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1 <br /> #er Sample )C,abel�ng and Handling <br />' Sample containers are labeled in the field with the job number, sample location, depth of <br /> sample (if appropriate), and date of sample and promptly placed in iced storage for transport to <br />' the laboratory. A Chain of Custody Record is initiated by the geologist and updated <br /> throughout handling of the samples and accompanies the samples to a laboratory certified by <br /> the State of California. Samples are transported to the laboratory promptly to help ensure that <br />' recommended sample holding times are not exceeded. <br /> _Reporting Results of Analyses <br />' Hydrocarbon constituents in <br /> y 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 (ppb) <br /> Evaluating the Groundwater Flow Direction and Gradient <br /> 1 <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 typically <br /> measured 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 potentiometnc surface map, which is used to evaluate the direction of groundwater flow and <br /> the magnitude of the groundwater gradient. <br /> 1 <br /> SHELLSIFLDMTHDS doc 4 <br /> 1 <br />