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.

OSU Press Release:

MEDIA CONTACT:  David Stauth, 541-737-0787

David Williams, 541-737-3277 or


CORVALLIS, Ore. – Researchers for the first time have developed a method to track through the human body the movement of polycyclic aromatic hydrocarbons, or PAHs, as extraordinarily tiny amounts of these potential carcinogens are biologically processed and eliminated.

PAHs, which are the product of the incomplete combustion of carbon, have been a part of everyday human life since cave dwellers first roasted meat on an open fire. More sophisticated forms of exposure now range from smoked cheese to automobile air pollution, cigarettes, a ham sandwich and public drinking water. PAHs are part of the food we eat, the air we breathe and the water we drink.

However, these same compounds have gained increasing interest and scientific study in recent years due to their role as carcinogens. PAHs or PAH mixtures have been named as three of the top 10 chemicals of concern by the Agency for Toxic Substances Disease Registry.

With this new technology, scientists have an opportunity to study, in a way never before possible, potential cancer-causing compounds as they move through the human body. The findings were just published by researchers from Oregon State University and other institutions in Chemical Research in Toxicology, in work supported by the National Institute of Environmental Health Sciences (NIEHS)

The pioneering work has been the focus of Ph.D. research by Erin Madeen at Oregon State, whose studies were supported in part by an award from the Superfund Research Program at NIEHS for her work at Lawrence Livermore National Laboratory.

“We’ve proven that this technology will work, and it’s going to change the way we’re able to study carcinogenic PAHs,” said David Williams, director of the Superfund Research Program at OSU, a professor in the College of Agricultural Sciences and principal investigator with the Linus Pauling Institute.

“Almost everything we know so far about PAH toxicity is based on giving animals high doses of the compounds and then seeing what happens,” Williams said. “No one before this has ever been able to study these probable carcinogens at normal dietary levels and then see how they move through the body and are changed by various biological processes.”

The technology allowing this to happen is a new application of accelerator mass spectrometry, which as a biological tracking tool is extraordinarily more sensitive than something like radioactivity measuring. Scientists can measure PAH levels in blood down to infinitesimal ratios – comparable to a single drop of water in 4,000 Olympic swimming pools, or to a one-inch increment on a 3-billion mile measuring tape.

As a result, microdoses of a compound, even less than one might find in a normal diet or environmental exposure, can be traced as they are processed by humans. The implications are profound.

“Knowing how people metabolize PAHs may verify a number of animal and cell studies, as well as provide a better understanding of how PAHs work, identifying their mechanism or mechanisms of action,” said Bill Suk, director of the NIEHS Superfund Research Program.

One PAH compound studied in this research, dibenzo (def,p)-chrysene, is fairly potent and defined as a probable human carcinogen. It was administered to volunteers in the study in a capsule equivalent to the level of PAH found in a 5-ounce serving of smoked meat, which provided about 28 percent of the average daily dietary PAH intake. There was a fairly rapid takeup of the compound, reaching a peak metabolic level within about two hours, and then rapid elimination. The researchers were able to study not only the parent compound but also individual metabolites as it was changed.

“Part of what’s so interesting is that we’re able to administer possible carcinogens to people in scientific research and then study the results,” Williams said. “By conventional scientific ethics, that simply would not be allowed. But from a different perspective, we’re not giving these people toxins, we’re giving them dinner. That’s how much PAHs are a part of our everyday lives, and for once we’re able to study these compounds at normal levels of human exposure.”

What a scientist might see as a carcinogen, in other words, is what most of us would see as a nice grilled steak. There are many unexpected forms of PAH exposure. The compounds are found in polluted air, cigarettes, and smoked food, of course, but also in cereal grains, potatoes and at surprisingly high levels in leafy green vegetables.

“It’s clear from our research that PAHs can be toxic, but it’s also clear that there’s more to the equation than just the source of the PAH,” Williams said. “We get most of the more toxic PAHs from our food, rather than inhalation. And some fairly high doses can come from foods like leafy vegetables that we know to be healthy. That’s why we need a better understanding of what’s going on in the human body as these compounds are processed.”

The Williams-led OSU laboratory is recruiting volunteers for a follow-up study that will also employ smoked salmon as a source of a PAH mixture and relate results to an individual’s genetic makeup.

Some of the early findings from the study actually back up previous research fairly well, Williams said, which was done with high-dose studies in laboratory animals. It’s possible, he said, that exposure to dietary PAHs over a lifetime may turn out to be less of a health risk that previously believed at normal levels of exposure, but more work will need to be done with this technology before such conclusions could be reached.

Collaborators on the study were from the Pacific Northwest National Laboratory, Lawrence Livermore National Laboratory, and the OSU Environmental Health Sciences Center.

“Further development and application of this technology could have a major impact in the arena of human environmental health,” the researchers wrote in their conclusion.

Continue reading

Today, NIEHS highlighted OSU SRC Trainee Andy Larkin from Project 1. Below is the spotlight from the SRP ePosted Notes.

Andy Larkin
Andy Larkin

Andy Larkin is working with David Williams and William Baird at OSU and just started his fourth year as a Ph.D. student. Larkin is doing great work and we look forward to his presentation on atmospheric pollutant models and smartphones in an upcoming Risk e Learning webinar.

Larkin’s Ph.D. research involves several different projects, all of which are designed to bridge the gap between basic research and risk assessment. Larkin is working on computational modeling for predicting biological responses to PAH mixtures, real time forecasts of atmospheric PM2.5, PM10, and ozone for the state of Oregon, and smartphone programs to predict and prevent atmospheric pollutant exposures.

While he has won an impressive seven awards* as a graduate student, he was most proud of winning second place in the Oregon State three-minute thesis competition. Although not the most prestigious of his awards, Larkin explains that, “Creating a summary of a thesis designed to be understood by the public and less than three minutes in length was by far the most challenging presentation of my graduate studies, and it was thoroughly rewarding to have so many members of the general public understand and enjoy the presentation.”

When he isn’t busy working on his outstanding graduate research projects, he enjoys community volunteer work and ultramarathon running. Larkin just ran the Portland Marathon on October 6 and his next ultramarathon is the Florida Keys 100 mile run in May!

After Larkin finishes his Ph.D., he hopes to work for a research group or regulatory agency to develop technologies for reporting real-time risk assessment and risk communication information. He also hopes these technologies will help to prevent unwanted exposures in sensitive populations.

*Note: The Training Core web site shares more specifics about Larkin’s recent awards.

ZebrafishRobert Tanguay, PhD (Project 3 ) focuses on examining the effects of selected chemicals and chemical classes on zebrafish development and associated gene expression pathways.

The Tanguay research group recently collaborated with Terrence J. Collins, PhD, a champion in the field of green chemistry at Carnegie Mellon University.

Collins and his collaborators showed that specific green chemicals (a group of molecules called TAML activators) used with hydrogen peroxide, can effectively remove steroid hormones from water after just one treatment. Steroid hormones are common endocrine disruptors found in almost 25 percent of streams, rivers, and lakes.  Collins needed to understand the safety of TAML activators to move forward on this problem.

Tanguay’s group exposed zebrafish embryos to seven different types of TAML activators. None of the TAML’s impaired embryo development at concentrations typically used for decontaminating water.

The collaboration resulted in a new journal publication in Green Chemistry.

These are important findings that contribute toward TAML activators getting commercialized for water treatment.

Endocrine disruptors and human health

Endocrine disruptors can disrupt normal functions of the endocrine system and impair development, by mimicking or blocking the activities of hormones in wildlife. Several animal studies suggest that endocrine disruptors can also affect human health, and may be involved in cancers, learning disabilities, obesity, and immune and reproductive system disorders.

Robert Tanguay’s leadership in utilizing  zebrafish

Robert Tanguay is Director of the Sinnhuber Aquatic Research Laboratory, which is the largest zebrafish toxicology lab in the world.

In 2012, Dr. Tanguay received an EPA grant award, “Toxicity Screening with Zebrafish Assay”.  The award is for three years and almost two million dollars in funding to examine the developmental toxicology of at least 1000 chemicals.

Dr. Tanguay and his research team  have tested over 3,000 compounds of interest to the National Toxicology Program (NTP), to complement the ongoing high-throughput screening efforts in the U.S. government’s multiagency Tox21 research program.

More Information:

Citation: Truong L, DeNardo MA, Kundu S, Collins TJ, Tanguay RL.  2013. Zebrafish assays as developmental toxicity indicators in the green design of TAML oxidation catalysts. Green Chem; doi:10.1039/C3GC40376A [Online 15 July 2013].