The Río Tinto, located in the Iberian Pyrite Belt (SW Spain), constitutes an extreme case of pollution by acid mine drainage. Mining in the area dates back to the Copper Age, although large-scale mining of massive sulfide deposits did not start until the second half of the 19th century. Due to acidic mining discharges, the Río Tinto usually maintains a pH close to 2.5 and high concentrations of pollutants along its course. From a detailed sampling during the hydrological year 2017/18, it was observed that most pollutants followed a similar seasonal pattern, with maximum concentrations during autumn due to the washout of secondary soluble sulfate salts and minimum values during large flood events. Nevertheless, As and Pb showed different behavior, with delayed concentration peaks. The dissolved pollutant load throughout the monitored year reached 5000 tons of Fe, 2600 tons of Al, 680 tons of Zn, and so on. While most elements were transported almost exclusively in the dissolved phase, Fe, Pb, Cr, and, above all, As showed high values associated with particulate matter. River water quality data from 1969 to 2019 showed a sharp worsening in 2000, immediately after the mine closure. From 2001 on, an improvement was observed.

中文翻译：

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受酸性矿山排水严重影响的河流中污染物浓度的演变：RíoTinto（西班牙西南部）

位于伊比利亚黄铁矿带（西班牙西南部）的里奥·廷托（RíoTinto）是酸性矿山排水污染的极端案例。该地区的开采可以追溯到铜时代，尽管直到19世纪下半叶才开始大规模开采大量硫化物矿床。由于酸性采矿的排放，RíoTinto通常在其运行过程中保持pH值接近2.5和高浓度污染物。从2017/18年水文年期间的详细采样中可以看出，大多数污染物遵循相似的季节性模式，由于次生可溶性硫酸盐的冲刷，秋季污染物浓度最高，而在大洪水事件中则最低。然而，砷和铅表现出不同的行为，具有延迟的浓度峰值。在整个监测年中，溶解的污染物负荷达到了5000吨铁，2600吨铝，680吨锌等。尽管大多数元素几乎都以溶解相形式运输，但Fe，Pb，Cr以及最重要的As表现出与颗粒物相关的高值。矿山关闭后，1969年至2019年的河水质量数据显示2000年急剧恶化。从2001年开始，观察到了改进。