In-Situ sampling of aqueous-phase contamination of chlorinated solvents

An In-Situ Sampler (ISS) has been designed, built, and field rested which can be directly deployed in groundwater wells to passively sample aqueous volatile organic compound (VOC) contamination, including the chlorinated volatile organic compounds (CVOC). Several of these samplers can be lowered into a well by hand to selected depths and allowed to remain in the wells until the sampler is in equilibrium with the dissolved analyte. During deployment, the ISS will passively adsorb CVOC (and VOC) contamination; no moving pairs or power sources are required during incubation. Upon removal from water, the adsorbed CVOC (or VOC) will slowly desorb. However, with the design of the ISS this desorption is a controlled process and vapor phase samples can be conveniently collected. The vapor phase concentration of CVOC (and VOC) is directly proportional to the aqueous phase contamination level. To collect vapors for analysis, the ISS is connected to a vapor collection apparatus. Individual aqueous phase CVOC contaminants can be detected to 5 ppb-wt (5 mu g/L), limited in part by the detection limits of the analyzer. The ISS approach has advantages over the conventional methods for ground water analyses in that both spatial and vertical profiles of VOCs without direct sampling of water. With field analyzers, results can be obtained within minutes.