A pilot-scale field test was conducted near an old chrome plating facility on the U.S. Coast Guard (USCG) Support Center near Elizabeth City, North Carolina to evaluate the in-situ remediation of ground water contaminated by hexavalent chromium using permeable reactive barrier technology. The reactive media consisted of two types of zero-valent iron mixed with natural aquifer material and coarse sand. The remedial effectiveness of this innovative in situ technology was monitored over a twenty month period following emplacement in September 1994. In addition to monitoring the removal of contaminants from the aqueous phase, performance monitoring included attempts at mass balance circulations, changes in aqueous and solid phase goechemistry and changes in permeability.