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Water Sample Labeling and Handling <br /> Sample containers are labeled in the field with the,lob number, sample location and depth, and <br /> date and promptly placed in iced storage for transport to the laboratory A Chain of Custody <br /> Record is initiated by the geologist and updated throughout handling of the samples and <br /> accompanies the samples to a laboratory certified by the State of California Samples are <br /> transported to the laboratory promptly to help ensure that recommended sample holding times <br /> will not be exceeded <br /> Reporting Results of Analyses <br /> Hydrocarbon constituents in soil samples are typically reported in units of parts per million <br /> (ppm). Hydrocarbon constituents in groundwater samples are typically reported by the <br /> laboratory in units of parts per billion (pbb) <br /> Evaluating the Groundwater Flow Direction and Gradient <br /> The elevations and positions ("x" and "y" lateral coordinates) of the monitoring well are <br /> surveyed with respect to a local datum that references the elevation according to mean sea <br /> level The elevation of the monitoring wells are measured within 0 01 foot of the local datum <br /> The horizontal distances are measured to the nearest 0 1 foot The elevations are measured <br /> • from either a notch or an arrow marked on the top northern edge of the well casing <br /> The groundwater elevation for each monitoring well is calculated by subtracting the depth to <br /> water from the wellhead elevation. The groundwater elevation information is used to construct <br /> a potentiometric surface map, which is used to evaluate the direction of groundwater flow and <br /> the magnitude of the groundwater gradient <br /> • SHELLSIFLDMTHDS doc 4 <br />