ARCHIVED REPORTS XR0010043 - Laserfiche WebLink

Home Browse Search

�J SES STANDARD OPERATING PROCEDURE SIERRA. GROUND WATER SAMPLING The following describes sampling procedures used by SES field personnel to collect and handle groundwater samples Before samples are collected, careful consideration is given to the type of analysis to be performed so that precautions are taken to prevent loss of volatile components or contamination of the sample, and to preserve the sample for subsequent analysis Wells will be sampled no less than 24 hours after well development. Collection methods specific to ground water sampling are presented below. Prior to sampling, each well is checked for the presence of free-phase hydrocarbons using an MMC flexi-dip interface probe Product thickness (measured to the nearest 0 OI foot) is noted on the sampling form Water level measurements are also made using either a water level meter or the interface probe. The water level measurements are also noted on the sampling form Pnor to sampling, each v ell is purged of a minimum of three well casing volumes of water using a steam-cleaned PVC bailer or a pre-cleaned pump Temperature, pH and electrical conductivity are measured at least three times during purging Purging is continued until these parameters have stabilized (i e , changes in temperature, pH or conductivity do not exceed t0 ST. 0 1 or 5%, respectively) OThe purge water is taken to Chevron's Richmond Refinery for disposal Ground«eater samples are collected from the wells%vith Chevron designated disposable bailers The water samples are decanted into the appropriate container for the analysis to be performed Pre- preserved sample containers may be used or the analytic laboratory may add preservau%e to the sample upon arrival Duplicate samples are collected from each well as a back-up sample and/or to provide quality control The samples are labeled to include the project number, sample 1D, date preservative and the field person s i utials The samples are placed in polyethylene bags and in an ice chest (maintained at 4 C) for transport under chain of custody to the laboratory The chain of custody form includes the project number, analysis requested, sample 1D date analysis and the SES field person s name The form is signed and dated (with the transfer time) by each person who yields or receives the samples beginning with the field personnel and ending with the laboratory personnel A trip blank accompanies each sampling set, or 5%trip blanks are included for sets of greater than 20 samples The trip blank is analyzed for some or all of the same compounds as the ground water samples n