Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution), 2013. / Pages 181 and 182 blank. Cataloged from PDF version of thesis. / Includes bibliographical references. / Steroidal estrogens are potent endocrine disrupting chemicals that are naturally excreted by vertebrates (e.g., humans and fish) and can enter natural waters through the discharge of treated and raw sewage. Because estrogens are detrimental to aquatic organisms at picomolar concentrations, many studies have measured so-called "free" estrogen concentrations in wastewater effluents, rivers, and lakes. Yet, to our knowledge, no studies have characterized the broader range of estrogens that includes free, conjugated, and halogenated forms. Conjugated estrogens are important because they can be easily converted to potent free forms by bacteria in wastewater treatment plants and receiving waters. And halogenated estrogens, produced during wastewater disinfection, are only slightly less potent than free estrogens but much more likely to bioaccumulate. We have developed a tandem mass spectrometry method that is capable of simultaneously quantifying free, conjugated, and halogenated estrogens at picomolar levels in wastewater effluent and coastal seawater. The method was validated using treated effluent from the greater Boston metropolitan area, where we found that halogenated estrogens represented over 50 % of the total estrogen discharge flux. A kinetic model of estrogen halogenation was used to predict the distribution of free and halogenated forms in wastewater effluent and suggested that chlorinated estrogens may be formed en route to the wastewater treatment plant. In the receiving waters of Massachusetts Bay, we detected a range of conjugated, free, and halogenated forms at concentrations that were well-predicted by dilution near the sewage outfall. Farther downstream, we found significantly higher estrone concentrations which points to large inputs of estrogens from sources other than sewage. Finally, we have used compound-specific measurements of 13C and 14C in commercial and pharmaceutical estrogen preparations to evaluate the potential for using carbon isotopes to distinguish between synthetic and endogenous steroids in wastewater and other environmental matrices. Our results show that synthetic estrogens and progestogens exhibit significantly depleted [delta]13 C values (~30 0/00) compared to endogenous steroids (-16 0/00 to -26 0/00). This isotopic difference should make it possible to apportion synthetic and endogenous hormone sources in complex environments. / by David R. Griffith. / Ph. D.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/85824 |
| Date | January 2013 |
| Creators | Griffith, David R. (David Richmond) |
| Contributors | Philip M. Gschwend., Woods Hole Oceanographic Institution., Joint Program in Oceanography/Applied Ocean Science and Engineering., Massachusetts Institute of Technology. Department of Civil and Environmental Engineering., Woods Hole Oceanographic Institution. |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 182 pages, application/pdf |
| Rights | M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582 |
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