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STANDARD OPERATING PROCEDURE- GROUNDWATER SAMPLING Gettler-Ryan Inc. (GR) field personnel adhere to the following procedures for the collection and handling of groundwater samples prior to analysis by the analytical laboratory. All work is performed in accordance with the GR Health&Safety Plan and all client-specific programs. The scope of work and type of analysis to be performed is determined prior to commencing field work. Prior to sampling, the presence or absence of free-phase hydrocarbons is determined using an interface probe. Product thickness, if present, is measured to the nearest 0.01 foot and is noted in the field notes. In addition, all depth to w ater level measurements are collected with a static water level indicator and are also recorded in the field notes,prior to purging and sampling any wells. After water levels are collected and prior to sampling,if purging is to occur,each well is purged a minimum of three well casing volumes of water using pre-cleaned pumps (stack, peristaltic or Grundfos), or disposable bailers. Temperature,pH and electrical conductivity are measured a minimum of three rimes during the purging(additional parameters such as dissolved oxygen,oxidation reduction potential,turbidity may also be measured,depending on specific scope of work.). Purging continues until these parameters stabilize. Groundwater samples are collected using disposable bailers. The water samples are transferred from the bailer into appropriate containers. Pre-preserved containers,supplied by analytical laboratories,are used. When pre-preserved containers are not available,the laboratory is instructed to preserve the sample as appropriate. Duplicate samples are collected for the laboratory to use in maintaining quality assurance/quality control standards,as directed by the scope of work. 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 4°C for transport to the laboratory. Once collected in the field,all samples are maintained under chain of custody until delivered to the laboratory. - The chain of custody document includes the job number,type of preservation, if any, analysis requested, 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, beginning with the field personnel and ending with the laboratory personnel. A laboratory supplied trip blank accompanies each sampling set. The trip blank is analyzed for some or all of the same compounds as the groundwater samples. As requested by Chevron Environmental Management Company, the purge water and decontamination water generated during sampling activities is transported by Clean Harbors Environmental Services to Evergreen Oil located in Newark,California. N;\California\forms\chevron-SOP-Jan.2012