Soil Responses to Nano-enhanced Bioremediation Technique: The Synergistic Effects of Vermicompost and Fe3O4 Nanoparticles Against Phthalate Contamination
摘要
Phthalate esters’ toxicity, bioaccumulation, and food safety challenges have drawn increased attention to their effects on soil health. This study aimed to improve the agricultural soil health under di(2-ethylhexyl) phthalate (DEHP) stress by comparing vermicompost, vermicompost assisted by Fe3O4 NPs, and Fe3O4 nano-enhanced remediating techniques. The randomized complete block design (RCBD) was set to evaluate soil responses. There was a significant difference between the final removal efficiencies (RE, %) of all three amended groups with the control (P-value < 0.0001) and compared to each other (P-value < 0.0001; R2 = 0.99). After 42 days, the removal efficiency was significantly higher in the mixed amended soil with vermicompost and Fe3O4 NPs (RE = 94.58%) compared to the soil assisted by Fe3O4 NPs (RE = 80.90%) and vermicompost (RE = 69.34%) (P-value < 0.05). The final C:N ratio in the vermicompost-consisted treatments was in the range of 10.24–13.16. The ultimate rate of nutrient decomposition in the S1VN treatment (DEHP concentration = 10 mg/kg (dw. soil), Fe3O4NP dose = 1.2 g/kg (media)) with synergistic efficiency followed this order: AP (81.25%) > SOM (43.64%) > TC (36.33%) > TN (32.09%) > EK (26.76%). The five dominant DEHP-degradation bacteria in S1VN were found to be Bacillus licheniformis, Bacillus subtilis, Pseudomonas stutzeri, Microbacterium hibisci, and Bacillus aerius. Following the DEHP breakdown, the Bacillus and Pseudomonas taxa demonstrated the function of phosphate-solubilizing bacteria (PSB) in phosphorus availability. These findings suggest the use of Fe3O4 NP-enhanced vermicompost as an eco-friendly remediation strategy for supporting soil health, nutrients, and microbial population.