EFFECTS OF ORGANIC-COMPONENT ON THE IMMOBILIZATION OF SELENIUM ON IRON OXYHYDROXIDE

The immobilization of selenourea and selenomethionine (organic forms o f selenium) onto iron oxyhydroxide (a model mineral) was studied and c ompared to that of selenite (inorganic Se). Selenourea and selenomethi onine were immobilized to a much lesser extent than selenite and while percentage immobilization onto a fixed mass of ferric oxyhydroxide de creased with increasing amount of selenite, that for selenourea and fo r selenomethionine increased. The presence of organic matter seemed to enhance selenite immobilization but decreased selenourea and selenome thionine immobilization. These results suggest that selenite and organ ic Se interact differently with ferric oxyhydroxide, with and without the organic matter present, resulting in a different immobilization be haviour.