Grantee Research Project Results
Mercury variability, speciation, and transport within Mid-Appalachian Forested headwater catchmentsEPA Grant Number: FP916941
Title: Mercury variability, speciation, and transport within Mid-Appalachian Forested headwater catchments
Investigators: Riscassi, Ami L
Institution: University of Virginia
EPA Project Officer: Just, Theodore J.
Project Period: September 1, 2008 through August 31, 2011
RFA: STAR Graduate Fellowships (2008)
Research Category: Academic Fellowships
Mercury is a highly toxic element which is recognized as a global pollutant of concern. Due to its high volatility, and corresponding atmospheric mobility, mercury has been deposited in terrestrial and aquatic ecosystems both near and far from point sources. This project will investigate the distribution, transport, and transformation of mercury in forested headwater catchments within Shenandoah National Park.
The objectives of this project are: 1) to quantify the relative contributions of mercury sources to the study catchments as well as the amount and location of mercury stored in soils; 2) to determine the relative importance of hydrologic and chemical variability on mercury movement within and between forested headwater catchments and 3) to determine the environmental controls on mercury methylation within a variety of catchments.Approach:
I will determine the relative contributions mercury sources by quantifying atmospheric depositional data currently being collected, assisting with a new atmospheric data collection effort to quantify dry depositional fluxes, and sampling and analyzing mercury content at spring sources. During storm events, frequent water samples will be taken and analyzed for particulate and dissolved mercury, as well as a suite of chemical constituents, including DOC, pH, and sulfate. A geochemical hydrograph separation will be employed to compute the relative discharge of each flow component which will be used to estimate the concentrations of mercury in individual flow paths. Methylmercury will be quantified in stream water as well as soil water and sediment throughout the year. All results will be compared between catchments which differ in hydrologic and chemical characteristics.Expected Results:
Results from this study will define the relative controls on mercury transport and methylation within stream ecosystems in forested landscapes. Specific to Shenandoah National Park, this data will be used to predict how changes in the environment will effect mercury and methylmercury concentrations in the future. On a broader scale, we will be able to determine where potential problems or ‘hotspots’ may occur in other forested catchments based on known deposition and chemistry data. These results will contribute to the knowledge base used to establish effective monitoring strategies and environmental legislation to protect our water and biological resources.Supplemental Keywords:
mercury, catchment, hydrology, storm events, contaminant transport, methylmercury, watershed, hydrograph separation,