Nanomaterials in the environment: Behavior, fate, bioavailability, and effects—An updated review

Abstract

The present review covers developments in studies of nanomaterials (NMs) in the environment since our much citedreview in 2008. We discuss novel insights into fate and behavior, metrology, transformations, bioavailability, toxicitymechanisms, and environmental impacts, with a focus on terrestrial and aquatic systems. Overall, the findings were that: 1)despite substantial developments, critical gaps remain, in large part due to the lack of analytical, modeling, and fieldcapabilities, and also due to the breadth and complexity of the area; 2) a key knowledge gap is the lack of data on environmentalconcentrations and dosimetry generally; 3) substantial evidence shows that there are nanospecific effects (different from theeffects of both ions and larger particles) on the environment in terms of fate, bioavailability, and toxicity, but this is not consistentfor all NMs, species, and relevant processes; 4) a paradigm is emerging that NMs are less toxic than equivalent dissolvedmaterials but more toxic than the corresponding bulk materials; and 5) translation of incompletely understood science intoregulation and policy continues to be challenging. There is a developing consensus that NMs may pose a relatively lowenvironmental risk, but because of uncertainty and lack of data in many areas, definitive conclusions cannot be drawn. Inaddition, this emerging consensus will likely change rapidly with qualitative changes in the technology and increased futuredischarges.