Hydrogeology Group Institute of Geological Sciences, Freie Universität Berlin, 12249, Berlin, Germany.
Environ Sci Pollut Res Int. 2017 Dec;24(34):26623-26633. doi: 10.1007/s11356-017-0239-0. Epub 2017 Sep 27.
Fluoride contamination is one of the most alarming issues for those countries that depend on groundwater drinking water supply. A careful examination of the hydrogeochemical conditions and routine monitoring of fluoride level are therefore quintessential. Estimation of natural background level (NBL) of fluoride becomes significant information for assessing the current and future contamination episodes. Vellore District in Tamil Nadu is a hard rock terrain known for its F-rich groundwater. In this study, we attempted to form a benchmark for fluoride using hydrochemical pre-selection (based on TDS and NO) and cumulative probability plots (CPP). Principle components analysis is (PCA) applied to evaluate the corresponding factor grouping of the total of 68 samples, which is later mapped using geostatistical tool in ArcGIS. From the CPP, we derived the NBL of F as 0.75 mg/L. This value is compared with the observed concentration in each sample and they were spatially plotted based on the NBL. Resultant plot suggests that W-NW part of the study area has exceeded and E-EW regions are below the NBL of F. Spatial variation of the factor scores also supported this observation. Grounding an NBL and extending it to other parts of the potential contaminated aquifers are highly recommended for better understanding and management of the water supply systems.
氟污染是依赖地下水作为饮用水供应的国家面临的最令人担忧的问题之一。因此，仔细检查水文地球化学条件并定期监测氟化物水平是至关重要的。估计氟化物的自然背景水平（NBL）对于评估当前和未来的污染事件是重要信息。泰米尔纳德邦的维洛尔区是一个以富氟地下水而闻名的硬岩地形。在这项研究中，我们试图使用水化学预选（基于 TDS 和 NO）和累积概率图（CPP）来为氟化物建立基准。主成分分析（PCA）用于评估总共 68 个样本的相应因子分组，然后使用 ArcGIS 中的地质统计工具进行映射。从 CPP 中，我们得出氟的 NBL 为 0.75mg/L。将此值与每个样本中的观察浓度进行比较，并根据 NBL 在空间上进行绘制。结果图表明，研究区的 W-NW 部分已经超过，而 E-EW 地区低于氟的 NBL。因子得分的空间变化也支持了这一观察结果。建议建立 NBL 并将其扩展到其他潜在污染含水层的部分，以更好地理解和管理供水系统。
