Two strains of Alcaligenes denitrificans, designated BRI 3010 and BRI 6011, were isolated from polychlorinated biphenyl (PCB) contaminated soil using 2,5-dichlorobenzoic acid (2,5-DCBA) and 2,4-DCBA, respectively, as sole carbon and energy sources. Both strains degraded 2-chlorobenzoic acid (2-CBA), 2,3-DCBA, and 2,5-DCBA. BRI 6011 alone degraded 2,4-DCBA. Metabolism of the chlorinated substrates resulted in the stoichiometric release of chloride, and degradation proceeded by intradiol cleavage of the aromatic ring. Growth of both strains on dichlorobenzoic acids induced pyrocatechase activities having catechol (catechol 1,2-dioxygenase) and chlorocatechols (chlorocatechol 1,2-dioxygenase) as substrates. Growth on 2-CBA and benzoic acid induced a pyrocatechase activity (catechol 1,2-dioxygenase) directed against catechol only. / The chlorocatechol 1,2-dioxygenase from BRI 6011 was purified, characterized, and compared with the chlorocatechol 1,2-dioxygenase from Pseudomonas sp. B13 and P. putida, organisms limited with respect to their CBA degradative versatility. These enzymes appear to be very similar based on biochemical and genetic data and possess sufficient broad substrate specificity to accommodate a wide range of chlorinated catechols, hence the increased versatility for chlorobenzoic acid degradation of A. denitrificans cannot be attributed to a more specialized chlorocatechol 1,2-dioxygenase. / Uptake of benzoic acid by BRI 3010 and BRI 6011 was inducible, exhibited saturation kinetics and the substrate was accumulated intracellularly against a concentration gradient by a factor of 8 and 10, respectively, indicative of active transport. Uptake of 2,4-DCBA by BRI 6011 was constitutive and saturation kinetics were not observed, suggesting passive diffusion of 2,4-DCBA and other CBAs into the cell down a concentration gradient. / Based on oxygen uptake experiments with whole cells, benzoic acid dioxygenase and chlorobenzoic acid dioxygenase activity was induced by benzoic acid and ortho-substituted chlorobenzoic acids, respectively. Since 2,4-DCBA diffuses across the membrane and the expected catecholic intermediates of 2,4-DCBA metabolism are metabolizable by BRI 3010, this suggests that the major difference between BRI 3010 and BRI 6011 might be the inability of the chlorobenzoic acid dioxygenase in BRI 3010 to recognize 2,4-DCBA as a substrate.

The accumulation of polychlorinated biphenyls (PCBs) into humans was described using CoZMoMAN, a mechanistic multimedia fate and transport model coupled to a human food chain model. Model results demonstrated that concentration-age relationships for population cross-sections and individuals over time are not equivalent and that, under steady-state conditions, the lipid-normalized concentration of PCBs in an individual does not monotonically increase with age. By considering the decades-long emission history of PCBs in the model simulations, it was shown that an individual’s concentration mostly depends upon when she/he was born relative to the peak in emissions. Similarly, the two most influential factors controlling the shape of cross-sectional concentration-age trends obtained in human biomonitoring studies are the time lapse between the peak in emissions and sample collection and chemical elimination half-life. As a result, it should be possible to deduce information on these two factors from the shape of cross-sectional concentration-age trend. Reproductive behaviours (parity, age at birth, breastfeeding) were shown to potentially have a significant impact on exposure (and can contribute substantially to the observed variability in biomonitoring studies) though the mother’s reproductive history has a greater influence on the prenatal and postnatal exposures of her children than it does on her own cumulative lifetime exposure. A case study of the influence of dietary transitions in a hypothetical Arctic community demonstrated that dietary transitions are an important factor underlying the variability in PCB body burdens within and between subpopulations in addition to partially explaining the observed temporal trends. Comparison of PCB partitioning to various lipid materials suggested that 1) triolein is a good surrogate for human storage lipids; 2) liposomes are not an appropriate surrogate for human storage tissues; and 3) that partitioning into human MCF-7 cells is dominated by the storage lipids rather than by membrane lipids. Finally, a new bioenergetically-balanced bioaccumulation (3B) fish model is presented. Comparison of results from the 3B model with that of existing models revealed that feeding and growth rates used by previous fish bioaccumulation models were not bioenergetically consistent. Differences in biomagnification factors with fish size and temperature as a result of differing energetic requirements demonstrated the importance of the assumptions regarding growth rate and feeding rate.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis (M.S.)--Bowling Green State University, 2008. / Document formatted into pages; contains ix, 57 p. Includes bibliographical references.

Thesis (Ph.D.). / Written for the Dept. of Mining, Metals and Materials Engineering. Title from title page of PDF (viewed 2008/05/12). Includes bibliographical references.

Thesis (Ph.D.)--Michigan State University. Environmental Engineering, 2008. / Title from PDF t.p. (viewed on Mar. 30, 2009) Includes bibliographical references. Also issued in print.

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 137-146).

Thesis (Ph.D.) - University of St Andrews, April 2010.

No description available.

Polychlorinated Biphenyls (PCBs) are a group of 209 congeners that are regulated under the Toxic Substance Control Act. They enter the environment as a result of industrial processes and can travel long distances. PCBs are environmentally persistent and bioaccumulate in animal populations. Painted surfaces are a common point source for PCBs and there are few options for remediating structures painted with PCB-contaminated paint. Removal of the paint can often spread contamination and disposing or burning of large structures is expensive. Experiments employing reductive dehalogenation through the use of a bimetal have shown that PCBs can be degraded in mild laboratory conditions. This dissertation describes the process of developing an application media that will enable the degradation process reported in literature to be used in a field application. An environmentally friendly reaction environment had to be established as well as the treatment‟s operating parameters. In collaboration with researchers at the National Aeronautics Space Administration (NASA), Kenney Space Center (KSC), researchers at the University of Central Florida (UCF) developed a bimetallic treatment system (BTS) that can remove and degrade PCBs from painted surfaces. The technology was evaluated during a field demonstration at a decommissioned Department of Defense facility in Badger, Wisconsin. Samples of treatment paste, paint and concrete were analyzed over a three week period. The PCB concentrations in both the paint and concrete dropped dramatically as a result of the demonstration, and in many instances, were lowered below the EPA action limit of 50ppm. In the laboratory, additional studies were conducted to further the degradation in the treatment system. Through this process, a novel degradation system was established containing zero-valent magnesium and ethanol acidified with acetic acid. The use of acidified ethanol permitted the degradation to occur with iv just magnesium powder and eliminated the use of a bimetal and therefore palladium. The technology was incorporated into a modified treatment system termed Activate Metal Treatment System (AMTS). The AMTS was used on samples from a second field site where paint chips from an manufacturing warehouse in New York state were degraded to thousands of mg/kg (ppm) below their starting concentrations.