Effects of di-(2-ethylhexyl) phthalate on microbial biomass carbon and microbial community structural diversity in a Mollisol

One of the most common persistent organic pollutants is di-(2-ethylhexyl) phthalate (DEHP), which has caused considerable pollution in the Mollisols of agricultural areas in northeast China. This research investigates the effects of different concentrations of DEHP from 0 to 35 days on microbial biomass carbon (MBC) and structural diversity in the microbial community of Mollisols. The results indicated that contamination by DEHP of more than 20 mg kg(-1) could clearly affect MBC and structural diversity of the microbial community of a Mollisol in a short time depending on the dose of DEHP. At concentrations of DEHP >20 mg kg(-1), we observed that the larger was the concentration of DEHP, the greater was the effect on the MBC and diversity of the soil microbial community. The DEHP concentration or incubation time had negative correlations with MBC, and the evenness (E-H), Shannon (H) and richness (S) indices of the microbial community, and the DEHP concentration had a dominant effect on microbial properties. The dominant bacterium in the DEHP-contaminated soil was Bacillus. Furthermore, bacterial community structure changed under different amounts of DEHP stress and with the increase in incubation time; Pseudomonas and Sphingopyxis clearly increased in number with large concentrations of DEHP. The change in the microbial population indicated that these two bacteria might have a strong resistance to change under the microbial DEHP stress. Highlights DEHP significantly changed MBC and microbial diversity of a Mollisol. The change in MBC was related to the composition of the soil microbial community structure. DEHP had a persistent effect on the microbial community in a Mollisol. Bacillus were the dominant bacteria in the DEHP-contaminated soil.