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Environmental Geology

, Volume 42, Issue 8, pp 871–882 | Cite as

Natural hexavalent chromium in groundwaters interacting with ophiolitic rocks

  • Donatella Fantoni
  • Gianpiero Brozzo
  • Marco Canepa
  • Francesco Cipolli
  • Luigi Marini
  • Giulio Ottonello
  • Marino Zuccolini
Original Article

Abstract.

Thirty of the 58 groundwaters sampled in September–October 2000 in the study area (La Spezia Province, Italy) have Mg–HCO3 to Ca–HCO3 composition, undetectable Cr(III) contents, and virtually equal concentrations of total dissolved Cr and Cr(VI). Therefore, dissolved Cr is present in toto as Cr(VI), with concentrations of 5–73 ppb. These values are above the maximum permissible level for drinking waters (5 ppb). Local ophiolites, especially serpentinites and ultramafites, are Cr-rich and represent a Cr source for groundwaters. However, since Cr is present as Cr(III) in rock-forming minerals, its release to the aqueous solution requires oxidation of Cr(III) to Cr(VI). This can be performed by different electron acceptors, including Mn oxides, H2O2, gaseous O2, and perhaps Fe(III) oxyhydroxides. Based on this evidence and due to the absence of anthropogenic Cr sources, the comparatively high Cr(VI) concentrations measured in the waters of the study area are attributed to natural pollution.

Groundwater Chromium Hexavalent chromium Ophiolites Liguria 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Donatella Fantoni
    • 1
  • Gianpiero Brozzo
    • 2
  • Marco Canepa
    • 1
  • Francesco Cipolli
    • 1
  • Luigi Marini
    • 1
  • Giulio Ottonello
    • 1
  • Marino Zuccolini
    • 1
  1. 1.Department for the Study of the Territory & its Resources, Genoa University, Corso Europa 26, 16132 Genoa, Italy
  2. 2.ACAM, via Alberto Picco 22, 19124 La Spezia, Italy

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