Heavy Metals Pollution in Iron Tailing Soil and its Effects on Microbial Communities Metabolism and Enzyme Activities

Abstract

The purpose of this research is to examine the relationship between the microbial communities and heavy metals, the activities of enzymes in tailing soils of iron ore in the upstream area of Hanjiang river in Shaanxi, China was a case study. Six soil samples were gathered from the tailing region at different distances. The samples were then grouped into two parts, one was sieved with a nylon sieve of 0.149μm, in other to obtain its chemical composition, and the type of heavy metals present, and the other was analyzed using the CLPP and soil enzymes test after been stored at 4ºC. Metals were digested and measured in ICP-AES solutions. Biolog ECO-micro plates was used to determine the community-level physiological profiles (CLPP).

Results and discussions of tailing soils of iron ore shown a significant variation, mainly manifested in the metabolic patterns of carbon sources such as polymer and amino acids, with an increasing soil heavy metals pollution. The utilization of carbon sources by microbial communities was activated in slightly polluted soils and was constrained in heavily polluted soils. Activities of soil urease, alkaline phosphatase, catalase and dehydrogenase declined with intensified soil heavy metals pollutions. The soil urease, protease, alkaline phosphatase and catalase activities in the tailing center site were 9.91%~21.19%, 29.94%~37.16%, 24.15%~29.90% and 10.0% lower than those in the farthest distance from the center respectively. The soil content affected; urease, alkaline phosphatase, and catalase which were negatively correlated.