RAPID: Preserving the geochemical and biological changes in an acid mine drainage reservoir undergoing rapid geochemical change

Acid mine drainage is a major pollution problem in the United States and abroad. It often results from mining activities that expose reactive minerals to oxygen in the atmosphere or in groundwater. As these minerals react, they create acid and release heavy metals that are damaging to downstream ecosystems.

Reservoirs can be constructed to hold back polluted sediments and water, preventing them from influencing downstream environments. However, these reservoirs can be difficult to manage long term. This project will examine an acid mine drainage reservoir near Redding, CA which contains contaminated sediments from the Iron Mountain Mining complex.

When the lake level becomes too low, the reservoir becomes acidic and metal-laden so it is managed to keep the lake above this level. In September 2024, the lake was nearly completely drained for dam maintenance which provides a rare opportunity to examine the chemical and biological processes that generate pollution. This proposal will sample the lake water and sediment as the lake level remains low to determine what processes generate pollution and to inform future remediation.

This research helps to improve the well-being of individuals in society by improving bioremediation in AMD-impacted reservoirs and will help to develop a diverse, globally competitive STEM workforce by training an undergraduate student.

The team will collect and archive samples of surface and pore water and sediment cores from Spring Creek Reservoir. Because some analyses are time-sensitive, the team will also analyze water samples for the concentration of metals using ICPMS and sediment samples for acid volatile sulfide. The remaining samples will be preserved and archived for future analysis of organic carbon content and microbial community composition.

Future work will also use the samples collected to perform an experiment that aims to determine if lake drawdowns can be a sustainable bioremediation technique for AMD reservoirs. This research helps to improve the well-being of individuals in society by improving bioremediation in AMD-impacted reservoirs and will help to develop a diverse, globally competitive STEM workforce by training an undergraduate student.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.