Totsche Oliver, Fyson Andrew, Kalin Margarete, Steinberg Christian E W
Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
Environ Sci Pollut Res Int. 2006 Jul;13(4):215-24. doi: 10.1065/espr2005.09.284.
BACKGROUND, AIMS AND SCOPE: The acidification of mine waters is generally caused by metal sulfide oxidation, related to mining activities. These waters are characterized by low pH and high acidity due to strong buffering systems. The standard acidity parameter, the Base Neutralization Capacity (BNC), is determined by endpoint titration, and reflects a cumulative parameter of both hydrogen ions and all buffering systems, but does not give information on the individual buffer systems. We demonstrate that a detailed interpretation of titration curves can provide information about the strength of the buffering systems. The buffering systems are of importance for environmental studies and treatment of acidic mining waters.
Titrations were carried out by means of an automatic titrator using acidic mining waters from Germany and Canada. The curves were interpreted, compared with each other, to endpoint titration results and to elemental concentrations contained therein.
The titration curves were highly reproducible, and contained information about the strength of the buffer systems present. Interpretations are given, and the classification and comparison of acidic mining waters, by the nature and strength of their buffering systems derived from titration curves are discussed. The BNC-values calculated from the curves were more precise than the ones determined by the standard endpoint titration method. Due to the complex buffer mechanisms in acidic mining waters, the calculation of major metal concentrations from the shape of the titration curve resulted in estimates, which should not be confused with precise elemental analysis results.
Titration curves provide an inexpensive, valuable and versatile tool, by which to obtain sophisticated information of the acidity in acidic water. The information about the strength of the present buffer systems can help to understand and document the complex nature of acidic mining water buffer systems. Finally, the interpretation of titration curves could help to improve treatment measurements and the ecological understanding of these acidic waters.
背景、目的与范围：矿井水的酸化通常是由与采矿活动相关的金属硫化物氧化引起的。由于强大的缓冲系统，这些水的特点是pH值低且酸度高。标准酸度参数——碱中和能力（BNC），通过终点滴定法测定，它反映了氢离子和所有缓冲系统的累积参数，但未提供关于各个缓冲系统的信息。我们证明，滴定曲线的详细解读可以提供有关缓冲系统强度的信息。缓冲系统对于酸性矿井水的环境研究和处理至关重要。
使用自动滴定仪对来自德国和加拿大的酸性矿井水进行滴定。对曲线进行解读，并相互比较，同时与终点滴定结果以及其中所含元素浓度进行比较。
滴定曲线具有高度可重复性，并包含了所存在缓冲系统强度的信息。给出了解读内容，并讨论了根据滴定曲线得出的缓冲系统的性质和强度对酸性矿井水进行分类和比较的情况。从曲线计算得出的BNC值比通过标准终点滴定法测定的值更精确。由于酸性矿井水中缓冲机制复杂，根据滴定曲线形状计算主要金属浓度只能得到估计值，不应与精确的元素分析结果混淆。
滴定曲线提供了一种廉价、有价值且用途广泛的工具，可借此获取酸性水中酸度的复杂信息。有关现有缓冲系统强度的信息有助于理解和记录酸性矿井水缓冲系统的复杂性质。最后，滴定曲线的解读有助于改进处理措施以及对这些酸性水的生态理解。
