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

Abstract

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.

Protein Fe–S Centers as a Molecular Target of Toxicity of a Complex Transition Metal Oxide Nanomaterial with Downstream Impacts on Metabolism and Growth

“…In the past two decades, substantial work has been carried out toward understanding the potential implications of the increasing commercial use of engineered nanomaterials (ENMs) on human health and the environment, with more than 18,000 nanotoxicology articles published between the years 2000 and 2018. − Over this period, studies of ENM impacts grew from basic toxicity exposures to increasingly sophisticated studies aimed at understanding how the ENM properties determine toxicity, mechanisms by which materials interact with biological systems, and how and what materials and their environmental transformations may be of potential concern. , To date, nanotoxicology has focused largely on first-generation ENMs (e.g., Au, Ag, and graphene). ,, When an underlying mechanism is proposed, toxicity is frequently attributed to reactive oxygen species (ROS) for a diversity of ENMs including Au, Ag, CeO, Si, and carbon nanotubes. − ROS such as superoxides, hydrogen peroxides, and hydroxyl radicals have long been classified as damaging to DNA, RNA, proteins, and lipids . However, research within the last decade has revealed ROSspecifically superoxide and its hydrogen peroxide product generated in the mitochondria or by NADPH oxidasesas important signaling molecules , involved in regulating the fundamental biological processes through oxidation of cysteines of protein redox sensors including metabolism (e.g., GAPDH, PKM2, and AMPK), proliferation (e.g., PTEN, PTP1b, and EGFR), autophagy (e.g., PTEN, AMPK, Atg4, and FOXO), and apoptosis (e.g., VDAC, caspases, ERO1, and PDI); and ROS are actively generated during and required for normal embryonic development across species .…”

Methods to Determine Chain-Breaking Antioxidant Activity of Nanomaterials beyond DPPH•. A Review

“…Of course, for a practical use on nanoantioxidants, this list must be integrated with toxicological and environmental considerations [119], that go beyond the aims of this review [120]. Nevertheless, we believe that the use of these guidelines will inspire the research of novel nanomaterials able to cope with the autoxidation of organic materials in fields spanning from foods to plastic to biological systems.…”

U. S. federal perspective on critical research issues in nanoEHS

“…The sheer number and diversity of ENM-containing products, systems, and devices have brought nanotechnology applications into everyday use by millions of consumers, making it difficult to gain detailed awareness of nanotechnology in the marketplace. 41 Understanding the commercial presence of ENMs will enable a more complete assessment of where exposures may occur and is fundamental to life-cycle assessments. Developing decision support tools and methods that regulatory agencies can use for risk assessment of nanomaterials in food and environmental media and then funding research to develop data as needed would represent a novel approach.…”