Thesis
Exposure of humans to polybrominated diphenyl ethers (PBDEs) via residential indoor environment in the U.S.: probabilistic exposure analysis and risk assessment
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/102775
Abstract
Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in commercial and household products and are ubiquitous in residential indoor air and dust. PBDEs exert liver, endocrine, neurodevelopmental and reproductive toxicities. People are exposed to PBDEs through dietary intake, incidental ingestion of and dermal contact with indoor dust, and inhalation of indoor air. Previous studies that focused on Americans exposure to PBDEs via food consumption cannot explain why US body burdens are higher than those in Europe. This study quantitatively evaluated the indoor exposure of two age-related demographic groups in the US to PBDEs. Monte Carlo methods were used to focus a probabilistic analysis specifically on exposure via incidental indoor dust ingestion, dermal absorption and inhalation of indoor air. Risks of both non-cancer and cancer effects were assessed. The 95th percentile (P95) of the average daily dose generated by the Monte Carlo analysis for adult indoor dust ingestion of congeners BDE-47, -99, -153 and -209 was 0.68, 0.85, 0.10, and 0.95 ng/kg-day, respectively. For children, the respective doses were 12.14, 15.65, 1.83 and 15.59 ng/kg-day. The cumulative daily dose through all three pathways for the sum of the four congeners ([sigma]BDE-4) was estimated to be 2.70 ng/kg-day for adults and 59.25 ng/kg-day for children at the P95 level of exposure. Indoor incidental dust ingestion accounted for over 71-83% of the total daily dose. This finding for the US population supports previous studies pointing to incidental dust ingestion as the primary contributor to the total indoor exposure and may serve as the missing link between the internal exposure and external exposure of the US population. The probabilistically characterized risks of non-cancer endpoints associated with indoor exposure of US children and adults to four PBDE congeners were less than 1.0. The cancer risk associated with BDE-209 was estimated to be 2.5x10-9 even at the P95 level of exposure. Both the non-cancer risk of [sigma]BDE-4 and cancer risk of BDE-209 were below the regulatory levels of concern.
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Details
- Title
- Exposure of humans to polybrominated diphenyl ethers (PBDEs) via residential indoor environment in the U.S.
- Creators
- Hua He
- Contributors
- Allan S. Felsot (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525058801842
- Language
- English
- Resource Type
- Thesis