title: Naturally dissolved arsenic concentrations in the Alpine/Mediterranean Var River watershed (France).
abstract: A detailed study on arsenic (As) in rocks and water from the Var River watershed was undertaken aiming at identifying (i) the origin and the distribution of As in this typical Alpine/Mediterranean basin, and (ii) As input into the Mediterranean Sea. Dissolved As concentrations in the Var River range from 0.1 to 4.5 μg⋅L(-1), due to high hydrological variability and the draining through different geological formations. In the upper part of the Var drainage basin, in the Tinée and the Vésubie valleys, high levels of dissolved As concentrations occur (up to 263 μg⋅L(-1)). The two main sources of As in rocks are the Hercynian metamorphic rocks and the Permian argilites. Highly heterogeneous distribution of As in waters draining through metamorphic rocks is probably related to ore deposits containing arsenopyrite. As, U, W and Mo concentrations in water and rocks correspond to the formation of As-rich ore deposits around Argentera granite by hydrothermal fluids deposited at the end of the Hercynian chain formation, which occurred about 300 My ago. In 2009, weekly monitoring was performed on the Var River (15 km upstream of the mouth), highlighting an average dissolved As concentration (<0.45 μm) of 2.7 ± 0.9 μg⋅L(-1), which is significantly higher than the world-average baseline for river water (0.83 μg⋅L(-1)). Taking the average annual discharge (49.4 m(3)⋅s(-1)) into account and the As levels in the dissolved phase and in deposits of the Var River, dissolved As input into the Mediterranean Sea would be 4. 2± 1.4 tons⋅year(-1) which represents 59% of the total As flux. This study also reveals a probable non-conservative As behaviour, i.e., possible transfer between aqueous and solid phases, during the mixing of the Var River with a tributary.
authors.affiliation: Université de Nice Sophia-Antipolis, Institut de Chimie de Nice, UMR CNRS 7272, 28 avenue de Valrose, 06108 Nice Cedex 2, France. Electronic address: aurelie.barats@unice.fr.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Barats
authors.affiliation: Université de Nice Sophia-Antipolis, Institut de Chimie de Nice, UMR CNRS 7272, 28 avenue de Valrose, 06108 Nice Cedex 2, France.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Féraud
authors.affiliation: Université de Nice Sophia-Antipolis, Institut de Chimie de Nice, UMR CNRS 7272, 28 avenue de Valrose, 06108 Nice Cedex 2, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Potot
authors.affiliation: Université de Nice Sophia-Antipolis, Institut de Chimie de Nice, UMR CNRS 7272, 28 avenue de Valrose, 06108 Nice Cedex 2, France.
authors.forename: Violaine
authors.initials: V
authors.lastname: Philippini
authors.affiliation: Université d'Avignon et des Pays du Vaucluse, EMMAH, UMR UAPV/INRA 1114, 33 rue Louis Pasteur, 84000 Avignon, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Travi
authors.affiliation: Université de Toulon, PROTEE, EA 3819, 83957 La Garde, France.
authors.forename: Gaël
authors.initials: G
authors.lastname: Durrieu
authors.affiliation: Université de Nice Sophia-Antipolis, CEPAM, UMR CNRS 7264, 24 avenue des Diables Bleus, 06357 Nice Cedex 4, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Dubar
authors.affiliation: Université d'Avignon et des Pays du Vaucluse, EMMAH, UMR UAPV/INRA 1114, 33 rue Louis Pasteur, 84000 Avignon, France.
authors.forename: Roland
authors.initials: R
authors.lastname: Simler
mesh_terms: D001151:Arsenic / Q000032:analysis*; D004784:Environmental Monitoring; D005602:France; D019015:Geologic Sediments / Q000737:chemistry; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D001151:Arsenic
keywords: Arsenic; Behaviour; Flux; Rocks; Transfer; Water