Influence of Landscape Weathering and Fire on Soil Contaminant Reactivity in Western Oregon
| dc.contributor.advisor | Polizzotto, Matthew | |
| dc.contributor.author | Obeidy, Chelsea | |
| dc.date.accessioned | 2024-08-07T22:42:23Z | |
| dc.date.issued | 2024-08-07 | |
| dc.description.abstract | Soil and water quality are global concerns that significantly impact human health and the environment. As the demand for soil and water resources increases, it is essential to understand the reactions that govern the fate of contaminants in the environment. Contaminants like arsenic (As), chromium (Cr), nickel (Ni), and manganese (Mn) can pose significant threats to soil and water quality, and complex landscape-scale processes influence their fate. However, understanding how these processes impact soil contaminant reactivity can be complicated due to the inherent spatial and temporal heterogeneity of earth surface processes. For example, soil weathering controls the pedogenic minerals that can react with contaminants and can release metals from parent materials into soils - processes that ultimately occur at the molecular scale but play out across landscapes over large time scales. External perturbations to soil systems, such as wildfires, can further influence soil and water quality by impacting soil contaminant cycling and the minerals governing these reactions. Wildfires are becoming more frequent and severe; hence, it is crucial to understand the landscape controls that drive contaminant reactivity.The objectives of this work were to (1) understand how soil weathering influences contaminant reactivity (2) quantify fire-induced Cr and Cr-reactive mineral generation and transport from burned soils as a function of landscape position; (3) determine how multiple contaminants (Co, Mn, Ni, and V) are impacted and transported from burned soils across a landscape. Data reveal that amorphous-pedogenic minerals, driven and maintained by soil weathering, greatly influence soil contaminant reactivity. When subjected to fire, amorphous phases associated with contaminants increase before transforming into more crystalline phases with reduced sorption capacities. Furthermore, Cr(VI), a Class A carcinogen, was generated during burning and correlated with amorphous soil minerals that varied across a landscape. Contaminants released and transported from burned soils exceeded drinking water standards for Cr(VI), Mn, and Ni; the degree and persistence of contamination depended on landscape position. These findings assist in understanding how soil contaminants are influenced by weathering across a landscape and the subsequent transformations and transport that can occur after fire. This dissertation includes previously published and unpublished coauthored materials. | en_US |
| dc.description.embargo | 2025-01-23 | |
| dc.identifier.uri | https://hdl.handle.net/1794/29836 | |
| dc.language.iso | en_US | |
| dc.publisher | University of Oregon | |
| dc.rights | All Rights Reserved. | |
| dc.subject | Critical Zone Science | en_US |
| dc.subject | Environmental Soil Chemistry | en_US |
| dc.subject | Soil Science | en_US |
| dc.title | Influence of Landscape Weathering and Fire on Soil Contaminant Reactivity in Western Oregon | |
| dc.type | Electronic Thesis or Dissertation | |
| thesis.degree.discipline | Department of Earth Sciences | |
| thesis.degree.grantor | University of Oregon | |
| thesis.degree.level | doctoral | |
| thesis.degree.name | Ph.D. |