Biogeochemical cycle and speciation of As and Cr in an acid mine environment : The case of Carnoulès Creek, France I. Le Hécho, C. Pecheyran, S. Charles, M. Monperrus, M.-P. Pavageau, C. Casiot, M. Potin-Gautier, M. Leblanc et O.F.X. Donard J. Phys. IV France, 107 (2003) 735-738 DOI: 10.1051/jp4:20030406