Effect of Increasing Concentrations of Chromium on Soil Enzymatic Activities and Soil Respiration.

The effects of various concentrations of chromium on the activity of dehydrogenase, catalase and soil respiration were studied after 14, 28, 56 and 112 days of incubation period. Chromium was applied as K2Cr2O7 in the amounts of 0, 25, 50, 100, 200, 400, 800 ìg g(-1) of soil. Soil contamination with Cr decreased the activity of dehydrogenase, catalase and soil respiration. About 36.92% and 44.88% inhibition in the activity of dehydrogenase was caused by 50 and 100 ìg g(-1) Cr addition respectively, after 14 days of incubation. Catalase activity significantly (P < 0.001) decreased with applied doses of chromium after 14 days of incubation. A significant inhibition in soil respiration was observed after 56 days of incubation with applied doses of chromium. These results suggest that soil respiration, dehydrogenase and catalase enzyme activities are suitable parameters for the toxicity test.