Nano/micro plastics – Challenges on quantification and remediation: A review

Nano and micro plastics (NP/MPs) represent one of the most challenging classes of micro-pollutants, with occurrence across all ecosystems and size distributions ranging from the nanometre to the millimetre scale. These broad composition and size distribution ranges limit the efficiency of detection methods, often inherently focused on a single and narrow class of NP/MPs sizes. In addition to their demonstrated native toxicity, NP/MPs may act as efficient carriers of pollutants and pathogens onto their surface, facilitating the transfer and penetration of other classes of hazardous materials. This comprehensive review presents the key challenges related to soil, air and water NP/MPs: (i) sampling and extraction, (ii) using defined synthetic NP/MPs for spiking environmental samples and for model studies, and (iii) characterisation. A major challenge discussed in this paper relates to the lack of relevant characterisation strategies for the NP/MPs materials, enabling simultaneous identification, quantification and generation of statistical size distributions. This critical discussion ends with a series of well-informed propositions to support the systematic assessment of the impact of NP/MPs materials, spanning from materials science and characterisation, as well as environmental and chemical engineering.