Unveiling hidden mercury and methylmercury sources

Mercury loads from Submarine Groundwater Discharge (SGD) may represent an overlooked source of methylmercury (MeHg) to the ocean, affecting human and ecosystem health. The SGD process involves the flow of fresh, saline, or mixed groundwater from coastal aquifers into the oceans classified in differe...

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Bibliographic Details
Authors: Lavergne, Céline|||0000-0002-2002-8655, Rodriguez-Puig, Júlia|||0000-0002-9648-290X, Ruiz González, Clara|||0000-0003-3568-4943, Montero-Curiel, María|||0000-0002-2190-5410, Casas, Gemma|||0000-0002-4197-2151, Romano-Gude, Daniel|||0000-0003-2630-9316, Alorda-Montiel, Irene|||0000-0002-6212-9171, Dordal-Soriano, Júlia|||0000-0002-7251-7178, Alorda-Kleinglass, Aaron|||0000-0002-5627-5412, Diego-Feliu, Marc|||0000-0002-4782-3210, Gilabert, Javier|||0000-0002-0988-5445, Campillo-de La Maza, Alex, Romera Castillo, Cristina|||0000-0002-4888-1340, Torres-Rodriguez, Natalia|||0000-0002-4649-2413, Heimbürger-Boavida, Lars-Eric|||0000-0003-0632-5183, García Orellana, Jordi|||0000-0002-0543-2641, Rodellas, Valentí|||0000-0002-5896-9987, Bravo, Andrea G.|||0000-0002-8341-3462
Format: article
Publication Date:2025
Country:España
Institution:Universitat Autònoma de Barcelona
Repository:Dipòsit Digital de Documents de la UAB
Language:English
OAI Identifier:oai:ddd.uab.cat:320009
Online Access:https://ddd.uab.cat/record/320009
https://dx.doi.org/urn:doi:10.1021/acs.est.5c07191
Access Level:Open access
Keyword:Biogeochemistry
Mercury budget
Methylmercury
Submarine groundwater discharge
Coastal aquifer
Mar Menor
Description
Summary:Mercury loads from Submarine Groundwater Discharge (SGD) may represent an overlooked source of methylmercury (MeHg) to the ocean, affecting human and ecosystem health. The SGD process involves the flow of fresh, saline, or mixed groundwater from coastal aquifers into the oceans classified in different components. Existing studies rarely report the fluxes supplied by the different SGD components; therefore, the relevance of SGD as a source of mercury remains unclear. We aimed to quantify SGD-driven mercury/methylmercury fluxes to the coast, focusing on the largest coastal lagoon in the western Mediterranean. We measured total dissolved mercury and MeHg in surficial and porewaters during the summer and autumn. Porewaters were enriched in total dissolved Hg and MeHg compared to the lagoon. Lagoon shore waters and porewaters with a high concentration of labile dissolved organic matter were prone to MeHg formation and thus had higher MeHg concentrations. The mercury input through SGD to the Mar Menor lagoon (4300 mmol year-1) was similar to atmospheric deposition and 1 order of magnitude greater than the stream input. Among different components of the SGD, long-scale lagoon water recirculation dominated. These findings have substantial implications for the regional Hg budget and raise awareness of the importance of considering the different SGD components for an accurate estimation of SGD-based Hg input to the coastal ocean.

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