This project will attempt to determine the importance of atmospheric hydroxyl (OH) radical in depleting persistent organic pollutants (POPs) in the Southern Hemisphere. The focus will be on polychlorinated biphenyls (PCBs). Atmospheric depletion reactions should be key processes for the removal of recalcitrant organic compounds based on laboratory-derived reaction rates. This, however, is not reflected in their abundance in field measurements. The project will take advantage of an upcoming cruise by the R/V Roger Revelle. The cruise track will lead to the South Pacific gyre where there is very low biological activity. This will prevent water column processes from dominating over atmospheric reactions with respect to PCB concentrations. Also, the location will be far away from primary and secondary sources of PCBs. Atmospheric and water samples will be collected and analyzed later in the laboratory. It is hypothesized that there will be a significant difference between concentrations observed during the day and at night, which will provide evidence for atmospheric removal of the PCBs.
This study is expected to contribute towards a better understanding of the atmospheric reactivity of persistent organic pollutants, which is key to understanding their atmospheric transport and fate. The project will provide partial support for a graduate student. Research results will also be included in classroom teaching.
