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f <br /> I <br /> ENVIRONMENTAL REMEDIATION GROUP P <br /> STANDARD OPERATING PROCEDURES <br /> GROUNDWATER PURGING & SAMPLING PROTOCOL <br /> Applications + <br /> f <br /> Whenever groundwater samples are collected for analysis,the following protocol shall be <br /> observed: <br /> Well Gauging and Water Level Monitoring <br /> A Solinst electronic well sounder will be used to measure groundwater levels to the j <br /> nearest 0.01 foot. The instrument uses an indicator probe attached by an insulated wire <br /> line to a signal light and an alarm. The signal light blinks when the probe comes in f <br /> contact with water and the alarm sounds when the probe comes in contact with floating <br /> hydrocarbons, and the electronic circuit is completed. All downhole equipment will be <br /> triple rinsed before and after use in each well, as detailed in ERG's Standard Operating <br /> Procedures,Decontamination Protocol.. The probe will be carefully lowered into the i <br /> i <br /> well to measure static water levels. Two successive readings within 0.01 foot of each <br /> other will be considered valid water level measurements. ! <br /> Groundwater Sampling Procedures <br /> 6 <br /> Purging. Generally, 3 to 10 well volumes will be purged from each well prior to <br /> sampling. The purpose of purging is to remove stagnant water from the well, and to <br /> obtain a fresh sample which is representative of the surrounding aquifer. Temperature, <br /> pH, and conductivity measurements will be conducted before,periodically during, and <br /> after the purging process. Stabilization of these measurements shall occur prior to <br /> r <br /> collection of a sample. The acceptable stabilization parameters are outlined below: <br /> 1 <br /> Parameter Stabilization Factor <br /> Temperature Within 1 degree Centigrade <br /> (equivalent to 1.8 degrees F) <br /> pH Within 0.1 <br /> p <br /> Conductivity Within 10% <br /> i <br /> I <br />