Dr. Paul G. Tratnyek currently is a Professor in the School of Public Health at the Oregon Health & Science University in Portland, OR. He received his Ph.D. in Applied Chemistry from the Colorado School of Mines in 1987; served as a National Research Council Postdoctoral Fellow at the U.S. Environmental Protection Agency Laboratory in Athens, GA, in 1988; and as a Research Associate at the Swiss Federal Institute for Water Resources and Water Pollution Control (EAWAG) from 1989 to 1991. In 1991, Tratnyek joined the faculty in the Department of Environmental Science and Engineering at the Oregon Graduate Institute (OGI) where he became involved in OGI’s Center for Groundwater Research and the University Consortium Solvents-In-Groundwater research program based at the University of Waterloo. Through that connection, he became involved in research on zero valent iron (ZVI) for remediation of contaminated groundwater. Since then, his areas of research have expanded to include most aspects of in situ chemical reduction and oxidation (ISCR, ISCO), including some of the earliest work on abiotic reduction of contaminants and the largest body of high-impact research on ZVI. Most of his recent and on-going research relates to enhanced formulations of ZVI (e.g., by sulfidation), treatment of high-recalcitrant emerging contaminants (e.g., 1,2,3-trichloropropane), and the characterization of in situ redox processes involved in ISCR and abiotic natural attention (ANA). For more details, see tratnyek.org.

How did you become involved in research on groundwater remediation with zerovalent iron?

P.T.  In 1992, during my first few months as an Assistant Professor at the Oregon Graduate Institute, the department head (Jim Pankow) introduced me to John Cherry, who introduced me to Bob Gillham (both at the University of Waterloo). They gave me some seed funding from the University Consortium Solvents-In-Groundwater Research Program to help characterize the chemistry of their technology.

Could you provide a brief high-level overview of some of your current research projects?

P.T.  Most of my research still involves ZVI, but the focus usually is not on groundwater remediation with ZVI per se; rather, we use ZVI as the model system for studying more fundamental issues related to contaminant fate, aquatic redox chemistry, etc. For example, recently, we have been using ZVI to create the divalent iron minerals that we think are involved in abiotic natural attenuation.

Is there a particular contaminant that you have studied that has presented a unique challenge or had unexpected chemistry to technologies that you tested?

P.T.  When we started our SERDP project on 1,2,3-trichloropropane (TCP), we didn’t realize that it would be far more recalcitrant than most other chlorinated solvents. That, together with California’s MCL of 5 ppt (ng/L), led us to investigate relatively extreme reductants, like zerovalent zinc. Also, we’ve recently realized that TCP’s recalcitrance makes it a good conservative tracer and internal standard for column studies on dechlorination of trichloroethylene.

What is the main piece of advice that you give to your junior graduate students or perspective students that are interested in pursuing a career in groundwater remediation?

P.T.  Riding the waves of interest caused by “emerging” contaminants can create lots of opportunities in the short/medium term, but that tends to distract from issues of broader and more lasting importance. I encourage my students to focus on the latter while they are working on the former.

Your biography mentions enhanced formulations of ZVI, can you describe the advantage(s) they provide and example(s) of how it has improved remediation of legacy and/or emerging contaminants?

P.T.  For most people, “enhancing” the performance of ZVI means increasing the rate of contaminant removal. We’ve done lots of work on how to quantify this and what material properties control this. But, now we are more interested in other performance metrics, like selectivity and efficiency. Sulfidation is a good example: sometimes contaminant removal is a bit faster, but the main benefit is that the reduction of water is much less, so the efficiency is much better.

You have done many studies that utilize computational chemistry calculations to probe remediation reaction mechanisms. Can you describe the advantages of this approach and do you see computational approaches becoming more of the norm with emerging contaminants?

P.T.  There are many possible applications of “in silico environmental chemical science” to remediation, but the most common one is in quantitative structure-activity relationships (QSARs) for predicting property data that have not been measured. The need for this is particularly acute for PFAS, and we are working on that now.

Is there a moment or achievement in your career that you are particularly proud of?

P.T.  Most of these achievements involve mentoring students. With the best ones, there’s a transition when they’ve acquired the knowledge and confidence to become professional peers. Often that transition is marked by a memorable moment when they tell me I am wrong about something important. It makes me proud when they do that.

Is there another area of science (outside of Environmental Chemistry) that you follow or find interesting?

P.T.  Lately, I have been teaching public health students, so I have been reading more of the primary literature on epidemiology. It is fascinating (and a bit depressing) to compare the data and analysis in the original research to the interpretations that reporters give when they cover these studies in the news.

What do you enjoy doing outside of your job?

P.T.  Now, mostly just running and gardening. Before my kids were born, I did a lot of alpine sports like cross-country ski racing, mountaineering, and rock climbing.

Contact: tratnyek@ohsu.edu