{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T03:57:19Z","timestamp":1776743839405,"version":"3.51.2"},"reference-count":47,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,17]],"date-time":"2026-01-17T00:00:00Z","timestamp":1768608000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, I.P.","award":["10.54499\/2021.06868.BD"],"award-info":[{"award-number":["10.54499\/2021.06868.BD"]}]},{"name":"University of Lisbon Institute of Civil Engineering Research and Innovation for Sustainability","award":["UID\/6438\/2025"],"award-info":[{"award-number":["UID\/6438\/2025"]}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Water"],"abstract":"<jats:p>Salinization represents a significant threat to freshwater resources worldwide, compromising water quality and security. In the Vieira de Leiria\u2013Marinha Grande aquifer, salinization mechanisms are a complex interaction between seawater intrusion and evaporite dissolution. Near the coast, groundwater is mainly influenced by seawater, evidenced by Na-Cl hydrochemical facies, high electrical conductivity, and Na+\/Cl\u2212, Cl\u2212\/Br\u2212 and SO42\u2212\/Cl\u2212 molar ratios consistent with marine signatures. In areas affected by diapiric dissolution, besides elevated electrical conductivity, groundwater is enriched in SO42\u2212 and Ca2+ and in minor elements like K+, Li+, B3+, Ba2+ and Sr2+, and high SO42\u2212\/Cl\u2212 and Ca2+\/HCO3\u2212 molar ratios, indicative of gypsum\/anhydrite dissolution. The relationship between \u03b418O and electrical conductivity further supports the identification of distinct salinity sources. This study integrates hydrogeochemical tracers to investigate hydrochemical evolution in the aquifer with increasing residence time and influence of water\u2013rock interaction, as well as the accurate characterization of salinization mechanisms in multilayer aquifers. A comprehensive understanding of these processes is essential for identifying vulnerable zones and developing effective management strategies to ensure the protection and sustainable use of groundwater resources.<\/jats:p>","DOI":"10.3390\/w18020252","type":"journal-article","created":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T09:57:02Z","timestamp":1768816622000},"page":"252","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Tracing the Origin of Groundwater Salinization in Multilayered Coastal Aquifers Using Geochemical Tracers"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9844-8756","authenticated-orcid":false,"given":"Mariana","family":"La Pasta Cordeiro","sequence":"first","affiliation":[{"name":"Civil Engineering Research and Innovation for Sustainability-CERIS, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal"}]},{"given":"Johanna","family":"Wallstr\u00f6m","sequence":"additional","affiliation":[{"name":"Department of Physical Geography, Stockholm University, 10691 Stockholm, Sweden"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5665-6744","authenticated-orcid":false,"given":"Maria Teresa","family":"Condesso de Melo","sequence":"additional","affiliation":[{"name":"Civil Engineering Research and Innovation for Sustainability-CERIS, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,17]]},"reference":[{"key":"ref_1","unstructured":"Kalin, R., Poeter, E., and Cherry, J. (2022). 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