Unveiling the Distribution Characteristics of Benzene-Based Pollutants in a Retired Industrial Park and Their Influence Factors: Soil Properties and Microbial Communities

With the transformation of industrial enterprises in China, the relocation of numerous factories has led to the emergence of retired industrial parks with serious pollution. This study investigated the contamination of benzene-based pollutants (BBPs) in soil and their relationship with soil texture, physicochemical properties, and microbial communities at a former factory site in Shanghai. The results indicated that benzene and toluene were the main pollutants in the region, accounting for 25.7-36.1% and 7.6-10.2% of the total pollutants, respectively. The horizontal contamination distribution pattern of BBPs at different sampling points were clearly related to the functional zoning of the area. Sampling points close to workshops and bathrooms possessed higher contamination levels of BBPs than those close to warehouses and office buildings. With the increase in sampling depth, the gradually rising soil density and soil porosity ratio reduced the adsorption capacity of soil for BBPs, thereby promoting the volatilization and release of BBPs in deeper soil layers to a certain extent, resulting in a "shallow > deep" trend for the content of BBPs. The abundance of norank_f__norank__o_norank__c__Bathyarchaeia in the soil may be the main functional microorganisms affecting the distribution of BBPs. Styrene and chlorobenzene exhibited significant correlations with microbial communities, primarily involving bacteria (Desulfobacterium, Thermincola, and Trichlorobacter) and archaea (including norank_f_Nitrosopumilaceae, norank_f_norank_o_norank_c_Nitrososphaeria, and Methanocella). This study identifies and analyzes the BBP contamination characteristics in a typical retired industrial park in Shanghai, providing valuable references for risk assessment and microbial remediation of such contaminated areas.