Impact of geology on hydrogeological and hydrochemical characteristics of groundwater in tropical environments: a narrative review

Abstract

Groundwater is critical in sustaining ecosystems, agriculture, and human livelihoods, particularly in tropical regions where it is often the primary source of freshwater. However, the management of groundwater resources is increasingly threatened by over-extraction, contamination, and the compounding effects of climate change. This review synthesizes critical challenges and future directions in understanding hydrogeology, hydrochemistry, and groundwater management in tropical environments, explicitly focusing on case studies from the Global South. Groundwater quality is shaped by natural geological factors and anthropogenic activities, with trace elements such as arsenic, fluoride, and heavy metals significantly contributing to contamination in several regions. Human-induced pollution, particularly from agricultural practices, mining, and urbanization, further degrades water quality, posing serious public health risks. Through case studies from Bangladesh, East Africa, Latin America, and coastal regions of India, this review explores the diverse ways in which natural and human-induced factors intersect to affect groundwater quality and availability. Each case highlights the complexity of managing groundwater resources in diverse geological and socio-economic contexts. In Bangladesh, the widespread issue of arsenic contamination due to naturally occurring elements mobilized by groundwater extraction has resulted in severe health impacts. High fluoride concentrations in the groundwater of East Africa, exacerbated by volcanic geology, have led to widespread dental and skeletal fluorosis. In Latin America, mining activities have contaminated aquifers with heavy metals, threatening human and agricultural water supplies. In coastal India, excessive groundwater extraction has caused saltwater intrusion, further complicating water security. This review identifies over-extraction, poor water quality, climate change impacts, and weak governance as significant challenges in groundwater management. Future directions include integrating advanced monitoring technologies, interdisciplinary research, community participation, and policy reforms to promote sustainable use and protection of groundwater. Effective management will require a combination of scientific innovation, robust regulatory frameworks, and increased public awareness to ensure long-term water security in tropical regions and beyond.

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