Environmental Factor, September 2011, National Institute of Environmental Health Sciences
Superfund webinar showcases trainees
By Eddy Ball
Rodriguez-Freire expects to complete her doctoral program in 2012. (Photo courtesy of Lucia Rodriguez-Freire)
O'Connell, who splits his time between his OSU lab and his field work collecting samples at a Superfund site, is now in his second year as a graduate student. (Photo courtesy of Steven O'Connell)
The NIEHS Superfund Research Program (SRP) aired the final installment in its 2011 Trainee Webinar Series Aug. 16, featuring two of its outstanding young environmental engineering researchers. In the approximately three webinars held each year, SRP showcases presentations from poster award winners from the previous SRP annual meeting.
As the webinar host, NIEHS Health Scientist Administrator Danielle Carlin, Ph.D., said at the beginning of the event, “The intent of this webinar series is to increase collaboration and exchange of ideas among our young investigators conducting SRP-funded research and activities, and to hear about their award-winning work.”
Some 100 online attendees listened as graduate student Steven O'Connell, of Oregon State University (OSU), presented his work on “Utilizing Silicone Passive Samplers to Expand Environmental Monitoring for the Portland Harbor Superfund, OR.” Following his talk, University of Arizona (UA) graduate student Lucia Rodriguez-Freire(http://portal.environment.arizona.edu/students/profiles/lucia-rodriguez-freire) explored “Biotransformation of Arsenic: The Role of Microorganisms in the Cycle of Arsenic in the Environment.”
Optimizing silicone for monitoring additional organic compounds
O'Connell, who is a member of the OSU Food Safety and Environmental Stewardship Program headed by Kim Anderson, Ph.D., described a pilot study conducted along a nine-mile stretch of the lower Willamette River Superfund site. The study was part of an ongoing search for advanced materials to complement passive sampling devices (PSDs) currently deployed in the harbor, which utilize lipid-free polyethylene tubing (LFT) to collect samples of bioavailable compounds in the air, water, and sediment that pose a potential threat to public health.
With a cross-disciplinary approach that combines biology with organic chemistry, O'Connell tested PSDs using silicone as the sampler matrix. O'Connell is interested in developing highly reproducible, cost-effective methods for the detection of semi-polar, or oxygen-containing, organic contaminants, in addition to the non-polar compounds so effectively sequestered by LFT.
O'Connell said there is a need for developing new deployment devices to preferentially sequester polycyclic aromatic hydrocarbons (PAHs) with higher octanol-water partition coefficients, such as oxygenated-PAHs (OPAHs), certain pesticides, and even steroid hormones, personal care products, and pharmaceuticals, commonly found in or near polluted areas. His experiments determined that co-deploying cost-effective silicon-based PSDs offers a good complementary deployment for detection of compounds along the spectrum of octanol-water partition coefficients that LFT is not picking up.
“This is exactly what we wanted to see,” he said. “We're getting some of those semi-polar organic compounds we were after.”
Using bacteria to cycle arsenic in the environment
As part of the UA Environmental Engineering program headed by Reyes Sierra, Ph.D., which is involved in studies of the biogeochemical cycle of arsenic in the environment, Rodriguez-Friere's research focuses on innovative ways to utilize microorganisms in the microbial conversion of arsenic in groundwater.
Arsenic in drinking water is a major public health concern worldwide, as exposure has been shown to increase the risk of skin, liver, bladder, and lung cancers. Elevated concentrations are found in many parts of the U.S. naturally and as a contaminant at many Superfund sites.
Rodriguez-Friere is striving to understand the specific chemical processes involved in oxidizing arsenite (As(III)) and reducing arsenate (As(V)). As Rodriguez-Friere explained, understanding the different chemical processes that determine biotransformation is important because speciation affects the mobility and toxicity of arsenic in the environment. “In an arsenic-contaminated aquifer,” she said, “most of As(III) will be the water phase, while As(V) will be in the soil phase.”
The ultimate goal of research by her group is the development of low-cost bioremediation strategy to utilize the microbial-catalyzed transformation of As(III) to As(V) by three strains of arsenite-oxidizing bacteria that can be applied in bioreactors, permeable reactive barriers, and in situ to help protect public health.
Lucia Rodriguez-Freire, Wenjie Sun, Reyes Sierra-Alvarez, and Jim Field. 2010. Metabolic Characterization of Three Arsenite-Oxidizing Nitrate-Reducing Bacterial Strains.
Steven O'Connell, Sarah Allan, Glenn Wilson, Lane Tidwell, Kim Anderson. 2010. Utilizing Silicone Passive Samplers to Expand Environmental Monitoring for the Portland Harbor Superfund, OR.