STREAMWATER MERCURY DYNAMICS DURING STORM EVENTS WITHIN THREE HEADWATER CATCHMENTS IN SHENANDOAH NATIONAL PARK, VA

Headwater terrestrial systems are a primary source of downstream contamination because they store large pools of mercury (Hg) in soils and sediments. This study evaluates particulate and dissolved Hg dynamics in streamwater during high-flow storm events, in three forested headwater catchments in the southern Appalachian region. The catchments are located in Shenandoah National Park within100 kilometers of one another, have similar physical features (size, slope, and vegetation) but are distinct in chemical and hydrological characteristics. Since April 2009, we have been measuring dissolved and particle-bound Hg, DOC, UV-absorbance at 254 nm, and discharge during storm events bi-hourly. We examine differences in Hg mobilization between the three watersheds for a range of discharge conditions and antecedent conditions. Ultimately, this analysis will offer insight into how the hydrology and water chemistry of a catchment affect the timing, amount, and physical fractioning of Hg transport during high-flow events.