Volatile Polonium and Tellurium Species in the Marine Environment

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ABSTRACTOCE-0425199In this project, researchers at the University of Delaware will study the formation of volatile polonium (Po) and tellurium (Te) species in marine environments. These two elements may provide a metric of air-sea metalloid evasion using the natural radionuclide 210Po by comparison to its stable Group XVI congener Te. The basic chemical properties of polonium and tellurium suggest that alkylation will occur via common reactions, and strong field evidence exists for the production of volatile species of both elements in marine environments. However, volatile species have not yet been directly observed in marine systems. The researchers hypothesize that stable alkyl species of polonium and tellurium contribute to their volatile flux across the marine atmospheric boundary. This hypothesis will be tested through analytical development, laboratory reactions, microbial methylation assays, and field sampling studies leading to the first direct volatile species identification in the marine environment. Analytical methods will be developed including GC-ICPMS technologies for species separation and identification. Laboratory studies will test for alkylated products of abiotic methylation reactions, and microbial cultures grown for biotic generation of volatile tellurium and polonium species. Finally, both head space analysis in batch incubation of natural sediments and downwind of marine areas with expected methylation activity will be sampled for naturally occurring volatile products of polonium and tellurium. Broader Impacts: This project will deal with globally significant biogeochemical processes that include potential pollutant transfer and marine biotic stress. Graduate and post-graduate students will gain experience developing next generation analytical techniques to address such processes. Undergraduate students will participate in the NSF-sponsored research resulting in educational and professional experiences by exposure to the proposed research under the NSF-REU (Research Experience for Undergraduates) program.