PIG: a numerical index for dissemination of groundwater contamination zones

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 HCO3-, and very high pollution zone from the downstream area, where the groundwater is associated with Cl-. 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-, HCO3-?:?Cl-, Na+?:?Ca2+ and Mg2+?:?Ca2+) 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. Copyright (C) 2011 John Wiley & Sons, Ltd.