Engineering Sustainability at the Nanoscale: Ethical, Normative, Risk, Safety, and Governance Dimensions

Nanotechnology is increasingly framed as a key facilitator of sustainable innovation through the development of waste-derived and bio-based nanomaterials aligned with circular economy principles. However, material performance or technological optimization alone cannot appropriately evaluate the sustainability of such systems. This article addresses nanoscale sustainability as a socio-technical challenge shaped by engineering practices, risk assessment approaches, and normative commitments. It critically reviews how risks related to sustainable nanotechnology are identified, prioritized, and managed, with particular attention to food- and agricultural-waste-derived nanomaterials. The study shows that risk and safety in nanotechnology serve as ethical infrastructures rather than neutral technical add-ons, translating normative assumptions about uncertainty, accountability, and acceptable risk into governance outcomes. Although waste-derived nanomaterials present exciting avenues for waste valorisation and bio-based innovation, their ethical acceptability is contingent upon the distribution of risks and rewards among social groups and generations, occupational and environmental safety, and life-cycle implications. This review provides an interpretive framework for responsible and sustainable nanotechnology by integrating perspectives from sustainable engineering, nanoethics, and risk governance, emphasizing the need for ethically sound, transparent, and reflective nanoscale decision-making.