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Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon

February 16, 2016

Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.

Publication Year 2016
Title Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon
DOI 10.1016/j.envpol.2015.11.047
Authors Ariel S. Lewis, Thomas G. Huntington, Mark C. Marvin-DiPasquale, Aria Amirbahman
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Pollution
Index ID 70168373
Record Source USGS Publications Warehouse
USGS Organization National Research Program - Western Branch; New England Water Science Center; Toxic Substances Hydrology Program