CHLORATE ION EFFECT ON ORGANIC-MATTER DESTRUCTION

The effects of different chlorate ion concentrations on aerobic and anaerobic glucose destruction, as a function of different mineral nitrogen forms, was studied under laboratory conditions. Under aerobic conditions, glucose oxidation did not depend on the form of the nitrogen in the medium. Under anaerobic conditions, chlorate ion effect on glucose oxidation depended to a significant degree on the form of nitrogen. If nitrogen was utilized in the ammonium form, then chlorate ions, at a concentration of 250 mg/ml, increased the glucose destruction rate, probably because under these conditions, it served as the sole electron acceptor. At a concentration of 500 mg/liter, chlorate ion did not have a stimulatory effect, but exhibited toxicity. In the presence of the nitrate form of nitrogen, at 250 mg/liter, chlorate ion did not accelerate glucose destruction and at 500 mg/liter inhibited this process. The significant decrease in the anaerobic destruction rate of glucose when nitrates were utilized may be due to competition between chlorate and nitrate ions for nitrate reductase.