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I! <br /> SIERRA <br /> SES STANDARD OPERATING PROCEDURE <br /> GROUND WATER SAMPLING - QUARTERLY MONITORING <br /> The following describes sampling procedures used by SES field personnel to collect and <br /> handle ground water samples Before samples are collected careful consideration is given to the <br /> type of analysis to be performed so that precautions are taken to prevent loss of volatile <br /> components or contamination of the sample, and to preserve the sample for subsequent analysis <br /> Wells will be sampled no less than 24 hours after well development Collection methods specific <br /> to ground water sampling are presented below <br /> Prior to sampling, each well is checked for the presence of free-phase hydrocarbons using <br /> an MMC flexr-dip interface probe Product thickness (measured to the nearest 0 01 foot) is noted <br /> on the sampling form Water level measurements are also made using either a water level meter <br /> or the interface probe The water level measurements are also noted on the sampling form <br /> Pnor to sampling each well is purged of a minimum of three well casing volumes of water <br /> using a steam-cleaned PVC bailer, or a pre-cleaned pump Temperature pH and electrical <br /> conductivity are measured during purging Purging is continued until these parameters have <br /> stabilized for consecutive readings <br /> Groundwater samples are collected from the wells with steam-cleaned Teflon bailers The <br /> water samples are decanted into the appropriate container for the analysis to be performed Pre- <br /> preserved sample containers may be used or the analytic laboratory may add preservative to the <br /> sample upon arrival Duplicate samples are collected frorn each well as a back-up sample and/or <br /> to provide quality control The samples are labeled to include the project number sample lD <br /> date preservative and the field person s initials The samples are placed in polyethylene bags and <br /> in an ice chest (maintained at 4 C with blue ice or Leel for ti ansport under chain of custody to the <br /> laboratory <br /> The chain of custody form includes the pro3ect number analysis requested sample ID <br /> date analysis and the SES field person s name 1'lle loan Ls signed and dated (with the transfer <br /> time) by each person who yields or receives the samples brgirrnrng with the field personnel and <br /> ending with the laboratory personnel <br />