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Ms. Erica Crosby <br />March 30, 2007 <br />Page 8 <br />Each monitoring well will be purged prior to sampling. Due to the anticipated low <br />hydraulic conductivities of the shale and long recovery times, it is doubtful that it will be <br />practical to purge three well casing volumes the day of sampling. Current practice at well <br />CEM-001 is to purge the well dry and then sample after sufficient watet recharges the well. <br />(Recent data collected at CEM-007 indicated it took 68 hours for the water level to xecovet <br />to [he pre-sampling elevation after the well was sampled on March 9, 2007.) At least one <br />bore volume will be removed from each monitoring well, and the well will then be allowed <br />to recover prior to sampling. The shallower alluvial well may be sampled with a bailer ox a <br />peristaltic pump, while the deeper wells will likely be sampled by another pump (Gmndfos, <br />etc.). Final sampling methods will be selected and documented once the site hydrology and <br />well characteristics axe confirmed in the field. Sampling equipment will be decontaminated <br />between sampling of each well using standard industry practices. Field pH, conductivity, <br />and temperature will be measured on groundwater samples collected from the monitoring <br />wells. <br />Water samples will be properly shipped overnight under chain-of-custody documentation to <br />a subcontract laboratory. The table below lists the proposed analytes and analytical <br />methods fox the side round of sampling proposed in this initial phase. The analytical <br />detection method fox selenium will be ICP-DRC-MS to avoid interferences from bromide <br />that could lead to false positives. The selected analytes axe expected to be helpful in <br />assessing potential impacts to groundwater duxingph-filling, but likely will not all be needed <br />fox longer-term monitoring. The analytical parameter suite will be evaluated upon <br />completion of a review of the hydrogeologic and chemical data generated by this initial <br />phase of investigation. <br />Parameter Method <br />Selenium, dissolved 6020 ICP-DRC-MS <br />Thallium, dissolved 6020 <br />Calcium, dissolved 6010B <br />Ma esium, dissolved 6010B <br />Sodium, dissolved 6010B <br />Potassium, dissolved 6010B <br />Fluoride 9056 <br />Bromide 9056 <br />Sulfate 9056 <br />Chloride 9056 <br />Alkalini 310.2 <br />Alkalini ,Bicarbonate 310.2 <br />Alkalini ,Carbonate 310.2 <br />Dissolved Solids 160.1 <br />Task 5.0 Pipelinelnvestigations <br />Brown and Caldwell will support CEMEX operational and maintenance staff in <br />investigating the integrity of the A-Pit pipeline that transports cooling water to the plant <br />spray tower, to determine whether any losses along this line maybe contributing water to C- <br />Pit. See Figure 2 for the approximate location of this line with respect to C-Pit. Anecdotal <br />accounts indicate that a pipeline break along the noxthem end of C-Pit in the last few years <br />-0594G86.doc <br />