Groundwater Quality Assessment in Tropical Environments

Groundwater in tropical settings is subject to a complex interplay of rapid recharge during monsoon seasons, intense weathering of minerals, high evaporation rates and land‐use pressures from agriculture and industry. Assessing its quality requires integration of hydrogeochemical analyses—measuring parameters such as salinity, hardness, fluoride and nitrate—with geospatial mapping and multivariate statistics to identify contamination hotspots. In many tropical regions, geogenic inputs of arsenic and fluoride combine with anthropogenic pollutants from fertilisers, sewage and industrial effluents to challenge public health and agricultural productivity. Effective assessment hinges on robust monitoring networks that link surface and subsurface data, supported by emerging tools such as remote sensing, machine learning and open‐access hazard mapping. These approaches inform risk management, guide treatment strategies and support sustainable water governance aligned with global water and sanitation goals.

Research from Nature Portfolio

Recent work has developed national‐scale groundwater‐quality hazard maps by integrating single‐point measurements with gridded observational datasets in a tropical island nation. Multi‐parameter indices encompassing chloride, alkalinity, nitrate, fluoride, total dissolved solids and trace metals were used to delineate regions where millions of inhabitants rely on water that fails to meet safe drinking thresholds. Spatial analysis highlighted critical contamination corridors linked to intensive agriculture and industrial effluents, revealing gaps in existing monitoring frameworks. The study underlined the urgency of establishing routine, nationwide water‐quality surveys and demonstrated how hazard mapping can prioritise resource allocation and infrastructure investment to achieve international drinking-water targets.

Groundwater Quality Assessment in Tropical Environments publication trend

The graph below shows the total number of articles in groundwater quality assessment in tropical environments across all publications each year (not limited to Nature Index journals).

Technical terms

Water Quality Index (WQI): A composite score derived from multiple chemical and physical water parameters to classify water suitability for human consumption and irrigation.

Total Dissolved Solids (TDS): The sum of all inorganic and organic substances dissolved in water, indicating its salinity and mineral content.

Geospatial Mapping Techniques: The use of geographic information systems and spatial interpolation methods to visualise and analyse the distribution of water quality variables across a region.

Hydrogeochemistry: The study of the chemical composition of groundwater and the processes—such as mineral dissolution, ion exchange and evaporation—that govern its evolution within aquifers.

References

1. Assessing the water quality hazard and challenges to achieving the freshwater goal in Sri Lanka. Scientific Reports (2025).
2. Assessing groundwater quality using the Water Quality Index (WQI) and GIS in the Uva Province, Sri Lanka. Applied Water Science (2022).
3. Seasonal Variations in Groundwater Quality and Hydrogeochemistry in the Endemic Areas of Chronic Kidney Disease of Unknown Etiology (CKDu) in Sri Lanka. Water (2021).
4. A geochemical classification of groundwater of Sri Lanka. Journal of the National Science Foundation of Sri Lanka (1985).
5. Groundwater-Based Drinking Water Supply in Sri Lanka: Status and Perspectives. Water (2022).