A holistic review on the assessment of groundwater quality using multivariate statistical techniques.

Water is an essential element in nature. It is used in drinking, irrigation, and industry mainly. Human health is directly linked to groundwater quality and is affected by poor groundwater quality caused by excessive fertilizer application and unhygienic circumstances. Because of increased pollution, investigating the water quality became a point of research for many researchers. There are numerous approaches to assessing water quality, and statistical methods are essential among them. This review paper discusses Multivariate Statistical Techniques, including Cluster Analysis, Principal Component Analysis, Factor Analysis, Geographical Information System, and Analysis of Variance, to name a few. We have presented the significance of each method concisely and how it is being used. In addition, an extensive table is prepared to demonstrate the individual technique along with the computational tool, the type of water bodies, and their respective regions. The advantages and disadvantages of the statistical techniques are also discussed therein. It is found that Principal Component Analysis and Factor Analysis are widely explored techniques.

A systematic and comparative study of Water Quality Index (WQI) for groundwater quality analysis and assessment.

Water is essential for human survival. Its quality must be maintained to prevent any potential health problems. Pollution and contamination are likely causes of the water quality decline. This may occur if the world's rapidly expanding population and industrial facilities fail to clean their effluent correctly. The Water Quality Index, often known as the WQI, is the indicator most frequently used to characterize surface water quality. This study emphasizes several WQI models that could be of use to us in determining the level of water quality available in the various areas. We have tried to cover multiple essential procedures and their corresponding mathematical counterparts. In this article, we also examine the applications of index models in different types of water bodies, such as lakes, rivers, surface water, and groundwater. The level of contamination in water due to pollution directly affects the overall quality of water. A pollution index is a valuable tool for measuring the level of pollution. Concerning this, we have discussed two approaches, namely, the Overall Index of Pollution and Nemerrow's Pollution Index, which demonstrate the most effective technique to evaluate the water standard. Examining the similarities and differences between these approaches may offer researchers a suitable starting point to delve further into assessing water quality.