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Case Study

OPTICS Study on Mercury Releases to South River

By Grace Chang, Ph.D., Technical Director


Elevated concentrations of mercury and methylmercury in water bodies can pose significant health risks to humans and wildlife. In Virginia, the South River is affected by historical mercury releases and mobilization of mercury from sources such as riverbed and riverbank sediments.


We conducted a study using the OPTically based In situ Characterization System (OPTICS)—a powerful and cost-effective technology for monitoring contaminants in surface water. OPTICS technology provided robust, high-frequency determinations of mercury and methylmercury concentrations in relation to water quality, physical forcing processes, and biogeochemical variability.


The high-frequency OPTICS results quantified sources of legacy mercury in the system that are contributing to recontamination and continued elevated mercury concentrations in fish tissue, including storm-induced resuspension and baseflow diel cycling that had never before been observed. Our results are published in the peer-reviewed journal River Research and Applications.

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Dr. Grace Chang has more than 25 years of experience in the fields of limnology and oceanography. Dr. Chang has... Full bio

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