title: Sorption of alkylphenols on Ebro River sediments: comparing isotherms with field observations in river water and sediments.
abstract: This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f(OC)) ranging from 0.0035 to 0.082 g(OC)g(-1). All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations.
authors.affiliation: Center of Applied Geoscience, University of Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany. anoqam@iiqab.csic.es
authors.forename: Alícia
authors.initials: A
authors.lastname: Navarro
authors.forename: Satoshi
authors.initials: S
authors.lastname: Endo
authors.forename: Tilman
authors.initials: T
authors.lastname: Gocht
authors.forename: Johannes A C
authors.initials: JA
authors.lastname: Barth
authors.forename: Sílvia
authors.initials: S
authors.lastname: Lacorte
authors.forename: Damià
authors.initials: D
authors.lastname: Barceló
authors.forename: Peter
authors.initials: P
authors.lastname: Grathwohl
mesh_terms: D000327:Adsorption; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D010636:Phenols / Q000032:analysis / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry; D013030:Spain; D013501:Surface-Active Agents / Q000032:analysis / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D010636:Phenols; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C474055:octylphenol; C025256:nonylphenol