Occurrence and sources of microplastics in dust of the Ebinur lake Basin, northwest China

Currently, there is a lack of studies on microplastic pollution in mountain terrains and foothills areas in Northwest China and Central Asia. Here, we collected monthly dusts samples for one year and we studied the distribution, pollution levels, and sources of microplastics in atmospheric dust fall in the Ebinur Lake Basin in Northwest China. Results showed that the average content of dust microplastic on construction land was 28.61 ± 1.13 mg/kg, followed by farmland (20.25 ± 1.56 mg/kg), forest (19.52 ± 1.06 mg/kg), and deserts (8.08 ± 0.56 mg/kg). Regarding different land use types, atmospheric dust reduction dominated on farmland (58.64%), followed by urban area (26.65%), forest (9.76%), and desert (4.95%). Regarding the shape of microplastics, the order of occurrence in dust was film (46.85%) > fiber (35.15%) > foam(12.35%) > fragment (5.65%). In this study, four colors of microplastics were found in dust, and white accounted for the largest proportion (52.15%), followed by transparent (18.65%), black (19.45%), and green (9.75%). The main components of film microplastics in atmospheric dustfall in the Ebinur Lake Basin were PE and PP, and their sources were mainly plastic products in daily life, plastic industrial packaging materials from urban enterprises, broken plastic woven bags, and PET mostly from fabric fragment emissions. The abundance of microplastics in dust was correlated with atmospheric dust pH, EC, and total salt content. The contents of seven heavy metals (Cu, Ni, Cd, Pb, Cr, Mn, and Co) adsorbed by microplastics were also correlated with pH, EC, and total salt content. Our results represent a reference for microplastics pollution prevention in mountain terrains and foothills areas in northwest China and Central Asia.