INFLUENCE OF TEMPERATURE AND ORGANIC AMENDMENTS ON THE MOBILIZATION OF SELENIUM IN SEDIMENTS

Toxic amounts of selenium have been found in sediments and water at Kesterson Reservoir (Merced County, Calif.). A sediment column study was established for determination of Se0 (Se volatilization potential) and k (Se voltalization rate coefficient) derived from a first-order kinetics model. Increasing the temperature from 15 to 35°C promoted volatilization of Se (Q10 = 1.96). The amount of Se leached out of the sediments was independent of the initial total Se inventory. Volatilization of Se followed a first-order reaction and was highly dependent on the initial Se concentration. The Se0 ranged from 0.18 to 3.63 mg Se kg-1 sediment with k values ranging from 0.003 to 0.053 day-1. The addition of organic amendments promoted volatilization with Se being less available for leaching. The application of gluten, a wheat storage protein, was found to enhance voltilization of Se (1.7 to 3.2-fold over the control) more strongly than other treatments (e.g. casein, orange peel and cattle manure). Volatilization may be an important dissipation mechanism for detoxification of seleniferous sediments. © 1990.