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DocuSign Envelope ID: 109A31 BO-29AD-4F2B-8257-8D55D4FF0808 <br /> Proposal for RI—Waste Characterization,Groundwater and Landfill Gas Monitoring <br /> ANNO•. Hillsborough Dump <br /> Z <br /> ID No. NONCDO000483 <br /> Task Orders 483DP-13 and 14 <br /> S&ME Project No.4305-17-061 E <br /> • Volatile organic compounds(VOCs) by EPA Method 8260 <br /> • 1,4-Dioxane by Method 8260SIM <br /> ■ Semi-volatile organic compounds(SVOCs) by Method 8270; <br /> • Metals by totals analysis(antimony,arsenic, beryllium,cadmium,chromium, copper,iron, lead, <br /> manganese, mercury, nickel,selenium,silver,thallium, and zinc) by Methods 6020 and 7471; <br /> • Ammonia by Method 350.1 or 9050; <br /> • Sulfate by Method 300 or 9056;and <br /> • Nitrate by Method 300, 9056, or 353.2. <br /> Subtask G Groundwater Sampling <br /> At five existing groundwater monitor wells(MW-2,3,4,6,and 7), S&ME will gauge depths to water and collect <br /> groundwater samples for analysis by a North Carolina certified laboratory using the most current USEPA Contract <br /> Laboratory Program Target Compound list for: <br /> ■ Volatile organic compounds(VOCs)by EPA Method 8260 <br /> ■ 1,4-Dioxane by Method 8260SIM <br /> ■ Semi-volatile organic compounds(SVOCs) by Method 8270; <br /> • Metals by totals analysis(antimony, arsenic,beryllium, cadmium,chromium,copper,iron, lead, <br /> manganese, mercury, nickel,selenium,silver,thallium, and zinc)by Methods 6020 and 7470; <br /> • Ammonia by Method 350.1 or 9050; <br /> • Sulfate by Method 300 or 9056; and <br /> • Nitrate by Method 300,9056,or 353.2. <br /> Subtask D Landfall Gas Monitoring <br /> Gas probe Installations <br /> Six permanent gas probes(GP-1 through GP-6) are proposed to be installed at the approximate locations shown <br /> on Attachment II. Gas probe locations were provided by the County based on guidance they received from the <br /> Unit. The gas probes will be installed as follows: <br /> A decontaminated 3 '/4"or 41/4"diameter auger will be extended with a Geoprobe unit up to eleven feet bgs.The <br /> bottom of the PVC well screen will be installed at least two feet or more above the estimated groundwater <br /> table elevation. If the estimated groundwater table is expected to be less than 13 ft.bgs, adjustments to the <br /> length of well screen will be made. {If the depth to the estimated groundwater is too shallow to allow at least <br /> a five-foot distance between the bottom of the bentonite seal and the top of the ground surface, a gas probe <br /> will not be installed. The Unit Project Manager will be contacted in this case and a Flux Chamber may be <br /> installed (if requested) instead of a gas probe. <br /> A one to five-foot long 1-inch diameter,0.010-inch slot screen with 1-inch diameter PVC well casing will be placed <br /> into the open boring. <br /> January 16, 2020 3 <br />