Enzymatic Activities in Soils Contaminated with Diesel Oil

The influence of soil contaminated with the diesel oil on the enzymatic activities (dehydrogenase, urease, phosphatase and lipase) was investigated and it focused on the changes in the levels of enzymatic activities to determine the possibility of using these values as indicators in assessing the bioremediation test. The relationship among enzymatic activities and biochemical parameters were analyzed. And the results indicated that the enzymatic activities were related to the total organic carbon content and the diesel oil strength in soil. The results of bioremediation test indicated that the microbial biomass and the soil enzymatic activities of dehydrogenase, urease and phosphatase increased after the disappearance of volatile aromatic hydrocarbons (VAHs) from the soil. But the lipase activity showed an inverse time course. This suggested that the inhibitory effect of diesel on the soil biological properties is a consequence of VAH content in the soil. The correlation among the different biological parameters showed that the lowest number of significant correlation was dehydrogenase activity, while the urease activity showed the highest number of correlations and followed by the phosphatase activity and lipase activity. It concluded that these biological parameters can be used as indicators of the soil biochemical quality.