Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon. (May 2016)

• Record Type: Journal Article
• Authors: Lewis, Ariel S.; Huntington, Thomas G.; Marvin-DiPasquale, Mark C.; Amirbahman, Aria
• Is Part Of: Environmental pollution. Volume 212(2016)
• Page Start: 366
• Page End: 373
• Publication Date: 2016-05
• Subjects: Mercury -- Zero valent iron -- Granular activated carbon -- Wetlands -- Remediation; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2015.11.047
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: 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. Highlights: ZVI and GAC treatment reduces pore-water MeHg concentration in wetland sediment. Reduction in pore-water MeHg is likely due to adsorption to ZVI and GAC. Reduction in pore-water MeHg due to ZVI and GAC treatments lowers MeHg uptake by L. stagnalis . Application of ZVI and GAC resulted in a higher sediment partition coefficient (KD ) and a lower bioaccumulation factor (BAF) for MeHg. Abstract : ZVI and GAC treatment reduces pore-water MeHg concentration in wetland sediment. Reduction in pore-water MeHg due to treatments lowers MeHg uptake by Lymnaea stagnalis .