Department of Earth Sciences, Annamalai University, Annamalai Nagar, Tamilnadu, India.
Water Research Centre, Kuwait Institute for Scientific Research, Kuwait, Kuwait.
Environ Sci Pollut Res Int. 2020 Jun;27(16):20037-20054. doi: 10.1007/s11356-020-08258-6. Epub 2020 Mar 31.
Hydrogeochemical understanding of groundwater is essential for the effective management of groundwater. This study has been carried out to have concrete data for the seasonal variations in hydrogeochemistry of groundwater in central Tamilnadu forming a complex geological terrain with a varied lithology. A total of 244 groundwater samples were collected during four different seasons, viz, southwest monsoon (SWM), summer (SUM), postmonsoon (POM), and northeast monsoon (NEM) from bore wells. The physical parameters such as pH, temperature, TDS, ORP, humidity, and electrical conductivity (EC) were measured insitu, whereas major ions were analyzed in the lab adopting standard procedures. Overall, higher EC and NO values were observed and exceeded the WHO permissible limit irrespective of seasons, except for NO in SWM. Na and HCO are the dominant cation and anion in the groundwater irrespective of seasons. The highest average values of Na (65.06 mg L) and HCO (350.75 mg L) were noted during SWM. Statistical analysis was carried out to elucidate the hydrogeochemistry of the region. Initially, to understand the ionic relationship, correlation matrix was used followed by factor analysis for determination of major geochemical control and later factor scores were derived to understand the regional representations. An attempt has also been made to identify the samples influenced by multiple geochemical processes and to understand their spatial variation in the study period. Correlation of geochemical parameters reveals a excellent positive correlation between Ca and NO in SUM, SWM, and NEM due to the dominant of anthropogenic sources and minor influence of weathering process. Strongly loaded factor scores are found to be mostly in the following order POM > NEM > SWM > SUM. Principal component analysis of different seasons indicates the interplay of natural weathering and anthropogenic factors. Overall, the predominant geochemical processes in this region, irrespective of seasons are weathering and, ion exchange and anthropogenic activities.
地下水的水文地球化学理解对于地下水的有效管理至关重要。本研究旨在为泰米尔纳德邦中部地下水的水文地球化学季节性变化提供具体数据，该地区地质构造复杂，岩性多样。总共采集了 244 个地下水样本，分别来自四个不同的季节，即西南季风（SWM）、夏季（SUM）、后季风（POM）和东北季风（NEM），取自钻孔。现场测量了 pH 值、温度、TDS、ORP、湿度和电导率（EC）等物理参数，而采用标准程序在实验室分析了主要离子。总体而言，无论季节如何，EC 和 NO 值都较高，且超过了世卫组织的允许限值，除了 SWM 中的 NO 值。Na 和 HCO 是地下水无论季节都占主导地位的阳离子和阴离子。SWM 期间记录到 Na（65.06 mg/L）和 HCO（350.75 mg/L）的最高平均值。为了阐明该地区的水文地球化学性质，进行了统计分析。最初，为了了解离子关系，使用了相关矩阵，然后进行因子分析以确定主要地球化学控制因素，之后得出因子得分以了解区域代表性。还尝试确定受多种地球化学过程影响的样本，并了解它们在研究期间的空间变化。地球化学参数的相关性表明，由于人为来源占主导地位，风化过程的影响较小，SUM、SWM 和 NEM 中的 Ca 和 NO 之间存在极好的正相关关系。强烈加载的因子得分大多按以下顺序排列：POM>NEM>SWM>SUM。不同季节的主成分分析表明自然风化和人为因素的相互作用。总的来说，无论季节如何，该地区主要的地球化学过程是风化、离子交换和人为活动。
