Fundamental Research (May 2021)
Characterization, occurrence, environmental behaviors, and risks of nanoplastics in the aquatic environment: Current status and future perspectives
Abstract
Microplastics (MPs) are emerging contaminants that have attracted worldwide attention in recent years. Compared with MPs, nanoplastics (NPs) may exhibit greater toxicity and higher potential risks because of their unique physiochemical nanoscale properties. However, the environmental fate, ecosystem toxicity, and potential risks associated with NPs have been less explored. This study summarizes the current research status of NPs through a comprehensive bibliometric analysis. The research hotspots and future trends of NPs were identified. We comprehensively searched the Web of Science Core Collection scientific database from its inception (2004) to November 26, 2020. The results showed that the number of papers on NPs has increased significantly since 2014. The keywords used in NP research were divided into three clusters. Cluster 1 related to the physical, chemical, and biological behaviors of NPs in aquatic environments. Cluster 2 represented a relatively new and hot research field concerning the exposure, accumulation, and toxicity of NPs in organisms. Cluster 3 corresponded to the identification and quantification of NPs in marine environments and sediments. Moreover, we systematically elaborated the main areas of NP research, such as the characterization, occurrence, environmental behavior, ecological toxicity, and human health risks of NPs. The results showed that the quantification of NPs at environmentally relevant concentrations remains a challenge. Most studies have investigated polystyrene NPs, spherical NPs, and NPs in marine environments, while few studies have examined the aggregation, deposition, and ecological toxicity of NPs under environmentally relevant conditions. In addition, much less is known about the human health risks associated with NPs because little research has been conducted on estimating the overall human exposure to NPs and its effect. Finally, the current challenges and future perspectives of NP research are discussed.
