Home Publications Research Grants Inventions & Patents Awards Additional Research Activities Faculties & Institutions Research Areas

Processes of Groundwater Contamination in Coastal Aquifers in Sri Lanka: A Geochemical and Isotope-Based Approach

Ratnayake MS, Senarathne SL, Diyabalanage S, Bandara C, Wickramarathne S, Chandrajith R (2025)

---

Publication Type: Journal article

Publication year: 2025

Journal

Book Volume: 17

Article Number: 1571

Journal Issue: 11

DOI: 10.3390/w17111571

Abstract

Over the last decade, concern has increased about the deterioration of groundwater quality in coastal aquifers due to salinization processes resulting from uncontrolled abstraction and the impacts of global climate change. This study investigated the groundwater geochemistry of a narrow sandy peninsula bounded by the ocean and brackish water lagoons in northern Sri Lanka. The population of the region has grown rapidly over the last decade with increasing agricultural activities, and therefore, the use of groundwater has increased. To investigate the effects of seawater intrusion and anthropogenic activities, selected water quality parameters and water isotopes (δ²H and δ¹⁸O) were measured in 51 groundwater samples. The results showed that selected shallow groundwater wells are vulnerable to contamination from anthropogenic processes and seawater intrusion, mainly indicated by Cl/Br ratios. Iron-rich groundwater (0.11 to 4.2 mg/L) could represent another problem in the studied groundwater. According to Water Quality Index calculations, 41% of shallow wells contained poor and unsuitable water for domestic and irrigation purposes. Most of the groundwater in the region was saturated with Ca and Mg containing mineral phases such as calcite, dolomite, magnesite and gypsum. Water isotopes (δ²H and δ¹⁸O) showed that about 50% of the groundwater samples were scattered near the local meteoric water line. This indicates sufficient rainwater infiltration. However, some samples exhibit elevated isotope values due to seawater admixture and secondary evaporation under semi-arid conditions. This study showed the utility of Cl/Br ratios as indicators for distinguishing anthropogenic sources of Cl contributions to groundwater in shallow, permeable aquifer systems.

Authors with CRIS profile

Involved external institutions

How to cite

APA:

Ratnayake, M.S., Senarathne, S.L., Diyabalanage, S., Bandara, C., Wickramarathne, S., & Chandrajith, R. (2025). Processes of Groundwater Contamination in Coastal Aquifers in Sri Lanka: A Geochemical and Isotope-Based Approach. Water, 17(11). https://doi.org/10.3390/w17111571

MLA:

Ratnayake, Movini Sathma, et al. "Processes of Groundwater Contamination in Coastal Aquifers in Sri Lanka: A Geochemical and Isotope-Based Approach." Water 17.11 (2025).

BibTeX: Download