(2010) Gold Hill, NC - Mercury Contamination of Floodplain

Project Scope

The first gold rush in the U.S. began in the Piedmont region of North Carolina in the early 1800s. Mining operations used mercury to recover fine gold particles, which led to the release of unprecedented amounts of mercury to the environment. Relatively little is known about the environmental impacts, long-term dispersal, and ultimate fate of this contaminant. Mercury is a major ecological and health concern because it can be transformed in aquatic environments into forms that can enter the food-chain and then be bioaccumulated and bioamplified in humans and biota.

Although North Carolina led the nation in gold production until 1848 and produced more gold than any other state in the southern Piedmont gold belt, few studies of mercury contamination associated with this mining exist.

The purpose of this study is to determine the magnitude and explain the distribution of mercury contamination in floodplain sediments nearly 100 years after large-scale gold mining ceased in the region. Preliminary data suggest that floodplain sediments are highly contaminated downstream from the most intensive area of mining at Gold Hill. This study provides a unique opportunity to gain insight into the nature of mercury dispersal in river systems, to assess the regional history of floodplain sedimentation, and to construct the first mercury mass budget for watersheds in the North Carolina Piedmont region.

Objectives

1. Describe the geomorphic and geochemical processes that influence the spatial and temporal variations of Hg contamination in floodplain deposits,
2. Identify the availability Hg for remobilization and release to the active channel system, and
3. Relate the timing of Hg contamination to rates of post-settlement floodplain sedimentation in the region.

Project Funding

National Geographic Society Committee for Research and Exploration Grant, 2007