Modeling mercury behavior in a contaminated desert stream and constructed wetland.

摘要

Aqueous mercury behavior was studied in a 480 m-long reach of the contaminated Steamboat Creek (SBC) and a nearby wetland mesocosm constructed in 2001 located in Reno/Sparks, NV. The SBC watershed was contaminated with mercury in the late 1800s due to gold and silver processing at the headwaters of SBC. Since then mercury has been distributed downstream and is discharged to the Truckee River. The objective of this study was to describe aqueous mercury behavior and create a set of models that described the mercury dynamics for use in the design of a restored SBC confluence with the Truckee River. The magnitude of flow greatly influences the spatial and temporal behavior of the two environments. The Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury (SERAFM) was employed in 28 scenarios to model unfiltered and dissolved, total mercury and methylmercury. The combined error for predicted mercury concentrations of these species was 12% and 17% for the reach and mesocosm, respectively. The model-predicted aqueous Hg0 concentration in the reach study area was two orders above measured values, suggesting the need for further research. Based on research, four criteria are proposed to minimize inorganic and organic mercury load to the Truckee River.