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' Environmental <br /> Mr Harlin Knoll Resources <br /> 21 February 2001 Management <br /> Page 2 <br /> ERM installed the new wells (MW-7 and MW-8) on 19 September 2000 <br />' Following installation, the monitoring wells were developed on 21 <br /> September 2000 and ground water sampling was conducted from all site <br /> wells in October 2000 The results of the monitoring well installation, <br /> development, and sampling activities were presented in a letter to the <br /> County dated 9 November 2000 The results of the second round of <br />' ground water sampling (as specified in the workplan) are presented <br /> below <br /> January 2000 Monitoring Well Sampling <br /> Water level measurements and ground water samples were collected <br /> ifrom eight monitoring wells on 9 January 2001 In accordance with the <br /> workplan, the ground water samples were analyzed for total petroleum <br /> hydrocarbons as gasoline (TPH-g) (United States Environmental <br /> Protection Agency [USEPA] Method 8015), and benzene, toluene, <br /> ethylbenzene, and xylenes (BTEX) (USEPA Method 8020) Analytical <br /> results for ground water for the current and previous sampling events <br /> are summarized in Tables 1 and 2 Ground water elevation <br /> measurements taken during the sampling event are included in Table 3 <br />' Copies of the well sampling records and laboratory analytical results are <br /> included as Attachments A and B, respectively <br />' The ground water sampling results are summarized below <br />' Former Tank 1 Location <br /> The results of ground water samples collected at former tank 1 are <br />' presented in Table 1 As shown, the concentrations of compounds <br /> detected in the shallow wells during the current sampling event were at <br /> or near the lowest concentrations ever detected in these wells At MW-3 <br />' (located upgradient of the former tank location), no detectable <br /> concentrations of chemicals were reported At MW-1 and MW-4 (located <br /> I downgradient of the former tank location), TPH-g and BTEX were <br /> detected at or near the lowest concentrations ever detected at these <br /> locations The decrease in concentrations at the wells appears to indicate <br /> that natural attenuation continues to decrease the chemical <br /> concentrations at this location <br /> In the dee - <br /> p well (MW-7), no detectable concentrations of TPH g or BTEX <br /> were present During the previous sampling event, conducted <br /> Iimmediately following monitoring well installation, TPH-g and xylenes <br />