Abstract Details
| Mercury Retention and Accumulation by Plants at the Abandoned New Idria Mine Site - a Preliminary µXRF and µXRD Study | |
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| Abstract ID | ENV-12 |
| Presenter | Hagar Siebner |
| Presentation Type | Poster |
| Full Author List | H. Siebner (1) , S. Webb (2) , G. E. Brown, Jr. (1,2) |
| Affiliations | (1) Surface & Aqueous Geochemistry Group, Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305-2115, USA (2) Stanford Synchrotron Radiation Laboratory, SLAC, MS 69, 2575 Sand Hill Road, Menlo Park, California 94025, USA |
| Category | Environmental Science |
| Abstract | Due to its high toxicity and increasing levels in ecosystems, Hg pollution has become a serious global problem. A lot of research has been conducted with regard to Hg biogeochemical cycles in aquatic systems. Much less is known about terrestrial Hg-cycles in general and in plants specifically. Plants play an important role in these cycles; they are known to be an important sink for both atmospheric and soil Hg, the vegetative cover significantly influences soil erosion and migration of contaminants into aquatic systems. However, the processes involved in the interactions of Hg with plants and plants products are poorly studied. Information concerning the interaction of Hg in plants at the molecular level is sparse. The present study is intended to provide new information on Hg retention, translocation, and accumulation in plants associated with mercury mine wastes in central California.
We present here preliminary results of Hg distribution in root and leave samples, taken from different plant species, which have adapted to the hostile environment at the New Idria site. Samples were taken at two locations that differ in water acidity and flooding regime. The distribution of Hg appears to be affected by plant species, growing conditions, and development stage. µXRF images of root sections show that Hg is mainly associated with Fe plaque at the outer surfaces and epidermis but is distributed differently in roots of the two plants. µXRD showed evidence for mineralogical changes in the plaque through the sections. Mercury in leaves was found to be highly diffuse in its distribution, and is not associated with Fe-rich particles attached to the outer surface of the leaf. This finding implies that Hg is assimilated in the leaf tissue. Further examination of Fe plaque characteristics and associated Hg, as well as Hg speciation in the different organs of these plants, is being conducted in our lab. |
| Footnotes | |
| Funding Acknowledgement | This research was supported by Vaadia-BARD Postdoctoral Fellowship Award No. FI-405-2007 from BARD, The United States - Israel Binational Agricultural Research and Development Fund. |