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Mr. James C. Stevens October 13, 1997 Page 2 Prior to sampling, each well was purged of a minimum of three well volumes of water or until the well was dry and allowed to recharge. On-site measurements of electric conductivity, pH, and temperature were recorded to ensure that the well stabilized so that a representative sample of the aquifer was collected. Copies of the field activity forms are attached. The bailer used to develop the wells was decontaminated with aphosphate-free detergent and distilled water between each well. Samples were collected with a Teflon disposable bailer and placed on iced until delivery to the laboratory for analyses. The samples analyzed for phenols, odor, radiochemistry, cyanide, foaming agents, metals, nitrates, nitrites, fluoride, alkalinity, chloride, color, total dissolved solids (TDS), sulfides, and pH were filtered in the field (.45 microns). Chain-of-custody forms accompanied the samples throughout the shipment and are included with the attached analytical report. Laboratory results indicate that samples obtained from wells MW1 and MWS were below detection limits for pesticides, PCBs, herbicides, semi-volatile organics, and volatile organics. Concentrations of herbicides, pesticides and PCBs were detected in the groundwater sample obtained from monitoring well MW4. No state groundwater standard is available for alpha-BHC. The 2,4-D concentration of 1.5 µg/L is below the Colorado Department of Health Basic Standards for Groundwater of 70 µg/L. However, the Aldrin concentration of 0.030 µg/L was above the State Standazd of 0.002 µg/L. This sample is being re-run by the laboratory. If the concentrations substantially decrease, the laboratory report will be submitted under separate cover. Total dissolved solids (TDS) were within [he acceptable range for groundwater. The remaining analytes, identified in the Human Health Standards and Secondary Drinking Water Standards tables with The Basic Standards for Ground water either were below the method detection limits or below the respective standards with the exception of barium and fluoride. Barium and fluoride concentrations were slightly above the Human Health Standard- spirt wells Ivf~#T, MW4, and MWS. MW 1 is located upgradient from the landfill. Therefore, the barium and fluoride concentrations may be naturally occurring as a result of local lithologies. Analytical results for the Human Health Standards and Secondary Drinking Water Standards are summarized in Tables 2 and 3, respectively. Copies of the laboratory report and chain-of-custody form are attached. 070297nm.ly\484\10/13/97 t