title: Occurrence and spatial distribution of emerging contaminants in the unsaturated zone. case study: Guadalete River basin (Cadiz, Spain).
abstract: Irrigation with reclaimed water is becoming a common practice in arid- and semi-arid regions as a consequence of structural water resource scarcity. This practice can lead to contamination of the vadose zone if sewage-derived contaminants are not removed properly. In the current work, we have characterized soils from the Guadalete River basin (SW Spain), which are often irrigated with reclaimed water from a nearby wastewater treatment plant and amended using sludge. Physico-chemical, mineralogical and hydraulic properties were measured in soil samples from this area (from surface up to 2 m depth). Emerging contaminants (synthetic surfactants and pharmaceutically active compounds, or PhACs) were also determined. Synthetic surfactants, widely used in personal care products (PCPs), were found in a wide range of concentrations: 73-1300 μg kg(-1) for linear alkylbenzene sulfonates (LAS), 120-496 μg kg(-1) for alkyl ethoxysulfates (AES), 19-1090 μg kg(-1) for alcohol polyethoxylates (AEOs), and 155-280 μg kg(-1) for nonylphenol polyethoxylates (NPEOs). The presence of surfactant homologues with longer alkyl chains was predominant due to their sorption capacity. A positive correlation was found between LAS and AEOs and soil organic carbon and clay content, respectively. Out of 64 PhACs analyzed, only 7 were detected occasionally (diclofenac, metoprolol, fenofibrate, carbamazepine, clarithromycin, famotidine and hydrochlorothiazide), always at very low concentrations (from 0.1 to 1.3 μg kg(-1)).
authors.affiliation: Department of Physical-Chemistry, Faculty of Marine and Environmental Sciences, University of Cadiz, Campus of International Excellence of the Sea (CEI.MAR), Río San Pedro, Puerto Real, Cadiz 11510, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Corada-Fernández
authors.affiliation: Geosciences Rennes UMR 6118 CNRS, University of Rennes 1, Rennes 35042, France.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Jiménez-Martínez
authors.affiliation: Department of Geotechnical Engineering and Geosciences, Technical University of Catalonia-UPC, Barcelona 08034, Spain.
authors.forename: Lucila
authors.initials: L
authors.lastname: Candela
authors.affiliation: Department of Physical-Chemistry, Faculty of Marine and Environmental Sciences, University of Cadiz, Campus of International Excellence of the Sea (CEI.MAR), Río San Pedro, Puerto Real, Cadiz 11510, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: González-Mazo
authors.affiliation: Department of Physical-Chemistry, Faculty of Marine and Environmental Sciences, University of Cadiz, Campus of International Excellence of the Sea (CEI.MAR), Río San Pedro, Puerto Real, Cadiz 11510, Spain. Electronic address: pablo.lara@uca.es.
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Lara-Martín
mesh_terms: D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis*; D004364:Pharmaceutical Preparations / Q000032:analysis*; D059027:Recycling; D045483:Rivers / Q000737:chemistry; D012722:Sewage; D012989:Soil Pollutants / Q000032:analysis*; D013030:Spain; D013501:Surface-Active Agents / Q000032:analysis*; D014865:Waste Disposal, Fluid
chemical_list: D004364:Pharmaceutical Preparations; D012722:Sewage; D012989:Soil Pollutants; D013501:Surface-Active Agents
keywords: Emerging pollutants; Pharmaceuticals; Soils; Surfactants; Vadose zone