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• Wright Environmental Services, Inc. <br /> Monitoring Well Development <br /> 1. Wells will be developed until the water is free of fine grained sediments <br /> and/or until field measurements of pH, and electrical conductivity have stabilized. <br /> Approximately 3 to 10 well volumes of water will be removed during development of <br /> the well. The actual number of volumes withdrawn for development is well <br /> dependent and based on the field judgment Duration of development will be specific <br /> for each well and site aquifer conditions and continue until the water clears and sand <br /> content is minimal or ceases <br /> Measurements of aquifer parameters may be taken to observe for aquifer conditions <br /> Notes of well development will be kept including quantity of water removed, <br /> turbidity, and sand yield and well recharge <br /> 2. Only precleaned equipment will be inserted into the well during development, <br /> and will be decontaminated by washing or steam cleaning after its use. Development <br /> water will be collected and stored in in drums. <br /> Monitoring Well Sampling <br /> 1. Depth to groundwater will be measured to the nearest 0.01 foot, and the well <br /> checked for presence of separate phase product If present, the apparent thickness <br /> of the product will be measured The well will not be sampled if separate phase <br /> product is present <br /> 2. The standing well volume calculated, and usually between 3 to 10 well volumes <br /> will be purged from the well prior to sampling depending on well performance and <br /> yield (USEPA (1985) sampling guidance indicates that the number of purge volumes <br /> are related to aquifer strata and specific for each well) <br /> Measurements of aquifer parameters (conductivity, temperature and the pH) of the <br /> water will be taken until parameters have stabilized to indicate that aquifer water is <br /> entering the well over at least two purge volumes The sampler will keep field notes <br /> for each well sampled That field log will record sampling measurements and <br /> observations Aquifer parameters which will be measured are, pH, temperature and <br /> electrical conductivity Aquifer water is assumed to be entering the well when these <br /> parameters are measured within a 10% range of the previous measurements. The <br /> sample will be collected when the well recovers to within 80% of the original depth <br /> to water measurement. <br /> 3. The groundwater samples may be collected using a Teflon® or disposable bailer <br /> or sampling pump discharge Sampling gear will be thoroughly steam-cleaned or <br /> cleaned with soapy (TSP) water, rinsed with with deiomzed or distilled water prior to <br /> the collection of each sample. When bailers are used, a separate clean bailer will be <br /> used to sample each individual well. <br /> • <br /> WES Sampling Protocols last rev 5/96 Page 5 <br />