Grantee Research Project Results
2005 Progress Report: Phototransformation of Contaminants at the Sediment-Water Interface
EPA Grant Number: R830394Title: Phototransformation of Contaminants at the Sediment-Water Interface
Investigators: Tratnyek, Paul G.
Institution: Oregon Health & Sciences University
EPA Project Officer: Packard, Benjamin H
Project Period: March 1, 2002 through February 28, 2004 (Extended to September 30, 2006)
Project Period Covered by this Report: March 1, 2004 through February 28, 2005
Project Amount: $198,226
RFA: Futures Research in Natural Sciences (2001) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Hazardous Waste/Remediation , Futures , Land and Waste Management
Objective:
The major hypothesis underlying this study is that the lack of information on photochemistry at the sediment-water interface (SWI) is a significant contributor to uncertainty in risk assessments involving contaminated sediments. The objectives of this research project are to: (1) survey a range of contaminant-sediment combinations using a variety of protocols to identify the types of situations where photoeffects at the SWI are most significant; (2) develop improved and alternative methods for studying SWI; (3) apply a range of chemical and physical probes to obtain a detailed understanding of the controlling processes; and (4) perform a preliminary assessment of the overall importance of these effects relative to other environmental fate processes and use this understanding to anticipate future problems and/or opportunities for improved management practice.
Progress Summary:
We have succeeded in demonstrating that there is enhanced photodegradation at the SWI interface using the pesticide disulfoton as a probe for contaminant transformations mediated by the photooxidant singlet oxygen. Although we have observed the effect with a variety of sediments and related probe-contaminants, preliminary experiments with the singlet oxygen trap, DABCO, have not confirmed that singlet oxygen is involved. Therefore, we have begun to investigate the possible role of other reactive oxygen or nitrogen species that might be formed at the sunlit sediment-water interface.
Future Activities:
We will identify which reactive oxygen or nitrogen species is most important at the sunlit sediment-water interface using appropriate trap and probe molecules.
Supplemental Keywords:
contaminated sediments, wetlands, organics, pesticides, exposure, risk assessment, toxics, oxidants, phototoxicity, UV effects, environmental chemistry, environmental monitoring, geochemical modeling,, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Waste, Water, Contaminated Sediments, Monitoring/Modeling, Ecology and Ecosystems, Environmental Monitoring, UV effects, sediment-water interface, geochemical modelingRelevant Websites:
http://www.ogi.edu/project/swi/ Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.