Impact of biochar-induced vertical mobilization of dissolved organic matter, sulfamethazine and antibiotic resistance genes variation in a soil-plant system

• Published in: Journal of hazardous materials 2021-09, Vol.417, p.126022-126022, Article 126022
• Main Authors: Qiu, Linlin, Wu, Jingjing, Qian, Yuan, Nafees, Muhammad, Zhang, Jingxian, Du, Wenchao, Yin, Ying, Guo, Hongyan
• Format: Article
• Language: English
• Subjects: Antibiotic resistance genes; Biochar; Dissolved organic matter; Sulfamethazine; Vertical migration
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.126022

The migration risk of antibiotic and antibiotic resistance genes (ARGs) have attracted lots of attentions due to their potential threaten to public health. Strategies to reduce their vertical mobilization risk are urgently required for groundwater safety and human health. Biochar enjoys numerous interests due to its excellent sorption affinity. However, little was known about the efficacy of biochar amendment in impeding the vertical mobilization of antibiotic and ARGs. To fill this gap, a column study was carried out to investigate biochar-induced variations in the leaching behavior of dissolved organic matter (DOM), sulfamethazine (SMZ) and ARGs. Results showed that biochar addition enhanced DOM export from soil, changed its composition and impeded the vertical transport of SMZ. Biochar amendment could effectively decrease the occurrence of extracellular and intracellular sul2 in soil and impede its vertical transportation, however, it did not work out with sul1 gene. Structural equation modeling analysis demonstrated that the abundance of sul2 was significantly controlled by SMZ concentration, while the primary drivers of sul1 were SMZ concentration and DOM content. These results indicated the failure in inhibiting the vertical transfer of sul1 under biochar amendment and highlighted the important role of DOM in the leaching of soil ARGs. [Display omitted] •Biochar enhanced the export of DOM from soil and changed its composition.•Biochar reduced the presence of soil sul2 in both eDNA and iDNA but not for sul1.•Biochar can impede the vertical transport of SMZ and sul2, not for sul1 and intI1.•The main driver of sul2 in leachate was SMZ and sul1 was also controlled by DOC.•Biochar-induced elevated DOC might compete with sul1 in eDNA for sorption sites.