Naslov
Copper speciation in the Krka River estuary (Croatia)

Autori
Marcinek, Saša ; Cindrić, Ana Marija ; Garnier, Cedric ; Pađan, Jasmin ; Omanović, Dario

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
42nd Mediterranean Science Commission Congress (CIESM)

Mjesto i datum
Cascais, Portugal, 07.10.2019. - 11.10.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Copper speciation ; CLE-AdCSV ; Spectroscopy ; Organic ligands ; Marine environment

Sažetak
Copper (Cu) is a naturally occurring micronutrient of eco-toxicological concern in natural waters. Approximately 99% of total dissolved copper exists in marine waters as organic complexes. Characterization and discrimination of trace metal-organic complexes in natural waters commonly rely on determination of their conditional stability constants (K’MLi) and concentrations of corresponding discrete ligand classes, [Li]T. Competitive ligand exchange–adsorptive cathodic striping voltammetry (CLE-AdCSV) is most widely used electrochemical technique in these studies. On the other hand, spectrophotometric methods are extensively used in studies of dissolved organic matter. Combining them with electrochemical methods can provide additional information about copper binding organic ligands and extend our knowledge about their sources and dynamics in water column. In the Krka River Estuary, both, Cu and Cu- binding ligands showed considerable seasonal differences. Samples were characterized by 2 Cu-binding ligand classes ; stronger L1 class was present in lower concentrations compared to weaker L2 class. Range of obtained complexation parameters is common for estuarine and coastal regions. Concentration of copper and both ligands, along with dissolved organic carbon (DOC) and absorbance coefficient, showed a maximum at halocline, indicating accumulation of trace metals and organic matter along the freshwater-seawater interface. Increase in Cu concentrations in the surface layer, in summer, was a consequence of intensified boat trafic. However, the free copper concentration stayed below its toxicity level. During the winter, higher river flow is introducing more land derived material than in summer, as suggested with higher humic like fluorescence. Low DOC values signify low concentrations of organic ligands introduced by the river, but they can be characterized by high molecular complexity and high copper affinity. Conversely, in summer DOC in the estuary was in averge higher but with lower terrestrial signature, due to the lower river flow, as well as the enhanced production and photodegradation. As a conequence, organic ligands in the surface layer, in summer, were showed higher concentrations but lower binding strength than in winter.

Izvorni jezik
Engleski

Znanstvena područja
Interdisciplinarne prirodne znanosti

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