The widespread use of diisobutyl phthalate (DiBP) and plastic products in agriculture has led to new characteristics of soil pollution in which DiBP coexists with microplastics, but their combined effects on soil ecosystems, especially saline soil microorganisms, are unclear. This study evaluated DiBP (1 and 10 mg/kg) and polyethylene microplastics (PE-MPs, 0.25w/w) on saline soil microorganisms’ effects (60 days) from bacterial and fungal community structure and nitrogen-carbon cycle. DiBP exposure changed bacterial and fungal community structures, and the changes were more significant after increasing DiBP concentration or adding PE-MPs. Nitrospira , MND1 , and Lecanicillium abundance decreased, while Sphingomonas and Mortierella abundance increased. Aromatic compound and hydrocarbon degradation functions were activated (61.47 %–177.96 %), while nitrate reduction was inhibited (0.16 %–14.18 %). The increase in DiBP concentration inhibited the nitrogen cycle by reducing denitrification genes nirK and nirS abundance, and promoted the carbon cycle by enhancing β -glucosidase activity. The combined exposure of DiBP and PE-MPs inhibited the carbon cycle by reducing carbon fixation genes cbbLG and cbbLR abundance, and promoted the nitrogen cycle by enhancing urease activity. DiBP and DiBP + PE-MPs exposure activated enzyme activity through hydrophobic forces. Prolonged exposure had a significant impact on dehydrogenase activity and cbbLR gene abundance, while dehydrogenase activity may serve as an early warning indicator of DiBP and DiBP + PE-MPs effect to soil microorganisms. DiBP toxicity to microorganisms increased with increasing concentration (8.06 %–17.78 %). PE-MPs increased DiBP toxicity to microorganisms (8.27 %–22.56 %). This study suggests that combined contamination of DiBP and MPs requires particular attention in saline agricultural soils.
Qingyun Ma,Hao Tan,Jinlong Song,Miaomiao Li,Zhiye Wang,Rebecca E. Parales,Lin Li,Zhiyong Ruan
This study aims to investigate the effects of long-term nicosulfuron residue on an herbicide factory ecosystem. High-throughput sequencing was used to investigate the environmental microbial community structure and interactions. The results showed that the main contributor to the differences in the microbial community structure was the sample type, followed by oxygen content, pH and nicosulfuron residue concentration. Regardless of the presence or absence of nicosulfuron, soil, sludge , and sewage were dominated by groups of Bacteroidetes, Actinobacteria, and Proteobacteria. Long-term exposure to nicosulfuron increased alpha diversity of bacteria and archaea but significantly decreased the abundance of Bacteroidetes and Acidobateria compared to soils without nicosulfuron residue. A total of 81 possible nicosulfuron-degrading bacterial genera, e.g., Rhodococcus , Chryseobacterium , Thermomonas , Stenotrophomonas , and Bacillus , were isolated from the nicosulfuron factory environmental samples through culturomics. The co-occurrence network analysis indicated that the keystone taxa were Rhodococcus , Stenotrophomonas , Nitrospira , Terrimonas , and Nitrosomonadaceae_MND1. The strong ecological relationship between microorganisms with the same network module was related to anaerobic respiration, the carbon and nitrogen cycle , and the degradation of environmental contaminants. Synthetic community (SynCom), which provides an effective top-down approach for the critical degradation strains obtained, enhanced the degradation efficiency of nicosulfuron. The results indicated that Rhodococcus sp. was the key genus in the environment of long-term nicosulfuron exposure.
危险品化学品经营许可证（带存储）