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Nitty Gritty H2O

Bill Johnson, professor in Geology & Geophysics and director of the William P. Johnson Contaminant Transport Group, is a GCSC faculty affiliate conducting research related to water. Bill came to the UU in 1995. As a hydrogeochemist, he researches transport and cycling – the fate and transport of things in water. In this installment of our regular research spotlight series, Bill answers our questions about his research, his role as an expert witness in a court case, and his pedagogy.

When you say “transport of things in water”, what kind of things are you talking about?

I focus on contaminants such as trace elements of all different kinds, like selenium or mercury, and theories to predict how long it will take for them to get from point A to point B or how much of the element will get from point A to point B. (The theories and the behaviors are different depending on the kind of contaminant.) I also do a lot of work on particles and understanding how to improve theories for transport of pathogens. My research program is split between these two areas; where half of it is about how particles transport and improving theory to predict that, and the other half is about trace elements in systems predominantly in Utah, but also a little international stuff, such as in Ecuador.

Can you say a bit more about the particles portion? What’s an example of a kind of particle that you study?

Every so often there are disease outbreaks in communities from organisms like cryptosporidium. A vast majority of these disease outbreaks come from groundwater and are typically associated with heavy rain. There’s a number of reasons why heavy rainfall would drive the transport of pathogens in the subsurface. We can make these predictions under particular conditions where we have control over the chemistry, and that’s what we do in water treatment plants where we use granular filtration to remove pathogens. The problem is that in the environment we don’t have control over the chemistry so the existing theories fail.

Beyond how far these particles are going to be transported during a heavy rain, what are other areas where these theories might be applicable?

Yes, heavy rain is just one example of why we care about pathogens in groundwater. There are lots of other contexts and practical engineered processes where having a guiding theory would help in design. For example, there are contaminated sites that are still a major challenge for clean-up. People are using nanosized zero valent iron to clean up different organic contaminates and reductively dechlorinate them. They’re using activated carbon particles injected into the groundwater to enhance attenuation and biodegradation of organic contaminants. And these practices have no design theory for how fast the particles should be pumped to optimize transport. So you have consultants doing this work without any useful tools to guide them on how best to do it. Having a theory to guide in these and other areas is valuable for doing these processes efficiently.

In another vein of your research, you were involved in a case against the proposed tar sands mine on the Tavaputs Plateau, battling against the U.S. Oil Sands company. What’s happened with that?

It’s idle! Between now and then, oil and gas prices crashed, so nobody’s trying to develop the site right now.

What aspect of your research did your work on that project fall under and how did you get involved?

It’s about the molecules and contaminant partitioning, exploring how organic contaminants behave in the environment. U.S. Oil Sands was using organic solvents to extract hydrocarbons from the ground and they were granted a permit by the State of Utah to dispose of those onsite with no liners and no monitoring. Western Resource Advocates asked me to weigh in on whether the solvent they were using was toxic. That solvent is called d-Limonene. It’s a citrus extract. In itself, it’s not all that toxic, at least at reasonably expected concentrations in groundwater. The hydrocarbons that U.S. Oil Sands were extracting from the tar sands with that solvent are more toxic than the solvent. They’ve been there for eons and the reason they’ve been there for eons – the tar sands in all the rocks – is that they don’t dissolve into water readily. But when you add this solvent to them and then leave this mixture of solvent and nitrogen compounds laying on the land surface, now you’ve made these compounds much more soluble. And I showed that that’s the problem. I did all these detailed thermodynamic calculations so that the expert witness for U.S. Oil Sands and I were battling over the thermodynamics of it all and our respective calculations, and the judge on the case punted. She just said “well, there’s no water at the site anyway”, which was a claim made by the State. And I thought it was over.

How did you get move from working on this issue of toxicity to addressing the overall hydrology of the area?

I thought it was over and then one of the leaders of the citizen action group called Living Rivers invited me to visit the site. I felt like I owed it to the process to actually see the area since I hadn’t seen it. And in fact, what’s so weird about that court case is I don’t think anybody who’d been arguing that court case had been to the site. U.S. Oil Sands was pointing to documents about the site made in the 1960s and 1970s that weren’t developed to address the hydrology of this specific place they were talking about. There are documents to address the whole region, and these regional-scale documents said there was no local water at the site. The whole court case rested on statements made in documents that clearly weren’t expressing scales appropriate to the problems at hand. So I went to the site and I was astounded.

It was lush. You get off the top of that plateau where it is dry and scraggily, and get down into the canyons adjacent and they have springs feeding these wonderful meadows that the local ranchers depend on. These ranchers steward the land down there and they depend on these springs for their own water as well as the livestock and the wildlife. Then I got mad because the State’s saying there’s no water and there’s no mention of the interest of the ranchers in these locations. It was just amazing to me. That’s when I started working for free and developed a research project out of it.

We put together a bunch of money to do an analysis and I pulled in some colleagues to help and a mixture of graduate and undergraduate students – a community effort. We ended up publishing a paper showing that the water in these springs comes from the ridges where U.S. Oil Sands was dumping this material. So you can’t rule out an impact. And I couldn’t say that there would definitely be an impact, nobody knows, but I could say there’s no way you can rule it out based on the data. And that was the argument I made. It ended up being a really fun thing to work on because we learned something interesting. It all culminated in a hearing that I thought was just going to be me and a lawyer and a Division of Oil Gas and Mining chief, and instead there were 100-200 expert people there, a mixture of activists, reporters, and so on. It was really interesting because the State kept making these statements about the area that were just flatly untrue and I was able to knock it down and the Chief of the Division of Oil Gas and Mining recognized that. He saw the data that we’d collected refuted what the State was saying. Then they required a monitor for the site. So that was a pretty satisfying outcome for that little project.

What was it like for your students to work on something that was so applied and urgent?

I think they really enjoyed that. I think they find it a satisfying extension of the nitty gritty, puzzle-solving research that we do.

What’s happening for you and your group right now related to the ‘nitty gritty’ stuff?

I just had a breakthrough on the particle transport theory. Existing theories for predicting the transport of particles fail because in the environment, the particles tend to be similarly charged, negatively, and so is the sediment. When things are charged the same way they repel each other. Basically, the theory fails because of that repulsion – particles and sediment shouldn’t attach, but yet they do and the particles get removed from the water. What it comes down to is that no surface is homogenous. There’s nanoscale heterogeneity that provides little zones where things are attracted and attach. What we’ve been doing for the past two years is backing up what that nanoscale heterogeneity should look like on surfaces through doing a bunch of attachment experiments. And that’s very puzzle solve-y. It’s something that when I was a master’s student working on the Himalayas in Pakistan, if you’d asked me what I was going to work on later in my life, I would have said you were crazy. But I love it because you have control over the system and we’re basically decorating Easter eggs with little heterogeneity dots on these little sand grains in our hypothetical models in our simulation trying to capture the data. We’ve been able to do that and now we’ve found that that representation predicts all these weird transport behaviors that you see under environmental conditions. We just submitted the manuscript.

We haven’t gotten it accepted yet, but I’m excited about it because it actually brings together this research that we’ve been doing for 15 years. I love the mix — I love this stuff where you really get into the mechanisms and I love the stuff where you get out in the field and measure things. So it’s really fun to have those aspects of my research program operating all at the same time. It’s good for the students because they all mix with each other. I get a critical mass of students going and they’re all teaching each other too, and that brings a lot of energy to the group.

What drew you to the GCSC?

I like to think I helped to make it. Before the GCSC existed, I was bringing together groups from Geology & Geophysics, Atmospheric Sciences, ecological people, Biology, environmental engineers, and the geographers. This was back probably in 1997, something like that, maybe 2000. I was bringing them together to say ‘hey, we should be developing work towards a big proposal.” Jim Ehleringer [GCSC director emeritus] was a part of that and some other people who helped lead included Craig Forster. This was before Brenda Bowen was even a grad student. We actually developed a precursor to GCSC called CWECS, the Center for Water and Ecosystem Climate… something or other, I can’t remember. But the point is, I was barely tenured at that point and didn’t really have a grand vision for the kind of thing that would become, like Jim Ehleringer did. So I dissolved CWECS and he developed GCSC. And what I focused on was developing work on the Great Salt Lake, because none was going on at that time from the University of Utah. That’s what I focused my efforts on while Jim Ehleringer built the GCSC, but I still feel like I had a hand in creating it.

How do you feel that GCSC support or programming has positively impacted your research or your teaching?

I can tell you that the Tar Sands work wouldn’t have happened without Logan Fredrick being a GCSC Fellow. She helped with the logistics of getting the field sampling done in a big way. Out of that fellowship, we had multiple papers. Obviously there was other support brought in to help with all that, but the GCSC was a critical piece. I think that’s a fundamentally important aspect of the GCSC — funding students to allow them to explore something that maybe isn’t so formulaic. You can explore a bit. And I really value that a lot.

Thank you, Bill!