Editorial: Challenges in characterizing nano- to macro-plastics and adhered substances in the aquatic environment

Globally, plastic contamination is one of the serious planetary threats, affecting almost all environmental matrices such as air, water, soil, sediment, and biota (including humans). It is estimated that ∼19 to 23 million metric tonnes of plastic waste were generated and entered the environment in 2016, worldwide (Borrellee et al., 2020). Moreover, as the trend goes, the predicted growth in plastic waste may exceed efforts to mitigate plastic pollution around the world. Even with immediate and concerted action, it is estimated that 710 million tons of plastic waste will enter the aquatic and terrestrial ecosystems by 2040 (Lau et al., 2020). Therefore, many countries around the world are struggling to manage the current volume of plastic waste and plastic contamination in the environment. Based on the size, plastic waste is categorized into nanoplastics (1 nm to <1,000 nm), microplastics (1 μm to 5 mm), mesoplastics (>5 mm to <10 mm), and macroplastics (≥10 mm). Plastic itself can be a pollutant, but it can also act as a vector to transport toxic chemicals (e.g., persistent organic pollutants, trace metals, pesticides, and antibiotics) and harmful organisms (e.g., pathogens and invasive species) to pristine ecosystems. Therefore, these pollutants are of great public concern due to their ubiquitous nature and the potential hazards posed for humans and ecosystems.