> � i <br /> Well Devel <br /> w -Development and Groundwater Samples. Each well installed <br /> ' ill be developed by surging and bailing until clean, sediment-free <br /> s water is produced from the well. . The length of development time <br /> will vary depending upon field conditions. Water produced during <br /> y <br /> development .and sampling will be contained on site. ARCO will be <br /> ` <br /> responsible for the disposal of water and pr-9uct collected. -- <br /> to--and following development, the thickness of free product, if any, <br /> will be <br /> gauged <br /> >>a Following Proper development of each well; a nitro en-dr' <br /> bladder uiii 9 zven <br /> P P. stainless steel bailer, or teflon bailer will be used <br /> x <br /> 1 <br />