Tracking antibiotic resistance through the environment near a biosolid spreading ground: Resistome changes, distribution, and metal(loid) co-selection

• Published in: The Science of the total environment 2022-06, Vol.823, p.153570-153570, Article 153570
• Main Authors: Hung, Wei-Cheng, Miao, Yu, Truong, Nhi, Jones, Adriane, Mahendra, Shaily, Jay, Jennifer
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Heavy metals; Land application; Solid waste; Spatial distribution
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.153570

The application of urban wastewater treatment plants (WWTPs) products to agricultural lands has contributed to the rising level of antibiotic resistance and drawn a critical public health concern. It has not been thoroughly investigated at which spatial scales a biosolid applied area as a potentially predominant source affects surrounding soil resistomes. This study investigated distribution and impact of WWTP biosolids treated with anaerobic digestion on an agricultural area. Heterotrophic plate counts (HPCs) and quantitative polymerase chain reaction (qPCR) were performed for detection of selected antibiotic-resistant bacteria (ARB), selected antibiotic resistance genes (ARGs), intI1 genes, and 16S rRNA genes. Biosolid samples contained significantly higher levels of selected ARGs than the raw agricultural soils (p < 0.05). The average relative abundances of intI1, sul1, blaSHV, and ermB genes were significantly higher in biosolid-amended soils than nearby agricultural soils (p < 0.05). Spatial interpolation analysis of relative gene abundances of intI1, sul1, sul2, and tetW across the studied area further indicated directional trends towards the northwest and southeast directions, highlighting possible airborne spread. Concentrations of Co, Cu, Ni, and Fe were found to be significantly and positively correlated with relative abundances of intI1, sul1, and tetW genes (p < 0.05). The resistance ratios of culturable antibiotic-resistant bacteria in agricultural soils with biosolid amendments were generally identical to those without biosolid amendments. This study will advance the understanding of the antibiotic resistome in agricultural soils impacted by long-term waste reuse and inform the evaluation strategies for future biosolids application and management. [Display omitted] •The effect of biosolid application on soil ARGs, ARB, and metal(loid)s was studied.•IntI1 and selected ARGs were higher in biosolid-added soils than agricultural soils.•ARGs were negatively correlated with distance to the biosolid spreading ground.•Soil ARGs distribution was consistent with the dominant wind direction in winter.•This study informs the evaluation strategies for long-term biosolids application.