Due to the rapidly developing urbanization in China, various strategical transformations of industry structure and city layout are promoted by local governments, uncovering the issues of numerous remained sites consist of abandoned industrial buildings and resources that have been facing the situation of relocation. A large number of heavily polluting industrial enterprises originally in the main urban area have been moved into industrial parks.

Along the long-time production history, a large amount of toxic and harmful substances are remained in the site soil by some heavily polluting enterprises, because of improper operations, leakages, insufficient environmental supervisions and some other reasons, adversely affecting the local ecological environment, the health of local people as well as land redevelopment and utilization. Chlorinated hydrocarbons are common pollutants in the soil of chemical pollution sites in Jiangsu Province. In addition to chemical detection and analysis methods, biological diagnosis is also an important means to assess the environmental risks associated with organically contaminated soils. Soil and groundwater microbial community diversity is very sensitive to changes in soil chemical properties and can be used as an important biological indicator to measure soil and groundwater quality and to assess the sustainability of soil ecosystems. The site pollution habitat is a special habitat composed of site pollutants-soil-groundwater-microorganisms. A series of physical and chemical changes caused by external pollutants will occur in the soil and groundwater, and profoundly affect the environmental and biological properties of the site.

We attempted to investigate microbial community responses to chlorinated hydrocarbons-contaminated sites, and identify distinct assemblages of bacteria and fungi capable of thriving in chlorinated hydrocarbons-rich environment use high-throughput sequencing technology. Therefore, the spatial variations of the microbial community structure collected from varying concentrations of chlorinated hydrocarbons within the contaminated site and identify microbial capable of chlorinated hydrocarbons degradation in groundwater environments were evaluated. Across all samples, a total of 3,840 unique operational taxonomic units (OTUs) were identified, with 6 taxa having strong correlations with increased chlorinated hydrocarbons concentration. Putative chlorinated hydrocarbons degrades such as Brevundimonas, Rhizobium and Pseudonmonas were present within groundwater and soil across all levels of chlorinated hydrocarbons contamination. In addition, 652 OTUs were obtained through our ITS rRNA gene survey, belong to 6 phyla, 16 classes, 35 orders, 67 families and 94 genera respectively. However, by principal component analysis of the OTU of the fungus in the control group within different contaminated environments, changes of fungi abundance and diversity in varying concentration of contaminated soil and groundwater environments are not significant. The results found that bacterial community structure shifted across chlorinated hydrocarbons contaminated level such that increasing chlorinated hydrocarbons contamination might enrich unique chlorinated hydrocarbons-degrading assemblages especially within these groundwater environments.