Source identification of Florida Bay's methylmercury problem: Mainland runoff versus atmospheric deposition and in situ production

Estuaries and Coasts
By: , and 

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Abstract

The first advisory to limit consumption of Florida Bay fish due to mercury was issued in 1995. Studies done by others in the late 1990s found elevated water column concentrations of both total Hg (THg) and methylmercury (MeHg) in creeks discharging from the Everglades, which had its own recognized mercury problem. To investigate the significance of allochthonous MeHg discharging from the upstream freshwater Everglades, we collected surface water and sediment along two transects from 2000 to 2002. Concentrations of THg and MeHg, ranging from 0.36 ng THg/L to 5.98 ng THg/L and from <0.02 ng MeHg/L to 1.79 ng MeHg/L, were elevated in the mangrove transition zone when compared both to upstream canals and the open waters of Florida Bay. Sediment concentrations ranged from 5.8 ng THg/g to 145.6 ng THg/g and from 0.05 ng MeHg/g to 5.4 ng MeHg/g, with MeHg as a percentage of THg occasionally elevated in the open bay. Methylation assays indicated that sediments from Florida Bay have the potential to methylate Hg. Assessment of mass loading suggests that canals delivering stormwater from the northern Everglades are not as large a source as direct atmospheric deposition and in situ methylation, especially within the mangrove transition zone.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Source identification of Florida Bay's methylmercury problem: Mainland runoff versus atmospheric deposition and in situ production
Series title Estuaries and Coasts
DOI 10.1007/s12237-010-9290-5
Volume 34
Issue 3
Year Published 2011
Language English
Publisher Estuarine Research Federation
Contributing office(s) Wisconsin Water Science Center, Toxic Substances Hydrology Program, Mercury Research Laboratory
Description 20 p.
First page 494
Last page 513
Country United States
State Florida
Other Geospatial Florida Bay
Online Only (Y/N) N
Additional Online Files (Y/N) N