Lofty James, Sonnino Sorisio Guglielmo, Kelleher Liam, Krause Stefan, Ouro Pablo, Wilson Catherine
Cardiff University, School of Engineering, Hydro-Environmental Research Centre, Cardiff, Wales, UK.
Cardiff University, School of Engineering, Hydro-Environmental Research Centre, Cardiff, Wales, UK.
Environ Pollut. 2025 Mar 1;368:125722. doi: 10.1016/j.envpol.2025.125722. Epub 2025 Jan 17.
Microplastics (MPs) are ubiquitous in river and freshwater ecosystems. However, the hydraulic and hydrological mechanisms that regulate the activation and emissions of MPs from both the land surface and subsurface into rivers are not well understood. This study aims to quantify the instream MP concentration and MP load in a remote headwater catchment river (Taff Bargoed, Wales, UK), which drains the UK's largest opencast coal mine (Ffos-y-fran), over a two-year period. Small fibers (< 1 mm) composed of acrylic and polyester dominated the MPs found in the Taff Bargoed, while less commonly observed MP fragments were mostly composed of polysulfone. River MP concentrations ranged from 0.27 to 28.87 MP/m³ (average: 14.60 ± 10.31 MP/m³), and MP load ranged one order of magnitude from 0.08 to 3.04 MP/s (average: 1.42 ± 0.81 MP/s). Statistically significant relationships were found between MP concentration, the number of dry weather hours and river discharge, which indicated rainfall-runoff induced, source limited, dilution effects on instream MP concentration. A negligible relationship between MP load and river discharge was observed, which suggests that MP load variability was independent of flow conditions, dry weather hours, and the MP concentration in the Taff Bargoed. Significant positive relationships between MP concentration and instream total suspended solids were also observed, indicating that this may provide a useful proxy for estimating MP variation in the Taff Bargoed. No longitudinal variation in MP concentration over a 2 km reach was observed, where differences in flow and drainage area were negligible, however, MP concentration increased by a factor of 2-4 downstream of an inflowing tributary, also sourced from the Ffos-y-fran coal mine. Overall, the results of this study provide evidence that mining activities can contribute MPs in rural and remote rivers, with their contribution being regulated by the hydraulic and hydrological processes in the catchment.
微塑料（MPs）在河流和淡水生态系统中无处不在。然而，调节微塑料从地表和地下进入河流的活化与排放的水力和水文机制尚未得到充分了解。本研究旨在量化一条偏远源头集水区河流（英国威尔士塔夫巴尔戈德，该河流经英国最大的露天煤矿——弗福斯 - 弗兰）在两年时间内的河流水体中微塑料浓度和微塑料负荷。在塔夫巴尔戈德发现的微塑料中，由丙烯酸和聚酯组成的小纤维（<1毫米）占主导，而较少见的微塑料碎片大多由聚砜组成。河流微塑料浓度范围为0.27至28.87个/立方米（平均：14.60±10.31个/立方米），微塑料负荷范围从0.08至3.04个/秒，相差一个数量级（平均：1.42±0.81个/秒）。研究发现微塑料浓度、干旱天气小时数和河流流量之间存在统计学上的显著关系，这表明降雨径流引发的、源有限的稀释效应会影响河流水体中的微塑料浓度。观察到微塑料负荷与河流流量之间的关系可忽略不计，这表明塔夫巴尔戈德的微塑料负荷变化与水流条件、干旱天气小时数以及微塑料浓度无关。微塑料浓度与河流水体中的总悬浮固体之间也存在显著的正相关关系，这表明总悬浮固体可能是估算塔夫巴尔戈德微塑料变化的一个有用指标。在2公里河段内未观察到微塑料浓度的纵向变化，该河段内的水流和流域面积差异可忽略不计，然而，在一条同样源自弗福斯 - 弗兰煤矿的支流汇入下游，微塑料浓度增加了2至4倍。总体而言，本研究结果表明采矿活动会向农村和偏远河流中排放微塑料，其排放受集水区的水力和水文过程调控。
