PIG: a numerical index for dissemination of groundwater contamination zones

Abstract

A pollution index of groundwater (PIG) is proposed for quantification of water contamination. PIG quantifies the status of concentrations of water quality measures with respect to their drinking water quality standards. The validity of the proposed index is verified by choosing the data of groundwater quality of the Varaha River Basin (Visakhapatnam District, Andhra Pradesh, India) as a case study. The computed index from the study area varies from 0.83 to 2.55. The index disseminates the area into zones of insignificant (PIG <1.0), low (PIG: 1.0 to 1.5), moderate (PIG: 1.5 to 2.0), high (PIG 2.0 to 2.5) and very high (PIG >2.5) pollution. Insignificant pollution zone is observed from the upstream area, where the groundwater is dominated by HCO À 3 , and very high pollution zone from the downstream area, where the groundwater is associated with Cl À . This indicates that the quality of groundwater in the study area is mainly influenced by the source of geogenic origin, but it is subsequently modified by the effects of anthropogenic and marine sources. Geochemical ratios (Na + : Cl À , HCO À 3 : Cl À , Na + : Ca 2+ and Mg 2+ : Ca 2+ ) also form the quantitative basis of the index. The present study paves the way to implement appropriate management strategies at a specific site to circumvent the pollution. As the classification of the pollution zones with PIG depends upon the drinking water quality standards, it becomes a universal assessment tool for groundwater contamination at any test area.

Intelligent soft computational models integrated for the prediction of potentially toxic elements and groundwater quality indicators: a case study

“…Subba Rao ( 2012 ) formulated the PIG, which has been successfully used in various locations for monitoring and assessing variations in drinking water quality (Egbueri, 2020 ; Subba Rao & Chaudhary, 2019 ; Subba Rao et al, 2018 ).…”

“…Step 1 This entails calculating the relative weight (R w ) (on a scale of 1–5) of the analyzed parameters based on their individual importance in assessing water quality and relative impact on human health (Table 2 ). (Subba Rao, 2012 ).…”

“…The PIG values represent the contributions of all chemical variables analyzed in each groundwater sample. As a result, they depict various scenarios of the impact of chemical contamination on aquifer systems (Egbueri, 2020 ; Subba Rao, 2012 ; Subba Rao & Chaudhary, 2019 ; Subba Rao et al, 2018 ). The classification scheme stated by Subba Rao et al ( 2018 ) for the PIG scores characterizes the extent of pollution in groundwater samples as: insignificant pollution (PIG < 1.0), low pollution (1.0–1.5), moderate pollution (1.5–2.0), high pollution (2.0–2.5), and very high pollution (PIG > 2.5).…”

A comprehensive assessment of groundwater for seasonal variation in hydro-geochemistry, quality, contamination and human health risk from Deccan Basaltic region, Western India

“…PIG is a numerical expression for rating the quantifying range of contamination by considering parameters such as pH, TDS, major cations and anions, boron and uoride based on their relative importance in de ning groundwater quality (Rao and Chaudhary 2019;Wagh et al, 2020b). PIG was based on considering WHO drinking standards; also, computed by following the methodology proposed by Subba Rao (2012).…”

Integration of Heavy Metal Pollution Indices and Health Risk Assessment of Groundwater in Semi-arid Coastal Aquifers, South Africa

“…Several numerical and statistical models developed globally are successfully used in water quality assessment. Such methods includes Heavy metal pollution index (HPI), Heavy metal evaluation index (HEI), degree of contamination (Cd), Ecological risk index (ERI), Pollution index of groundwater (PIG), Synthetic pollution index (SPI), and Overall index of pollution (OIP), Correlation analysis (CA), Principal Component Analysis (PCA) and Hierarchical cluster analysis (HCA) (Mohan et al 1996;Prasad and Bose 2001;Edet and Offiong 2002;Prasanna et al 2012;Subba Rao 2012;Solangi et al 2019;Egbueri 2020;Wu et al 2014Wu et al , 2020Li et al 2015Li et al , 2016Li et al , 2019bRen et al 2021). About 40% of the groundwater samples in Nigeria ispolluted by heavy metals rendering it inappropriate for human consumption (Egbueri and Unigwe 2020).…”