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ffl � ..��"_ �- $, ,r''` w.�rr�. �.�..� .+t r .,.�. ty.+ .r.«. ,ham"". �ry eek ,+Y 2.2 SAT ENVIROPIIOBE(R) SAMPLING SYSIZM The BAT EnviroProbetR7 system consists of a stainless steel probe which is attached to the end of a string of one-inch I.D. steel casing. The probe and casing are pushed into the ground using the CPT rig. Upon reaching the desired sampling depth,the probe is opened by retracting the casing approximately one foot,thereby exposing a stainless steel sampling screen. Groundwater and/o-., sail gas samples are collected by lowering a cylindrical sampling kit down the casing containing an evacuated glass or TeflonR sample vial. As the sampling kit reaches the bottom of the casing and makes contact with the top of the probe, a double ended spring loaded hypodermic needle contained at the bottom of the sampling kit temporarily punctures a self sealing septum at the top of the probe. At the same time, the other end of the double ended needle temporarily penetrates a similar septum sealing the bottom of the sample vial. The vacuum inside the sample vial then draws the formation fluids into the probe, and up through the needle into the sample vial. The sample is retrieved by pulling the sampling kit up out of the casing. As the needle retracts from both septa the septa immediately reseal themselves. The initial fluid sample collected at a given location purges the volume inside the probe. An indefinite number of subsequent samples can be collected once the probe is in place at the desired depth, and purged. A 35-ml double ended glass sample vial is used for purging. While the formation fluids enter the purge vial,the increase in pressure w inside the vial is monitored using a pressure transducer which is connected to the top end of the vial by means of another hypodermic needle and septum. The transducer is connected via an electric cable to a digital readout box at the surface. The change in pressure inside the vial as a function of time indicates the speed of sample collection. When input into a specially programmed portable computer, this data can also provide an estimate of the hydraulic conductivity of the formation being sampled. The SAT EnviroProbeiRi system can thus be used as a permanent monitoring point by leaving the probe and casing in the ground and sampling periodically, or it can be installed repeatedly at different locations. Between sampling locations, the probe is disassembled and subjected to a three-stage decontamination procedure before reassembly. The first stage consists of washing and scrubbing using a lab detergent solution. The components of the probe are then rinsed twice in deionized v;ater. Some components, including the stainless steel screen and various o-rings,are replaced after each use. RM