Bacterial immobilization and oxidation of arsenic in acid mine drainage (Carnoulès creek, France).
The acid waters (pH=2.73-3.37) originating from the Carnoulès mine tailings contain high dissolved concentrations of arsenic (1-3.5 mmol l(-1)) and iron (20-40 mmol l(-1)). At the outlet, arsenite predominates. During the first 30 m of downflow, 20-60% is removed by coprecipitation with Fe(III). This process results from bacterially mediated As- and Fe-oxidation. The precipitation rates in the creek depend on the oxygen concentration in spring water and are lower during the dry summer period when the anoxic character of the spring water inhibits the activity of oxidizing bacteria. Ex situ experiments show that the presence of bacteria-rich precipitates increases the As- and Fe-removal rates. Three strains of bacteria promoting the oxidation of As have been isolated, and two of them have the characteristics of Thiomonas ynys1. The third strain, which is not identified yet, also catalyzes the oxidation of Fe.
Casiot
Corinne
C
Laboratoire Hydrosciences Montpellier, UMR 5569, Université Montpellier 2, Place E Bataillon, 34095 Montpellier cedex 05, France. casiot@msem.univ-montp2.fr
Morin
Guillaume
G
Juillot
Farid
F
Bruneel
Odile
O
Personné
Jean Christian
JC
Leblanc
Marc
M
Duquesne
Katia
K
Bonnefoy
Violaine
V
Elbaz-Poulichet
Françoise
F
D001151:Arsenic / Q000737:chemistry / Q000378:metabolism*; D001419:Bacteria; D011232:Chemical Precipitation; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D008906:Mining; D010084:Oxidation-Reduction; D010100:Oxygen; D014873:Water Pollutants / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
D014873:Water Pollutants; D007501:Iron; D001151:Arsenic; D010100:Oxygen