Oil and POPs Research Group, Korea Institute of Ocean Science and Technology, Geoje, 53201, Republic of Korea; Department of Ocean Sciences, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea.
Oil and POPs Research Group, Korea Institute of Ocean Science and Technology, Geoje, 53201, Republic of Korea.
Water Res. 2019 Sep 1;160:228-237. doi: 10.1016/j.watres.2019.05.053. Epub 2019 May 18.
Although rivers represent an important pathway for the transport of microplastics to the oceans, research on riverine microplastics is limited compared to the marine environment. Hence, we investigated the spatiotemporal distribution of microplastics in the Nakdong River down to 20 μm in size and characterized them using Fourier transform infrared spectroscopy in surface and mid waters and sediment. The mean (±standard deviation) abundance of microplastic in the Nakdong River was in the range of 293 ± 83 (upstream, February 2017) to 4760 ± 5242 (downstream, August 2017) particles/m in water, and 1970 ± 62 particles/kg in sediment. The abundance of microplastics was about three times higher in surface than mid waters in the downstream area. Polypropylene and polyester accounted for 41.8% and 23.1% of microplastics in the water, respectively, whereas about 50% in the sediment was composed of polypropylene and polyethylene. Microplastics smaller than 300 μm in size accounted for 74% in the water and 81% in sediment, and the distribution peaked in the 50-150 μm size range. Based on these results, we estimated the annual load of microplastics carried by the Nakdong River in 2017 to be 5.4-11 trillion by number and 53.3-118 tons by weight. The proportions of the total load transported through surface water and the water column were 8% and 92%, respectively. In addition, the microplastic load was concentrated in the wet season, which makes up 71% in number and 81% in weight. These results indicate that it is necessary to reflect seasonal variation and sample both in the surface water and water column to estimate microplastic transport. Without considering these factors, the annual load of microplastics may be overestimated or underestimated.
尽管河流是将微塑料输送到海洋的重要途径，但与海洋环境相比，河流微塑料的研究还很有限。因此，我们调查了到 20μm 大小的南渡河中的微塑料的时空分布，并使用傅里叶变换红外光谱法在地表水和中层水以及沉积物中对其进行了特征描述。南渡河中微塑料的平均（±标准偏差）丰度范围为 293±83（上游，2017 年 2 月）至 4760±5242（下游，2017 年 8 月）个/立方米水，沉积物中为 1970±62 个/千克。下游地区的表面水中微塑料的丰度约为中层水的三倍。在水中，聚丙烯和聚酯分别占微塑料的 41.8%和 23.1%，而约 50%的沉积物由聚丙烯和聚乙烯组成。粒径小于 300μm 的微塑料在水中占 74%，在沉积物中占 81%，分布峰值在 50-150μm 粒径范围内。根据这些结果，我们估计 2017 年南渡河携带的微塑料数量为 5.4-11 万亿个，重量为 53.3-118 吨。通过地表水和水柱输送的总负荷比例分别为 8%和 92%。此外，微塑料负荷集中在雨季，占数量的 71%，重量的 81%。这些结果表明，有必要反映季节性变化，并在地表水和水柱中同时采样，以估计微塑料的输送。如果不考虑这些因素，微塑料的年负荷可能会被高估或低估。
