The dissipation of Di (2-ethylhexyl) phthalate in soil with different moisture: A comprehensive analysis of its relationship with microbial community structure

Abstract

Phthalate esters (PAEs) have become an increasing pollutant in agricultural soils, and soil moisture plays a crucial role in influencing the dissipation of PAEs in soil. Di (2-ethylhexyl) phthalate (DEHP) was selected as a representative of PAEs in the soil microcosm experiment to investigate the effects of soil moisture on the dissipation of PAEs. Soil microorganisms were analyzed by phospholipid fatty acids (PLFAs) and DNA-based (bacteria 16S rRNA gene and fungi ITS gene) high-throughput sequencing to reveal the relationships between microbial communities and PAEs dissipation. The results showed that 60 % water-holding capacity (WHC) was an appropriate moisture for DEHP dissipation. According to the PLFAs analysis, DEHP significantly increased the total microorganism biomass and the growth of actinomycetes, and it significantly decreased the H value and the growth of gram (−) bacteria. Significant correlations were found between soil moisture and the biomass of fungi, gram (−) bacteria, gram (+) bacteria, anaerobe, and actinomycetes. The fungal biomass was higher in the soils with 60 % WHC than those in the soils with 100 % WHC. The relative abundance of DEHP-degrading bacteria (Sphingoaurantiacus, Sphingomonas, Lysobacter, and Arthrobacter) and DEHP-degrading fungi (Fusarium) were higher in the soils with 60 % WHC than those in the soils with 100 % WHC, based on DNA-based high-throughput sequencing analysis. Meanwhile, significant positive correlations were observed between the dissipation of DEHP and the abundance of degrading microorganisms. DEHP significantly decreased the bacterial diversity but increased the richness of bacteria and actinomycetes, as well as the relative abundance of DEHP-degrading bacteria (Proteobacteria, Sphingomonas, Gemmatimonas, and Ramlibacter) and fungi (Fusarium and Talaromyces).