Influence of pollutants on soil microbial community structure and function at a petrochemical landfill site: a high-throughput sequencing study

The petrochemical industry produces a large amount of solid wastes, including toxic and harmful pollutants．Landfill disposal of such wastes may cause potential harm to surrounding environment．Thus, it is urgent to study environmental influence of pollutants at petrochemical landfill site．In this work, 16S rDNA and metagenomics were examined to study soil microbial community structure and functions at a typical landfill site in northern China．Soil microbial community structure was found shifted when compared with a normal background site．At the genus level, abundance of Solirubrobacter was found decreased, abundance of Mycobacterium, Sphingomanas, Arthrobacter and Bradyrhizobium increased．Functions of soil microbial community at this landfill site showed marked differences from a control background site．High-abundance biological functions, as annotated by Cluster of Orthologous Groups of proteins (COG), were found involved in both maintaining normal physiological activities of microorganisms and adapting to exogenous pollution stress．Compared with the background site, differentially expressed genes at landfill site were found, mainly related to microbial degradation and toxicity response to pollution stress．Constructed impermeable system and low permeability medium conditions could effectively lessen impacts of landfill on microbial community structure and functions in the surrounding soil．Correlation analysis confirmed that pollution stresses, especially polycyclic aromatic hydrocarbons pollution stress, were an important factor causing alterations in soil microbial community structure and function ．