Deciphering chromium oxidation state in staple food

Organic wastes produced on Réunion island exceed the French total chromium (Cr) standard values for their sales as soil amendment. Accordingly, the French Agency for Food, Environmental and Occupational Health & Safety (Anses) explicitly required additional information about the distinction between CrIII/CrVI in the edible parts of market gardening and forage crops grown on soils amended with organic wastes. XAS is an ideal probe to determine the oxidation state of Cr in plant matrix. We propose to use High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy (HERFD-XAS) to characterize the speciation of Cr in plants samples with “natural Cr levels” collected from field and laboratory experiments. The first objectives consists in producing sound data about Cr speciation in staple food required by authorities. The secondary goal is to fill the gap in fundamental knowledge of the Cr speciation in plants at low but environmentally-relevant range of concentrations.