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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 HelonT"f <br /> water level indicator The water level indicator was decontaminated before and after taking a <br /> measurement at a well Groundwater depth measurements were recorded from a mark that is typically on <br /> the north side of the top of the uncapped PVC monitoring 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 each <br /> PVC monitoring well casing <br /> The water level indicator was decontaminated prior to arrival on the site and between measurements at <br /> each groundwater monitoring well Decontamination procedures include waslivig the probe with a non- <br /> phosphate detergent (Alconox ) followed by rinsing with tap watei and a final rinse with deionized <br /> water <br /> Groundwater Oissolved Oxygen Measurements <br /> Groundwater dissolved oxygen measurements were obtained at each groundwater monitoring well using <br /> the YSI-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 probe was then slowly raised and lowered through the water within an <br /> approximate one-foot interval The measurement was taken when the reading stabilizes and showed signs <br /> of reversal Several minutes may pass before the measurement stabilizes 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 the <br /> well was calculated before purging began Approximately three well volumes of water were removed <br /> (purged) from each monitor well casing during well purging activities Groundwater was purged from the <br /> wells by bailing or pumping <br /> 1 <br />