微小プラスチックの輸送経路解明に関する新研究(New Study Helps Trace How Microplastics Transport on “Roof of the World”)

2026-04-02 中国科学院(CAS)

中国科学院西北生态环境资源研究院(NIEER)の研究チームは、青蔵高原・祁連山地域における大気中マイクロプラスチックの輸送・沈着メカニズムを解明した。現地観測と定量分析により、粒子のサイズや形状、ポリマー種を詳細に解析した結果、微小粒子の70%以上が破片状で、長距離輸送と劣化を経ていることが示された。また「球形度」を指標として導入し、形状が輸送距離に影響することを確認。球形度が低いほど遠距離輸送されやすく、高い粒子は局所沈着しやすい。高地でも大気経由の汚染が進行している実態を示し、環境リスク評価や対策に重要な知見を提供した。

<関連情報>

チベット高原北東部祁連山脈における大気浮遊マイクロプラスチックの動態と湿性沈着 Dynamics of suspended atmospheric microplastics and their wet deposition in the Qilian Mountains, Northeast Tibetan Plateau

Xi Luo, Yulan Zhang, Shichang Kang, Tanguang Gao, Rensheng Chen, Yujiao Zhao
Journal of Environmental Sciences  Available online: 5 August 2025
DOI:https://doi.org/10.1016/j.jes.2025.08.002

Graphical abstract

微小プラスチックの輸送経路解明に関する新研究(New Study Helps Trace How Microplastics Transport on “Roof of the World”)

Highlights

  • SAMPs exhibited fragmentation, enhancing atmospheric suspension potential.
  • SAMPs were more stable than WDMPs and had a larger size range.
  • Precipitation intercepted microplastics in transport and deposited them in the remote area.
  • Morphological parameters unified atmospheric microplastic transport capacity.

Abstract

The Earth’s environment is full of microplastics, but the characteristics of atmospheric microplastics in remote areas are still limited to constrain the understanding of the life cycle of microplastics. Hence, we conducted quantitative characteristics of suspended atmospheric microplastics (SAMPs) and wet deposition microplastics (WDMPs) in the Qilian Mountains, northeast Tibetan Plateau. The concentrations of SAMPs (> 50 µm) ranged from 0.05 to 1.36 items/m3 with a mean of 0.33 ± 0.35 items/m3. The fluxes of WDMPs (> 50 µm) ranged from 14.94 to 450.04 items/(m2·day) with a mean of 124.06 ± 115.67 items/(m2·day). In general, microplastic abundance in this remote area was lower than that in high-density population areas. SAMPs and WDMPs were dominated by fragments (> 70 %). Polymers were dominated by polyamide, polyethylene, polyethylene terephthalate, polyurethane, and polyvinyl chloride. In detail, polyamide was higher in WDMPs, and polyurethane was higher in SAMPs. These differences may be attributed to the distinct wettability and aging behaviors of the polymers. The conditional fragmentation-based model revealed that the size range of SAMPs was larger and more fragmented than that of WDMPs. While SAMPs were more irregular than WDMPs, further indicating that irregular morphology favored the suspension of microplastics. Concentration-weighted trajectory revealed that sphericity is a key indicator for revealing potential source regions of microplastics. This study provided insights into the dynamics of SAMPs and WDMPs in remote mountain regions. It highlighted the need to unify the assessment of microplastic transport capacity across different shapes and sizes.

1902環境測定
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