Microbial role in the failure of natural attenuation of chromium(VI) in long-term tannery waste contaminated soil

Surface complexation mechanism and modeling in Cr(III) biosorption by a microalgal isolate, Chlorella miniata

“…The binding pattern would be affected by metal speciation resulted from the hydrolysis reaction [2,6,8]. Species such as Cr 3+ , CrOH 2+ , Cr(OH) + , Cr(OH) 3 , and Cr(OH) − 4 were reported to coexist in solution but only Cr 3+ and CrOH 2+ were the main species at pH range of 1.0 to 6.0 [2]. The concentrations of these two species were:…”

“…Cr(III) is thought to be an essential nutrient required for sugar and fat metabolism in organisms [1], however, long time exposure causes skin allergic and cancer [2]. Moreover, Cr(III) can be oxidized to the more carcinogenic and mutagenic Cr(VI) by MnO 2 in the environment or by some bacteria in soil under proper conditions [3].…”

Surface characterization and comparative adsorption properties of Cr(VI) on pyrolysed adsorbents of Acacia mangium wood and Phoenix dactylifera L. stone carbon

“…Although, it is well known that Cr(VI) is more toxic than chromium(III), prolong exposure to Cr(III) species could also cause skin allergies and cancer in human beings [1]. In addition, Cr(III) under certain conditions can be oxidized to the state of more carcinogenic and mutagenic Cr(VI) by some bacteria or manganese oxide present in the environment [2]. Hexavalent chromium is known to be a strong oxidant.…”

Rhizoremediation of metals: harnessing microbial communities

“…Addition of a bacterial strain P. maltophila was shown to reduce the mobile and toxic Cr(VI) to immobile and nontoxic Cr(III) thereby minimizing the mobility of metal ions [20]. Results also reveal that in longterm chrome contaminated sites, the complete microbial reduction of Cr(VI) is challenging [60].…”