Vanadium redox speciation in the acid-extractable phase of Krka River estuary surface sediment

Knežević, Lucija; Cukrov, Nuša; Bura-Nakić, Elvira; Mlakar, Marina (2024) Vanadium redox speciation in the acid-extractable phase of Krka River estuary surface sediment. Marine Chemistry, 267 . ISSN 0304-4203

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Abstract

This study investigated the redox speciation and mobility of V in the acid-extractable fraction of surface sediments from the Krka River estuary using an optimized IC-UV/Vis analytical method. The separation of V(IV) and V(V) redox species was done using anion-exchange based chromatographic method, while pseudo-total V concentrations were measured using HR ICP-MS analytical instrumentation. Extracted V concentrations from the sediment fraction (pH=5, HCl) and determined pseudo-total V concentrations were used to calculate the Enrichment Factor (EF) and Risk Assessment Code (RAC), indicating potential anthropogenic influence and environmental risk. A simple PHREEQC model was developed to asses V speciation in the oxic bottom seawater layer simulating possible remobilization of the leached sediment phase. The results of the study show that minor fraction of V is present in the acid-extractable phase across the surface sediment of Krka River estuary. Higher V mobility is mostly observed at locations rich with clay minerals, terrigenous input, and carbonates. Anthropogenic influence was linked to higher enrichment but lower mobility, suggesting binding to less mobile sediment phases (reducible, organic and residual fractions). The predominance of reduced V(IV) species in the acid-extractable sediment fraction indicates a potentially low V toxicity risk in the sediments of Krka River estuary, even in cases of high potential remobilization of V. However, the model predicted complete oxidation of V(IV) to V(V) upon remobilization into the oxic bottom water layer. This highlights the complexity of V behavior in natural estuarine systems, where the toxicity risks of possible V remobilization still remain unclear. Results of this study demonstrate the need for the strengthening efforts in speciation of V in the mobile sediment phase to obtain a cohesive outlook on its potential toxicity and biogeochemical cycling.

Item Type:	Article
Uncontrolled Keywords:	Vanadium redox speciation; Mobile sediment phase; Ion chromatography; Krka River estuary
Subjects:	NATURAL SCIENCES > Interdisciplinary Natural Sciences > Marine Science
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Understanding copper speciation and redox transformations in seawater Elvira Bura-Nakić IPCH-2020-10-4965 HRZZ
Depositing User:	Elvira Bura Nakić
Date Deposited:	07 Nov 2024 13:12
URI:	http://fulir.irb.hr/id/eprint/9254
DOI:	10.1002/elan.202400090

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