Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202604005
To elucidate the effects of exogenous antibiotic-resistant bacteria (ARB) exposure on wheat growth and associated bacterial community assembly, the inhibitory impacts of exogenous ARB on wheat seedling root and shoot length, shifts in root endophytic and rhizosphere bacterial communities, and the horizontal transfer of exogenous antibiotic resistance genes (ARGs) to indigenous endophytic bacteria were investigated using plate culture counting and 16S rRNA high-throughput sequencing. The results showed that exogenous ARB exposure significantly suppressed wheat seedling root and shoot growth, with inhibition rates increasing in an ARB concentration-dependent manner. At an exogenous ARB concentration of 108 CFU/mL, the inhibition rates of seedling root and shoot length reached 68.83% and 36.87%, respectively. During the period of ARB exposure, the relative abundance of Clostridium_sensu_stricto_5 in root endophytic bacteria increased rapidly, becoming the most dominant genus (45.02%) by the end of the exposure period. In contrast, Betaproteobacteriales remained the dominant order in the rhizosphere bacterial community throughout the experiment, with its relative abundance increasing continuously over time. The proportion of ARB-carrying endophytic bacteria initially decreased and then increased during exposure, showing a significant positive correlation with the relative abundances of Clostridium_sensu_stricto_5, Clostridium_sensu_stricto_1, Bacillus, and Paenibacillus (P<0.05). In summary, exogenous ARB exposure significantly inhibits wheat seedling growth and alters the community structure of both root endophytic and rhizosphere bacteria. Sustained ARB exposure leads to the transfer of exogenous ARGs to root endophytes, and Clostridium_sensu_stricto species may act as potential hosts for ARGs in wheat seedling roots.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025022704
Secondary inorganic aerosols (SNA), comprising sulfate, nitrate, and ammonium, are critical contributors to PM2.5 pollution in the Fenwei Plain, yet their formation mechanisms remain poorly characterized. Wintertime observations in Taiyuan revealed SNA as the dominant PM2.5 component, with a mean mass concentration of 33.19 ± 18.72 μg m−3, accounting for 47.13% of total PM2.5 mass. SNA concentrations increased markedly with pollution severity, but even under relatively clean conditions, SNA maintained a high mass fraction. Diurnal variation and correlation analyses indicated that nitrate formation pathways differed between day and night, largely governed by relative humidity (RH). During daytime, high RH (>55%) facilitated the partitioning of gaseous HNO3 to particulate nitrate. At night, RH positively correlated with nitrate concentration and nitrogen oxidation rate (NOR), with increased aerosol liquid water content (AWC) promoting NO2-to-nitrate conversion. The PM2.5 pH ranged from 4.3 to 5.2, and sulfate formation was primarily driven by H2O2 oxidation, with NO2 oxidation as a secondary pathway. These findings enhance understanding of SNA formation in the Fenwei Plain and provide a scientific basis for air quality policy.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202511043
Zero-valent iron (ZVI) suffers from surface passivation and low electron utilization in reductive removal of nitrobenzene (NB). To address these issues, a ball-milled iron/digestate biochar composite (BM-Fe/DBC) was prepared and compared with a physically mixed counterpart (PM-Fe/DBC). Characterization revealed that ball milling tightly embedded ZVI particles into the carbon matrix, forming Fe–C chemical bonds and a strong interfacial coupling structure that established efficient electron transfer channels. This structure significantly enhanced the micro-galvanic effect between iron and carbon, yielding superior reduction performance across a wide pH range (3–9). Under optimal conditions (Fe:C mass ratio 2:1, dosage 1.0 g·L−1, pH 5), BM-Fe/DBC achieved 79.9% NB removal, and the generation of aniline (AN) was 1.85 times that of PM-Fe/DBC. Mechanistic studies indicated that the intimate Fe–C interfacial coupling promoted sustained ZVI corrosion and enhanced the production of indirect reducing species, including adsorbed Fe(II) and atomic hydrogen (H*). Electrochemical analyses showed that BM-Fe/DBC exhibited a lower corrosion potential, a higher corrosion current density (approximately 2.15 times higher), and lower charge transfer resistance, kinetically confirming its superior electron transfer capability. These findings reveal that constructing strong interfacial coupling in iron–carbon composites via mechanochemical methods can effectively overcome key limitations of ZVI in reduction reactions, providing a theoretical basis and practical pathway for designing high-performance water treatment materials.