This session, "Biogeochemical Factors Impacting in situ Remediation of Chlorinated Contaminants" will feature presentations from Edward Bouwer at Johns Hopkins University, Lisa Alvarez-Cohen at the University of California, Berkeley, Jay Gan and Daniel Schlenk at the university of California, Riverside, and Frank Loeffler at the University of Tennessee. Their presentation abstracts are presented below.
Researchers led by Edward Bouwer at Johns Hopkins Whiting School of Engineering are evaluating a novel technology — a flow-through barrier containing granular activated carbon coated with anaerobic and aerobic microorganisms — to see if it can completely break down chlorobenzenes and benzene contaminants, which are known or suspected carcinogens. The researchers seek to understand the environmental processes and conditions that influence interactions among contaminants and the barrier to improve its effectiveness in contaminated groundwater. Laboratory and field tests are being conducted at the Standard Chlorine of Delaware, Inc. Superfund site where dense non-aqueous phase liquid (DNAPL) chlorobenzene contamination is present in wetland sediments and groundwater.
Jay Gan and Daniel Schlenk lead a project at the University of California, Riverside to develop a simple method for measuring and accounting for contaminant aging in risk assessments and remediation. They will apply the method to sediment samples collected from various depths (reflecting deposition at different historical times) and location (reflecting different sediment properties) at the Palos Verdes Shelf Superfund site off the Los Angeles coast. Sediments at this site contain high levels (up to 200 mg/kg) of DDTs and PCBs deposited from as far back as 60 years ago.
At the University of Tennessee, Frank Loeffler and his research team are designing and validating the B12-qChip — an innovative, high-throughput quantitative PCR tool — that can be used to recognize when the bioavailability of nutrients called corrinoids limit the ability of chloroflexi bacteria to dechlorinate solvents such as tetrachloroethene (PCE) and TCE. Using samples from Third Creek, a polluted creek in Knoxville, Tennessee, they are conducting detailed studies that combine cultivation-based approaches, high-throughput sequencing, bioinformatics analyses, and state-of-the art analytical procedures to reveal the best biogeochemical conditions for bioremediation.
Scientists led by Lisa Alvarez-Cohen at the University of California, Berkeley are using a combination of molecular, biochemical, and analytical tools to evaluate how microbes used for trichloroethene (TCE) bioremediation interact with co-existing organisms in various geological, chemical, and biological conditions. The researchers are constructing simplified groups of microbes living symbiotically that they will expose to stresses such as changes in pH and salinity as well as the introduction of potential competitive electron acceptors to the system (e.g., sulfate ions) to see how TCE bioremediation is effected. They will also combine intercellular data gained from both microarray and RNA sequencing techniques to develop mechanistic models that describe the effects of geochemical parameters on bioremediation.