Fluridone is a commonly used herbicide for the control of invasive aquatic weeds in surface water. After application, fluridone can sorb strongly to bed sediment, which can complicate both analytical fluridone quantification and estimations of fluridone persistence. When present in high concentrations in sediment and water, fluridone can cause damage to non-target plants and aquatic life. Here we developed a simple method for the extraction of fluridone from complex clay-based alluvial sediments, compared this method with an existing and well-established pesticide extraction method, validated both extraction methods in laboratory samples spiked with fluridone, and successfully applied both methods to field samples collected from ongoing fluridone applications in the California delta. These extraction techniques were then utilized to quantify the persistence of fluridone in sediment and water samples monitored for over two months to determine the effect of temperature, UV light, and sediment clay content on fluridone’s half-life. Temperature impacted degradation of fluridone in both sediment and water. In water, results suggest a linear relationship between temperature and decreasing half-life. In sediment, results suggest a preference for mesophilic microbial degradation, meaning that degradation is increased and statistically identical between 20°C-40°C. UV light greatly increased degradation in water but displayed insignificant impact on degradation in sediment. Increased clay content slightly prolonged the persistence of fluridone in sediment. To estimate the transport of fluridone through the subsurface, a simple Ogata-Banks based analytical transport model was tested in various scenarios of initial concentration, half-life, and groundwater velocity. Results suggest that subsurface lateral transport of fluridone is limited to less than 10 meters over a 1-month period. Water velocity contributes the most to overall transport of fluridone in subsurface water, while half-life and initial application concentration have smaller localized effects. The findings of this study can be used to further understand of the fate and transport of fluridone in deltaic environments and help make informed decisions regarding fluridone application in ambient water bodies.
|Advisor:||Pandey, Pramod K.|
|Commitee:||Harter, Thomas, Sandoval Solis, Samuel|
|School:||University of California, Davis|
|School Location:||United States -- California|
|Source:||MAI 81/1(E), Masters Abstracts International|
|Subjects:||Hydrologic sciences, Environmental science, Chemistry|
|Keywords:||Degradation, Extraction, Fluridone, Herbicide, Sediment, Transport|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be