This session, "Biogeochemical Factors Impacting in situ Remediation of Metals and PAH Mixtures" will feature presentations from Michael Unger and Aaron Beck at the Virginia Institute of Marine Science, James Ranville at the Colorado School of Mines, Heileen Hsu-Kim at Duke University, and Upal Ghosh at the University of Maryland Baltimore. Their presentation abstracts are presented below.
Researchers led by Michael Unger and Aaron Beck at the Virginia Institute of Marine Science are developing new techniques to evaluate and quantify the biogeochemical mechanisms controlling the transport from sediment to water and bioavailability of DNAPLs and dissolved hydrophobic compounds within groundwater and at the groundwater-surface water interface. They are also testing the hypothesis that advection dynamics and seawater intrusion increase bioavailable PAH flux and NAPL transport in permeable cap materials used for in situ remediation at contaminated sites in the Elizabeth River in Virginia.
At Duke University, scientists led by Helen Hsu-Kim are studying sediment dwelling microorganisms that methylate mercury, and identifying factors that may be used to control and reduce toxic methylmercury production. The research is focusing on two critical drivers of methylmercury production: the environmental conditions that promote the growth of sediment microorganisms that produce methylmercury and the processes that influence the bioavailability of mercury for these microorganisms. The researchers are working at the Berry's Creek Study Area, a site in New Jersey with historical mercury contamination, as well as other sites to implement the research, interpret results, and establish a guiding framework for assessments at specific field sites and the selection of remediation strategies.
At the University of Maryland Baltimore County, Upal Ghosh leads a research team to develop an empirical model of the factors influencing mercury and methylmercury bioavailability in contaminated areas. Using this model, they plan to identify biogeochemical characteristics that make sites suitable for remediation with sorbent remediation approaches, such as activated carbon amendments. The researchers will also design sorbent amendment/thin capping strategies that reduce methylmercury bioavailability. The main study site is a salt marsh in Berry's Creek, N.J., where they are conducting a field trial of in situ sorbent remediation using activated carbon and also evaluating the relative efficacy of a wider range of black carbons.
Researchers led by James Ranville at the Colorado School of Mines are developing and refining techniques — including environmental molecular diagnostics and stable isotope assays — used to detect, assess, and evaluate the bioavailability of metals that occur in mixtures and can be taken up by aquatic organisms, including nickel, zinc, copper and cadmium. They will test these approaches in a metals-contaminated stream at the North Fork Clear Creek Superfund site in central Colorado. This project will improve knowledge on the risks posed by mixtures of contaminant metals.