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dc.contributor.authorJurinski, Joseph Bernard Jr.en_US
dc.date.accessioned2014-03-14T20:22:17Z
dc.date.available2014-03-14T20:22:17Z
dc.date.issued1998-06-10en_US
dc.identifier.otheretd-61898-133517en_US
dc.identifier.urihttp://hdl.handle.net/10919/30632
dc.description.abstractOver the course of our lives we are exposed to airborne particulate matter in the workplace, home, and environment that results in the deposition of millions of particles in the lung. These exposures may result in disease if they are significant enough. The potential for harmful exposure depends in part on the dust's biodurability and the bioavailability of harmful constituents derived from the particles. A mixed flow reactor was used to evaluate two applications of geochemical methods to characterize the behavior of inhaled particles in the body. Dissolution rates of a well-characterized sample of powdered talc were measured in solvents that mimic fluids found in the human lung. These studies showed that variation of solvent chemistry, including the addition of organic chelators and proteins at intercellular fluid concentrations, does not markedly affect the measured dissolution rate of talc at 37 degrees Celcius and the data further indicate that the dissolution mechanism for talc in aqueous solutions is independent of pH over a range of pH from 2 to 8. The dissolution rate, determined by measuring the silicon release rate per unit surface area of talc is 1.4 (+/- 1.0) x 10-11 mol Si/(m2 -sec). A geometric shrinking particle model using this dissolution rate predicts an estimated lifetime (upper limit) of approximately 8 years for a 1 micron talc particle under pulmonary conditions. Talc dissolves considerably faster than quartz, but slower than chrysotile and olivine in the body. These data can be used to place constraints on the role of particle dissolution in the disease models associated with airborne respirable particulate matter. Secondly, the bioavailability of As and Cr was determined from a sample of coal fly ash from an eastern U.S. power plant. The time-release profiles of As and Cr were determined for these materials in physiologically-based solvents and incorporated into a toxicokinetic model to predict the exposure potential to As and Cr from occupational exposures to the coal fly ash. Predicted occupational exposure contributions from the ash relative to total environmental exposures were insignificant. The exposure predicted from the geochemical approach was compared with results observed in a cohort occupationally exposed to coal fly ash and found to be within one order of magnitude of the response of the occupational cohort. These results support the application of geochemical techniques to evaluate exposures to complex respirable materials.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartdiss.pdfen_US
dc.relation.haspartappa.pdfen_US
dc.relation.haspartappb.pdfen_US
dc.relation.haspartappc.pdfen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectbiodurabilityen_US
dc.subjectbioavailabilityen_US
dc.subjectrespirableen_US
dc.subjecttalcen_US
dc.subjectcoal fly ashen_US
dc.subjectarsenicen_US
dc.subjectchromiumen_US
dc.subjecthealth effectsen_US
dc.subjectmineral dustsen_US
dc.titleGeochemical Investigations of Respirable Particulate Matteren_US
dc.typeDissertationen_US
dc.contributor.departmentGeological Sciencesen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineGeological Sciencesen_US
dc.contributor.committeechairRimstidt, James Donalden_US
dc.contributor.committeememberCraig, James R.en_US
dc.contributor.committeememberMahar, Harryen_US
dc.contributor.committeememberRibbe, Paul H.en_US
dc.contributor.committeememberSeifried, Harold E.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-61898-133517/en_US
dc.date.sdate1998-06-10en_US
dc.date.rdate1999-07-22
dc.date.adate1998-07-22en_US


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