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1� <br /> Environmental <br /> r Mr Harlin Knoll Resources <br /> 4 November 1998 Management <br /> Page 3 <br /> could be used to document the vertical depth of chemical impact in soil <br /> and ground water downgradient of the former tank locations Mr Knoll <br /> also suggested that the ground water samples collected from the new <br /> monitoring well be sampled for oxygenated compounds including <br /> tertiary butyl alcohol, MTBE, di-isopropyl alcohol, ethyl tertiary butyl <br /> ether, and tertiary amyl methyl ether using EPA Method 8260 <br /> PROPOSED SCOPE OF ADDITIONAL WORK <br /> Based on the letter from the County (19 October 1998), ERM proposes to <br /> install one monitoring well at a location approximately 10 feet <br /> downgradient of each of the two former UST locations and at a location <br /> upgradient of each of the two former UST locations The proposed <br /> locations of the monitoring wells for UST #1 (MW-3 and MW-4) are <br /> shown on Figure 2 The proposed locations of the monitoring wells for <br /> UST#2 (MW-5 and MW-6) are shown on Figure 3 As shown, the <br />. downgradient wells (MW-4 and MW-6) will be located outside of the <br /> areas excavated around each tank during UST removal activities <br /> Each of the proposed monitoring wells will be constructed of 2-inch PVC <br /> and screened from a depth of approximately five to ten feet bgs The <br /> wells will be constructed in accordance with applicable regulations Soil <br /> samples will be collected during the installation of each well for <br /> lithologic interpretation according to the uniform soil classification <br /> system In addition, a soil sample will be collected at the bottom of each <br /> of the downgradient wells (MW-4 and MW-6) to determine the depth of <br /> chenucal impact to soils downgradient of the tanks These two soil <br /> samples will be analyzed for TPH-g (EPA Method 8015M) and BTEX <br /> compounds (EPA Method 8020) <br /> Following the installation and development of the wells, ground water <br /> samples will be collected from each well In accordance with County <br /> recommendations, each of the samples will be analyzed for TPH-g, BTEX <br /> compounds, and oxygenated compounds (EPA Method 8260) During <br /> the initial sampling of the new monitoring wells, ground water samples <br /> will also be collected from pre-existing monitoring wells MW-1 and <br />. MW-2 and analyzed for the same compound list present above <br /> A second round of ground water samples will be collected from all wells <br /> at the site one month after the initial sampling event The samples will <br /> be analyzed for the same compounds last above However, if no <br /> oxygenated compounds are detected in the first round of ground water <br />