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' E0 GROUNDWATER SAMPLING AND ANALYSIS To help ensure that samples are representative of the groundwater environment,samplers will be experienced and will observe good sampling procedures. Good sampling procedures will include donning clean latex gloves at each well and as often as necessary to prevent inadvertently contributing contaminants to the sample,using new disposable sampling equipment at each well,cleaning all re-usable equipment prior to use at each well with a non-phosphate detergent(e.g., Liqui-Nox,Alco-Nox)and distilled water,and keeping a detailed written field monitoring report of gauging,purging,and sampling activities. A copy of a field monitoring report sheet is included as Appendix B. F.1 Well Gauging ' Prior to purging or sampling,all wells will be gauged for depth to water and total well depth using an electronic water- level sounder calibrated to 0.01 foot. If the top of any well screen is submerged below groundwater,then the well will be vented to the atmosphere for a minimum of 30 minutes prior to gauging.Depth to water and total well depth will be ' measured relative to the surveyed reference mark at the top of each well casing. The results of well gauging will be recorder in the field monitoring log. Well gauging data will be used to calculate the potential purge water-volume as three wetted casing volumes of the well, ' and the results of the calculation shall be recorded on the field monitoring report sheet. E2 Well Purging Each well will be purged of a minimum of three wetted casing volumes or until dryness or until field measurements of purge water pH and specific conductance have stabilized. Due to the low yield of the wells at the site,purging will be accomplished using a new disposable bailer and polypropylene twine at each well,or using a bailer and twine assembly ' which is dedicated to at each well and stored in the well. Purge water will be collected in a five gallon bucket for the purpose of measuring the volume purged,and the bucket will be emptied to the ground surface near the well as often as required in a fashion which will not allow for runoff into surface water. ' Field measurement of pH and or specific conductance will be made at the beginning and the end of purging and each well and after each wetted casing volume of water has been removed from the well. The results of each field measurement for pH and or specific conductance and the total volume of purge water at each well will be recorded on the field monitoring report sheet. F3 Sample Collection ' Groundwater samples will be collected from each well after purging at a well has been completed. Groundwater samples are to be transferred from the bailer directly into appropriate laboratory cleaned sample containers containing required chemical preservatives. All samples will be labeled and stored on ice immediately after collection.After all wells at the ' site have been sampled,samples will be transported,under proper chain of custody,to the laboratory for analysis. Quality assurance and quality control(QA/QC) samples(i.e.,field blanks,trip blanks,laboratory blanks)are not ' anticipated for use during this project,but may be collected if the groundwater professional overseeing sampling activities determines a need for QA/QC sample analysis. FA Sample Analysis Groundwater samples along with any QA\QC samples shall be transported,under proper chain of custody,to a California certified analytical laboratory for analysis. Table 2 lists the sample analytical parameters,the analytical ' methods,and the frequency of analysis to be used. It is anticipated that analytical results will be available 10 to 15 days after sample submittal.