A small-scale field test was intitiated in September 1994 to evaluate the in situ remediation of ground water contaminated with chromate using permeable reactive barrier. In addition to monitoring the removal of chromate from the aqueous phase, efforts were made to identify resultant mineral phases formed as a result of the corrosion process. Frequent geochemical monitoring of waters in the test zone were also conducted to confirm or elucidate the proposed chemical mechanisms responsible for remediation. Testing and monitoring continues to provide information required for long-term performance assessment of such remedial technologies.