The connection between Submarine Groundwater Discharge and seawater quality : The threat of treated wastewater injected into coastal aquifers
Alorda-Kleinglass, Aaron (Universitat Autònoma de Barcelona. Departament de Física)
Rodellas, Valentí (Universitat Autònoma de Barcelona. Departament de Física)
Diego-Feliu, Marc (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Marbà, Núria (Institut Mediterrani d'Estudis Avançats)
Morell, Carlos (Institut Mediterrani d'Estudis Avançats)
Garcia-Orellana, Jordi (Universitat Autònoma de Barcelona. Departament de Física)

Date:	2024
Abstract:	Submarine Groundwater Discharge (SGD) delivers nutrients to the coastal sea triggering phytoplankton blooms, eutrophication, and can also serve as a pathway for contaminants. Wastewater treatment plants (WWTP) including injection wells in coastal areas influence coastal aquifers and might impact the composition and magnitude of SGD fluxes. In tourist areas, wastewater treatment may be less efficient and larger in volume during high seasons, potentially impacting nutrient fluxes from SGD and exacerbating environmental impacts. This study analyzes the nutrient transfer from treated wastewater injection in karstic aquifers to the coastal sea via SGD, considering the impacts of tourism seasonality. This study is conducted in Cala Deià, a small cove in the Balearic Islands, a Mediterranean tourist destination. The findings suggest that the seasonality of tourism, leading to variations in the volume of wastewater treated in the WWTP, influences the dynamics of the coastal aquifer. This leads to increased SGD water and nutrient fluxes to the sea in summer, i. e. the peak tourist season. The measured DIN, DIP, and DSi inventories in the cove are much larger in August than in April (3, 10, and 1. 5 times higher, respectively) due to higher input of nutrients in summer due to SGD impacted by the WWTP. These elevated nutrient flows can support algal blooms in the cove, compromising water quality for local swimmers and tourists. Indeed, in August, shoreline stations exhibited eutrophic Chl-a concentrations, with peaks reaching approximately 4 mg Chl-a L. These elevated levels suggest the presence of an algal bloom during the survey. The anthropogenic origin of SGD-driven nutrients is traced in seawater and seagrass meadows, as evidenced by high ∂N signatures indicative of polluted areas. Thus, the high pressure exerted on coastal areas by tourism activities increased the magnitude of SGD nutrient fluxes, thereby threatening coastal ecosystems and the services they provide.
Grants:	Ministerio de Ciencia e Innovación CEX2019-000940-M Agencia Estatal de Investigación CEX2021-001198 Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-640 Agencia Estatal de Investigación PID2019-110311RB-C21 Agencia Estatal de Investigación MDM2015-0552-17-1 Agència de Gestió d'Ajuts Universitaris i de Recerca 2019/BP-00241 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/FI_B_00365 Ministerio de Economía, Industria y Competitividad BES-2017-080740
Note:	Altres ajuts: acords transformatius de la UAB
Note:	Unidad de excelencia María de Maeztu CEX2019-000940-M
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Submarine groundwater discharge ; Nutrients ; Eutrophication ; WWTP ; Tourism
Published in:	Science of the total environment, Vol. 922 (April 2024) , art. 170940, ISSN 1879-1026

DOI: 10.1016/j.scitotenv.2024.170940

14 p, 4.1 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut de Ciència i Tecnologia Ambientals (ICTA)
Articles > Research articles
Articles > Published articles