Journals Information
Environment and Ecology Research Vol. 13(5), pp. 619 - 633
DOI: 10.13189/eer.2025.130502
Reprint (PDF) (2142Kb)
Geochemical Indicators of Secondary Contamination in Rivers and Springs: A Novel Monitoring Approach for Seawater Intrusion in Deep Coastal Aquifers
Lalita Zakharikhina *, Polina Lesnikova , Vadim Kerimzade , Sergey Chernenkoa
Federal Research Centre the Subtropical Scientific Centre of the Russian Academy of Sciences, Russian Federation
ABSTRACT
Seawater intrusion into coastal aquifers poses a significant threat to groundwater quality, potentially contaminating freshwater sources with saline water. This process is exacerbated by anthropogenic activities such as well drilling and excessive groundwater extraction in coastal zones. In this study, conducted on the Abrau Peninsula on the Russian Black Sea coast, we identified, for the first time, the phenomenon of secondary contamination of river and spring waters resulting from seawater intrusion into deep aquifers. We also established geochemical indicators to monitor this process. A suite of persistently enriched chemical elements (Se, Sr, Cl, Br, S, Na, Ca, Mg, B) was identified, demonstrating a strong correlation with the primary seawater anions, Cl⁻ and SO₄²⁻. Notably, marine-derived elements exhibited a statistically significant decrease in river waters compared to spring waters, while rare earth element (REE) concentrations were consistently higher in river waters, reflecting terrestrial influences. To quantify the dynamics of secondary contamination, we propose a Geochemical Intrusion Coefficient (GIC): GIC = ∑ (Se, Cl, Br, S, Na - marine elements) / ∑ (REEs - terrestrial elements) / 10000. An increase in GIC values indicates enhanced seawater intrusion into deep aquifers, whereas a decrease reflects diminished intrusion. We found that deeply incised watercourse valleys in mid-mountain regions exhibit a relatively increased influence of secondary contamination on river waters. These geochemical indicators serve as critical monitoring tools for assessing the intensification of negative impacts from seawater intrusion during heightened groundwater exploitation in coastal areas, facilitating informed decision-making to mitigate groundwater quality degradation and associated water supply challenges.
KEYWORDS
Hydrogeochemistry, Seawater Intrusion, Groundwater, Deep Aquifer, Water Security
Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Lalita Zakharikhina , Polina Lesnikova , Vadim Kerimzade , Sergey Chernenkoa , "Geochemical Indicators of Secondary Contamination in Rivers and Springs: A Novel Monitoring Approach for Seawater Intrusion in Deep Coastal Aquifers," Environment and Ecology Research, Vol. 13, No. 5, pp. 619 - 633, 2025. DOI: 10.13189/eer.2025.130502.
(b). APA Format:
Lalita Zakharikhina , Polina Lesnikova , Vadim Kerimzade , Sergey Chernenkoa (2025). Geochemical Indicators of Secondary Contamination in Rivers and Springs: A Novel Monitoring Approach for Seawater Intrusion in Deep Coastal Aquifers. Environment and Ecology Research, 13(5), 619 - 633. DOI: 10.13189/eer.2025.130502.