The Known and Unknown about the Environmental Safety of Nanomaterials in Commerce.

The widespread nanomaterial use in commercial products has fed significant concern over environmental health and safety ramifications. Initially, little was known as to how these highly reactive particulates interacted with biological systems. Nanomaterials have introduced complexities not normally considered in traditional safety assessments of chemicals and therefore have generated uncertainty in the reliability of standard tests of safety. Advances in understanding the potential impacts of nanomaterials have occurred since their introduction, particularly for those used in the greatest quantities in commerce. The impact of characteristics such as charge, size, surface functionalization, chemical composition, and certain transformations on the potential effect of nanomaterials in the environment continue to move the field forward. However, generalizations of risk based on any one factor across nanomaterials is not possible. Estimating risk also remains difficult due to the introduction of materials that are new and more complex, minimal information on the specific molecular interactions of nanomaterials and organisms, and the need for more tools for measuring the dynamics of nanomaterial state and fate in complex matrices. Finally, exposure estimates are difficult due to difficulty of environmental monitoring which may be exacerbated by lack of information on nanomaterials in products and new uses in the marketplace.