Effects of novel bio-organic fertilizer on the remediation of PAEs-contaminated soil and its bacterial community composition

Phthalates (PAEs) are emerging organic pollutants that threaten agroecosystems by diminishing agricultural productivity and posing risks to human health. However, traditional organic fertilizers have limited effectiveness in remediating PAE-contaminated soils, while bacterial remediation often lacks stability in heterogeneous soil environments. Here, a novel bio-organic fertilizer (N-BOF) containing the PAE-degrading Bacillus megaterium YJB3 was evaluated in pot experiments for its effectiveness in remediating PAEs-contaminated soils. Results revealed that N-BOF significantly reduced PAE concentrations in soil. At PAE levels of 20 and 100 mg/kg, N-BOF reduced DBP and DEHP concentrations by over 96 %, with a maximum reduction of 99.39 %. Additionally, N-BOF significantly enhanced soil physicochemical properties, increasing organic matter (OM), total organic carbon (TOC), cation exchange capacity (CEC), nutrient availability, and pH. N-BOF also improved the soil bacterial community, enhancing diversity, degradation capacities, and the abundance of aromatic compound-degrading bacteria. Ecological risk assessments demonstrated that N-BOF effectively mitigated PAE contamination risks, reducing the risk quotients (RQ) of DBP and DEHP to safe levels. This study provides practical strategies and theoretical insights for the sustainable remediation of PAE-contaminated soils, utilizing composting to simultaneously improve soil fertility and effectively eliminate PAEs.