With the large amount of attention being given to microplastics in the environment, several researchers have begun to consider the fragmentation of plastics down to lower scales (i.e., the sub-micrometer scale). The term "nanoplastics" is still under debate, and different studies have set the upper size limit at either 1000 nm or 100 nm. The aim of the present work is to propose a definition of nanoplastics, based on our recently published and unpublished research definition of nanoplastics. We define nanoplastics as particles unintentionally produced (i.e. from the degradation and the manufacturing of the plastic objects) and presenting a colloidal behavior, within the size range from 1 to 1000 nm.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

While several studies have investigated the potential impact of nanoplastics, proof of their occurrence in our global environment has not yet been demonstrated. In the present work, by developing an innovative analytical strategy, the presence of nanoplastics in soil was identified for the first time. Our results demonstrate the presence of nanoplastics with a size ranging from 20 to 150 nm and covering three of the most common plastic families: polyethylene, polystyrene and polyvinyl chloride. Given the amount of organic matter in the soil matrix, the discrimination and identification of large nanoplastic aggregates are challenging. However, we provided an innovative methodology to circumvent the organic matter impact on nanoplastic detection by coupling size fractionation to molecular analysis of plastics. While photodegradation has been considered the principal formation pathway of nanoplastics in the environment, this study provides evidence, for the first time, that plastic degradation and nanoplastic production can, however, occur in the soil matrix. Moreover, by providing an innovative and simple extraction/analysis method, this study paves the way to further studies, notably regarding nanoplastic environmental fate and impacts.

Main finding Nanoplastics are able to sorb high amount of Pb(II) through sorption and intraparticle diffusion processes. They could be important vector of metallic pollutant in the environment. Highlights • Pb(II) binding experiments onto nanoplastics extracted from environmental micro-plastics were performed. • Pb(II) was largely bound onto nanoplastics by specific adsorption and intraparticle diffusion.

Forced penetration of large hydrosoluble polymer chains through track-etched membranes has been investigated as a function of both solvent flow rate in the pores and the ratio of polymer hydrodynamic radius to pore radius. We measure the rejection coefficient R obs from retentate and permeate mean concentrations, and its corrected value R including polymer accumulation at the membrane. The variations of R as a function of solvent flow rate per pore in adimensional units collapse into the same curve well fitted by de Gennes' ''suction model''. This curve, universal for flexible polymers in good solvents, leads to an estimate of the critical penetration flow.