Remediation efforts at contaminated terrestrial sites aim to reduce Cr(VI) to Cr(III). The effect of the electron shuttle anthraquinone-2,6-disulfonate (AQDS) on Cr(VI) reduction and Cr(III) oxidation was investigated using A and B horizons from 9 Maryland soils from 3 different toposequences, which consist of top position, middle position, and bottom position soils along the same slope. Representative soil samples were shaken for 24 hours with either a Cr(VI) or Cr(III) solution, and with or without AQDS. All 18 samples demonstrated reduction of Cr(VI), and 10 demonstrated more than 2% oxidation of Cr(III). The addition of AQDS enhanced reduction, and inhibited oxidation in many of the same soils. A time study was conducted to investigate enhanced reduction over a 14-day period for all samples. Over the course of 14 days, reduction continued to increase in all samples, but the AQDS effect diminished. The addition of the electron shuttle initially enhanced reduction, but the effect proved ephemeral. Using A horizon soils from only one toposequence, soil and AQDS effects on reduction and oxidation of Cr were again investigated, but at different temperatures to assess biological effects. Representative soil samples were shaken for 24 hours at 4, 25, and 35 º C with either a Cr(VI) or Cr(III) solution, and with or without AQDS. For the top position soil, reduction at 4º C without AQDS was less than the other two soils without AQDS, and reduction for the bottom position soil was less at 4º C than the other two soils with AQDS. Overall, a decrease in temperature did not significantly decrease Cr(VI) reduction, indicating abiotic reduction independent of biological activity.