By Lisandra Santiago-Delgado, Project 5 Trainee

Lisandra Santiago-Delgado
Lisandra Santiago-Delgado

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.

Research Benefits

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.

Career Impact

The experimental setup used for one-dimensional steam injections.  It consists of two ISCO syringe pumps (left), steam generator (upper middle), column with soil sample (middle), and the computer to collect temperature data in the right.
The experimental setup used for one-dimensional steam injections. It consists of two ISCO syringe pumps (left), steam generator (upper middle), column with soil sample (middle), and the computer to collect temperature data in the right.

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.

The EPA provided a welcoming atmosphere and the OSU beaver was a nice touch.
The EPA provided a welcoming atmosphere and the OSU beaver was a nice touch.
Author:  Gail Wells
Original Story at
Published on July 7, 2015
Staci Simonich, OSU environmental chemist
Dr. Staci Simonich led the study team. Photo by Lynn Ketchum, OSU
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.

Scott Lafontaine
Scott Lafontaine

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.

SRP Trainee Mitra Geier was able to attend The International Neurotoxicology Association and Neurobehavioral Teratology Society joint meeting last month with her Externship Award from the SRP Training Core. The aim of the Externship Award is to support opportunities for SRP trainees that will provide enhanced experiential learning activities that benefit the trainee’s career goals.

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 Geier
Mitra Geier



Mitra Geier is a PhD student working under Dr. Robert Tanguay with Project 3: Systems Approach to Define Toxicity of Complex PAH Mixtures.

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.


On May 20, 2015, Dr. Staci Simonich and Dr. Kim Anderson presented to the Oregon State Air Toxics Science Advisory Committee (ATSAC). This committee is part of State of Oregon Department of Environmental Quality (DEQ) Air Quality Division Environmental/Technical Services.clouds

ATSAC is currently setting ambient air benchmarks for PAHs, as well as diesel and particulate matter.

Dr. Simonich (Project 5 Leader) presented on”Monitoring PAHs in Ambient Air, the Big Picture.”  Dr. Anderson (Project 4 Leader) presented on “Challenges of PAH Analysis and Availability of Standards”.  Both provided an overview of their research programs, as well as addressed specific technical issues for the Committee.

Dr. Dave Stone (RTC Co-Leader), who is a member of ATSAC,  reiterated the value of both presentations, as well as the overall contribution of the Superfund Research Program at OSU in assisting the State on important public health and environmental issues.

This is an Oregon State University press release from 5-8-15 that shares about the collaborative research project of Project 1 and Core C – Biostatistics and Modeling.

– By Gail Wells, 541-737-1386,, on Twitter @OregonStateExt
Source: Susan Tilton, 541-737-1740,

CORVALLIS, Ore. – Scientists at Oregon State University have developed a faster, more accurate method to assess cancer risk from certain common environmental pollutants.

Researchers found that they could analyze the immediate genetic responses of the skin cells of exposed mice and apply statistical approaches to determine whether or not those cells would eventually become cancerous.

The study focused on an important class of pollutants known as polycyclic aromatic hydrocarbons, or PAHs, that commonly occur in the environment as mixtures such as diesel exhaust and cigarette smoke.

Dr. Susan Tilton
Dr. Susan Tilton

“After only 12 hours, we could predict the ability of certain PAH mixtures to cause cancer, rather than waiting 25 weeks for tumors to develop,” said Susan Tilton, an environmental toxicologist with OSU’s College of Agricultural Sciences.

For at least some PAH mixtures, the new method is not only quicker but produces more accurate cancer-risk assessments than are currently possible, she said.

“Our work was intended as a proof of concept,” said Tilton, who is also affiliated with the OSU’s multidisciplinary Superfund Research Program, a center funded by the National Institute of Environmental Health Sciences (NIEHS).

“The method needs to be tested with a larger group of chemicals and mixtures. But we now have a model that we can use to develop larger-scale screening tests with human cells in a laboratory dish.”

Such a method will be particularly useful for screening PAHs, a large class of pollutants that result from combustion of organic matter and fossil fuels. PAHs are widespread contaminants of air, water and soil. There are hundreds of different kinds, and some are known carcinogens, but many have not been tested.

Humans are primarily exposed to PAHs in the environment as mixtures, which makes it harder to assess their cancer risk. The standard calculation, Tilton said, is to identify the risk of each element in the mix – if it’s known – and add them together.

But this method doesn’t work with most PAH mixes. It assumes the risk for each component is known, as well as which components are in a given mix. Often that information is not available.

This study examined three PAH mixtures that are common in the environment – coal tar, diesel exhaust and cigarette smoke – and various mixtures of them.

They found that each substance touched off a rapid and distinctive cascade of biological and metabolic changes in the skin cells of a mouse. The response amounted to a unique “fingerprint” of the genetic changes that occur as cells reacted to exposure to each chemical.

By matching patterns of genetic changes known to occur as cells become cancerous, they found that some of the cellular responses were early indicators of developing cancers. They also found that the standard method to calculate carcinogenic material underestimated the cancer risk of some mixtures and overestimated the combined risk of others.

“Our study is a first step in moving away from risk assessments based on individual components of these PAH mixtures and developing more accurate methods that look at the mixture as a whole,” Tilton said. “We’re hoping to bring the methodology to the point where we no longer need to use tumors as our endpoint.”

Tilton collaborated on the research with Katrina Waters of the Pacific Northwest National Laboratory, and others. Their findings appeared in a recent edition of Toxicological Sciences.

The study was funded by NIEHS, which supports the Superfund Research Program, a multi-partner collaboration that includes OSU and PNNL.