Speciation, toxicity, microbial remediation and phytoremediation of soil chromium contamination

摘要

Contamination of soil by toxic chromium (Cr) is a rising health issue due to over-exploitation and industrial production. Toxicity can be decreased by bioremediation because some microorganisms are able to convert highly toxic hexavalent chromium Cr(VI) into less toxic trivalent chromium Cr(III) by secreting chromate reductase. Moreover, microorganisms are able to remove Cr by adsorption on microbial cell walls. Plants can also be used for phytoremediation by uptaking Cr from soil into plant organs. Here, we review the speciation of Cr in soil, remediation methods to remove Cr, bioremediation challenges, and remaining ecological impacts after bioremediation. We present the mechanisms of microbial remediation, phytoremediation and plant-microbial combined remediation and applications.