Department of Earth Sciences , University of Western Ontario , London , Ontario N6A 5B7 , Canada.
Surface Science Western , University of Western Ontario , London , Ontario N6G 0J3 , Canada.
Environ Sci Technol. 2020 Jan 21;54(2):818-825. doi: 10.1021/acs.est.9b04896. Epub 2020 Jan 9.
Investigations of microplastic abundances in freshwater environments have become more common in the past five years, but few studies concern the factors that control the distribution of microplastics in river systems. We sampled benthic sediment from 34 stations along the Thames River in Ontario, Canada, to determine the influence of land use, grain size, river morphology, and relative amount of organic debris on the distribution of microplastics. Once counted and characterized for shape, color, and size, microplastic abundances were normalized to the results from Fourier transform infrared spectroscopy on randomly selected particles. The results indicate that 78% of the fragments and only 33% of the fibers analyzed were plastic. The normalized microplastic quantities ranged from 6 to 2444 particles per kg of dry weight sediment (kg dw). The greatest number of microplastics were identified in samples of the finest grain sizes and with the greatest amount of organic debris. Although there was no significant difference between microplastic abundances in urban versus rural locations, the average microplastic count for urban samples was greater (269 vs 195 kg dw). In terms of river morphology, samples from along straight courses of the river contained fewer microplastics than samples from inner and outer bends. Overall abundances confirm how rivers contain a significant number of plastic particles and thus may be major conduits of microplastics to lake and ocean basins.
在过去五年中，对淡水环境中微塑料丰度的研究变得越来越普遍，但很少有研究关注控制河流系统中微塑料分布的因素。我们从加拿大安大略省的泰晤士河沿线上的 34 个站点采集了底栖沉积物样本，以确定土地利用、粒径、河流形态和有机碎屑相对量对微塑料分布的影响。在对微塑料的形状、颜色和大小进行计数和特征描述后，将微塑料丰度归一化为随机选择的颗粒傅里叶变换红外光谱的结果。结果表明，78%的碎片和仅 33%的纤维是塑料。归一化的微塑料数量范围为每公斤干重沉积物（kg dw）6 至 2444 个颗粒。在粒径最小和有机碎屑最多的样本中，微塑料数量最多。尽管城市和农村地区的微塑料丰度没有显著差异，但城市样本的平均微塑料计数更高（269 与 195 kg dw）。就河流形态而言，来自河流直道的样本比来自内弯和外弯的样本含有更少的微塑料。总体丰度证实了河流中含有大量的塑料颗粒，因此可能是微塑料进入湖泊和海洋盆地的主要通道。
