Cheema, Amina, et al (2024) Unraveling the mechanisms of free radicals-based transformation and accumulation of potentially toxic metal(loid)s in biochar- and compost-amended soil-plant systems. Journal of Cleaner Production. https://doi.org/10.1016/j.jclepro.2024.141767

In a world facing escalating soil contamination, particularly by potentially toxic metal(loid)s (PTMs), the quest for effective remediation strategies intensifies. Amidst this urgency, biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More (BC) emerges as a promising soil amendmentA soil amendment is any material added to the soil to enhance its physical or chemical properties, improving its suitability for plant growth. Biochar is considered a soil amendment as it can improve soil structure, water retention, nutrient availability, and microbial activity.   More, renowned for its ability to immobilize contaminants. However, the intricate mechanisms underlying BC’s efficacy, particularly concerning free radicals, remain obscure.

Recent research delves into this complexity, exploring how BC-generated free radicals influence the immobilization and transformation of PTMs in soil-plant systems. The study, employing various BC and compost (Comp) treatments, investigates their effects on maize growth and the geochemical dynamics of PTMs. Results unveil a notable rise in free radical concentration in BC and Comp treatments, indicating their pivotal role in PTM immobilization.

Interestingly, BC treatment displays a slight reduction in functional groups, suggesting adsorption onto its surface, while Comp treatment enhances organic matter content, potentially aiding in PTM stabilization. The combined treatment exhibits intermediate effects, hinting at synergistic interactions between BC and Comp. Moreover, X-ray diffraction analysis suggests minimal direct effects of BC on soil mineralogy.

This study sheds light on the critical role of BC-generated free radicals, particularly hydroxyl radicals (•OH), in PTM immobilization within soil-plant systems. By unraveling the interplay between BC, free radicals, and PTMs, the research provides novel insights into soil remediation strategies, offering potential avenues for optimized soil management practices.

Ultimately, these advancements not only hold promise for sustainable agriculture and food security but also pave the way for a healthier future, safeguarding both ecosystems and human well-being from the perils of soil contamination.