Date of Award
Master of Science (MS)
Plants growing in metalliferous soils may restrict metal uptake and transport depending on metal concentration, sediment characteristics, and plant species. As native plants are replaced by invasives, different patterns of metal cycling can occur, making continued study of this process important. Sediments and tissues of four aquatic plant species/genera: Phragmites australis (common reed); Iris versicolor (blueflag iris); Typha latifolia (broadleaf cattail); and genera Cyperus sp. (sedge) from three urban and two rural sites in Albany County, NY were analyzed for total mercury (HgT) by cold vapor atomic absorption spectroscopy. Sediments were also measured for organic carbon (OC) by coulometry. Sediment HgT ranged from 54 to 483 ng/g and root tissues ranged from 11 ng/g to 354 ng/g. Strong Hg partitioning was found between roots and other tissues by comparing sediment:root and root:rhizome Hg concentration ratios which ranged from 1:1 to 10:1 and 1:1 to 18:1, respectively, indicating strong Hg partitioning among sediment, root, and rhizome. However, the two sites with the highest Hg sediment levels (356 ng/g and 483 ng/g), had markedly different sediment:root ratios (3.5:1 and 1.5:1, respectively) that correlated directly with sediment OC levels (4.51% and 1.87%, respectively). These results suggest that sediment OC may limit the bioavailability of Hg to plants as Hg becomes bound to OC in sediment. Since sediment Hg can exist in several forms, sequential chemical extraction may be a better predictor of Hg available for plant uptake than HgT. Root plaques were observed on samples of common reed at two different sites. One sample had the highest HgT seasonal root concentration for common reed at that site, samples from the other site had both the highest and lowest seasonal HgT concentrations. While SEM microprobe analysis revealed concentrations of iron (Fe) and Manganese (Mn), it is inconclusive if root plaques are an important adheration site for Hg.
Neumann, Bernd G., "Mercury Uptake by Aquatic Macrophytes in Urban and Rural Watersheds, Albany County, NY" (2009). Geology Theses and Dissertations. 63.