{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/86523"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/86523","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Selenium and Chromium Stable Isotopes and the Fate of Redox-Active Contaminants in the Environment","abstract":"In the second part of this study, I developed the chromium stable isotope system as a biogeochemical indicator and monitoring tool. After initial work designing the techniques, I measured chromium stable isotope fractionation in laboratory experiments and natural waters. I observed that the products of Cr(VI) reduction had delta53Cr values that were 3.4 +/- 0.1‰ less than that of the reactant. The 53Cr/ 52Cr ratios in water samples from three chromium-contaminated sites ranged from 1.1‰ to 5.8‰, relative to the standard and indicate the extent of reduction, a critical process that renders toxic Cr(VI) immobile and less toxic. Finally, I show that Cr stable isotope fractionation during sorption on alumina and goethite in laboratory experiments is insignificant and variations in 53Cr/52Cr values can be used to determine extent of reduction in natural waters.","abstract_html":"In the second part of this study, I developed the chromium stable isotope system as a biogeochemical indicator and monitoring tool. After initial work designing the techniques, I measured chromium stable isotope fractionation in laboratory experiments and natural waters. I observed that the products of Cr(VI) reduction had delta53Cr values that were 3.4 +/- 0.1‰ less than that of the reactant. The 53Cr/ 52Cr ratios in water samples from three chromium-contaminated sites ranged from 1.1‰ to 5.8‰, relative to the standard and indicate the extent of reduction, a critical process that renders toxic Cr(VI) immobile and less toxic. Finally, I show that Cr stable isotope fractionation during sorption on alumina and goethite in laboratory experiments is insignificant and variations in 53Cr/52Cr values can be used to determine extent of reduction in natural waters.","abstract_has_math":false,"creators":["Ellis, Andre Savio"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Geology","degree_department":null,"school":null,"contributors":["Johnson, Thomas M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-28T15:12:28Z","date_published":"2015-09-28T15:12:28Z","updated_at":"2026-07-22T22:26:27Z","subjects":["Environmental Sciences"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3086053"],"render_values":[{"text":"(MiAaPQ)AAI3086053","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/86523","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Johnson, Thomas M."]},{"key":"dc:creator","label":"Author","values":["Ellis, Andre Savio"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-28T15:12:28Z","10000-01-01","2003"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Environmental Sciences"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/86523","(MiAaPQ)AAI3086053"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In the second part of this study, I developed the chromium stable isotope system as a biogeochemical indicator and monitoring tool. After initial work designing the techniques, I measured chromium stable isotope fractionation in laboratory experiments and natural waters. I observed that the products of Cr(VI) reduction had delta53Cr values that were 3.4 +/- 0.1‰ less than that of the reactant. The 53Cr/ 52Cr ratios in water samples from three chromium-contaminated sites ranged from 1.1‰ to 5.8‰, relative to the standard and indicate the extent of reduction, a critical process that renders toxic Cr(VI) immobile and less toxic. Finally, I show that Cr stable isotope fractionation during sorption on alumina and goethite in laboratory experiments is insignificant and variations in 53Cr/52Cr values can be used to determine extent of reduction in natural waters.","Made available in DSpace on 2015-09-28T15:12:28Z (GMT). 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After initial work designing the techniques, I measured chromium stable isotope fractionation in laboratory experiments and natural waters. I observed that the products of Cr(VI) reduction had delta53Cr values that were 3.4 +/- 0.1‰ less than that of the reactant. The 53Cr/ 52Cr ratios in water samples from three chromium-contaminated sites ranged from 1.1‰ to 5.8‰, relative to the standard and indicate the extent of reduction, a critical process that renders toxic Cr(VI) immobile and less toxic. Finally, I show that Cr stable isotope fractionation during sorption on alumina and goethite in laboratory experiments is insignificant and variations in 53Cr/52Cr values can be used to determine extent of reduction in natural waters.","Made available in DSpace on 2015-09-28T15:12:28Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3086053.pdf: 3113528 bytes, checksum: bc95da8576fddd963092c5d06c8e5d1c (MD5) Previous issue date: 2003","Embargo set by: Seth Robbins for item 87804 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","61 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2003."],"dc:identifier":["http://hdl.handle.net/2142/86523","(MiAaPQ)AAI3086053"],"dc:language":["eng"],"dc:subject":["Environmental Sciences"],"dc:title":["Selenium and Chromium Stable Isotopes and the Fate of Redox-Active Contaminants in the Environment"],"dc:type":["text"],"thesis:degree_discipline":["Geology"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:27Z"}