Date of Award

Summer 2004

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Environmental Science - (Ph.D.)

Department

Chemistry and Environmental Science

First Advisor

Daniel Watts

Second Advisor

S. Mitra

Third Advisor

Robert Pfeffer

Fourth Advisor

Joseph W. Bozzelli

Fifth Advisor

Rose Ann Dios

Sixth Advisor

Trevor Tyson

Abstract

The rapid development of particle technology and the growing use of particulate materials in industries are bringing large amounts of manufactured particles into the environment. Epidemiological studies suggest that fine particles (particles with aerodynamic diameter smaller than 2.5 μm, i.e., PM2.5) have an association with various adverse health effects in humans. Mass studies have been performed on the toxicity and toxicological mechanisms of airborne particles such as PM2.5 and PM10, but there are very few investigations which contribute to the knowledge base on biological implications of manufactured particulate materials. Up to now, the published toxicity studies on manmade particulate materials focus on human health effects. No investigations have addressed to the ecological effects of the particulate materials. Toxicities of manufactured particles are evaluated by means of a root elongation test in this study. The particles studied include 13-nm alumina, 14-nm hydrophilic silica, 21-nm titania, 161.2-nm spherical hydrophilic silica, 1 .0-μm alumina, 667.6-nm spherical hydrophilic silica, and 0.96-μm titania. Six plant species, Zea mays (corn), Cucumis sativus (cucumber), Avena sativa (oat), Glycine max (soybean), Brassica oleracea (cabbage), and Daucus carota (carrot) were used in this study of the phytotoxicity of the commercially available manufactured particles. Physical and chemical characterization techniques of FTIR, SEM/EDS, the BET method, and particle size analysis, as well as liquid phase coating techniques were applied simultaneously to facilitate the study on toxicological mechanisms of these manufactured particles. The results indicate that phytotoxicity of particles does not depend solely on the particle mass concentration, particle chemical composition, particle size, as well as the particle specific surface area. It also depends on particle surface characteristics.

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