It is with heavy heart that the OSU SRP says goodbye to long-time scientist and mentor, Sharon Krueger. Sharon passed away December 27, 2015 at her home in Corvallis, OR. Sharon was a Research Assistant Professor in the Linus Pauling Institute (OSU) and the Research Coordinator for the OSU Superfund Research Program. Sharon began working at OSU in 1993 as a post-doctoral fellow in the laboratory of Dr. David Williams. Her work focused on the flavin-containing monooxygenase (FMO) enzyme and how it influenced drug metabolism and toxicology. Sharon was an active researcher, working with a many OSU and SRP scientists and publishing 39 scientific articles, in addition to serving as co-investigator on nine funded research grants. Sharon was dedicated to her research, and was an essential mentor to many undergraduate and graduate students that worked with her. Outside of work, Sharon enjoyed cooking, traveling and photography.
Back in April, I was awarded the SRP Trainee Externship Award through OSU’s SRP Training Core to help support my training opportunity at the Pacific Northwest National Laboratory (PNNL) as an Alternate Sponsored Fellow. The aim of this internship was to predict the formation of hydroxy- and oxygenated‑PAHs (OHPAHs and OPAHs, respectively) in the environment using a computational chemistry approach. OPAHs and OHPAHs can be formed from the degradation of PAHs. OPAHs in air samples have been found to be more mutagenic than the unsubstituted PAHs.
To achieve this objective, I used the NWChem software, which is a high performance computational chemistry software developed by PNNL scientists. Through a collaboration set-up by Dr. Dayle Smith (previously in Core C), I spent two months learning how to use NWChem under the supervision of Dr. Kurt Glaesemann.
Using this approach, my goal was to be able to predict which OHPAHs and OPAHs are likely to form in the environment based on their thermodynamic properties, specifically the reaction Gibbs free energy. There were three main areas related to Project 5’s focus where this predictive capability will be helpful. First, the results could assist in explaining why toxicity in remediated soils increased, even after PAHs’ concentrations went down (e.g. Chibwe et al., 2015). Secondly, prior data of OHPAHs found in human urine, (e.g. Motorykin et al., 2015) can be compared with computational results to see if I can formulate a prediction of which OHPAHs are likely to form in human urine. Finally, continuing on prior work that has predicted the formation of NPAHs in ambient air (e.g. Jariyasopit et al., 2013), I could then apply similar approach, but for OHPAHs and OPAHs.
The learning curve during my externship was quite steep. Although I was able to understand how to use NWChem, I also learned that a one-size-fits-all approach was not possible and I would need to tailor my modeling approach to successfully predict formation of OHPAHs and OPAHs. It was during this time that I found out how valuable it was for me to be able to spend time at PNNL. Being in a facility where there were experts in almost every imaginable field, I was able to talk to many experts about issues that I faced. These conversations led me to the field of chemometrics which helped me tailor the computational chemistry approach accordingly. One of the online programs that I found to be useful was XenoSite, which can predict CYP450 inhibition sites on a given compound. This program can potentially be useful when narrowing down potential OHPAHs that might form through bioactivation.
In addition, the myriad instruments and facilities that are available at PNNL have also assisted me greatly during my internship. For example, the NWChem software that I used was connected to the supercomputing facility, which helped speed up the calculation, resulting in faster computational time. Another perk of being in Richland, was that I managed to tour the Hanford B Reactor—coincidentally a couple of days before the anniversary of the atomic bomb being dropped in Japan.
All in all, the externship challenged me to get me out of my comfort zone, but also rewarded me with a new skill and unique
experience. In a way, the internship at PNNL served as a preview of what may come once I am finished with my Ph.D. More importantly, I found the networking opportunity and exposure to a possible career path while at PNNL to be invaluable. Currently, I am excited to combine the in silico approach that I learned at PNNL with the analytical chemistry approach at the Simonich lab into my research projects. The chemical analysis component will verify how accurate the prediction capabilities are. If this approach is proven to be reliable, I hope that this perspective can offer a different insight in predicting the formation of OHPAHs and OPAHs.
Earlier this summer I conducted research at the USEPA Robert S. Kerr Research Laboratory in Ada, Oklahoma under the guidance of Dr. Eva L. Davis. This experience was made possible through the KC Donnelly Externship Award Supplement that I received in late April.
The main objective of my externship was to collaborate and learn from Dr. Davis, an expert in the field of thermal remediation of contaminated soils and groundwater. I focused on utilizing steam injections on a laboratory scale to thermally remediate creosote-contaminated Superfund soils.
Another goal of this externship was to understand the chemical processes that occur during and after remediation. I looked at measurements of polycyclic aromatic hydrocarbons (PAHs) and their transformation to oxygenated PAHs (oxy- and hydroxy-PAHs) in soils, as well as their potential developmental toxicity and mutagenicity.
This partnership was a great fit, because it combined the expertise of Dr. Davis, involving thermal remediation of soil, with our expertise in soil analysis for PAHs and oxygenated PAHs, and toxicity assays in our SRP Project 3, directed by Dr. Robert L. Tanguay.
I have always considered a career path with the federal government. This experience allowed me to experience first-hand what it would be like. Preparing to work in a federal facility was probably, and surprisingly, one of the greatest initial challenges of the project. It included paperwork, security clearance procedures, and training, among many other things.
Having the opportunity to meet, collaborate, and have one-on-one conversations with Dr. Davis was a fulfilling experience, especially since she is a female scientist. I also met other scientists working in the same facility, but base their research here in the Willamette Valley. Other experiences included participating in their weekly seminars, where they present trending topics of importance to the environment and the USEPA, as well as their own research updates.
Outside of research, weather was a big challenge, especially since my externship began in the middle of tornado season. One afternoon I had to spend over a half hour in a closet while the sirens were blaring. My next visit will be before May, for sure!
The externship was definitely an incredible experience, and it provided me with better understanding of thermal remediation and new knowledge about soil and how chemicals behave underneath the surface. I encourage other SRP trainees to apply for the KC Donnelly Externship Award Supplement. You will not regret it, and the outcome will be very valuable for your current research and future work as well.
CORVALLIS, Ore. – Air pollution controls installed at an Oregon coal-fired power plant to curb mercury emissions are unexpectedly reducing another class of harmful emissions as well, an Oregon State University study has found.
Portland General Electric added emission control systems at its generating plant in Boardman, Oregon, in 2011 to capture and remove mercury from the exhaust.
Before-and-after measurements by a team of OSU scientists found that concentrations of two major groups of air pollutants went down by 40 and 72 percent, respectively, after the plant was upgraded. The study was published in the journal Environmental Science & Technology this month.
The Boardman plant, on the Oregon side of the Columbia River about 165 miles east of Portland, has historically been a major regional source of air pollution, said Staci Simonich, environmental chemist in OSU’s College of Agricultural Sciences and leader of the study team (OSU SRP Project 5).
“PGE put control measures in to reduce mercury emissions, and as a side benefit, these other pollutants were also reduced,” she said.
The pollutants in question are from a family of chemicals called polycyclic aromatic hydrocarbons (PAHs), which are formed from incomplete combustion of fossil fuels and organic matter. PAHs are a health concern because some are toxic, and some trigger cell mutations that lead to cancer and other ailments.
Simonich and her team tracked concentrations of airborne PAHs during 2010 and 2011 at Cabbage Hill, Oregon (elevation 3,130 feet), about 60 miles east of the Boardman plant, and also at the 9,065-foot summit of Mount Bachelor 200 miles to the southwest.
They sampled approximately weekly from March through October of 2010, and again from March through September of 2011. They analyzed the samples for three major groups of PAHs: the parent chemicals and two “derivatives”— groups of PAH chemicals resulting from the decomposition of the parent PAHs.
The 2011 measurements at Cabbage Hill showed significantly reduced concentrations of the parent PAHs and also of one of the derivative groups, called oxy-PAHs (OPAHs). The other derivative group, called nitro-PAHs (NPAHs), did not show significant reduction. The NPAHs were more likely to have come from diesel exhaust associated with Interstate Highway 84, Simonich said.
Some of the individual PAH chemicals were reduced so much after the upgrade that the researchers couldn’t tell from the data whether the plant was running or not, she added.
“The upgrades reduced the PAH emissions to the point where we could hardly distinguish between air we sampled along the Gorge and at the top of Mount Bachelor.” While Oregon’s mountaintops typically have less air pollution than lower-lying areas, Simonich’s previous work has shown that they are not pristine.
She and her student Scott Lafontaine stumbled upon the Boardman findings while studying PAHs that originate in Asia and ride high-level air currents across the Pacific Ocean. They were measuring how much of each PAH type was coming from Asia, and how much from within the Northwest or elsewhere.
“We wanted to see if there was the same level of trans-Pacific transport at lower elevations—where people actually live—as we’ve previously found at Mount Bachelor,” Simonich said.
When the researchers analyzed the Cabbage Hill data for 2010, they found high levels of the chemicals they were studying, but the pollutants did not have an Asian signature.
Then in 2011, they found that the Cabbage Hill concentrations of the parent PAHs and OPAHs were much lower than they’d been in 2010.
“We looked at the data and said, ‘Wow! 2010 is different from 2011, and why should that be?’” Simonich said. “We had trouble understanding it from a trans-Pacific standpoint. So we started thinking about regional sources, and that’s what led us to look at emissions from Boardman.”
They got in touch with officials at PGE and learned about the April 2011 upgrade. Their review of PGE’s emission records revealed correlations with their own measurements. They concluded that the reductions in PAH concentrations at the Cabbage Hill site were caused by the 2011 upgrade.
The upgrade may also aid her research, Simonich said. “When you have a major point source of pollution nearby, it’s hard to pick out the signal of the Asian source coming from farther away. Now that these emissions are reduced, we may be able to pick up that signal much better.”
More important, she said, the air is cleaner.
“Boardman used to be a major source of PAH pollution in the Columbia River Gorge, and now it’s not,” she said. “That’s a good thing for PGE and a good thing for the people living in the Gorge.”
The study was funded by the OSU Superfund Research Program, a multidisciplinary center administered by the National Institute of Environmental Health Sciences. Pacific Northwest National Laboratory and the Confederated Tribes of the Umatilla Indian Reservation collaborated on the research.
Scott Lafontaine received his MS in Chemistry at OSU and is now pursing a Ph.D. in Food Science with Dr. Thomas Shellhammer in the Food Science Department.
I am focusing on brewing science and specifically on advancing the understanding of the chemical behavior of hop flavor and aroma in beer. I am very excited to have the opportunity to continue my graduate studies at OSU, within a program that has been analyzing hops since 1932. I look forward to using my unique background and education to bridge some of the concepts I learned while working on my master’s thesis. I want to be able to bring a new perspective to some of the key questions in this field.
Networking and face-time with peers and scientists is an essential part of an Externship opportunity. At the conference, Mitra was able to interact and formalize her connections with other trainees from five different SRP centers across the country, including students whose work involved epidemiology, cell culture, fish, and mammalian model systems. She will be reporting back to the OSU SRP trainees at their monthly meeting about what she learned from the other trainees at the conference related to their Superfund Centers, their activities, and their interests.
Mitra was also able to attend sessions and interact with leading scientists. She attended sessions to learn about different methods for assessing neurotoxicity, including mechanistic and behavioral effects, especially in the context of how the different models can be used to approach similar questions. Mitra attended the sessions on neurotoxicants in air pollutants and inhaled particles, which are particularly relevant to her research. There was also sessions related to neurotoxicology screening studies and non-mammalian models of neurotoxicity including fish studies that were highly applicable to her screening work in zebrafish. The sessions on epigenetics and the microbiome were not directly related to her work, but she found them very useful in her long-term research interest development.
Mitra received her B.S. in Environmental Science from Western Washington University. Her current research is focused on defining the developmental toxicity of parent and methylated PAHs, the neurobehavioral effects of these compounds during the embryonic stage and in adulthood, and the molecular pathways involved in these effects using the embryonic zebrafish model.
The Superfund Research Program is federally funded and administered by the National Institute of Environmental Health Sciences (NIEHS grant #P42 ES016465), an institute of the National Institutes of Health.