HR: 11:50h
AN: H52D-07    [Abstracts]
TI: Mercury Mobilization in Urban Stormwater Runoff
AU: * Eckley, C S
EM: chris.eckley@utoronto.ca
AF: University of Toronto, 3359 Mississauga Rd N, Mississauga, ON L5L 1C6, Canada
AU: Branfireun, B
EM: brian.branfireun@utoronto.ca
AF: University of Toronto, 3359 Mississauga Rd N, Mississauga, ON L5L 1C6, Canada
AB: Higher mercury (Hg) concentrations in urban rivers have been found compared to rural rivers with the majority of the increase associated with particles (HgP) during periods of stormflow (Lawson et al. 2001; Hurley et al., 1998). It is unclear whether the increase in concentrations is a result of internal mobilization (e.g. bank erosion) or from external loading from stormwater runoff. The objectives of this research are: to use high frequency sampling to characterize the water and Hg export dynamics from an urban micro-catchment during individual rain events under a range of conditions; determine the relationship between suspended sediments and Hg transport; assemble event-scale mass balances of atmospheric Hg inputs, surface Hg associated with street dust, and Hg export in runoff for the micro-catchment to evaluate the relative importance of rainfall-derived Hg and surface- derived Hg in runoff; and finally, to compare the yield of Hg from the urban micro-catchment to that of a much larger mixed land-use urban catchment to evaluate the feasibility of scaling the results. Overall, the results from this research show that large Hg loads are delivered to an adjoining waterway during storm events and that the majority of the load was HgP. A significant relationship was also observed between the TSS and Hg concentrations. Comparison of the inputs of Hg in rain and the outputs in runoff indicated that the urban surfaces could act as both sinks and sources depending on the rain and runoff characteristics.
DE: 1804 Catchment
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1871 Surface water quality
DE: 1879 Watershed
SC: Hydrology [H]
MN: 2007 Fall Meeting