Study of Five Discrete-Interval-Type Ground Water Sampling Devices

Five relatively newly developed discrete-interval-type ground water sampling devices-the KABIS, HydraSleeve, Discrete Interval, Pneumo-Bailer, and USGS passive diffusion bag (PDB) samplers-were tested to determine their ability to recover representative concentrations of a variety of analytes-volatile organics, explosives, pesticides, and metals-from a standpipe and trichloroethylene (TCE) from a deep monitoring well. Samples taken from a well were compared with samples taken using low-flow sampling. The PDB sampler was the easiest to use, but could only be used to sample volatile organic compounds (VOCs). The HydraSleeve and the KABIS samplers were also easy to use; these devices produced representative concentrations of explosives, pesticides, and metals in the standpipe experiments, but elevated the turbidity in our monitoring well. Although there were statistically significant differences for some VOCs with both devices, these differences were generally very small (< 5%). The one exception was an 18% loss of TCE with the KABIS sampler. The Discrete Interval sampler and the Pneumo-Bailer are pressurized devices that are designed to only collect a sample when activated. The Pneumo-Bailer was heavy and awkward to handle, required a nitrogen tank in the field, and involved many steps to operate. The Discrete Interval sampler only required a bicycle pump to pressurize the chamber and was lighter and easier to handle and operate than its counterpart. Both devices generally delivered representative concentrations of all the analytes tested.