Environmental and health effects of graphene-family nanomaterials: Potential release pathways, transformation, environmental fate and health risks

Abstract

Since its advent, graphene has been hailed as a revolutionary two-dimensional (2D) carbon-based nanomaterial for the 21st century. At present, graphene-family nanomaterials (GFNs), a class of similar graphene-like structured materials with various sizes, layers, surface chemistry, and defects, are creatively designed and applied because of their unique characteristics. At the same time, the environmental and biological impact of the emerging GFNs on ecosystems and animals is also a focus for sustainable utilization of this exciting technology. Although considerable progress has been made in assessing the toxicity of pristine graphene, knowledge gaps about the safety effects of environmentally transformed GFNs have yet to be addressed. Therefore, it is of great importance to systemically dissect the environmental transformation of GFNs after release and the toxicological properties associated with this transformation. Here, we comprehensively reviewed the process from GFN release to adverse outcomes. GFNs environmental release during their life cycle and GFNs transformation in the air, soil, and aquatic environment were assessed. This is followed by discussion about the possible toxic alternations and potential mechanisms caused by environmental transformation. Finally, we reviewed the toxicity of environmentally transformed GFNs from a three-aspect view of terrestrial organisms, aquatic organisms, and in vitro cell models. This review increases the understanding of new trends in GFN environmental risks, including the identification of knowledge gaps regarding adverse outcome of transformed GFNs.