Mercury cycling and species mass balances in four North American lakes.
A mass balance model for mercury based on the fugacity concept is applied to Lake Superior, Lake Michigan, Onondaga Lake and Little Rock Lake to evaluate model performance, analyze cycling of three mercury species groups (elemental, divalent and methyl mercury), and identify important processes that determine the source-to-concentration relationship of the three mercury species groups in these lakes. This model application to four disparate ecosystems is an extension of previous applications of fugacity-based models describing mercury cycling. The model performs satisfactorily following site-specific parameterization, and provides an estimate of minimum rates of species interconversion that compare well with literature. Volatilization and sediment burial are the main processes removing mercury from the lakes, and uncertainty analyses indicate that air-water exchange of elemental mercury and water-sediment exchange of divalent mercury attached to particles are influential in governing mercury concentrations in water. Any new model application or field campaign to quantify mercury cycling in a lake should consider these processes as important.
Qureshi
Asif
A
Safety and Environmental Technology Group, Institute for Chemical and Bioengineering, ETH Zürich, CH-8093 Zürich, Switzerland.
MacLeod
Matthew
M
Scheringer
Martin
M
Hungerbühler
Konrad
K
D000393:Air Pollutants / Q000737:chemistry; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D006114:Great Lakes Region; D008628:Mercury / Q000032:analysis / Q000737:chemistry*; D008745:Methylation; D008767:Methylmercury Compounds / Q000737:chemistry; D008956:Models, Chemical; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D000393:Air Pollutants; D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury