title: Dynamics of suspended sediment borne persistent organic pollutants in a large regulated Mediterranean river (Ebro, NE Spain).
abstract: Mediterranean rivers are characterized by highly variable hydrological regimes that are strongly dependent on the seasonal rainfall. Sediment transport is closely related to the occurrence of flash-floods capable to deliver enough kinetic energy to mobilize the bed and channel sediments. Contaminants accumulated in the sediments are likely to be mobilized as well during such events. However, whereas there are many studies characterizing contaminants in steady sediments, those devoted to the transport dynamics of suspended-sediment borne pollution are lacking. Here we examined the occurrence and transport of persistent organic microcontaminants present in the circulating suspended sediments during a controlled flushing flow in the low part of the River Ebro (NE Spain) 12 km downstream of a well-known contaminated hot-spot associated to a nearby chloro-alkali industry. Polycyclic aromatic hydrocarbons (PAHs) and semi-volatile organochlorine pollutants (DDT and related compounds, DDX; polychlorinated byphenils, PCBs; and other organochlorine compound, OCs) were measured in the particulate material by GC-MS and GC-MS/MS, using previously developed analytical methods. The concentration levels observed were compared to previously reported values in steady sediments in the same river and discussed on a regulatory perspective. Hydrographs and sedigraphs recorded showed a peak-flow of 1,300 m(3)s(-1) and a corresponding peak of suspended sediments of 315 mg L(-1). Combination of flow discharge, suspended sediments and pollutants' concentrations data allowed for quantifying the mass flows (mass per unit of time) and setting the load budgets (weight amount) of the different pollutants transported by the river during the monitored event. Mean mass-flows and total load values found were 20.2 mg s(-1) (400 g) for PAHs, 38 mg s(-1) (940 g) for DDX, 44 mg s(-1) (1,038 g) for PCBs and 8 mg s(-1) (200 g) for OCs. The dynamic pattern behavior of PAHs differs substantially to that of organochlorine pollutants, thus reflecting different pollution origins.
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, E-08034 Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Quesada
authors.affiliation: Department of Environment and Soil Sciences, University of Lleida, E-25198 Lleida, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Tena
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, E-08034 Barcelona, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Guillén
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, E-08034 Barcelona, Spain. Electronic address: antoni.ginebreda@idaea.csic.es.
authors.forename: A
authors.initials: A
authors.lastname: Ginebreda
authors.affiliation: Department of Environment and Soil Sciences, University of Lleida, E-25198 Lleida, Spain; Forest Technology Centre of Catalonia, E-25280 Solsona, Spain; Institute of Geography and Earth Sciences, Aberystwyth University, Wales, Ceredigion SY23 3DB, UK.
authors.forename: D
authors.initials: D
authors.lastname: Vericat
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, E-08034 Barcelona, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Martínez
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, E-08034 Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Navarro-Ortega
authors.affiliation: Department of Environment and Soil Sciences, University of Lleida, E-25198 Lleida, Spain; Catalan Institute for Water Research (ICRA), Emili Grahit 101, E-17003 Girona, Spain; Forest Technology Centre of Catalonia, E-25280 Solsona, Spain.
authors.forename: R J
authors.initials: RJ
authors.lastname: Batalla
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, E-08034 Barcelona, Spain; Catalan Institute for Water Research (ICRA), Emili Grahit 101, E-17003 Girona, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Barceló
mesh_terms: D004784:Environmental Monitoring; D055868:Floods; D019015:Geologic Sediments / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D011078:Polychlorinated Biphenyls / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D045483:Rivers / Q000737:chemistry*; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D006843:Hydrocarbons, Chlorinated; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Flushing flows; Mass loads; Persistent organic pollutants; Pollutants' transport; River Ebro; Suspended sediments