Laserfiche WebLink
SOP #12 <br /> Date:9/1/93 <br /> Page 11 of 31 <br /> 5.2.3 Ground Water Sampling <br /> The necessary sampling equipment shall be assembled and checked before ground <br /> water sampling. Ground water samplers currently available for use with the CPT rig <br /> include the QED HydroPunch and the BAT sampler. The sampler is hydraulically <br /> pushed with the CPT rig to the water table or to a depth specified in the sampling <br /> and analysis plan. The HydroPunch is equipped with a disposable stainless steel <br /> screen that is replaced between each sampling location. Samples will be collected at <br /> descending depths. <br /> The HydroPunch consists of an air-tight, water-tight, sealed intake screen and <br /> sample chamber that is isolated from soil and ground water while the tool is <br /> advanced. As the tool advances, soil particles are displaced to the side and <br /> compacted into the walls of the hole, producing a tight annular seal around the tool. <br /> The surface of the HydroPunch is designed to prevent the downward transport of <br /> chemical constituents. Collection of a discrete ground water sample from a specific <br /> depth is made possible by the tight annular seal. <br /> Upon reaching the desired depth for collecting a sample, the HydroPunch is opened <br /> by pulling back on the tool shaft. The drive cone (with attached screen) is held in <br /> place by soil friction as the body is pulled back. Once the HydroPunch is open and <br /> the O-ring seal (between the drive cone and the body of the tool) is broken, the tool <br /> fills from the bottom with ground water. No aeration and minimal agitation of the <br /> water sample occurs during this procedure. <br />