HR: 1330h
AN: B33B-02    [Abstracts]
TI: Environmental Biomonitoring of Cr and As in Shallow Groundwater: Do Red Oak Trees Preserve Long-Term Records of Contaminant Loading?
AU: * Shailer, M
EM: mark.shailer@gmail.com
AF: EEOS, UMass-Boston, 100 Morrissey Blvd., Boston, MA 02125-3393
AU: Brabander, D
EM: dbraband@wellesley.edu
AF: Department of Geosciences, Wellesley College, 106 Central Street, Wellesley, MA 02481
AB: The use of dendrochemical analysis has been shown to be a valuable, although controversial, tool in monitoring historical trends in trace metal deposition and mobilization in groundwater and sediments. Neutron activation analysis (NAA) is one method that has been used to determine annual dendrochemical patterns in tree rings. The use of NAA may also provide a practical tool for revealing sub-annual differences in metal concentrations between earlywood and latewood. In a variety of geochemical settings, Cr and As can be mobile in the groundwater-root environment and are subsequently taken up by trees and stored in xylem tissues specifically associated with groundwater transport. For the purposes of determining historical patterns in Cr and As bioavailability at a Woburn, MA, superfund site along the Aberjona River, Quercus rubra (red oak) sectioned tree rings were analyzed. Sub-annual dendrochemical analyses were used to identify different As and Cr loading pathways in oak stem wood. A sixty-year record of [As] and [Cr] in stem wood was obtained, and results suggest seasonally dependent correlations with Aberjona River flow and with pumping rates for a municipal well in close proximity to the sampling location. These two hydrological pathways likely dominate in providing a flux of dissolved As and Cr into oak stem wood.
DE: 0400 Biogeosciences
DE: 1035 Geochronology
DE: 1065 Trace elements (3670)
DE: 1094 Instruments and techniques
DE: 1829 Groundwater hydrology
SC: Biogeosciences [B]
MN: 2005 Joint Assembly