Kinetics and Adsorption Isotherms of Bisphenol A, Estrone, 17β-Estradiol, and 17α-Ethinylestradiol in Tropical Sediment Samples Bruno B. Cunha & Wander Gustavo Botero & Luciana Camargo Oliveira & Viviane M. Carlos & Marcelo L. M. Pompêo & Leonardo F. Fraceto & André H. Rosa Received: 20 December 2010 / Accepted: 8 June 2011 / Published online: 22 June 2011 # Springer Science+Business Media B.V. 2011 Abstract The sorption of four endocrine disruptors, bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) in tropical sediment samples was studied in batch mode under different conditions of pH, time, and sediment amount. Data obtained from sorption experiments using the endo- crine disruptors (EDs) and sediments containing different amounts of organic matter showed that there was a greater interaction between the EDs and organic matter (OM) present in the sediment, particularly at lower pH values. The pseudosecond order kinetics model successfully explained the interaction between the EDs and the sediment samples. The theoretical and experimentally obtained q e values were similar, and k values were smaller for higher SOM contents. The k F values, obtained from the Freundlich iso- therms, varied in the ranges 4.2–7.4×10 -2 (higher OM sediment sample, S 2 ) and 1.7×10 -3 –3.1×10 -2 (lower OM sediment sample, S 1 ), the latter case indicating an interaction with the sediment that increased in the order: EE2>>E2>E1>BPA. These results demonstrate that the availability of endocrine disruptors may be directly related to the presence of organic material in sediment samples. Studies of this kind provide an important means of understanding the mobility, transport, and/or reactivity of this type of emergent contaminant in aquatic systems. Keywords Endocrine disruptors . Sediment . Sorption . Organic matter 1 Introduction Endocrine disruptors are exogenous substances that act like hormones in the endocrine system and disrupt the physiologic function of endogenous hormones. They are sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds (EDs). EDs are a focus of current environmental concern, as they can cause adverse health effects in an intact organism, or its progeny, following alteration of endocrine function (Schwarzenbach et al. Water Air Soil Pollut (2012) 223:329–336 DOI 10.1007/s11270-011-0861-2 B. B. Cunha Department of Analytical Chemistry, Institute of Chemistry, São Paulo State University (UNESP), CP 355, 14801-970 Araraquara, SP, Brazil B. B. Cunha : V. M. Carlos : L. F. Fraceto : A. H. Rosa Department of Environmental Engineering, São Paulo State University (UNESP), 18087-180 Sorocaba, SP, Brazil W. G. Botero (*) Federal University of Alagoas (UFAL), CP 61, 57309-005 Arapiraca, Alagoas, Brazil e-mail: wander_iq@yahoo.com.br L. C. Oliveira Federal University of São Carlos (UFSCar), 18052-780 Sorocaba, São Paulo, Brazil M. L. M. Pompêo Institute of Biosciences, University of São Paulo (USP), 05508–900 São Paulo, São Paulo, Brazil