Natural and Fe(II)-induced reduction of hexavalent chromium in soil

In this study the influence of iron sulphate (FeSO4) on the dynamics of Cr(VI) - Cr(III) reduction in Cr(VI) spiked soil was evaluated, together with the concomitant assessment of the effect of the different treatments on soil microbial biomass size and activity. The results indicate that during the incubation period, the concentration of Cr(VI) in soil decreased over time, thus evidencing a natural attenuation capacity of soil towards chromate reduction. However, soil microbial biomass and respiration rate were both negatively affected by the presence of Cr(VI), and did not recover during the experiment. Soil amendment with FeSO4 increased the Cr(VI) reduction rate and mitigated its negative effect towards soil microbial biomass and activity.