@article{fdi:010058969,
  title = {{C}r({VI}) genesis and dynamics in {F}erralsols developed from ultramafic rocks : the case of {N}iquelandia, {B}razil},
  author = {{G}arnier, {J}. and {Q}uantin, {C}. and {G}uimaraes, {E}. {M}. and {V}antelon, {D}. and {M}ontarges-{P}elletier, {E}. and {B}ecquer, {T}hierry},
  editor = {},
  language = {{ENG}},
  abstract = {{D}espite high chromium concentrations in soils developed on ultramafic rocks, {C}r availability is generally low, as {C}r-bearing minerals are considered stable in supergene conditions. {H}owever, {KH}2{PO}4 extractions have shown high hexavalent chromium availability in {F}erralsols developed on the ultramafic massif of {N}iquelandia ({B}razil). {A} study combining mineralogical, geochemical, mu {SXRF} and {XANES} approaches was performed to assess the solid speciation of {C}r and to understand its genesis. {C}hromium is mostly present in the trivalent form and is included in chromites and {F}e-oxides. {N}evertheless, a large amount of {C}r({VI}) is associated with the clay-sized fraction in the mineral horizons. {M}n-oxides, the only natural {C}r({III}) oxidants, are also present in these horizons. {M}icroscale investigations revealed the close association of {C}r({VI}) with {M}n-oxides and strongly suggest that {M}n-oxides can oxidize {C}r({III}) into {C}r({VI}). {T}he {XANES} analyses show the occurrence of {C}r({VI}), which is removed by {KH}2{PO}4 extraction, demonstrating that the {C}r({VI}) is completely sorbed onto the soil matrix, i.e., {F}e-oxides. {F}inally, the high mobility of {C}r({VI}), associated with the finest {F}e-oxide particles mobilized during runoff following rainy events, may have harmful environmental consequences. {T}his approach of combining direct and indirect observations allows us to characterize the total extractable {C}r({VI}) pool of these soils and to give key information on its mobility and localization.},
  keywords = {{XANES} ; mu {SXRF} ; {C}hromium ; {M}etals ; {A}vailability ; {M}obility ; {BRESIL}},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {193},
  numero = {},
  pages = {256--264},
  ISSN = {0016-7061},
  year = {2013},
  DOI = {10.1016/j.geoderma.2012.08.031},
  URL = {https://www.documentation.ird.fr/hor/fdi:010058969},
}