Assessing Groundwater Quality and Pollution Risk Using an Integrated Water Quality Index (WQI) and Spatial Mapping Approach

Abstract

Groundwater is one of the most important sources of fresh water on Earth, and it supports drinking, farming, and industrial needs in many parts of the world. Despite its value, groundwater is facing growing pressure from human activity, weak waste handling, and natural rock interaction. This pressure leads to pollution that is often invisible until the water is tested. The present study brings together physicochemical data and the Water Quality Index (WQI) method to judge the drinking suitability of groundwater and to map pollution risk across space. Twelve common chemical parameters, namely pH, electrical conductivity, total dissolved solids, hardness, calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulfate, and nitrate, were used to build the index, following the weighted arithmetic method. Data drawn from a well-documented Middle Eastern aquifer system, covering 246 groundwater wells, were used as a real-world case to show how the method performs in practice. Results show that just over half of the samples fall in the good category, while a smaller share falls in the excellent class, and the rest show fair to poor quality, mostly because of high chloride, nitrate, and total dissolved solids levels. Spatial mapping points to farming activity and wastewater leakage as the leading drivers of pollution in the more affected zones. The paper proposes a practical, low-cost framework that links the WQI score to direct management actions, such as well protection, monitoring priority, and land-use control. This approach gives planners a single number that is easy to read, yet still backed by solid chemistry. The findings support wider use of WQI mapping as a routine tool for groundwater protection in regions facing similar pressure from agriculture, growing cities, and limited rainfall.