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Appendix B Groundwater Sampling and Analysis Procedures rGroundwater Sampling The static water level in each well was measured to the nearest 0 01 foot with a Solmst electric water level indicator cleaned with a laboratory-grade, non-phosphatic detergent and deionized water before use in each well A clean bailer was used to obtain a surface water sample from within each well for a subjective analysis of hydrocarbons The sample was retrieved and visually examined for floating product, sheen, color, and clarity Approximately three casing volumes of groundwater were purged from the wells using a stainless-steel, electrical, submersible pump or disposable bailer The pump, cables, and hoses were cleaned with a laboratory-grade, non-phosphatic detergent and water before use in each well The wells were purged until withdrawal was of sufficient duration to result in stabilized pH, temperature, and electrical conductivity of the water, as measured by portable meters calibrated to a standard buffer and conductivity standard A sample of the formation water was then collected from the surface of the water in each of the wells with the TeflonTM bailer and slowly transferred to laboratory-cleaned sample containers Sample Labeling and Handling Water samples were preserved in laboratory-cleaned, 40-milliliter glass vials that contained concentrated hydrochloric acid as a preservative as necessary The water samples were sealed with TeflonTM-lined lids to eliminate air bubbles The sample containers were labeled in the field with the site identification, monitoring well number and depth, and date, and promptly placed in iced storage for transport to the laboratory The technician initiated chain-of-custody records in the field that accompanied the samples to a laboratory certified by the state of California for the analyses requested Samples were transported to the laboratory promptly Evaluating the Groundwater Flow Direction and Gradient The elevations and positions of the monitoring well were surveyed by California-licensed land surveyors The elevations of the monitoring wells were surveyed to within 0 01 feet of the bench mark The lateral distances were measured to the nearest 0 1 feet The elevations references were either the notch or the arrow made on the top of the well casing rThe groundwater elevations for each monitoring well were calculated by subtracting the depth to water from the wellhead elevation The groundwater elevations were used to construct a total head elevation map (a k a water table or potentiometric surface) The map was used to estimate the groundwater gradients and directions of flow K 1880039 Don Rodgers\Momtonng RptsMQ3 doc SHAW ENVIRONMENTAL,INC B-1