Perspectives on palladium-based nanomaterials: green synthesis, ecotoxicity, and risk assessment

Palladium-based nanomaterials (Pd-NMs) have been mass produced and applied due to their remarkable properties and high earth abundance. This makes Pd-NMs come into frequent contact with the environment and enter the ecological environment. Comparative analysis of the toxicological data revealed that Pd-NMs have acute or chronic toxicity in both in vitro and in vivo biological receptors models, but only limited information has been provided on the possible environmental migration and transformation or concentration distribution in the environmental media of Pd-NMs. Therefore, a perspective is needed of the existing data to provide a more professional and comprehensive assessment of their ecotoxicity and sustainable development. This perspective describes the critical knowledge needed to assess their ecological risks. We recommend focusing on the current and future concentration and distribution of Pd-NMs in the environment, guiding the assessment of the full-cycle ecotoxicity of Pd-NMs, and strongly encourage the quantitative measurement of the concentration level of Pd-NMs in the real environment. By comprehensively analyzing and discussing the application progress, environmental behavior and ecotoxicology of palladium-based nanomaterials (Pd-NMs), guidelines are provided for the sustainable development of Pd-NMs.