Institute of Environmental Assessment and Water Research (IDÆA-CSIC), c/Jordi Girona 18-26, 08034 Barcelona, Spain.
Sci Total Environ. 2012 Feb 1;416:418-28. doi: 10.1016/j.scitotenv.2011.11.079. Epub 2012 Jan 4.
The Tinto River is an extreme case of pollution by acid mine drainage (AMD), with pH values below 3 and high sulphate, metal and metalloid concentrations along its main course. This study evaluates the impact of releases from a freshwater reservoir on the Tinto River, identifying the metal transport mechanisms. This information is needed to understand the water quality evolution in the long term, and involves the comprehension of interactions between AMD sources, freshwaters, particulate matter and sediments. This work proposes a methodology for quantifying the proportions in which the different sources are contributing. The method is based on the mass balance of solutes and accounts for the uncertainty of end-members. The impact of the releases from the Corumbel Reservoir on the hydrochemistry of the Tinto River was significant, accounting up to a 92% of river discharge. These releases provoked a sharp decrease in dissolved metal concentrations, especially for Fe (approximately 1000 fold) due to dilution and precipitation. Cadmium, Zn, Cu, Co, Ni and Al suffered a dilution to a 12-16 fold decrease while Ca, Sr, Na, Pb and Si were less affected (2-4 folds decrease). However, these releases also gave rise to an increase in particulate transport, mainly Fe, As, Cr, Ba, Pb and Ti, due to sediment remobilisation and Fe precipitation. Aluminium, Li, K, Si, Al, Ni and Sr, together with Cu were present in the particulate phase during the discharge peak. The proposed 2-component mixing model revealed the existence of non-conservative behaviour for Al, Ca, Li, Mn, Ni and Si as a consequence of the interactions between the acidic Tinto waters and the clay-rich reservoir sediments during the bottom outlet opening. These results were improved by a 3-component mixing model, introducing a new end-member to account the chemical dissolution of clay-rich sediments by acidic Tinto waters.
廷托河是受酸性矿山排水（AMD）污染的极端案例，其主要河道的 pH 值低于 3，且硫酸盐、金属和类金属浓度很高。本研究评估了淡水水库释放对廷托河的影响，确定了金属迁移机制。这对于了解长期水质演变非常重要，涉及到 AMD 源、淡水、颗粒物和沉积物之间的相互作用。本工作提出了一种量化不同来源贡献比例的方法。该方法基于溶质的质量平衡，并考虑了端元的不确定性。Corumbel 水库的释放对廷托河的水化学产生了重大影响，占河流流量的 92%。这些释放导致溶解金属浓度急剧下降，特别是 Fe（约 1000 倍），原因是稀释和沉淀。Cd、Zn、Cu、Co、Ni 和 Al 因稀释而减少了 12-16 倍，而 Ca、Sr、Na、Pb 和 Si 的减少程度较小（减少 2-4 倍）。然而，这些释放也导致了颗粒物输送的增加，主要是 Fe、As、Cr、Ba、Pb 和 Ti，这是由于沉积物的再悬浮和 Fe 的沉淀。Al、Li、K、Si、Al、Ni 和 Sr 以及 Cu 在排放高峰期存在于颗粒物相中。提出的 2 组分混合模型表明，由于酸性廷托河水与底部出水口开启时粘土丰富的水库沉积物之间的相互作用，Al、Ca、Li、Mn、Ni 和 Si 表现出非保守行为。通过引入一个新的端元来解释酸性廷托河水对粘土丰富沉积物的化学溶解，该模型得到了改进。
