Study On Effect Of Arsenic On Soil Microbial Quantity And Soil Biological Activity

Coal is one of major sources of arsenic in the environment, coal gangue releasing arsenic contaminants into the environment can damage on soil. This paper takes gangue weathered soil and natural soil of Xinqiu opencast coal mine in Fuxin as the research object, determines the arsenic content and physical and chemical properties of soil, and uses pot experiment on soil to acclimate microorganism. By measuring quantity of soil microorganism, respiration intensity and enzyme activity of soil with different concentration of arsenic, reveals the impact of arsenic on microorganism and biological activity in different soil. The results indicated that,(1) Natural soil fertility is at the medium level, arsenic content is 5.547 mg/kg, and fertility of gangue weathered soil is lower than that, arsenic content is 2.854mg/kg. Heavy metals (Cr, Cd, Pb, Cu, Zn) in gangue weathered soil are higher than that in natural soil.(2) The quantity of microorganism in natural soil is higher than that in gangue weathered soil, and the largest number of soil microorganisms is bacteria, actinomyce secondly, and fungus least. The quantity of bacteria, actinomyce and fungus decreased with the increase of arsenic concentration, bacteria and actinomycete are sensitive to arsenic, downward trends of these quantities are obvious with arsenic content increasing, and arsenic has little effect on fungus.(3) Respiration intensity of natural soil is greater than that of gangue weathered soil. Arsenic inhibits respiration intensity of soil significantly. The trend of soil respiration intensity with arsenic content is consistent with the trend of microorganism quantity in soil.(4) Arsenic has different degrees of inhibition to soil enzyme activity, urease and sucrase activity is more sensitive to arsenic, and catalase activity inhibition is relatively weak; Under the same arsenic content, the activities of sucrase and catalase in natural soil are greater than that in gangue weathered soil, but the urease activity in gangue weathered soil is greater than that in natural soil. Soil enzyme activity and quantity of microorganism have significant positive correlation.