Rose-Hulman CHEM 490 - Chemical Characteristics on the Sorption of Selected Endocrine Disruptors (12 pages)

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Chemical Characteristics on the Sorption of Selected Endocrine Disruptors



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Chemical Characteristics on the Sorption of Selected Endocrine Disruptors

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Rose-Hulman Institute of Technology
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Chem 490 - Chemical Research
Chemical Research Documents
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Environ Sci Technol 2003 37 2646 2657 Effects of Physical Chemical Characteristics on the Sorption of Selected Endocrine Disruptors by Dissolved Organic Matter Surrogates H I R O S H I Y A M A M O T O HOWARD M LILJESTRAND YOSHIHISA SHIMIZU AND MASATOSHI MORITA Department of Civil Engineering The University of Texas at Austin 1 University Station C1786 Austin Texas 78712 0273 Research Center for Environmental Quality Control Kyoto University Otsu Shiga Japan and National Institute for Environmental Studies Tsukuba Ibaraki Japan Sorption coefficients Koc values of selected endocrine disruptors for a wide variety of dissolved organic matter DOM were measured using fluorescence quenching and solubility enhancement 17 Estradiol estriol 17Rethynylestradiol p nonylphenol p tert octylphenol and dibutylphthalate were selected as endocrine disruptors Aldrich humic acid Suwannee River humic and fulvic acids Nordic fulvic acid alginic acid dextran and tannic acid were selected as DOM surrogates The resulting sorption coefficients log Koc were independent of octanolwater partitioning coefficients log Kow of the selected endocrine disruptors indicating the hydrophobic interaction is not the predominant sorption mechanism Moreover the Koc values for the selected endocrine disruptors especially the steroid estrogens correlated much better with UV absorptivity at 272 nm A272 and phenolic group concentration of the DOM than with either the H O or the O N C atomic ratio of the DOM This suggests that the sorption mechanism is closely related to the interaction between electrons and the hydrogen bonds i e the affinity between phenolic groups of the steroid estrogens and DOM is suggested to provide a relatively large contribution to the overall sorption and yield the Koc values of the steroid estrogens as high as those of the alkylphenols and dibutylphthalate which are suggested to be dominated by nonspecific hydrophobic interaction Introduction It is widely recognized that the sorption of hydrophobic organic compounds onto dissolved natural organic matter may significantly increase their aqueous solubility 1 6 This solubility enhancement affects the fate of these chemical Corresponding author phone 81 29 850 2855 fax 81 29850 2880 e mail yamamoto hiroshi nies go jp Present address National Institute for Environmental Studies Endocrine Disruptors and Dioxin Research Project 16 2 Onogawa Tsukuba Ibaraki 3058506 Japan The University of Texas at Austin Kyoto University National Institute for Environmental Studies 2646 9 ENVIRONMENTAL SCIENCE TECHNOLOGY VOL 37 NO 12 2003 species in an aqueous environment 7 9 and water treatment processes 10 11 Furthermore increases in dissolved organic matter DOM concentration results in decreases in the bioavailability and the bioaccumulation of these chemicals 12 14 while attenuating their toxicity 15 17 Consequently trends in sorption of hydrophobic chemical compounds by DOM are of critical importance for the understanding of the solubility fate and impact of these compounds in the environment Steroid estrogens and endocrine disrupting phenolic compounds e g alkylphenols and bisphenol A are one class of hydrophobic organics ubiquitous in the environment whose fates are important They have been linked to recent reproductive health problems reported in humans and wild animals e g ref 18 In wastewater treatment plant effluents and surface waters concentrations of steroid estrogens have been found as high as 200 ng L 19 26 while those for alkylphenols and phthalates have been reported as high as 40 g L 20 23 25 27 Given the difficulties in quantifying these trace chemicals and DOM little is known about how their interactions influence the fate of endocrine disrupting compounds Consequently the sorption of endocrine disruptors including steroid estrogens by DOM is of critical importance for the understanding of the fate of these compounds in the environment Although the sorption of highly hydrophobic compounds such as PAHs PCBs and pesticides by DOM have been extensively studied over the last three decades 1 6 28 53 little is known about the sorption of moderately hydrophobic compounds such as steroid estrogens and alkylphenols by organic matter except for some recent studies on the sorption of steroid estrogens by sediments 54 55 and the sorption of nonylphenol by terrestrial soil 56 Hence the sorption of three steroid estrogens 17 estradiol estriol and 17R ethynylestradiol and three endocrine disrupting chemicals p nonylphenol p tert octylphenol and dibutylphthalate by a wide variety of DOM surrogates are investigated using fluorescence quenching and solubility enhancement The correlation between the measured sorption coefficients log Koc value and the octanol water partitioning coefficients log Kow for these species are evaluated and compared with other reported results Moreover the relationships between log Koc and physical chemical characteristics e g absorptivity H O atomic ratio and the concentration of phenolic group of the DOM surrogates are also investigated to better understand the sorption mechanisms Experimental Section 17 Estradiol was selected as one of the most common steroid estrogens one often used as a positive control for the screening tests for estrogenic compounds Additional steroid estrogens selected were estriol E3 an important pregnancy estrogen as well as a metabolite of 17 estradiol E2 and 17R ethynylestradiol EE2 the main component of contraceptive pills p Nonylphenol NP p tert octylphenol OP and dibutylphthalate DBP were selected as synthetic estrogenic compounds because of their high production and release to the environment as well as their ability to fluoresce The chemical structure and physical chemical properties of the selected compounds are shown in Table 1 17REthynylestradiol 98 HPLC grade and dibutylphthalate 98 were purchased from Sigma Chemical Co St Louis MO while 17 estradiol Minimum 97 estriol 98 p nonylphenol tech grade and p tert octylphenol 97 were purchased from Aldrich Chemical Co Milwaukee WI 10 1021 es026405w CCC 25 00 2003 American Chemical Society Published on Web 05 21 2003 TABLE 1 Structure and Physicochemical Properties of Selected Endocrine Disruptors a From ref 67 b From ref 68 c From ref 69 d Values inside parentheses are estimated using KowWin Log P software 70 e From ref 71 Estimated from phenol using the fragment method 72 fEstimated from Hammet and Taft Equations 73 The selected DOM surrogates included Aldrich


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