Measuring and modeling DDT, chlordane, and mercury in activated carbon amended sediments and water
Abstract/Contents
- Abstract
- Activated carbon (AC) as an in-situ amendment for the remediation of contaminated sediments has attracted considerable attention from researchers, regulators, and industry. However, knowledge gaps related to field measurements of AC performance and long-term modeling of AC-amended sediments currently impede the widespread adoption of the technology. The intent of this study is to improve in-situ measurements of AC-amended sediments and to test the prevailing conceptual and mathematical models describing AC performance in the field. Polyethylene (PE) passive samplers can be used to estimate water concentration of hydrophobic organic contaminants. A Fickian approach to modeling hydrophobic organic compound uptake by PE developed in this study significantly improved the accuracy of these water measurements in non-equilibrium conditions, particularly in well-agitated systems in which PE-phase mass transfer resistance is significant. Polyethylene partitioning and diffusion coefficients were measured for the organochlorine pesticides DDT, DDT metabolites, chlordane, and dieldrin. An 18-month field mesocosm study was conducted at an intertidal marsh creek impacted with organochlorine pesticides to evaluate AC amendment under several application conditions. Organochlorine pesticide availability, as measured by PE concentration, was reduced throughout the trial period, with chlordane and DDT PE concentration reductions of 85-91% and 83-85%, respectively, 18 months post-treatment in the mesocosms amended with granular activated carbon (GAC). A substantial particle size effect was observed. For example, chlordane concentration in PE was reduced by 91% 6-months post deployment in the powdered AC mesocosm (PAC), compared with 68% in the GAC mesocosm. An existing mass transfer model was parameterized and applied to the mesocosms for model validation purposes. Overall, the mass transfer model reproduced the field observations well for the major constituents of pore water concentration and the model captured the relative impact of the application conditions. In preliminary field studies, AC amendment reduced mercury and methylmercury sediment pore water concentration by 70 and 81%, respectively. Activated carbon dosed at 5% reduced mercury pore water concentration by > 85% in confirmatory laboratory tests.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2015 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Thompson, Jay Michael |
|---|---|
| Associated with | Stanford University, Department of Civil and Environmental Engineering. |
| Primary advisor | Luthy, Richard G |
| Thesis advisor | Luthy, Richard G |
| Thesis advisor | Mitch, William A |
| Thesis advisor | Werner, David, 1973- |
| Advisor | Mitch, William A |
| Advisor | Werner, David, 1973- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Jay Michael Thompson. |
|---|---|
| Note | Submitted to the Department of Civil and Environmental Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2015. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2015 by Jay Thompson
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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