ARCHIVED REPORTS_XR0006341 - Laserfiche WebLink

Home Browse Search

rr � SES STANDARD OPERATING PROCEDURE SIERRA GROUND WATER SAMPLING The following describes sampling procedures used by SES field personnel to collect and handle ground water 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 dei elopment Collection methods specific to ground water sampling are presented below Prior to sampling, each%i ell is checked for the presence of free-phase hydrocarbons using an MMC flexr-dip interface probe Product thickness (measured to the nearest 0 01 foot) is noted on the sampIirng form Water Ievel measurements are also made using either a water level meter or the interface probe The water Ievel measurements are also noted on the sampling form Prior to sampling, each «ell is purged of a minimum of three well casing volumes of water using a stearn-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 conductix ity do not exceed±O 5'F, 0 1 or 5%, respectively) The purge water is taken to Chevron s Richmond Refinery for disposal Ground water samples are collected from the«ells with Chevron designated disposable bailers The water samples are decanted into the appropriate container for the analysis to be performed Pre- presen ed sample containers may be used or the analytic laboratory may add preservatix e to the sample upon amval 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 ID, date, preservative, and the field person's initials The samples are placed in polyethylene bags and in an ice chest (maintained at 4'C) for transport under chat i of custody to the laboratory The chain of custody form includes the project number, analysis requested, sample ID, date analysis and the SFS field person's name The form is signed and dated (with the transfer tune) by each person who yields or receives the samples beginning with the field personnel and ending with the laboratory personnel A tnp blank accompanies each sampling set, or 5%trip blanks are included for sets of greater than 20 samples The tnp blank is analyzed for some or all of the same compounds as the ground water samples GUS-CHH Sop