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Research Teams Collaborate on Unique Biodiesel Study

October 10, 2014
Dr. Traviss' research associate Nathan Martin and Tara Pratt feeding epithelial lung cells in the lab. (Will Wrobel photo)
Dr. Traviss' research associate Nathan Martin and Tara Pratt feeding epithelial lung cells in the lab. (Will Wrobel photo)

Biodiesel can power our vehicles—even heavy equipment—and heat our homes. It’s renewable—it can be made from things we grow: from soybeans to algae, and from the millions of gallons of waste vegetable oil from all those fry-o-lators in restaurants and fast-food joints around the country. Biodiesel spill? No problem—it’s biodegradeable. And, combusting biodiesel fuel produces less particulate pollution than does petroleum diesel. That’s true even with B-20, the standard ratio of 20% biodiesel, 80% petroleum diesel.

Efficient, renewable, healthier for the environment, made right here in the USA—biodiesel sounds like a near-perfect solution to our energy needs. Several researchers are studying biodiesel, but, probably due to the assumption that it’s likely to be less toxic than petroleum diesel, few are looking into its impact on human health. Realizing this, Associate Professor of Environmental Studies Nora Traviss began researching the toxicology of biodiesel particulates. "We began this project using exposure as our measurement of health," she explained. "We examined whether or not the pollution created by biodiesel combustion resulted in higher exposure for workers than the pollution created by petroleum diesel. It was very much an exposure assessment."

Real-world sampling

With the cooperation of the Keene Recycling Center, Dr. Traviss and her research team mounted particle impactors in the operator’s cabs in machinery at the Center, collecting samples of both petroleum diesel and biodiesel exhaust. The impactors can separate out different sizes of extremely tiny particles, which lets the researchers see exactly what the drivers are breathing. This approach makes Dr. Traviss’ study different from all the others, which collect samples from diesel engines set up in a lab. Dr. Traviss’ samples are real-world. "The exhaust we’re collecting is diluted in the air, it’s going through chemical reactions from the sunlight, and it’s combining with other molecules in the air," Dr. Traviss explained. "We’re studying the quantity of the particulate matter the driver is breathing and its unique chemical composition, which we hypothesize will be different from particles collected directly from the tailpipe."

Her team found that, although the amount of particulates in biodiesel exhaust is indeed lower than those from petroleum diesel, their chemical composition is different, which raised another question: Though there are fewer particulates in biodiesel exhaust, what if those particulates are more toxic than their petroleum-based counterparts? If so, that has implications for human health, which led Dr. Traviss to refocus her research. "We’ve moved from just measuring exposure levels to looking at toxicity," she said. She received a $400,000 grant from the National Institute of Health’s (1R15ES022431-01) Academic Research Enhancement Award (AREA) Program (R15) to continue her work.

Dr. Traviss put together an interdisciplinary team to conduct the research, drawing in two environmental studies majors, Rachel Klaski and Tara Pratt; a chemistry major, Patrick Kelley; a biology major, Andrew Bosco; and a research associate with a degree in biology, Nathan Martin, insuring that the team had a broader scientific perspective than if they just approached the work from a single discipline. However, she realized that it would be very expensive to send the particle samples out for chemical and physical analysis, so she enlisted the help of Assistant Professor of Physics Steven Harfenist and Associate Professor of Chemistry James Kraly to do the work in house and give more Keene State science students valuable research experience.

An image of a typical biodiesel particulate—the scale bar reads 500 nanometers (1/2 micrometer) or 500 billionths of a meter.
An image of a typical biodiesel particulate—the scale bar reads 500 nanometers (1/2 micrometer) or 500 billionths of a meter.
Dr. Harfenist is using a transmission electron microscope (TEM) at Dartmouth College to get images of the particulates (agglomerations of nanometer-sized particles) to determine if there are physical differences in the size and shape of the biodiesel and diesel particles. "From the images, we can get information through statistical analyses of size and shape distributions regarding the way in which the particles were formed (directly from the combustion process and/or through aggregation), which tells us something about how well the fuel was burned as well as how the particulates can affect human lung tissue," he explained. "The agglomerate particles are about 1–2 micrometers long (the average diameter of a human hair is approximately 50 micrometers), and the primary particles they are composed of are approximately 10 nanometers (1/100 of a micrometer!). Bombarding materials with electrons helps us image them, but also can cause the materials to give off x-rays characteristic to particular elements, so we’re interested to see what types of elements we can detect while imaging them. The TEM creates an electron beam that passes through a number of magnetic lenses and then passes through our sample, showing an image of up to one million times magnification."

Dr. Kraly and his team of student researchers analyze the particles for their chemical composition. From his work on other projects, including his studies of polyaromatic hydrocarbons (PAHs) on lichens, Dr. Kraly knew that he could perform the analysis Dr. Traviss needed with precision and accuracy. He put together his own inquisitive team of student researchers: Mike Cavacas, a chemistry major; Niko Brown, a chemistry and biology major; and Ethan Hotchkiss, a chemistry major with a strong interest in environmental studies.

This is graduate-level research.

Both Dr. Traviss and Dr. Kraly pointed out that their students were conducting graduate-level research. "Part of the challenge is the number of chemicals we are screening for," Dr. Kraly explained. "We’re trying to measure as many as four- to six-dozen compounds from each filter—37 different organic acid constituents, and it requires a very systematic approach." In total, his team screens for four different classes of compounds (polycyclic hydrocarbons, fatty acid methyl esters, and hopanes/steranes) with a total of 69 standard chemicals.

"There are other people looking at biodiesel particulate matter, but they’re mainly at the grad school level," Dr. Traviss said. "We’re doing everything we’re doing with undergrads. The National Renewable Energy Lab finds it really interesting that we’re doing this work at the undergraduate level, and we’ve collaborated with them on various analyses. A lot of researchers look at one aspect, but we’re looking at the physical, the chemical, and the toxicological—all in one lab, which is also very unusual, and all within one school."

Once Dr. Kraly’s team has analyzed the chemical composition of the particulates, Dr. Traviss’ group takes the particles and runs toxicological tests. "We use epithelial cells from human lung tissue that we grow and culture," she explained. "We dose the lung cells with different concentrations of the particles to see how it affects them."

"We really need to know the chemical composition to relate it to the results that we get in our cell studies, because, if we get results that say one fuel or the other is really toxic, we must determine which compound class is producing this toxicity," Dr. Traviss said. "How does this play out in the real world? If we were to find out that one or the other fuel produces a certain chemical or effect that’s toxic, this would help inform engine manufacturers that they should design their engines to reduce the particulate matter. Maybe they need to invest in more after-treatment technologies to burn off such compounds as PAHs or fatty-acid methyl esters."

A great opportunity for the student researchers

The opportunity to do graduate-level research, working closely with their professors and expanding their understanding of the work by collaborating with team members from different disciplines gives these student researchers extremely valuable experience. "This opportunity will help me professionally and going towards grad school. It also broadens my experience beyond being just focused on chemistry, because now I see how samples are collected, and the entire process up to and including the data analysis. So I get to hone in on what I really like to do and what I want to focus on when I go for a PhD in chemistry," explained Patrick Kelley, a senior chemistry major and member of Dr. Traviss’ team.

"I’m getting a lot of experience that I didn’t have before," noted Tara Pratt. "This project is giving me a lot of chemistry and biology experience. As environmental studies majors, we don’t usually get a lot of lab experience. We do a lot of field work, but not as much lab work."

Begin pull-quote…We’re better prepared for the future, when we can tell our employers or grad school faculty that they don’t have to spend time training us on this equipment, because we’ve already used it. …end pull-quote
– Niko Brown

Bi-weekly meetings during the summer, where the teams shared their progress with everyone on the project also helped everyone see the bigger picture beyond their piece of the puzzle. Presentations such as these, and the yearly Academic Excellence Conference, also gives students experience presenting and articulating their work. This year, the students will present their work at national conferences.

Engaging students in real-world problem solving also lets them see the value in their study, and gets them motivated about learning. "I got this research internship right after my freshman year," said sophomore Rachel Klaski. "I started as a PE major, but I took a class with Dr. Traviss my second semester. That, and this opportunity, made me want to enter this field, and it’s made me excited about school."

Skills and experience you can take with you

As Niko Brown pointed out, this research opportunity is very different than what would have been open to him at a larger research university, where, if he got to do research at all, he would be working under a grad student. "We have more opportunity to work and interact with our professors," he said. "It’s a solid opportunity for students who want to go to grad school, or show research experience on their resume. It’s been very important to me, and it’s also been fun. It helps you develop a greater appreciation for the field you might be entering. Also, we’re gaining skills on the equipment professionals work with, such as the gas chromatography – mass spectrometer. We’re better prepared for the future, when we can tell our employers or grad school faculty that they don’t have to spend time training us on this equipment, because we’ve already used it."

"To get into a top-notch graduate program, you have to have done research. You have to have your name on a research paper as a co-author, or even as a first author. Without research like this, Keene State wouldn’t have students going to grad school," said chemistry student Mike Cavacas.

"It’s great for students to be on projects like this. Even though it’s a big one that’s not going to be finished before some of these students graduate. But for those students who are involved—even though they may only participate in part of it—after they graduate and go out into the world, they’re taking the skills and experiences, and sometimes the papers, that allow them to do bigger and better things other places," Dr. Kraly explained.

"I’ve published work on my previous exposure research, but I never was able to cultivate students to get to the level of co-authors," Dr. Traviss noted. "But I’m feeling very excited about Steve and Jim and the teams we’ve put together, and we’re going to have student co-authors, and that’s going to be a big step for the project and also their careers—and for Keene State."

(If you’re interested in the science behind this project, check out the chart, "Analysis of Organic Compounds Associated with Biodiesel Exhaust (pdf).)