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GROUNDWATER MONITORING AND SAMPLING PROCEDURES <br /> Groundwater Depth Measurements <br /> Groundwater depth measurements were obtained at each groundwater monitoring well using a Heron TM <br /> water level indicator Groundwater depth measurements were recorded from the surveyed mark that is <br /> typically on the north side of the top of the uncapped PVC well casing Measurements were recorded to <br /> the nearest 0 01-foot by the technician on a field data sheet along with the measurement time The <br /> groundwater elevation in each well was calculated by subtracting the measured depth to groundwater <br /> from the surveyed wellhead elevation established at the designated measuring point on the top of the <br /> each PVC monitoring well casing <br /> The water level indicator was decontaminated prior to arrival at the site and between measurements at <br /> each groundwater monitoring well Decontamination procedures include washing the probe with a non- <br /> phosphate detergent (Alconox®) followed by rinsing with tap water and a final rinse with deionized <br /> water <br /> Groundwater Dissolved Oxygen Measurements <br /> Groundwater dissolved oxygen measurements were obtained at each groundwater monitoring well using <br /> the YST-85 dissolved oxygen probe The probe was decontaminated before and after taking a <br /> measurement at a well Measurements were taken by lowering the probe approximately two to five feet <br /> into groundwater The measurement was taken when the reading stabilized The measurement was <br /> recorded on the field data sheet with the depth to groundwater measurements <br /> Groundwater Purging <br /> Based on the groundwater level and the total depth of the well, the volume of water to be purged from <br /> the well was calculated before purging began Approximately three well volumes of water were purged <br /> from each monitor well casing prior to sampling Groundwater was purged from the wells by bailing and <br /> pumping <br /> IDuring this sampling event, "B" casing wells were purged by bailing 1&7/8"x 3' and 1&7/8 x 8' bailers <br /> were used to remove the necessary water from the well casings The "C" casing wells were purged with <br /> a 2" Grundfos "Reds-flo" submersible pump <br /> l <br />