Abstract
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, B.G., 2009. Mercury Uptake by Aquatic Macrophytes in
Urban
and Rural Watersheds, Albany County, NY.
Unpublished MSc. thesis, State University of New York at
Albany.
80 pp., +ix
University at Albany Science Library call number: SCIENCE
Oversize
(*) QC 869 Z899 2009 N48
MS thesis text
pdf 1.8MB
Return to MS Theses completed in the
Geological
Sciences Program, University at Albany