Elevated levels of mercury and methylmercury in aquatic systems can pose significant health risks to humans and wildlife. The South River (Virginia, USA) is affected by historical mercury releases and mobilization of mercury from secondary sources such as riverbed and riverbank sediments. To understand the exchange of mercury and methylmercury to the water column and to quantify mass fluxes of these chemical contaminants in the river, Integral scientists Grace Chang, Ph.D., Todd Martin, P.E., Frank Spada, Brandon Sackmann, Ph.D., Craig Jones, Ph.D., and Kenia Whitehead, Ph.D., conducted a study using the OPTically based In situ Characterization System (OPTICS)—a powerful and cost-effective technology for monitoring contaminants in surface water. The results of the study were recently published in the peer-reviewed journal River Research and Applications.
Titled “OPTically‐based In situ Characterization System (OPTICS) to quantify concentrations and mass fluxes of mercury and methylmercury in South River, Virginia, USA,” Integral’s article discusses the methods and results of OPTICS modeling at the South River. OPTICS technology provided robust, high-frequency determinations of mercury and methylmercury concentrations in relation to water quality, physical forcing processes, and biogeochemical variability. Storm flow and diel cycling, potentially from nocturnal bioturbation, were identified as important mechanisms by which particulate-bound mercury and methylmercury are redistributed to the water column. The results of this study will contribute to remediation efforts to reduce mercury levels in the South River and, ultimately, revise fish consumption advisories.