Groundwater quality evaluation using the water quality index (WQI), the synthetic pollution index (SPI), and geospatial tools: a case study of Sujawal district, Pakistan

Abstract

Under changing climate scenario, groundwater aquifers in the coastal areas of Pakistan are under serious threat. Looking at the gravity of the problem, and concerns of the civil society, this study was conducted to evaluate and map the quality of groundwater in the Sujawal district, a coastal area of Pakistan based on the physicochemical analysis of 94 samples using two standard numerical models and geospatial techniques. The WQI model revealed that 2.13%, 6.38%, 55.32%, 22.34%, and 13.83% of water samples were excellent, good, poor, very poor, and unsuitable for drinking purposes. Also, the SPI model identified that 32%, 13.83%, 20.12%, 18.1%, and 15.95% of samples were slightly polluted, moderately polluted, highly polluted, suitable, and unsuitable. Though the model's input is different, the proportionate of ranking revealed a significant correlation (R²=0.78) between the outcomes of both models. Overall, the study revealed that groundwater in most of the areas does not meet WHO guidelines. The prevalence of water-related diseases in the area suggests that groundwater is contaminated and using that water is of high risk for human health. The study highlights the significance of using numerical models and geospatial techniques for water quality evaluation in the coastal areas of the world.

Keywords:

• Groundwater
• spatial analysis
• water quality index models
• principal component analysis
• human health impacts
• Pakistan
• Sujawal

Acknowledgment

We are also thankful to Dr. Rick Bereit, Professor, University of Utah (UU), United States of America (USA) for his constructive comments and suggestions for improvement of the manuscript. We also appreciate positive and constructive comments and suggestions of the anonymous reviewers.

Additional information

Funding

We wish to express our gratitude to the U.S.-Pakistan Center for Advanced Studies in Water, Mehran University of Engineering and Technology, Jamshoro, Pakistan for funding the project “Climate Change: Assessing the Impact of Seawater intrusion on soil, water, and environment using GIS and RS tools” under the Applied Research Grant Policy.