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June 29, 2017 | Page A-1 File No. 0504-119-00 <br />APPENDIX A <br />FIELD PROCEDURES <br />General <br />Groundwater was sampled at the Kittitas County Lower Shop site on May 12, 2017, at the monitoring well <br />locations shown on Figure 2. Field methods generally were performed in compliance with the project Work <br />Plan assessment procedures. <br />Groundwater Sampling <br />Groundwater samples from these wells were collected on May 12, 2017. <br />Groundwater Depths <br />Depths to groundwater were measured relative to the north side of the monitoring well casing rims using <br />an electric water-level indicator. The probe of the water-level indicator was decontaminated between wells <br />with a detergent wash, followed by two distilled water rinses. <br />Low-Flow Sampling Procedures <br />Groundwater sampling was performed consistent with the EPA’s low-flow groundwater sampling procedure, <br />as described by EPA (2010) and Puls and Barcelona (1996). Monitoring wells were purged using a <br />peristaltic pump equipped with disposable tubing. During purging activities, water quality parameters, <br />including pH, conductivity, temperature, turbidity, ORP and DO, were measured using a YSI Pro <br />multi-parameter meter equipped with a flow-through cell; measurements were recorded approximately <br />every 3 minutes. The meter calibration was verified at the beginning of each work day consistent with <br />manufacturer recommendations prior to purging and sampling activities. <br />Groundwater samples were collected after: (1) water quality parameters had stabilized; or (2) a maximum <br />purge time of at least 30 minutes was achieved. During purging and sampling, the purge rate was not <br />allowed to exceed 500 milliliters per minute. Water quality parameter stabilization criteria include the <br />following: <br />■ Turbidity: ±10 percent for values greater than 5 NTU; <br />■ DO: ±10 percent for values greater than 0.5 milligrams per liter; <br />■ Conductivity: ±3 percent; <br />■ pH: ±0.1 unit; <br />■ Temperature: ±3 percent; and <br />■ ORP: ±10 millivolts. <br />After groundwater quality stabilization criteria were reached, the pump’s discharge tubing was <br />disconnected from the flow-through cell and groundwater samples were collected for analysis. <br />Each sample was pumped directly into sample containers supplied by the laboratory. A duplicate <br />groundwater sample was collected from well MW-3. Groundwater samples collected for chemical analysis