REDUCTION OF CHROMIUM(VI) AT SUB-MUG 1-1 LEVELS BY FULVIC-ACID

The rate of chromium(VI) reduction by a reference fulvic acid is studied by the separation of 51Cr-labelled Cr(VI) from the reaction mixture with a cobalt tetramethylenedithiocarbamate carrier complex and γ-analysis of the carrier precipitates. This carrier is shown to suffer less from interferences than iron(III) hydroxide, the carrier used by previous workers to separate the reaction product, Cr(III). Information is obtained about the effects of pH, temperature and reactant concentrations on the rate of the reduction at the low levels (sub-μg l-1) of dissolved chromium that occur in clean natural waters. The method is used to study Cr(VI) reduction in an organic-rich, acidic lake water. © 1990.