20 Hydrogeology and Marine/Coastal Geoscience

This session covers aspects related to SGDs & their associated aquifers, including but not limited to: water–rock interaction, coastal aquifer contamination, geochemical transformation, hydrological flows, saline intrusion, coastal estuaries, and environmental, economic, and social SGD-related issues.

Thursday, 23 April 2026
8:00 AM - 10:00 AM
LMH, Meeting Room

Metal Fluxes into Mar Menor Coastal Lagoon (Spain) Through Submarine Groundwater Discharge

Paper number: 20-6
Program: Technical Sessions
Time: 9:30 AM – 9:45 AM

Authors

Abstract

Mar Menor coastal lagoon located at the Southeast of Spain, has been recognized in the Mediterranean coast as one of the largest hypersaline water systems (38-51 ppt), besides presenting relatively long residence time of water in it due to its geomorphology. These characteristics, in addition to the anthropogenic activities in the area (agriculture, fishing, tourism, historical mining activity) could lead to the presence of high metal concentrations in its waters. There are several studies related to metal water levels in Mar Menor, nevertheless, metal fluxes into the lagoon through submarine groundwater discharges (SGD) haven’t been yet explored, even though it is a potentially relevant source of metals. In the present study, two sampling campaigns (July and November 2021), reflecting different hydrological seasons, were performed to collect samples from groundwater, streams and lagoon water, with the objective of understanding the magnitude of SGD-driven inputs as well as the spatial and temporal distribution of the analyzed metals (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). The results showed that SGD had more relevance than surficial inputs into Mar Menor, showing higher metal fluxes of As, Fe, Mn, Pb and Zn. It also revealed higher metal concentrations in the North and South areas, which could be associated with the agriculture (North) and the tailings from Cartagena-La Unión mining district (South). This research shows a broader picture of all the possible water metal pathways towards Mar Menor coastal lagoon and highlights the relevance of SGD metal inputs into aquatic systems.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-410940

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