RESUMEN
We examined the distribution characteristics of atmospheric microplastics in typical desert agricultural regions, with a focus on the agricultural areas surrounding the Taklamakan Desert, Xinjiang, China. We collected samples of total suspended particulate matter (TSP), atmospheric deposition, and atmospheric dust using both active and passive collection methods. The chemical composition, particle size, shape, and color of atmospheric microplastics were examined using a stereomicroscope and a Fourier-transform infrared spectrometer to analyze their characteristics. The results showed that the primary chemical compositions of microplastics included polypropylene (PP), polyethylene, polyethylene terephthalate, polymethylmethacrylate, and cellophane. Particle sizes were mainly within the range of 0 to 1000 µm. Fibrous microplastics constituted the majority of the TSP and atmospheric deposition, whereas film-like microplastics constituted the largest proportion of atmospheric dustfall. The deposition flux of atmospheric microplastics in the first quarter was measured at 103.21 ± 22.12 particles/m2/day, which was lower than that observed in conventional agricultural areas. The abundance of microplastics in atmospheric dustfall was found to be 1.36 particles/g. The proportion of PP microplastics in atmospheric dustfall can be as high as 35%. Through a comparison of microplastic content in TSP during dust storms and under normal weather conditions, it was found that dust storms can lead to an increase in the abundance of microplastics within the atmospheric TSP. The present study provides a scientific basis for understanding the distribution of atmospheric microplastics in typical desert agricultural regions. Environ Toxicol Chem 2024;00:1-14. © 2024 SETAC.
RESUMEN
Polyethylene mulching film plays a critical role in agricultural production. To clarify the impact of residual film and microplastics on soil microorganisms, this study examined four cotton fields with different film coverage years in typical areas of Xinjiang and analyzed the changes in soil bacterial and fungal community structure and diversity under residual film and microplastics using high-throughput sequencing technology. The results showed that the residual film in the 0-150 mm soil layers and 150-300 mm soil layers at the same sampling point had spatial distribution characteristics of 60-70% and 30-40%, respectively. The short period of the 0-10 years film mulching treatment increased the soil microbial diversity of the cotton field, whereas continuous film mulching for 25 years significantly decreased the soil microbial diversity, in which Proteobacteria was the dominant bacterial phylum and Ascomycetes was the dominant fungal phylum. The microbial diversity of the film-covered soil was lower than that of the control group. The spatial distribution of the residual film and microplastic changed the distribution of the microbial communities. The diversity of the microbial community structure of the 0-150 mm soil layers was higher than that of the 150-300 mm soil layers. The increase in residual film and microplastics had no significant effect on the diversity of the fungal community but decreased the diversity of the soil bacterial community and decreased the relative abundance of Proteobacteria and Campylobacter. In conclusion, long-term film mulching reduced the soil microbial diversity in cotton fields. This study provides a theoretical basis for understanding the impact of film residues on microorganisms and the ecological environment in typical areas.
