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Ji STANDARD OPERATING PROCEDURE i GROUNDWATER SAMPLING Itl i Gettler-Ryan Inc. field personnel adhere to the following procedures for the collection and handling of groundwater samples prior to analysis by the analytical laboratory. Prior to sample!collection, the type of analysis to be performed is determined. Loss prevention of volatile compounds is controlled'!'and sample preservation for subsequent analysis is maintained. Prior to well development, each well is monitored for the presence of free-phase hydrocarbons and�l,the depth to water is recorded. Wells are then developed by alternately surging the well with the bailer, then ' purging the well with a pump to remove accumulated sediments and draw groundwater into the well. Development continues until the groundwater parameters (temperature, pH, and conductivity) have stabilized. Prior to sampling, the presence or absence of free-phase hydrocarbons is determined using an interface probe. Product thickness ifresent is measured red to the nearest 0.01 foot and is noted in the field notues. In addition, static water level measurements are collected with the interface probe and are also recorded r in the field notes. After water levels are collected and prior to sampling, each well is purged a minimum of three well a casingvolumes of water using re-cleaned 1 g p pumps (stack, suction, Grundfos), or polyvinyl chloride bailers. Temperature, pH and electrical conductivity are measured a minimum of three times during the purging. Purging continues until these parameters stabilize. !'I Groundwater samples are collected using Chevron-designated disposable bailers. The;water samples are transferred from the bailer into appropriate containers. Pre-preserved containers, supplied by analytical laboratories, are used when possible. When pre-preserved containers are not available, the laboratory,is 1 instructed to preserve the sample as appropriate. Du Date samplesles are collected fbthe lab orato Dry to use in maintaining quality assurance/quality control standards. The samples are labeled to include the job number,sample identification,collection date and time, analysis,preservation (if any), and the sample collector's initials. The water samples are placed in a cooler, maintained at 4oC for transport to the } laboratory. Once collected in the field, all samples are maintained under chain of custody until delivered to the laboratory. if s The chain of custody document includes the job number,type of preservation,if any, analysis requested, i sample identification, date and time collected, and the sample collector's name. The chain of custody�is ' signed and dated (including time of transfer) by each person who receives or surrenders the samples, i beginning with the field personnel and ending with the laboratory personnel. I A laboratory supplied trip blank accompanies each. sampling set. For sampling sets greater than 20 samples, 5% trip blanks are included. The trip blank is analyzed for some or all of the!same compounids as the groundwater samples. , i As requested by Chevron Products Company, the purge water and decontamination water generated during sampling activities is transported by IWM to McKittrick Waste Management located in ; McKittrick, California. , - li N-,XCalifomiaVb m Nchevmn•SOP-Dev.•5m y li