Legacy and Fate of Mercury and Methylmercury in the Florida Everglades

Authors

Guangliang Liu, Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University
G. Melodie Naja, Everglades Foundation, Science DepartmentFollow
Peter Kalla, United States Environmental Protection Agency, Region 4, Science and Ecosystem Support DivisionFollow
Dan Sceidt, United States Environmental Protection Agency, Region 4, Water Protection Division
Evelyn E. Gaiser, Department of Biological Sciences and Southeast Environmental Research Center, Florida International UniversityFollow
Yong Cai, Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University

Abstract

Mass inventories of total Hg (THg) and methylmercury (MeHg) and mass budgets of Hg newly deposited during the 2005 dry and wet seasons were constructed for the Everglades. As a sink for Hg, the Everglades has accumulated 914, 1138, 4931, and 7602 kg of legacy THg in its 4 management units, namely Water Conservation Area (WCA) 1, 2, 3, and the Everglades National Park (ENP), respectively, with most Hg being stored in soil. The current annual Hg inputs account only for 1−2% of the legacy Hg. Mercury transport across management units during a season amounts to 1% or less of Hg storage, except for WCA 2 where inflow inputs can contribute 4% of total MeHg storage. Mass budget suggests distinct spatiality for cycling of seasonally deposited Hg, with significantly lower THg fluxes entering water and floc in ENP than in the WCAs. Floc in WCAs can retain a considerable fraction (around 16%) of MeHg produced from the newly deposited Hg during the wet season. This work is important for evaluating the magnitude of legacy Hg contamination and for predicting the fate of new Hg in the Everglades, and provides a methodological example for large-scale studies on Hg cycling in wetlands.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Liu, G., M. Naja, P. Kalla, D. Scheidt, E.E. Gaiser, Y. Cai. 2011. Legacy and fate of mercury and methylmercury in the Florida Everglades. Environmental Science and Technology 45(2): 496-501.