Mercury body burdens in Gambusia holbrooki and Erimyzon sucetta in a wetland mesocosm amended with sulfate
S.M. Harmona, J.K. King b, J.B. Gladden c,
G.T. Chandler a, L.A. Newman a,d
a Department of Environmental Health Sciences,
Arnold School of Public Health, University of South Carolina, Columbia.
SC 29208, United States
b US Army Corps of Engineers, 100 West Oglethorpe Avenue, Savannah,
GA 31402, United States
c Westinghouse Savannah River Company, Aiken, SC 29808, United
States
d University of Georgia, Savannah River Ecology Laboratory,
Drawer E, Aiken, SC 29808, United States
Received 30 March 2004; received in revised form 30 September 2004; accepted
29 November 2004
Abstract
This study used an experimental model of a constructed wetland to evaluate
the risk of mercury methylation when the soil is amended with sulfate.
The model was planted with Schoenoplectus californicus and designed
to reduce copper, mercury, and metal-related toxicity in a wastestream.
The sediments of the model were varied during construction to provide
a control and two levels of sulfate treatment, thus allowing characterization
of sulfate's effect on mercury meth- ylation and bioaccumulation in periphyton
and two species of fish-eastem mosquitofish (Gambusia holbrooki)
and lake chubsucker (Erimyzon sucetta). After one year in the
experimental model, mean dry-weight normalized total mercury concentrations
in mosquitofish from the non-sulfate treated controls (374 ± 77
ng/g) and the reference location (233 ± 17 ng/g) were significantly
lower than those from the low and high sulfate treatments (520 ±
73 and 613 ± 80 ng/g, respectively). For lake chubsucker, mean
total mercury concentration in fish from the high sulfate treat- ment
(276 ± 63 ng/g) was significantly elevated over that observed in
the control (109 ± 47 ng/g), the low sulfate treatment (122 ±
42 ng/g), and the reference population (41 ± 2 ng/g). Mercury in
periphyton was mostly inorganic as methylmercury ranged from 6.6 ng/g
(dry weight) in the control to 9.8 ng/g in the high sulfate treatment,
while total mercury concentrations ranged from 1147 ng/g in the control
to a high of 1297 ng/g in the low sulfate treatment. Fish methylmercury
bioaccumulation factors from sediment ranged from 52 to 390 and from 495
to 3059 for water. These results suggest that sulfate treatments add a
factor of risk due to elevated production of methylmercury in sediment
and porewater which biomagnified into small fish, and may potentially
increase through the food web.
@ 2005 Elsevier Ltd. All rights reserved.
Keywords: Mercury; Methylmercury; Gambusia holbrooki;
Erimyzon sucetta; Sulfate
SREL Reprint #2848
Harmon, S. M., J. K. King, J. B. Gladden, G. T. Chandler and L. A. Newman. 2005. Mercury body burdens in Gambusia holbrooki and Erimyzon sucetta in a wetland mesocosm amended with sulfate. Chemosphere 59:227-233.
