Trends and probabilistic stability index for evaluating groundwater quality: The case of quaternary alluvial and quartzite aquifer system of India

Using grey clustering to evaluate nitrogen pollution in estuaries with limited data

“…These methods show useful results for the evaluation of incomplete environmental monitoring data (Scannapieco et al, 2012). Sen's slope has been used in many applications for water quality analysis to detect trends in pollutants (Koh et al, 2017;Machiwal et al, 2019;Tabari et al, 2011aTabari et al, , 2011b as it represents an absolute measure of change (Miró et al, 2018). As such, we used the Sen's slope to derive an indicator which represents the temporal trend in nitrogen concentrations.…”

Groundwater Quality Evaluation of the Dawu Water Source Area Based on Water Quality Index (WQI): Comparison between Delphi Method and Multivariate Statistical Analysis Method

“…In Canada, British Columbia introduced a new Water Quality Index in the mid-1990s as British Columbia Water Quality Index (BCWQI), and the Water Quality Guidelines Working Group of the Council of Canadian Ministers of the Environment (CCME), recognizing the need to assess the suitability of water for different uses, revised the index in 2001 to become known as the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) [17]. The groundwater quality index (GWQI) for groundwater quality was first derived by Backman et al in 1998 [17,18]. Subsequently, researchers have globally developed and used WQI technology, but the parameter selection and weight determination were primarily conducted using the Delphi method, which is subjective and random; the use of statistical multivariate analysis technology has been limited [17].…”

“…In the research on the application of multivariate statistical analysis technology, the scientific application of principal component analysis (PCA) and other methods using the WQI, as well as a comparative study with that of the Delphi method, are lacking. In groundwater evaluation, the focus is primarily laid on general chemical parameters, such as Total Dissolved Solids (TDS), hydrogen ion concentration(pH), Electrical Conductivity (EC), and heavy metals such as Hydrargyrum (Hg), Arsenic (As), and Chromium (Cr), with limited consideration for organic pollutants [18]. Previous studies on the application of WQI technology in groundwater quality analysis in China are few, and the application of groundwater environmental quality assessment in the Dawu water source area has not yet been reported.…”

Hydrogeochemical evaluation and mechanisms controlling groundwater in different geologic environments, Western Sokoto Basin, Northwestern Nigeria

“…Results have indicated anthropogenic inputs through variation in total dissolved solids (TDS), chloride (Cl − ), sulfate (SO 4 2− ), nitrate (NO 3 − ), and sodium (Na + ) concentrations. Likewise, many studies have observed that rock weathering, aridity, and saltwater intrusion, are the major controls on hydrochemistry of aquifers [4,32,71,91,106,115].…”