Rhenium Distribution and Behavior in the Salinity Gradient of a Highly Stratified Estuary and Pristine Riverine Waters (The Krka River, Croatia)

Bura-Nakić, Elvira; Knežević, Lucija; Mandić, Jelena; Cindrić, Ana-Marija; Omanović, Dario (2021) Rhenium Distribution and Behavior in the Salinity Gradient of a Highly Stratified Estuary and Pristine Riverine Waters (The Krka River, Croatia). Archives of environmental contamination and toxicology, 81 . pp. 564-573. ISSN 0090-4341

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Abstract

The abundance and distribution of dissolved Re (DRe) were determined in the freshwater part of the Krka River (Croatia), which drains a karst landscape, and in the salinity gradient of its highly stratified estuary. Due to the low DRe concentration, a batch procedure consisting of a pre-concentration step using an anion exchange resin (Dowex) and analysis of DRe in 8 M HNO3 eluate using high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS) was applied. Due to potentially inconsistent recoveries, which ranged from 60 to 87%, quantification was performed using the isotope dilution technique (ID). DRe concentrations in the Krka River increased downstream, from 6.2 pM at the spring site to 11.9 pM upstream of the estuary region. Weathering of the surrounding carbonate lithology is assumed to be the source of the natural Re. Two specific anomalies were registered: a strong increase in DRe concentration due to anthropogenic input near the town of Knin (27.5 pM) and a decrease at a downstream site caused by subsurface input of freshwater from the Zrmanja River, resulting in a relatively low DRe concentration (8.5 pM). In the estuarine region, a near- conservative behavior of DRe was found in the salinity gradient of the upper surface layer, with DRe concentrations ranging from 18 to 38 pM. Anthropogenic input was suspected within the estuarine segment near the urban area, causing a small positive deviation from the conservative line. In the bottom seawater layer, a minor decrease in DRe concentration in the most upstream estuarine regions was apparent, implying weak scavenging of Re

Item Type:	Article
Uncontrolled Keywords:	Rhenium ; estuarine
Subjects:	NATURAL SCIENCES > Interdisciplinary Natural Sciences NATURAL SCIENCES > Interdisciplinary Natural Sciences > Marine Science
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Novi metodološki pristup biogeokemijskim istraživanjima specijacije metala u tragovima u obalnim vodenim ekosustavima Omanović, Dario IP-2014-09-7530 HRZZ Geokemija i zapis redoks indikatora u različitim uvjetima okoliša: prema boljem razumijevanju redoks uvjeta u prošlosti-REDOX Elvira Bura-Nakić IP-2018-01-7813 HRZZ
Depositing User:	Lucija Knežević
Date Deposited:	19 Apr 2023 10:46
URI:	http://fulir.irb.hr/id/eprint/7941
DOI:	10.1007/s00244-021-00876-6

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