The advent of nanotechnology has revolutionized diverse industries, offering innovative solutions in agriculture, environmental remediation, and sustainable energy. However, because of their distinct physicochemical properties and wide range of applications, the effects of nanomaterials on the environment and ecotoxicity continue to be an important concern. This chapter explores nanomaterials with a focus on the fate, transport, and transformation across soil, water, and air ecosystems. It highlights the intricate pathways through which these materials interact with non-target organisms, inducing potential toxicological effects such as oxidative stress, bioaccumulation, and ecosystem disruption. A comprehensive analysis of nanomaterial-induced risks to human health has been provided. Emphasizing the significance of sustainable design principles, current frameworks for risk assessment and regulatory efforts to mitigate the adverse effects of nanomaterials have also been assessed. Emerging trends in green nanotechnology, coupled with circular economy strategies, are proposed as pathways to balance innovation with environmental stewardship. By addressing knowledge gaps and fostering interdisciplinary collaboration, this work aims to guide future research and policymaking, ensuring that the integration of nanomaterials into modern technologies aligns with ecological and human health priorities. The dual role of nanomaterials as both solutions and challenges has been underscored, advocating for a more sustainable and resilient approach to their application.