Department of Geography, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan; Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan.
Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan.
Ecotoxicol Environ Saf. 2023 Aug;261:115100. doi: 10.1016/j.ecoenv.2023.115100. Epub 2023 Jun 6.
The widespread distribution of plastic debris in riverine environment is one of the major concerns of environmental pollution because of its potential impact on the aquatic ecosystem. In this study, we investigated the accumulation of metal(loid)s on polystyrene foam (PSF) plastics collected from the floodplain of the Tuul River of Mongolia. The metal(loid)s sorbed on plastics were extracted from the collected PSF via sonication after peroxide oxidation. The size-dependent association of metal(loid)s with plastics indicates that PSFs act as vectors for pollutants in the urban river environment. The mean concentrations of metal(loid)s (i.e., B, Cr, Cu, Na, and Pb) indicate a higher accumulation of the metal(loid)s on meso-sized PSFs compared with macro- and micro-sized PSFs. In addition, the images from scanning electron microscopy (SEM) indicated not only the degraded surface of plastics showing fractures, holes, and pits but also the adhered mineral particles and microorganisms on the PSFs. The interaction of metal(loid)s with plastics was probably facilitated by the physical and chemical properties of altered surface of plastics through photodegradation, followed by an increase in surface area by size reduction and/or biofilm development in the aquatic environment. The enrichment ratio (ER) of metals on PSF samples suggested the continuous accumulation of heavy metals on plastics. Our results demonstrate that the widespread plastic debris could be a carrier of hazardous chemicals in the environment. Considering that the negative impacts of plastic debris on environmental health are major concerns to be addressed, the fate and behavior of the plastics especially their interaction with pollutants in aquatic environments should be further studied.
塑料碎片在河流环境中的广泛分布是环境污染的主要关注点之一，因为它可能对水生生态系统造成潜在影响。在这项研究中，我们调查了从蒙古国图勒河漫滩收集的聚苯乙烯泡沫（PSF）塑料上金属（类）的积累情况。通过过氧化物氧化后的超声处理，从收集的 PSF 中提取吸附在塑料上的金属（类）。金属（类）与塑料的尺寸依赖性结合表明，PSF 是城市河流环境中污染物的载体。金属（类）（即 B、Cr、Cu、Na 和 Pb）的平均浓度表明，中尺寸 PSF 上金属（类）的积累高于大尺寸和小尺寸 PSF。此外，扫描电子显微镜（SEM）的图像不仅显示了塑料的降解表面出现裂缝、孔和凹坑，还显示了 PSF 上附着的矿物颗粒和微生物。金属（类）与塑料的相互作用可能是通过光降解改变塑料的物理和化学性质来促进的，随后通过减小尺寸和/或在水生环境中生物膜的发展来增加表面积。PSF 样品上金属的富集比（ER）表明重金属在塑料上的持续积累。我们的结果表明，广泛存在的塑料碎片可能是环境中有害化学物质的载体。考虑到塑料碎片对环境健康的负面影响是需要解决的主要问题，因此应进一步研究塑料的命运和行为，特别是它们与水生环境中污染物的相互作用。
