Soil, Water and Air Team, Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton, Devon, EX20 2SB, UK.
Sci Total Environ. 2011 Feb 15;409(6):1095-103. doi: 10.1016/j.scitotenv.2010.12.005. Epub 2011 Jan 14.
Evidence for the movement of agricultural slurry and associated pollutants into surface waters is often anecdotal, particularly with relation to its 'particulate' components which receive less attention than 'bio-available' soluble phases. To assess the extent of movement of slurry particles artificial fluorescent particles were mixed with slurry and applied to a field sub-catchment within a headwater catchment. Particles were 2-60 μm in diameter and two different densities, 2.7 and 1.2 g cm(-3) representing 'inorganic' and 'organic' material. Water samples from the field and catchment outlet were collected during two storm events following slurry application and analysed for particle and suspended sediment concentrations (SSC). SSC from the field and catchment outlet always formed clockwise hysteresis loops indicating sediment exhaustion and particles of the two densities were always found to be positively correlated. Particles from the field formed clockwise hysteresis loops during the first discharge event after slurry application, but anti-clockwise hysteresis loops during the second monitored event which indicated a depletion of readily mobilisable particles. Particles from the catchment outlet always formed anticlockwise hysteresis loops. Particle size became finer spatially, between field and catchment outlet, and temporally, between successive storm events. The results indicate that slurry particles may be readily transported within catchments but that different areas may contribute to pollutant loads long after the main peak in SSC has passed. The density of the particles did not appear to have any effect on particle transport however the size of the particles may play a more important role in the 2-60 μm range.
农业泥浆及其相关污染物进入地表水的证据通常是传闻，特别是与泥浆的“颗粒”成分有关，这些成分比“生物可利用”的可溶性相受到的关注更少。为了评估泥浆颗粒迁移的程度，人工荧光颗粒与泥浆混合并应用于一个集水区的子流域。颗粒的直径为 2-60μm，密度为 2.7 和 1.2g/cm3，分别代表“无机”和“有机”物质。在施浆后两次风暴事件中，从田间和集水区出口采集水样，并分析颗粒和悬浮泥沙浓度（SSC）。田间和集水区出口的 SSC 总是形成顺时针滞后环，表明泥沙耗竭，两种密度的颗粒总是呈正相关。施浆后第一次排放事件中，田间颗粒形成顺时针滞后环，但第二次监测事件中形成逆时针滞后环，表明易迁移颗粒耗尽。集水区出口的颗粒总是形成逆时针滞后环。颗粒大小在空间上从田间到集水区出口变得更细，在时间上从连续的风暴事件之间变得更细。结果表明，泥浆颗粒可能在集水区内很容易迁移，但不同区域可能在 SSC 主要峰值过后很长时间内对污染物负荷产生影响。颗粒的密度似乎对颗粒运输没有影响，但颗粒的大小可能在 2-60μm 范围内发挥更重要的作用。
