Evaluation of microplastic pollution in Shihezi city, China, using pine needles as a biological passive sampler

Microplastic (MP) pollution has attracted much attention. To understand the characteristics of atmospheric MP pollution in Shihezi, Northwest China, this study used pine needles from trees in Shihezi City as passive samplers. MP contamination was found in all pine needle samples, with an average concentration of 16.52 +/- 3.76 items/g. MPs were mainly in the shape of fragments (<0.05 mm). Differences in MP pollution were observed in different functional areas. The abundance of MPs in pine needles was the highest on the main traffic road (19.02 +/- 2.52 items/g). Spectral analysis showed that the main polymer of MPs was polyethylene (17.2%), followed by polystyrene (15.5%) and polypropylene (13.8%). By analyzing the principal components and spatial distribution, fragments and pellets were found to have similar sources (mainly industrial activities), whereas films and fibers were influenced by traffic flow. The source of films was related to the packaging industry. The purpose of this study was to provide a reference for the future use of pine needles as atmospheric MP passive samplers, for the traceability and prevention of urban atmospheric MP pollution and for the formulation of national atmospheric MP environmental standards.

Automated summary

This study used pine needles as passive samplers to investigate atmospheric microplastic pollution in Shihezi, China. The results showed contamination in all samples, with variations in different functional areas. Spectral analysis revealed the main polymers of the microplastics, and principal component analysis identified their sources.