Salinity origin in the coastal aquifer of the Southern Venice lowland

Luigi Alessandrino; Mattia Gaiolini; Francisco Aldo Cellone; Nicolò Colombani; Micòl Mastrocicco; Marta Cosma; Cristina Da Lio; Sandra Donnici; Luigi Tosi

doi:10.1016/j.scitotenv.2023.167058

Salinity origin in the coastal aquifer of the Southern Venice lowland

Sci Total Environ. 2023 Dec 20:905:167058. doi: 10.1016/j.scitotenv.2023.167058. Epub 2023 Sep 13.

Authors

Luigi Alessandrino¹, Mattia Gaiolini², Francisco Aldo Cellone³, Nicolò Colombani⁴, Micòl Mastrocicco¹, Marta Cosma⁵, Cristina Da Lio⁵, Sandra Donnici⁵, Luigi Tosi⁵

Affiliations

¹ DiSTABiF - Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Campania University "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy.
² SIMAU - Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy.
³ IGG - Institute of Geosciences and Earth Resources, National Research Council, Via G. Gradenigo 6, 35131 Padova, Italy; Centro de Investigaciones del Medio Ambiente, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de La Plata (CIM-UNLP-CONICET), Buenos Aires, Argentina.
⁴ SIMAU - Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy. Electronic address: n.colombani@univpm.it.
⁵ IGG - Institute of Geosciences and Earth Resources, National Research Council, Via G. Gradenigo 6, 35131 Padova, Italy.

PMID: 37709072
DOI: 10.1016/j.scitotenv.2023.167058

Abstract

Groundwater salinization can be natural and anthropogenic in origin, although it often results from a combination of both, especially in low-lying coastal regions that are hydraulically controlled. This study proposes a method to assess the origin of salinity using environmental tracers in porewater, like Cl^- and Br^-, combined with depositional facies associations detected in sediment cores. Such integrated approach was tested in a target area south of the Venice Lagoon (Italy), where groundwater salinization is triggered by multiple mechanisms due to the complexity of the hydro-geomorphological environment. Batch tests were performed on sediment core samples from boreholes to quantify major anions and total inorganic N. Cl^- and Br^- porewater concentrations coupled with sedimentary facies association provided insights into the origin of groundwater salinity from a variety of sources, including past and present seawater intrusion, agricultural leaching, and evaporites. The strengths and limitations of the integrated approach are discussed to provide a pathway for improving water resource management and planning measures to prevent groundwater salinization in coastal areas.

Keywords: Aquifer salinization; Cl(−)/Br(−) molar ratio; Depositional environments; Sediment porewater.