Laserfiche WebLink
iff"Mmsaw <br /> aw li <br /> 3.23 GROUNDWATER SAMPLING <br /> The general monitoring well sampling procedures are described below; well installation <br /> procedures are described in Section 4.3. Sampling procedures are as follows: 1 <br /> — • Check all equipment to ensure that it is properly decontaminated as <br /> described in Section 4.3.3. <br /> • Determine the static water level, using an electronic sounder. <br /> • Check for light, nonaqueous phase liquids (e.g., gasoline) by collecting a <br /> sample of the upper 1 to 2 feet of liquid in the well with a clear acrylic <br /> bailer. <br /> • Calculate the water volume in the casing based on the static water level. <br /> w Purge the well using a submersible pump or bailer. The purged water <br /> will be measured for electrical conductivity, pH, and temperature at least <br /> I be purged until the conductivity is <br /> once per well volume. The well wil <br /> stable within 10 percent and the pH within 0.20. A minimum of three <br /> well volumes of water will be purged. if conductivity, temperature, and <br /> pH have.not stabilized after 10 well volumes, a sample will be taken. <br /> Slow recovering wells will be purged dry and allowed to recover twice, <br /> en sufficient water has accumulated in the <br /> then purged and sampled wh <br /> well. <br /> • Temporarily store the purged water onsite pending disposal. <br /> • Collect water samples for organics from the pump discharge or with a <br /> teflon or stainless steel bailer. Discharge the first two bailers of well <br /> water. The third and subsequent bailer will be transferred to clean <br /> s sample containers. <br /> i:d '" When collecting the water samples for volatile organic analysis, the <br /> ., sample will be filled from the pump discharge or with a bailer with a <br /> bottom-emptying valve fitting. The sample bottle will be filled to over <br /> flowing so that no air bubbles pass through the sample as the bottle is <br /> being filled. The bottle will be sealed so that no air bubbles are trapped. <br /> • The containers will be sealed with custody seals according to chain-of- <br /> custody procedures [Section 4.4.1] and shipped to the laboratory for <br /> analysis. <br /> • Ali relevant field information will be recorded in a fi: :1 notebook (e.g., <br /> instrument calibration,.well..designation,volume of water extracted, and <br /> time of sampling). <br /> — <br /> 3-5 <br /> sro3t6w�wao7si <br />