Abstract:Taking the water around the uranium tailing pond in the upper reaches of Lake Poyang Basin as the research object, the pollution characteristics of chromium (Cr) were studied, and the contents of Cr in different speciations were calculated by the hydrogeochemical simulation software PHREEQC. Then the morphological variations under different conditions were discussed, and health risk assessment was realized. The results showed that the concentrations of Cr in the uranium tailing discharge water, tailing leachate and shallow groundwater did not exceed the relevant standard values. It was found that trivalent chromium was the main form with exhibition of Cr(OH)2+ and Cr(OH)2+ in most samples. Chromium speciation were affected by pH and electron activity (pe) together. In the condition of pH=3-5, CrF2+ was the dominant species. When pH>5, the effect of pe value on the chromium speciation was more obvious with the increase of pH. When the pe value increased, the concentration of hydrolysate Cr(Ⅲ) decreased gradually but the oxidation product Cr(Ⅵ) increased gradually. The health risk assessment proves that chromium in shallow groundwater did not cause carcinogenic risk and non-carcinogenic risk to human health. While the pH and pe changed, the carcinogenic risk coefficient of chromium will be higher than the maximum acceptable level recommended by ICRP and USEPA. As the toxicity of hexavalent chromium is much stronger than trivalent, it is necessary to pay close attention to the pe and pH values in the water to avoid the increase of pollution.