Heavy metal mitigation in soil and plants using organic and inorganic amendments alone and in combination

The use of organic and inorganic amendments like stilbite-zeolite (SZ) and nano-biochar (NBC) in phytoremediation holds immense promise, long-term stability, and its effectiveness necessitate comprehensive research. This study aimed to evaluate their potential in mitigating heavy metal contamination in soil and plants. Our results shows that SZ and NBC treatments significantly impacted heavy metal levels, notably reducing arsenic (As), nickel (Ni), lead (Pb), cadmium (Cd), and mercury (Hg) accumulation in plant tissues. The treatments exhibited varying degrees of effectiveness in reducing heavy metal levels. Notably, SZ₂ treatment decreased As and Pb levels by 33.33% and 20%, respectively, while NBC₃ achieved even greater reductions, lowering As by 53.33% and Pb by 30%. Moreover, SZ₂, SZ₅, and NBC₃ treatments halved Cd levels, showcasing their potential in mitigating heavy metal contamination in rice. However Hg levels remained largely unaffected, except for NBC₁, which unexpectedly doubled its concentration. In soil, SZ₂ treatment significantly reduced metal concentrations, particularly Cd (66.8% reduction) and Hg (70.7% reduction). Conversely, SZ₃ and SZ₇ treatments increased metal concentrations, suggesting that certain zeolite applications might enhance metal bioavailability. NBC treatments showed varying effectiveness, with NBC₃ being the most effective, substantially reducing As, Pb, and Cd levels.