projects > interactions of mercury with dissolved organic carbon in the florida everglades > 2001 Proposal
Project Proposal for 2001
Workplan FY 2001
Interactions of mercury (Hg) with dissolved organic matter (DOM) play important roles in controlling reactivity, bioavailability and transport of Hg in the Florida Everglades. Our project is designed to better define the nature and magnitude of these interactions. During Phase 1, we studied the distribution and nature of DOM in the northern Everglades. In this work we noted the importance of source materials (peat versus vegetation and periphyton), and the importance of hydrologic factors on the quality and amount of DOM in a given location. Differences in the DOM were clearly apparent in regions exhibiting different behavior with regard to the generation of methylmercury. The results of this research are being written up (2 journal articles) and are expected to be ready for colleague review by Sept. 30, 2000. We also studied the reactivity of Everglades DOM with mercury through cinnabar (HgS) dissolution and formation experiments, and an ion-exchange technique designed to yield information on Hg-DOM binding constants. The results of the cinnabar interactions have been published as 2 journal articles (ES & T). The ion-exchange results are contained in a PhD thesis and are in the process of being converted into a journal article. Finally, we have attempted to include DOM-Hg binding components to geochemical models. The results of these efforts will be submitted for publication shortly.
Progress was made in FY 2000 in both the field and laboratory experiments. In the field, mesocosms were deployed at select locations to be used in experiments designed to test hypotheses concerning Hg speciation and reactivity. Preliminary experiments were carried out in conjunction with other team members (Krabbenhoft, Orem, eg). As part of this effort, we collected water from F1 and isolated a large amount of organic matter for future mesocosm experiments and to provide organic matter for ongoing lab experiments assessing the interactions of Hg with DOM that may control bioavailability. In FY 2000, we will continued ongoing lab studies to better define interactions of Hg with DOM. These studies included:
We have authored a number of high quality journal articles describing our efforts in Phase 1. This effort will continue in FY 2001. In addition to submitting our contributions to the synthesis report, the following reports are anticipated this FY:
Reddy, M. M., Aiken, G. R., and Schuster, P. F., Hydroperiod driven solute transport at the peat-water interface in the Florida Everglades: Hydrophobic acid diffusion from peat. Journal article scheduled for review by Nov. 30, 2000.
Reddy, M. M., and Aiken, G. R., Fulvic acid-sulfide ion competition for mercury ion binding in the Florida Everglades. Submitted for publication to Water, Air and Soil Pollution. Publication anticipated in FY 2001.
Ravichandran, M., Aiken, G. R., Reddy, M. M., and Ryan, J. N., Complexation of mercury by dissolved organic matter isolated from the Florida Everglades. Journal article scheduled for review by March 30, 2001.
Aiken, G. R., Reddy, M. M., and Schuster, P. F., Organic geochemistry of dissolved organic carbon in the northern Everglades, Florida Journal article scheduled for review by Jan. 2001.
Hurley, J. P., Cleckner, L. B., Krabbenhoft, D. P., and Aiken, G. R., Pigment distribution in plankton and periphyton of the Florida Everglades. Journal article scheduled for review by FY 2001.
Benoit, J. M., Mason, R. P., Gilmour, C. C., and Aiken, G. R., Mercury binding constants for dissolved organic carbon isolates from the Florida Everglades, to be submitted to Limnology and Oceanography. Scheduled for publication in FY 2001.
In FY 2001 we plan to: