Graduation Year

2014

Document Type

Thesis

Degree

M.S.P.H.

Degree Granting Department

Public Health

Major Professor

Yehia Y. Hammad, Sc. D.

Committee Member

J. David Krause, Ph. D.

Committee Member

René R. Salazar, Ph. D.

Keywords

Biodegradation, C. cladosporiodes, Exposure assessment, Metal building insulation

Abstract

This study examined the effects of the presence of fungal growth on the phthalate ester content of plasticized polyvinyl chloride (pPVC) used as the vapor barrier component of metal building insulation and the impact the fungal growth may have on the resulting exposure potential to the workers in the building. Individual pieces of the pPVC material exhibiting fungal growth and individual pieces of the pPVC material exhibiting no fungal growth were collected from the building being investigated. Twenty-five pieces each of the pPVC material exhibiting fungal growth and of the pPVC material exhibiting no fungal growth were weighed, reduced to small pieces, and extracted with dichloromethane. The extracts were analyzed using a gas chromatograph coupled with a mass spectrometer. The phthalate content of four phthalate esters identified in the pPVC: diethyl phthalate (DEP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), and di-(2-ethylhexyl) phthalate (DEHP), was quantified and the results extrapolated to concentration based on weight ([um]g/Kg) and area ([um]g/m2). A paired samples t test and independent samples t test was used to identify where significant differences occurred (α = 0.05) in the phthalate content between pieces. Using the mean concentration for each phthalate ester, a worst-case-scenario exposure was modeled. There was a statistically significant difference in the phthalate ester content between the pPVC exhibiting fungal growth and pPVC exhibiting no fungal growth for all four phthalate esters investigated. The mean phthalate ester concentration ranged from 13.74 [um]g/m2-34.94 [um]g/m2 in the pPVC exhibiting no fungal growth and 12.00 [um]g/m2-30.63 [um]g/m2 in the pPVC exhibiting fungal growth. The modeled exposure concentration in the building ranged from 0.39 [um]g/m3-0.98 [um]g/m3 and was generally lower than published exposure concentrations in similar settings.

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