Department of Civil and Environmental Engineering
University of Maine
5711 Boardman Hall
Orono, ME 04469
Estuaries are dynamic environments. As rivers flow toward the sea and freshwater meets salt, the changes in salinity and channel widening cause sediment to accumulate in the estuarine zone. As a result, estuaries may function as traps for river-borne contaminants, including mercury.
In the lower Penobscot River estuary, high levels of mercury in water and sediment are the result of industrial point sources upstream. University of Maine associate professor Aria Amirbahman and graduate student Karen Merritt measured porewater distribution of highly toxic methylmercury (MeHg) in the contaminated sediments within Frankfort Flats in the Penobscot estuary. MeHg production occurs about 2-8 cm below the sediment-water interface, but a significant decrease in porewater MeHg concentration is observed in the vicinity, suggesting a lack of MeHg release into the overlying water column.
1-year project: 2005-2006
Amirbahman, A. and K.A. Merritt. 2008. Mercury in the Penobscot River Estuary: the Sediment-Water Interface. Research in Focus Fact Sheet. Orono, ME: Maine Sea Grant.
Merritt, K.A., and Amirbahman, A. 2008. Methylmercury cycling in estuarine sediment pore waters (Penobscot River estuary, Maine, USA). Limnology and Oceanography 53:1064-1075.
Merritt, K.A. and Amirbahman, A. 2007. Mercury dynamics in sulfide-rich sediments: Geochemical influence on contaminant mobilization within the Penobscot River estuary, Maine USA. Geochimica et Cosmochemica Acta 71:929-941.
Merritt, K.A. and Amirbahman, A. 2007. Mercury mobilization in estuarine sediment porewaters: a diffusive gel time-series study. Environmental Science and Technology 41:717-722.