In an article published on January 19, 2018 in the peer-reviewed journal Environmental Pollution, Julien Gigault and colleagues from the University of Rennes and several other French institutions proposed a common definition for the term “nanoplastics.” The scientists suggested to “define nanoplastics as particles unintentionally produced (i.e. from degradation and the manufacturing of the plastic objects) and presenting a colloidal behavior, within the size range from 1 to 1000 nm.” Importantly, this definition “excludes the use of the term nanoplastics for any manufactured nanomaterials present in . . . common products (cosmetics, materials, biomedical).”
In a mini review, the authors explained that, in their opinion, nanoplastics result “from the degradation of plastic objects and could be formed during the break-down of aged-microplastics, the manufacturing process, or even during the use of the object.” They emphasized that there are “no analogies possible between nanoplastics and others “nanomaterials” due to the different production pathways and physical and chemical properties.” When characterizing nanoplastics, their colloidal behavior is particularly relevant, because “nanoplastics may directly associate with dissolved organic and inorganic colloids to form both stable and unstable aggregates.” Further, because nanoplastics are “highly polydisperse in physical properties and heterogeneous in composition,” the common model nanoparticles such as polymer latex standards cannot be considered a suitable model for nanoplastics.
With regard to future research needs, the scientists called for “a major effort to develop methods for the identification and especially quantification of nanoplastics in natural samples.” They further stated that “compared to macro- and microplastics, it is even more inconceivable to develop a removal strategy for nanoplastics,” and argued that “a new, specific planetary boundary for plastic litter should be established.”
Gigault, J., et al. (2018). “Current opinion: What is a nanoplastic?” Environmental Pollution (published January 19, 2018).