Aquatic Systems Research Group, Department of Ecology and Resource Management, University of Venda, Thohoyandou, 0950, South Africa.
School of Biological Sciences, Queen's University Belfast, Belfast, BT9 5DL, UK.
Environ Sci Pollut Res Int. 2020 Jul;27(19):23880-23887. doi: 10.1007/s11356-020-08640-4. Epub 2020 Apr 16.
Microplastics have become a major environmental concern globally due to their potential impact on ecosystem function. They are known to be ubiquitously present, persistent and bio-accumulative, yet there is a lack of abundance quantifications in freshwater shorelines. Furthermore, there is little understanding of combined effects of seasonality and human population density on the extent of microplastic pollution. In this study, we assessed microplastics in sediment along a subtropical reservoir shoreline across three seasons and seven sites to understand microplastic pollution dynamics along a human population gradient. Multivariable analysis was used to assess relationships among substrate embeddedness, sediment organic matter, human population density and microplastic particle densities and characteristics. Microplastic densities were relatively high during the hot-dry season (mean range 120-6417 particles kg dwt) whilst the hot-wet season had the lowest densities (mean range 5-94 particles kg dwt). Microplastic abundances were positively correlated with population density, demonstrating the direct effects of human activity on microplastic contamination. These results highlight the need to further explore microplastic distribution patterns in freshwater ecosystems in the Southern Hemisphere. Furthermore, our findings suggest particular risk for fauna during low rainfall periods through microplastic concentration effects.
由于微塑料对生态系统功能可能产生的影响，其已成为全球范围内主要的环境关注点。微塑料普遍存在且持久、具有生物蓄积性，但其在淡水湖滨带的丰度尚未得到充分量化。此外，人们对于季节性和人类人口密度综合作用对微塑料污染程度的影响也知之甚少。在这项研究中，我们评估了亚热带水库湖滨带三个季节七个地点的沉积物中的微塑料，以了解人口梯度沿线的微塑料污染动态。多变量分析用于评估基质嵌入度、沉积物有机质、人口密度与微塑料颗粒密度和特征之间的关系。在炎热干燥的季节，微塑料密度相对较高（平均范围为 120-6417 个颗粒 kg 干重），而炎热湿润的季节微塑料密度最低（平均范围为 5-94 个颗粒 kg 干重）。微塑料丰度与人口密度呈正相关，这表明人类活动对微塑料污染的直接影响。这些结果突出表明，需要进一步探索南半球淡水生态系统中微塑料的分布模式。此外，我们的研究结果表明，在降雨量较低时期，微塑料的集中效应可能会对动物区系造成特别风险。
