Mercury Distribution and Transformation In Roots at the Abandoned Hg Mine Site, New Idria, CA.

Mercury is a serious global pollutant. Although plants play an important role in its terrestrial cycles, the uptake and translocation of Hg in plants, especially at the molecular level, are not well understood. The present study examined the Hg-phases developed at the soil-root interface of plants growing on Hg-mine wastes. Various Hg distribution patterns were found for different plant species, site conditions, and root age, using micro-XRF imaging. The accumulation and change in Hg speciation, shown by X-ray absorption fine structure (XAFS) spectroscopy in different parts of the roots, imply the existence of labile Hg fraction.  Potential translocation mechanisms between the soil source and the above-ground organs of plants growing in contaminated area will be discussed.