An overview of nanoplastics present in the environment

Abstract

Plastic pollution is an internationally recognized problem and an understanding of the behavior of plastic particles in the environment is still under development [1]. In the environment, plastics degrade into microplastics, i.e. fragments and fibers, then fragmented to nanoplastics (NPs) eventually. These microplastic particles range between 1 mm to 5 mm [2], while the definition of NPs is still under debate; different studies have set the upper size limit from 1 nm to 1 mm [3]. Daily discharges of microplastics are estimated in the range of 50,000 up to 15 million particles, whereas no information on NPs discharges is available yet [4]. The present overview highlights the importance of NPs as a contributor to environmental pollution, which are considered emerging pollutants nowadays. NPs are homo- and/or heteroaggregates conformed with colloidal behavior [3]. The presence of these particles has been evidenced in the atmosphere [5], soil and marine environment, that represents an ultimate sink for contamination [6]. According to the International Standard Organization (ISO), a manufactured nanomaterial is intentionally produced for commercial purposes to have specific properties or specific composition, therefore, the NPs cannot be considered as such [3]. Moreover, release and impact on the environment of these particles is still not evident. Though several studies with engineered plastic nanomaterials showed toxicity and sub-lethal effects with consequences not only at organism and population level but on the overall ecosystem [6], are not representatives results [8]. However, current difficulties in sampling, identifying and characterizating nano-sized debris make it hard to assess their occurrence in the environment. Thus, NPs is a recent issue in the scientific community and deserves further attention to establish new remediation technologies.