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1 <br /> EGG Groundwater Sampling <br /> 1 (GWS) <br /> • <br /> 1 Gregg In Situ, Inc conducts groundwater sampling using a Hydropunch® type <br /> groundwater sampler, Figure GWS The groundwater sampler has a retrievable <br /> 1 <br /> stainless steel or disposable PVC screen with steel drop off tip This allows for <br /> samples to be taken at multiple depth intervals within the same sounding <br /> location In areas of slower water recharge, provisions may be made to set <br /> 1 temporary PVC well screens during sampling to allow the drill rig to advance to <br /> the next sample location while the groundwater is allowed to infiltrate <br /> 1 The groundwater sampler operates by <br /> advancing 1 % inch hollow push rods ' <br /> with the filter tip in a closed , <br /> 1 xi <br /> configuration to the base of the <br /> desired sampling interval Once at the <br />' <br /> desired sample depth, the push rods <br /> are retracted, exposing the encased Prev,nusly <br /> filter screen and allowin roundwater s <br /> 9 9 Interval perched <br />' to infiltrate hydrostatically from the = Groundwater <br /> formation into the inlet screen A small <br /> diameter bailer (approximately 1/2 or % <br /> inch) is lowered through the push rods <br /> into the screen section for sample <br /> collection The number of downhole <br /> tnps with the bailer and t€me <br /> necessary to complete the sample `�� ; , a <br /> I g`collection at each depth interval is a <br /> function of sampling protocols, volume Y <br /> requirements, and the yield <br />' characteristics and storage capacity of Aquifer <br /> the formation Upon completion of <br /> sample collection, the push rods and <br />' sampler, with the exception of the PVC <br /> screen and steel drop off tip are <br /> retrieved to the ground surface, <br /> decontaminated and prepared for the <br /> next sampling event <br /> Figure GWS <br /> A summary of the groundwater samples collected, including the sampling date, <br /> depth and location identification, is presented in Table 'I and the corresponding <br /> ICPT plot <br /> • For a detailed reference on direct push groundwater sampling, refer to Zemo et <br /> al , 1992 <br />