Agro-industrial waste-derived biochar in sustainable remediation of Arsenic from rice and vegetables for food safety and public health

Arsenic (As) contamination in groundwater, soil, and food crops perturb the environmental sustainability and human health. The geogenic weathering with concomitant up-surge in agro-chemicals application remarkably pollute the environment with this carcinogenic metalloid that adversely influence the food safety, public health, and human well-being. Multiple threats necessitate the need of a sustainable biomass-based technology in As remediation. Present systematic review quests the knowledge gaps in role of ‘agriculture-waste/residues-derived biochar’ (ARB) to address the As contamination in staple food crops of wide dietary consumptions like rice and vegetables. This discussion follows the standard methodologies to prioritize that elucidation of physico-biochemical mechanisms and molecular biotechnology advances-based scalable deployments of nano-biochar. Nano-biochar possess the potential to fill knowledge voids and mitigate twin environmental challenges. Firstly, restricting the health hazardous practice of biomass burning by valorising agro-industrial-waste, while second being the substitution of harmful chemical methods with bio-based ARB-technologies in As remediation. Results reveal that the nano-biochar modulate oxidative stress tolerance pathways, ‘reactive oxygen species’ (ROS) capture, phytohormones or signal molecules interactions, and regulatory gene expressions, together potentially leveraging the As remediation. Unlike heavy metals, ARB-driven As remediation is constrained in climate change-impacted paddy agroecosystems by multiple biotic and abiotic factors. Nevertheless, the techno-economic manoeuvring or innovations in nano-biochar can conquer these challenges of As contaminated agroecosystems by ameliorating the antioxidant and molecular responses. Likewise, other limitations in biochar-driven As remediation and their addressal through future research on efficient feedstock selection, ARB-production methods, enzymatic pathways, functional nano-composites, and machine learning are critically discussed to potentially deal with pervasive As pollution. Therefore, deploying nano-biochar can help achieve public food safety, environmental sustainability, and ‘climate-resilient-smart’ sustainable agriculture, together catalysing the United Nations-Sustainable Development Goals (UN-SDGs). In future perspective, the scalable deployments of nano-biochar can be strengthened by encouraging participatory approaches among stakeholders like scientists, farmers, regional consumers, and policy makers for sustainable As remediation.