• Login
    View Item 
    •   UMB Digital Archive
    • School, Graduate
    • Theses and Dissertations All Schools
    • View Item
    •   UMB Digital Archive
    • School, Graduate
    • Theses and Dissertations All Schools
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UMB Digital ArchiveCommunitiesPublication DateAuthorsTitlesSubjectsThis CollectionPublication DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    Display statistics

    Bioaccumulation, Metabolism, and Biological Responses to Firemasters(RTM) 550 and BZ-54

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Find Full text
    Author
    Bearr, Jonathan
    Advisor
    Mitchelmore, Carys L.
    Date
    2010
    Type
    dissertation
    
    Metadata
    Show full item record
    Abstract
    Firemaster® 550 is a replacement for Penta- formulations of polybrominated diphenyl ether (PBDE) flame retardants. This formulation includes 2,3,4,5-tetrabromo-ethylhexylbenzoate (TBB), 2,3,4,5-tetrabromo-bis(2-ethylhexyl) phthalate (TBPH), triaryl phosphate isomers, and triphenyl phosphate. TBB and TBPH have been measured in several environmental matrices, including but not limited to freshwater sediment and marine mammals. However, few studies have assessed their environmental fate or impact. In this thesis, bioavailability, metabolism, and biological responses of TBB and TBPH were investigated in a variety of toxicological model species. Long-term dietary studies were conducted with fathead minnows (Pimephales promelas). TBB and TBPH bioaccumulated in the fish tissues and debrominated metabolites of TBB were observed. Hepatic DNA damage increased during the exposure, but quickly returned to background levels after the exposure ceased. Exposures were also linked to decreased sperm density in the fathead minnow. Incubations of hepatic sub-cellular fractions (e.g., S9, microsomes, cytosol) with Firemaster® BZ-54 were used to determine species specificity of TBB and TBPH metabolism. TBB was metabolized by the fathead minnow, common carp (Cyprinus carpio), and mouse (Mus musculus, wild type); but not in the snapping turtle (Chelydra serpentina serpentina). All species examined exhibited a reduction in TBPH, but there were no observable metabolites which suggest that some metabolites may not be effectively extracted using these techniques. Bioaccumulation of TBB and TBPH from sediments was evaluated over 28 days using the California blackworm (Lumbriculus variegatus), and chironomid (Chironomus tentans). Biota Sediment Accumulation Factor values of TBB and TBPH in the blackworms were less than those previously reported for Penta-BDEs, the fire retardant formulation these Firemaster® chemicals replaced. In chironomids, TBB bioaccumulated to a greater extent than TBPH. These results indicate that bioaccumulation may be a significant transport pathway by which TBB is transported from the aquatic environment as the chironomids emerge as flies. In conclusion, this work has demonstrated that components of Firemaster® 550 are capable of bioaccumulation, metabolism, and adverse effects in aquatic organisms. Future studies will need to focus on effects resulting from exposure to environmentally relevant concentrations of TBB and TBPH, further elucidation of their metabolism, and evaluation of the effects of contaminated emergent insects on birds.
    Description
    University of Maryland in Baltimore. Toxicology. Ph.D. 2010
    Keyword
    aquatic
    bioavailability
    Firemaster
    tetrabromobenzoate
    tetrabromophthalate
    Aquatic animals--Effect of water pollution on
    Aquatic animals--Toxicology
    Fireproofing agents--Environmental aspects
    Metabolism
    Biological Availability
    Identifier to cite or link to this item
    http://hdl.handle.net/10713/928
    Collections
    Theses and Dissertations All Schools
    Theses and Dissertations School of Medicine

    entitlement

     
    DSpace software (copyright © 2002 - 2023)  DuraSpace
    Quick Guide | Policies | Contact Us | UMB Health Sciences & Human Services Library
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.