Thesis (Ph.D.) --Murdoch University, 2004. / Thesis submitted to the Division of Science and Engineering. Includes bibliographical references (leaves 300-336).

Thesis (M.A.)--University of Adelaide, Dept. of Geography, 1993. / Three maps on folded leaves in pocket. Includes bibliographical references (leaves 146-157).

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Tracy A.O. Dougher. Includes bibliographical references (leaves 247-258).

Highways are known to be a source of several toxic pollutants including the heavy metals lead, zinc and chromium. The need to manage highway runoff in a manner which reduces or eliminates the loading of heavy metals to receiving waters is evident, but more research has been required to develop cost-effective ways of meeting this need. Recent studies have indicated that the soil is a significant "sink" for heavy metals, allowing speculation that management practices which make use of the soil to retain metals from highway runoff should be employed. The purpose of this study is to evaluate the ability of the soil to retain heavy metals and to document some of the soil properties and reactions which are responsible for this ability. This was accomplished through a combined effort of literature review and laboratory analysis of in situ soils from the right-of-way area of 5 Central Florida highways. A total of 13 samples were analyzed, for pH, cation exchange capacity, organic matter content, grain size, and concentrations of lead, zinc and chromium. The samples were separated into 6 fractions according to density and each fraction was analyzed for lead, zinc, and chromium. The step allowed reasonable estimates of the relative importance of soil components (clay minerals, organic matter) and/or soil-heavy metal interactions (precipitation, complex formation, etc.). It was found that the soils tested can likely retain between 10 and 500 times their existing lead content. Evidence for the formation of a dense lead compound (or precipitate) in edge of pavement surface soils was found. Organic matter was identified as an important soil component for retention of lead, zinc, and chromium. However, metal retention was found to be dependent on many soil properties and chemical reactions.

The purpose of this work was to demonstrate the effectiveness of neutron activation analysis in studying a complex environmental problem. The area chosen for study was the exhaust emitted by automobiles and its dispersion into soil and selected plants near highways. The elements chosen for this study were the major traceable components of gasoline and automobile exhaust. Variations in the concentrations of these trace elements in soil, grass and wash off the grass at various distances from two highways were investigated. Of the elements found in gasoline and in automobile exhaust, bromine most clearly indicated where some of the atmospheric components were going and, therefore, would be the most suitable element for neutron activation studies of atmospheric and turbulence modeling and possibly for following biological effects of automobile traffic. / Master of Science