Isabelle Cozzarelli, a USGS organic geochemist based in Reston, Virginia, and George Aiken, a USGS organic chemist based in Boulder, Colorado, are taking water samples with syringes from core of aquifer material from the Bemidji Toxics Site that was just collected using the sample-freezing drive shoe. The core is encased in a plastic tube. Small holes are drilled in the tube, the syringes are placed in the hole, and a small amount of water is withdrawn. A tank of nitrogen gas is used to place a small amount of pressure in the tube to make withdrawing water from the core easier. This technique allows Isabelle and George to collect undisturbed ground-water samples at closely spaced intervals. The chemistry of contaminant plumes can change drastically over short distances, and this technique allows our scientists to study these important changes that control the fate of contaminants.

Back to the Photo Gallery of the Sample-Freezing Drive Shoe in Action