Interactions of chromium with microorganisms and plants

Abstract

Chromium is a highly toxic non-essential metal for microorganisms and plants. Due to its widespread industrial use, chromium (Cr) has become a serious pollutant in diverse environmental settings. The hexavalent form of the metal, Cr(VI), is considered a more toxic species than the relatively innocuous and less mobile Cr(III) form. The presence of Cr in the environment has selected microbial and plant variants able to tolerate high levels of Cr compounds. The diverse Cr-resistance mechanisms displayed by microorganisms, and probably by plants, include biosorption, diminished accumulation, precipitation, reduction of Cr(VI) to Cr(III), and chromate efflux. Some of these systems have been proposed as potential biotechnological tools for the bioremediation of Cr pollution. In this review we summarize the interactions of bacteria, algae, fungi and plants with Cr and its compounds.

Determination of chromium valence over the range Cr(0)–Cr(VI) by electron energy loss spectroscopy

“…Furthermore, valence of 3d or 4d [30]) to biologically important inorganic anions, such as transition metals can be analyzed by X-ray fluorescence SO-and PO3-is likely responsible for their ability to spectrometry (XRS) [50], X-ray photoemission spectroscopy readily transverse cell membranes, via the sulfate transport (XPS) [51], X-ray absorption spectroscopy (XAS) [3,52], system, and be incorporated into cells (for reviews, see electron paramagnetic resonance (EPR) (also known as Refs. [32,33]). In contrast, most water soluble Cr(III) electron spin resonance (ESR)).…”

Chromium-Containing Organic Fertilizers from Tanned Hides and Skins: A Review on Chemical, Environmental, Agronomical and Legislative Aspects

“…However, once in the xylem, Cr moves more readily [26,29,33,34]: very little translocation of Cr to the shoot is expected to occur when plants are supplied with either form of Cr. In fact conversion of Cr(VI) to Cr(III) occurs in the roots where Cr(III) is the most predominant form: once Cr is transformed, translocation is very little, being Cr(III) a form with low solubility [26,31].…”

“…The two ions do not share a common uptake mechanism: the uptake of Cr(III) is largely a passive process, whereas the uptake of Cr(VI) is mediated by low affinity sulphate carriers, specific for the uptake of essential metals [29,30,33,34] and quickly converted to Cr(III) in roots by Fe(III) reductase enzymes [31].…”

Remediation of chromium(VI) at polypyrrole-coated titanium

“…Hexavalent chromium, Cr(VI), is a well-documented carcinogen, mutagen and redox active species [1][2][3][4][5][6]. However, the use of chromium in industrial processes including corrosion inhibition, metal finishing, tanning and pigment production is still prevalent [2,7].…”

“…However, the use of chromium in industrial processes including corrosion inhibition, metal finishing, tanning and pigment production is still prevalent [2,7]. Pollution due to Cr(VI) is a considerable problem due to its extremely hazardous nature and the relative ease with which it may contaminate the environment.…”