Hydrochemistry and trace metals in water and sediments in forest coastal wetlands influenced by tidal regime in the middle Río de la Plata estuary, Argentina

• Published in: Marine pollution bulletin Vol. 202; p. 116359
• Main Authors: Santucci, Lucía, Carol, Eleonora, Borda, Laura G., García, M. Gabriela
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2024
• Subjects: Argentina; Environmental Monitoring; Estuaries; Forests; Geologic Sediments - chemistry; Groundwater; Metals - analysis; Punta Lara natural reserve; Sediment cores; Trace Elements - analysis; Water chemical composition; Water Pollutants, Chemical - analysis; Water-sediment interaction; Wetlands; Argentina; Punta Lara natural reserve; Groundwater; Water chemical composition; Sediment cores; Water-sediment interaction
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2024.116359

Coastal wetland ecosystems are of utmost importance in regulating the mobility and distribution of elements in water and sediments, being the flooding by tidal events a recurrent process that strongly controls the hydrodynamics of the system. The aim of this work is to assess the control of the tidal regime and anthropogenic influence on the dynamics of some trace metals in water and sediments in the Punta Lara Natural Reserve situated in the Río de la Plata littoral. For that purpose, relationship between tidal flows, surface water and groundwater was evaluated. Also, hydrochemistry was analyzed based on the study of major ions and trace metals, being the presence of high concentrations of elements in groundwater, such as Fe and Mn, probably favoured by redox processes associated with organic matter decomposition in the water - sediment interaction. Sediments in the wetland register deficient to minimal enrichment in most of the studied trace metals despite the numerous contributions that the Río de la Plata receives in relation to dissolved and particulate trace metals from diverse anthropogenic contributions. Despite that, there is a moderate enrichment in Pb and Cr in the surface sediments of the wetland. The data analyzed within the natural reserve in relation to the chemical composition of the water and sediments of the coastal wetland showed the strong influence of the tidal regime over the area. [Display omitted] •Estuary-coast flow exchanges influence the hydrochemistry in the wetland.•Tidal flow contributes trace metals to water and sediments of the wetland environment.•High concentration of Fe and Mn were determined in groundwater of the natural reserve.•Moderate enrichment of Pb and Cr in uppermost superficial sediments was determined.•Mn shows moderate enrichment in sediments in the groundwater level fluctuating zone.