The Soil-Plant Interaction Team at the Institute of Agricultural Resources and Regional Planning (IARRP), part of the Chinese Academy of Agricultural Sciences, recently found out the mechanism by which biochar inhibits the microplastic-mediated spread of antibiotic resistance genes (ARGs) in soil. In a study, the team systematically constructed a tripartite interaction mechanism and a data-driven prediction framework involving microplastics, biochar, and ARGs. The related findings were published in the Journal of Hazardous Materials, a leading publication in the field of environmental science and engineering, under the title "Biochar as a strategy to intercept microplastic-mediated ARGs spread in soil: Mechanisms, predictive insights, and research framework".

ARGs represent a long-term ecological threat lurking in soils. When microplastics enter the soil, they are not merely inert particles, rather, they can transform into "hotbeds" that adsorb antibiotics, heavy metals, and pathogenic microorganisms, thereby providing a unique "plastisphere" micro-environment for microbial colonization and the formations of biofilms. The high density of microbial aggregates, selection pressure from pollutants, and frequent cell-to-cell contacts collectively foster the enrichment, horizontal transfer, and long-distance spread of ARGs. These antibiotic-resistant bacteria or extracellular DNA attached to microplastics might even spread along the "soil-plant-food chain" pathway, posing severe threats to ecosystems and public health.

Biochar, as a highly promising ecological remediation technology, shows broad application prospects in the field of soil emerging pollutants management. The review systematically elucidated biochar's inhibitory mechanisms from physical-chemical, genetic, and ecological dimensions. In the physical-chemical dimension, biochar can heterogeneously aggregate with microplastics and coat their surfaces, effectively weakening their functions as pollutant carriers and microbial colonization hotspots. Simultaneously, through pore filling, electrostatic attraction, and hydrogen bonding, biochar can achieve efficient adsorption of free antibiotics and extracellular DNA. In the genetic dimension, biochar can significantly reduce the abundance of mobile genetic elements, or MGEs, such as integrons and transposons, thereby inhibiting horizontal gene transfer processes like conjugation, natural transformation, and phage transduction. In the ecological dimension, biochar reshapes microbial community structures by regulating soil pH, dissolved organic carbon, and nutrient availability, thereby weakening the ecological competitive advantage of high-risk resistance gene hosts. Additionally, the study emphasizes that the ultimate remediation efficacy of biochar is constrained by multiple factors such as raw material sources, pyrolysis temperatures, degrees of microplastic aging, and soil background conditions, and its inhibitory effect is significantly environment-dependent, meaning that not all biochars can consistently achieve the expected outcomes.

Moreover, the research team conducted a comprehensive evaluation using bibliometrics and random forest analysis. CiteSpace analysis showed that between 2018 and 2025, while research on biochar or microplastics alone in relation to ARGs has grown, soil studies involving the tripartite interaction among biochar, microplastics, and ARGs remain relatively scarce. By using random forest modeling on 168 data sets from 12 studies, the research identified that Verrucomicrobia was a key predictor for ARGs (tetA and macB), while Bacteroidota significantly contributed to the prediction of ARGs (TxR) . The result revealed the association between specific phyla and ARGs, providing quantitative support for selecting microbial indicator groups and optimizing biochar remediation strategies.

Based on this, the study also proposed priority research directions for management: First, to distinguish the relative contributions of conjugation, transformation, and transduction in horizontal gene transfer processes; second, to establish the relationships among raw material,  pyrolysis conditions, and biochar effects; third, to analyze the impacts of microplastic characteristics (type, morphology, aging) on the "plastisphere" resistome, and to verify the inhibitory effects of biochar across multiple scales (soil columns, runoffs, fields). Additionally, it advocated the establishment of standardized data reporting, open databases, and external validation models to promote the transition of researches from descriptive analysis to predictive risk management, thereby providing theoretical support for the collaborative management of emerging pollutants and farmland soil safety. 

A framework diagram illustrating how biochar regulates the spread of ARGs in soil co-contaminated with microplastic

Dr. Zhao Shuwen, a graduate of the Institute of Agricultural Resources and Regional Planning at Chinese Academy of Agricultural Sciences, is the first author, and Prof. Zhang Qianru is the sole corresponding author. The research was jointly supported by the State Key Laboratory of Efficient Utilization of Arable Land in China, the Jing-Jin-Ji Regional Integrated Environmental Improvement-National Science and Technology Major Project and the Earmarked Fund for China Agriculture Research System.

Citation:

Zhao S, Zhang Q, Huang Q, et al. Biochar as a strategy to intercept microplastic-mediated ARGs spread in soil: Mechanisms, predictive insights, and research framework[J]. Journal of Hazardous Materials, 2026，515：143049.

Link: https://doi.org/10.1016/j.jhazmat.2026.143049