title: Implications of effluent organic matter and its hydrophilic fraction on zinc(II) complexation in rivers under strong urban pressure: aromaticity as an inaccurate indicator of DOM-metal binding.
abstract: The zinc binding characteristics of dissolved organic matter (DOM) fractions from the Seine River Basin were studied after being separated and extracted according to their polarity: hydrophobic, transphilic, and hydrophilic. The applied experimental methodology was based on a determination of labile zinc species by means of differential pulse anodic stripping voltammetry (DPASV) at increasing concentrations of total zinc on a logarithmic scale and at fixed levels of: pH, ionic strength, and temperature. Fitting the DOM fractions with two discrete classes of ligands successfully allowed determining the conditional zinc binding constants (Ki) as well as total ligand density (LiT). The binding constants obtained for each DOM fraction were then compared and discussed with respect to the hydrophobic/hydrophilic nature and sample origin. Results highlighted a strong complexation of zinc to the effluent organic matter and especially the most hydrophilic fraction, which also displayed a very low specific UV absorbance. Although the biotic ligand model takes into account the quality of DOM through UV absorbance in the predictions of metal bioavailability and toxicity, this correction is not efficient for urban waters.
authors.affiliation: Université Paris-Est, LEESU (UMR MA 102), UPEC, UPEMLV, ENPC, AgroParisTech, 94010 Créteil, France; Laboratoire LGCIE, Université de Lyon, INSA-Lyon, Bât. Carnot, 9 rue de la Physique, 69621 Villeurbanne, France. Electronic address: yoann.louis@insa-lyon.fr.
authors.forename: Yoann
authors.initials: Y
authors.lastname: Louis
authors.affiliation: Université Paris-Est, LEESU (UMR MA 102), UPEC, UPEMLV, ENPC, AgroParisTech, 94010 Créteil, France; Université Européenne de Bretagne, Rennes, France; Université de Bretagne Occidentale, IUEM, Lemar, UMR CNRS 6539, rue Dumont D'Urville, 29280 Plouzané, France. Electronic address: benoit.pernet-coudrier@univ-brest.fr.
authors.forename: Benoît
authors.initials: B
authors.lastname: Pernet-Coudrier
authors.affiliation: Université Paris-Est, LEESU (UMR MA 102), UPEC, UPEMLV, ENPC, AgroParisTech, 94010 Créteil, France. Electronic address: varrault@u-pec.fr.
authors.forename: Gilles
authors.initials: G
authors.lastname: Varrault
mesh_terms: D004784:Environmental Monitoring; D057927:Hydrophobic and Hydrophilic Interactions; D008956:Models, Chemical; D009994:Osmolar Concentration; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D015032:Zinc
keywords: Dissolved organic matter; Metal speciation; Stripping voltammetry; Urban; Wastewater; Zinc