Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset BH12 5BB, UK.
Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset BH12 5BB, UK.
Sci Total Environ. 2022 Sep 10;838(Pt 3):156477. doi: 10.1016/j.scitotenv.2022.156477. Epub 2022 Jun 2.
Urban freshwaters, their sediments and resident biota are often highly susceptible to microplastic contamination from catchment-specific sources. Water velocity and spatiotemporal dynamics within the system can impact microplastic loads, while biological features may additionally impact levels within freshwater biota. Here, we investigated the spatiotemporal variations in microplastic loads collected from sediment, macroinvertebrate and fish samples from an urban watercourse (Bourne Stream) in Dorset, southwest England. Sediment particles were mostly fragments of colours (especially orange and purple) whereas microplastics in both macroinvertebrates and fishes were blue/green and fibres. Across all sample types, the dominant particle size class was ≤100 μm. Median (M) and range (R) of microplastic loads within each sample type were sediment: M = 0.06, R = 0-0.36 particles g; macroinvertebrates: M = 0, R = 0-4 particles per batch; and fishes: M = 1, R = 0-6 particles per individual. Sediment loads varied spatially, with the highest load in the most upstream site, whereas biotic loads did not vary across space and time. Macroinvertebrate batch loadings varied between taxa and feeding guild, with counts significantly higher in annelids but lower in herbivores. Fish counts were higher in species with true, differentiated stomachs, but with the effects of species, feeding guild and body size being non-significant. Within sites, mean microplastic loads did not correlate between sediment, macroinvertebrate and fish samples. These results suggest that sediment freshwater microplastic loadings may vary spatially but that these trends are not reflected by, or correlated to, those in the biota where ingestion varies with biological traits. Assessments of freshwater microplastic contamination must therefore consider sampling spatiotemporally and across different biotic communities to fully understand the scale of contamination, and to subsequently undertake effective mitigation steps.
城市淡水及其沉积物和栖息生物通常极易受到集水区特定来源的微塑料污染。系统内的水流速度和时空动态会影响微塑料负荷，而生物特征可能会进一步影响淡水生物群体内的水平。在这里，我们调查了从英格兰西南部多塞特郡的一条城市水道（伯恩溪）的沉积物、大型无脊椎动物和鱼类样本中收集的微塑料负荷的时空变化。沉积物颗粒主要是各种颜色的碎片（尤其是橙色和紫色），而大型无脊椎动物和鱼类中的微塑料则是蓝色/绿色和纤维。在所有样本类型中，主要的粒径类别为≤100μm。每个样本类型中微塑料负荷的中位数（M）和范围（R）分别为沉积物：M=0.06，R=0-0.36 个颗粒/g；大型无脊椎动物：M=0，R=0-4 个/批；鱼类：M=1，R=0-6 个/个体。沉积物负荷在空间上存在差异，上游位置的负荷最高，而生物负荷在空间和时间上没有变化。大型无脊椎动物批次负荷因分类群和摄食群而异，环节动物的计数明显更高，而草食动物的计数则更低。具有真正分化的胃的鱼类物种的计数更高，但物种、摄食群和体型的影响不显著。在各站点内，沉积物、大型无脊椎动物和鱼类样本之间的平均微塑料负荷没有相关性。这些结果表明，沉积物淡水微塑料负荷可能在空间上存在差异，但这些趋势并未反映在生物群中，因为摄食随生物特征而变化。因此，对淡水微塑料污染的评估必须考虑时空采样和不同的生物群落，以充分了解污染的规模，并随后采取有效的缓解措施。
