The connection between Submarine Groundwater Discharge and seawater quality : The threat of treated wastewater injected into coastal aquifers

Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved..

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-1. 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 ∂15N 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.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:922

Enthalten in:

The Science of the total environment - 922(2024) vom: 20. März, Seite 170940

Sprache:

Englisch

Beteiligte Personen:

Alorda-Kleinglass, Aaron [VerfasserIn]
Rodellas, Valentí [VerfasserIn]
Diego-Feliu, Marc [VerfasserIn]
Marbà, Núria [VerfasserIn]
Morell, Carlos [VerfasserIn]
Garcia-Orellana, Jordi [VerfasserIn]

Links:

Volltext

Themen:

Eutrophication
Journal Article
Nutrients
Submarine groundwater discharge
Tourism
WWTP

Anmerkungen:

Date Revised 19.03.2024

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1016/j.scitotenv.2024.170940

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM368503925