Shelby Defeo

Mercury is a global contaminant that can have serious health impacts for people and wildlife. Lakes and reservoirs are important elements of the mercury cycle, and sorbents, materials which mercury can stick to, can be part of the solution to mercury problems in water bodies. This work focuses on understanding different techniques of applying sorbents to remediate mercury in lakes and reservoirs.

Mercury is a contaminant that can negatively affect neurological processes for people and wildlife. California’s history of gold and mercury mining has contributed to the contamination of lakes and reservoirs, and many agencies within and beyond the state have an interest in remediating mercury problems. Guadalupe Reservoir in San Jose, California is among the state’s mercury impacted reservoirs, and past interventions to decrease mercury concentrations in the reservoir, such as hypolimnetic oxygenation, have had undesirable consequences for other water quality parameters. Sorbents offer an alternative approach through their ability to adsorb mercury and sequester it from the aquatic environment. This work evaluated four treatment approaches (sediment application, treatment bag, flow through, and an unamended control) for applying sorbents through bench scale chamber experiments under oxic and anoxic conditions using samples from Guadalupe Reservoir. Results from this study indicate that sorbent application can reduce total and methylmercury concentrations relative to unamended controls, however unique considerations and variations in efficacy exist within the methods at the bench top scale.