Development of a mercury speciation, fate, and biotic uptake (BIOTRANSPEC) model: Application to Lahontan Reservoir (Nevada, USA)

Environmental Toxicology and Chemistry
By: , and 



A mathematically linked mercury transport, speciation, kinetic, and simple biotic uptake (BIOTRANSPEC) model has been developed. An extension of the metal transport and speciation (TRANSPEC) model, BIOTRANSPEC estimates the fate and biotic uptake of inorganic (Hg(II)), elemental (Hg(0)) and organic (MeHg) forms of mercury and their species in the dissolved, colloidal (e.g., dissolved organic matter [DOM]), and particulate phases of surface aquatic systems. A pseudo-steady state version of the model was used to describe mercury dynamics in Lahontan Reservoir (near Carson City, NV, USA), where internal loading of the historically deposited mercury is remobilized, thereby maintaining elevated water concentrations. The Carson River is the main source of total mercury (THg), of which more than 90% is tightly bound in a gold-silver-mercury amalgam, to the system through loadings in the spring, with negligible input from the atmospheric deposition. The speciation results suggest that aqueous species are dominated by Hg-DOM, Hg(OH)2, and HgClOH. Sediment-to-water diffusion of MeHg and Hg-DOM accounts for approximately 10% of total loadings to the water column. The water column acts as a net sink for MeHg by reducing its levels through two competitive processes: Uptake by fish, and net MeHg demethylation. Although reservoir sediments produce significant amounts of MeHg (4 g/d), its transport from sediment to water is limited (1.6 g/d), possibly because of its adsorption on metal oxides of iron and manganese at the sediment-water interface. Fish accumulate approximately 45% of the total MeHg mass in the water column, and 9% of total MeHg uptake by fish leaves the system because of fishing. Results from this new model reiterate the previous conclusion that more than 90% of THg input is retained in sediment, which perpetuates elevated water concentrations.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Development of a mercury speciation, fate, and biotic uptake (BIOTRANSPEC) model: Application to Lahontan Reservoir (Nevada, USA)
Series title Environmental Toxicology and Chemistry
DOI 10.1897/06-468R.1
Volume 26
Issue 11
Year Published 2007
Language English
Publisher SETAC
Contributing office(s) Toxic Substances Hydrology Program
Description 14 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Environmental Toxicology and Chemistry
First page 2260
Last page 2273
Country United States
State Nevada
Other Geospatial Lahontan Reservoir
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