Groundwater is the most vulnerable, exploited natural resource which is a key source of freshwater in the world. Its regular decline in both quality and quantity are an important concern of research. The focus of the present study is to understand the important hydrogeochemical processes involved in the groundwater evolution of Vishwamitri River Basin (VRB), Gujarat, India, using Principal Component Analysis (PCA) technique. To achieve a symmetrical data distribution, log-transformation was applied in this study. This statistical approach decreases the data outlier. A Shapiro-Wilk statistic was employed to test the normal distribution of the data set. The results revealed that ten elements (TDS, bicarbonate, chloride, sulfate, sodium, calcium, magnesium, fluoride, iron and strontium) showed normal distribution. The PCA of 60 groundwater samples using 10 normally distributed chemical parameters indicates that the dominant geochemical process is rock-water interaction through dissolution and cation exchange reactions within the VRB aquifers. This study also reveals that, due to over use of chemical and fertilizers, the sulfate loading is high in groundwater. Therefore, the combined process of natural rock-water interaction, weathering and anthropogenic activities play a significant role in controlling the chemical composition of groundwater of VRB.

中文翻译：

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古吉拉特邦维什瓦米特里河流域 (VRB) 地下水演变研究的统计方法

地下水是最脆弱、最易开发的自然资源，也是世界上淡水的主要来源。其质量和数量的定期下降是研究的一个重要问题。本研究的重点是使用主成分分析 (PCA) 技术了解印度古吉拉特邦 Vishwamitri 河流域 (VRB) 地下水演化所涉及的重要水文地球化学过程。为了实现对称的数据分布，本研究中应用了对数变换。这种统计方法减少了数据异常值。Shapiro-Wilk 统计量被用来检验数据集的正态分布。结果表明，十种元素（TDS、碳酸氢盐、氯化物、硫酸盐、钠、钙、镁、氟化物、铁和锶）呈正态分布。使用 10 个正态分布化学参数的 60 个地下水样品的 PCA 表明，主要的地球化学过程是通过 VRB 含水层内的溶解和阳离子交换反应的岩水相互作用。这项研究还表明，由于过度使用化学品和化肥，地下水中的硫酸盐含量很高。因此，天然岩水相互作用、风化和人为活动的综合过程对控制VRB地下水的化学成分具有重要作用。