URANIUM ISOTOPES IN THE HOOGHLY ESTUARY, INDIA

Uranium isotopes are measured in the estuarine waters, bed sediments a nd suspended matter of the most polluted estuary of India, the Hooghly , which flows through the metropolis of Calcutta. The uranium concentr ations in the freshwater-endmember of the estuary are higher (3.9-3.5 mug/l) than in any other estuary so far studied; the U-234/U-238 activ ity ratios in the river channel (Cl less-than-or-equal-to 7.29 g/l) ar e low, namely < 1.10 +/- 0.02. Uranium behaves non-conservatively in t he Hooghly estuary, its concentrations are less than the values expect ed from the theoretical dilution curve obtained by joining the two end member-concentrations. Based on one set of measurements, it is estimat ed that approximately 25% of the uranium entering the estuary in the d issolved form is getting removed from the estuarine waters, most likel y onto sediments.