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oai:www.ideals.illinois.edu:2142/86523 2023-07-11 col_2142_5131 col_2142_16322 com_2142_5130 com_2142_16321 com_2142_13459 com_2142_8903

Johnson, Thomas M. Ellis, Andre Savio 2015-09-28T15:12:28Z 2015-09-28T15:12:28Z 10000-01-01 2003 2003 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). 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. http://hdl.handle.net/2142/86523 (MiAaPQ)AAI3086053 eng Environmental Sciences Selenium and Chromium Stable Isotopes and the Fate of Redox-Active Contaminants in the Environment text Geology Geology University of Illinois at Urbana-Champaign Dissertation Ph.D.