Departamento de Recursos Hídricos y Ciencias Ambientales, Facultad de Ingeniería & Facultad de Ciencias Químicas, Universidad de Cuenca, Cuenca, Ecuador.
Departamento de Recursos Hídricos y Ciencias Ambientales, Facultad de Ingeniería & Facultad de Ciencias Químicas, Universidad de Cuenca, Cuenca, Ecuador.
Sci Total Environ. 2022 Aug 20;835:155560. doi: 10.1016/j.scitotenv.2022.155560. Epub 2022 Apr 27.
Monitoring solute fluxes in water quality studies is essential to reveal potential ecosystem disturbances, and is particularly important in Andean headwater catchments as they are the main sources of water for downstream populations. However, such studies have mainly focused on organic matter and nutrients, disregarding other solutes that can threaten water quality (e.g. arsenic, lead, calcium or magnesium). Additionally, routine low-resolution (weekly or monthly) sampling schemes may overlook important solute dynamics. Therefore, we collected water samples every four hours for the analysis of twenty-four solutes in a pristine tropical Andean páramo catchment. Solute fluxes were calculated using five different methods. The 4-hourly data set was filtered to test for an optimum sampling frequency without compromising export rates. Based on the available 4-hourly data, the results showed that the interpolation export method was best suited, due to a weak correlation with discharges. Of the twenty-four solutes analyzed, Dissolved Organic Carbon (DOC), Total Nitrogen bound (TNb), Si, Ca, Mg, K, and Na presented the highest input rates (with DOC = 4.167E+08 mEq km yr and Si = 1.729E+07 mEq km yr) and export rates (with DOC = 2.686E+08 mEq km yr and Si = 2.953E+08 mEq km yr). Moreover, DOC, TNb, NH-N, NO-N, NO-N, PO, Al, B, Cu, Fe, Zn, As, Cd, Cr, Pb, and V presented more input than export, while Ca, K, Mg, Na, Rb, Si, Sr, and Ba presented more export than input (geogenic sources). Filtered sampling frequencies demonstrated that a minimum of daily grab samples would be required to obtain reliable export rates with differences consistently below 10%, when compared to the 4-hourly solute export. These findings can be particularly useful for the implementation of long-term monitoring programs at low cost, and they provide high-quality information, for the first time, on biogeochemical budgets in a pristine páramo catchment.
监测水质研究中的溶质通量对于揭示潜在的生态系统干扰至关重要，特别是在安第斯山区的源头集水区，因为它们是下游人口的主要水源。然而，此类研究主要集中在有机物和养分上，而忽略了可能威胁水质的其他溶质（例如砷、铅、钙或镁）。此外，常规的低分辨率（每周或每月）采样方案可能会忽略重要的溶质动态。因此，我们在一个原始的热带安第斯高山湿地集水区每四小时采集一次水样，以分析 24 种溶质。使用五种不同的方法计算溶质通量。通过过滤 4 小时数据集来测试最佳采样频率，而不会影响出口率。根据可用的 4 小时数据，结果表明插值出口方法最适合，因为与排放量的相关性较弱。在所分析的 24 种溶质中，溶解有机碳（DOC）、总氮结合物（TNb）、Si、Ca、Mg、K 和 Na 表现出最高的输入率（DOC = 4.167E+08 mEq km yr，Si = 1.729E+07 mEq km yr）和出口率（DOC = 2.686E+08 mEq km yr，Si = 2.953E+08 mEq km yr）。此外，DOC、TNb、NH-N、NO-N、NO-N、PO、Al、B、Cu、Fe、Zn、As、Cd、Cr、Pb 和 V 的输入量大于输出量，而 Ca、K、Mg、Na、Rb、Si、Sr 和 Ba 的输出量大于输入量（地球成因来源）。过滤后的采样频率表明，与 4 小时溶质出口相比，每天至少需要进行一次随机水样采集，才能获得可靠的出口率，差异始终低于 10%。这些发现对于以低成本实施长期监测计划特别有用，并且首次提供了原始高山湿地集水区的生物地球化学预算的高质量信息。
