Water Resources Research Act Program

Details for Project ID 2009AZ312B

Transport and fate of mercury and other metals in Tucson’s urban metropolitan area: Role of watershed sources versus atmospheric deposition

Institute: Arizona
Year Established: 2009 Start Date: 2009-03-01 End Date: 2010-02-28
Total Federal Funds: $10,000 Total Non-Federal Funds: $22,225

Principal Investigators: Kathleen Lohse, Paul Brooks, Jennifer McIntosh

Abstract: In arid to semi-arid environments, such as Arizona, runoff from urban areas is often actively managed as a part of storm water management but also as active and/or focused recharge to groundwater. These activities result in a modified hydrologic template in which to understand water quality issues and raise concerns and questions about the tradeoffs between urban storm-recharge and water quality. There is growing attention on the adverse effects of mercury and other metals in the environment. In particular, mercury is a persistent bioaccumulative toxin; it persists in the environment for long periods by cycling between the air, water, and soil and bioaccumulates in animal and plant tissues. Preliminary data from a study conducted in the Tucson Basin show high concentrations of mercury (Hg) in the urban runoff across different urban sites, suggesting high deposition of Hg to the Tucson Basin. However, questions remain about whether these samples are representative of storm events and seasonal loads and whether they are biased towards peak concentrations because they were a small subset of samples screened for Hg. Here we propose to examine the impacts of urbanization on storm runoff and transport and fate of mercury and other metals in soils and to surface and ground waters. Specifically, we seek funding to 1) analyze runoff and soil samples for mercury and other metals to verify patterns in runoff and explore the fate of mercury and other metals in soils, 2) train and support two graduate students in field and laboratory procedures, and 3) inform water managers about best management practices for storm water and emerging threats to water quality. We suggest that an alternative means to evaluate potential exposure to atmospherically deposited mercury may be quantifying fluxes of mercury in storm runoff. The proposed research will enhance our understanding of the possible tradeoffs of enhanced recharge and increased loads of metals, particularly mercury, to our environment, surface waters and possibly groundwaters.