Overview
- A recent study published in Urban Ecosystems by Dorothy Zahor and Kenneth Glynn, then graduate students at EMU (they have since both moved to Oregon State for Ph.D studies), demonstrated American robins can be used as bio-indicators of soil contamination. They examined robins in Ypsilanti (EMU campus was the control site) and Flint, Michigan, and found that high blood lead levels in robins can accurately predict areas with contaminated soil.
- The study found that robins captured in areas irrigated with Flint’s contaminated water had significantly higher blood lead levels compared to robins on the EMU campus (which was representative of a typical irrigated, urban area), highlighting the lasting effects of lead pollution in Flint.
- They also showed that a strong correlation exists between the lead levels in robin blood and soil contamination, suggesting that robins can provide reliable data on the extent of lead pollution in urban environments. This is due to robins' primary diet being earthworms and grubs at the surface of the soil near their nesting sites.
- The research emphasizes the potential risk of lead exposure to human health, particularly children, who may come into contact with contaminated soil, leading to developmental issues, brain damage, and hearing problems.
- Zahor and Glynn’s approach demonstrates that robins, which forage locally and accumulate environmental exposure, can serve as a practical and cost-effective alternative to traditional soil sampling for monitoring toxins like lead, especially in areas with a history of contamination.
Transcription
David Fair: The cold of winter can certainly make you miss the sounds of the summer's songbirds. Well, there is a comfort to be found in looking out the window and seeing the return of the robin. I'm David Fair, and welcome to this week's edition of Issues of the Environment. Recent research out of Eastern Michigan University shows that the robin isn't just singing a song. It can tell an important environmental story. If we listen and look close enough, robins can tell us about soil contamination. That's the findings in the study conducted by our guest. Dorothy Zahor and her research partner, Kenneth Glynn, were master's students at EMU when the research was conducted. Both are now doctoral students at Oregon State University. And, Dorothy, thanks for making time from an entirely different time zone!
Dorothy Zahor: Thanks for having me! Of course!
David Fair: We all know that birds and other wildlife can tell us a great deal about our environment. Frogs, for example, are a great indicator of the health of rivers and wetlands. What led you to take a look at the robins?
Dorothy Zahor: Yeah, well, robins is such a common and widespread backyard bird. We share a lot of our spaces with them in urban parks and out in our front lawns. And so, we're kind of interested in how we're both being exposed to the environments that we share and what they might be able to tell us about the environments that we're utilizing also.
David Fair: In specific, you were looking at whether there were indicators of lead contamination in robins. Choosing Flint seems like an obvious choice, given the Flint water crisis. Were you able to make a direct connection between the lead in the Flint water to the lead contamination in Flint soil through the study of robins?
Dorothy Zahor: The robins that were foraging at those irrigated Flint sites that we studied, the soil levels were high, as well as the robin blood-lead levels. And those were correlated across sites that we measured from urban sites that were not contaminated with water, rural sites that had no irrigation and then not-irrigated sites within Flint. So, it seemed to be that the higher the soil level, the higher the robin blood-lead level.
David Fair: Now, you compared the robins you studied in Flint with robins found in Ypsilanti and on the EMU campus, right?
Dorothy Zahor: Yep. Correct. So, the Ypsilanti sites served as our irrigated but not contaminated.
David Fair: Issues of the Environment and our conversation with Oregon State University integrative biology Ph.D. student Dorothy Zahor continues on 89 one WEMU. And we're discussing scientific research that Dorothy coauthored while a master's student at Eastern Michigan University. While this particular research focus was on robins, Dorothy, I'm curious as to whether you've also been looking at other songbirds that might tell a similar story when it comes to land or lead contamination.
Dorothy Zahor: Yeah. So, we focused on the robin because they're earthworm specialists, because they're always digging their face right in the soil, consuming earthworms that are covered in soil, as well as just consuming soil during their foraging. But we also took a look at a few other species that share the same environment but don't utilize those same foraging behaviors, such as goldfinches and starlings and house sparrows. They're not earthworm specialists. So, while we found them in the same exact park and sampled them in the same area, they didn't have as high as lead levels as the robin because they weren't participating in those same foraging behaviors that allowed them to be exposed to much higher soil levels.
David Fair: So, in theory, if robins can serve as a bio-indicator for lead contamination, might the birds also serve as an indicator for other kinds of soil pollution?
Dorothy Zahor: Yeah, that could be possible. We didn't study anything besides lead, but I have seen other studies looking at such as pesticides that are put into the grass or into the soil that they're also foraging in. Anything that's able to bio-accumulate, the robins could be picking that up from the soil.
David Fair: Do you expect this research to be applied when it comes to further protecting human health?
Dorothy Zahor: I think that it does shed a good light on how we weren't really so focused on not irrigating lawns when there's a water crisis. And lead contaminated water is not just an issue in Flint. But when we're mitigating the impacts of lead impacting humans, we should also probably think about if we're irrigating lawns, because wildlife can also be exposed through high soil levels, but also humans that share those same parts that we sampled could be playing--having played in the lawn, having a picnic--be exposed to that soil, which can be aerosolized in the warm season and inhaled. And so, there is still a route for human exposure, also for irrigation practices.
David Fair: You know, when I was a kid, our parents used to always send us outside and play in the dirt. And some will tell you that because we did, we have higher resistance to certain bugs and those kinds of things. Do you think that the more knowledge we gain, the less apt we are to actually get outside and enjoy the environment?
Dorothy Zahor: I don't think that we should think about it as not being able to go out and enjoy the environment when we're aware that there's a potential risk. But we should just be more informed and have more intentional behaviors, so that we're reducing our potential exposure to things that may be harmful for us.
David Fair: This is Issues of the Environment on 89 one WEMU, and we're talking with scientific researcher Dorothy Zahor on the program. Now, again, the focus of your research with robins was on the urban environment. You kind of touched on it, but I want to dig a little deeper. Can robins or other songbirds potentially be used as bio-indicators in the more rural areas and farming communities to better protect human health and to allow us to get out into the environment more safely?
Dorothy Zahor: I would say anything that's being put into the environment, whether it's more rural or urban, if it's a pollutant that gets into the soil that has the potential for bioaccumulation, that's an opportunity for the robin to accumulate those elements and could inform us about what's out there that we may also be being exposed to.
David Fair: Well, now that you've departed Ypsilanti and southeast Michigan, will others take on and advance the research and the project of advancing the research in this area?
Dorothy Zahor: I wish that we could study robins forever. Unfortunately, this project has ended, and there wasn't really another team to take it on. Both me and Ken, who are running it, sort of were the ones leading it, and we both moved on to new projects.
David Fair: Well, I'm glad you brought that up. Both you and your research partner, Ken Glynn, are now working toward your doctorate degrees at Oregon State University. Where is your research taking you? Are you doing something similar but exploring the western part of the country?
Dorothy Zahor: We're both still studying birds. I'm still studying urban spaces, too. Right now, I'm looking at how urban songbirds and free-ranging domestic cats have an interaction. So, how well are birds able to perceive cats as a threat? How might they respond behaviorally or physiologically in order to avoid predation by cats? And Ken has moved on to studying shorebirds where he's looking at how drought impacts their movement, migrations and overall health.
David Fair: And what can we do with these research projects? What are you hoping to find or what is the hypothesis?
Dorothy Zahor: For our bird and cat study, we're hoping we can see how well these birds are able to recognize a cat. Right now, we're looking at a suite of urban and rural birds to see if urban birds might recognize them better or rural birds might recognize them worse. Overall, I'm hoping to sort of shed light on how outdoor cats are negatively impactful for wild birds, where a lot of outdoor cats are pets. And hopefully, we can shed light on pet owners to think about what impacts they might be having when they're letting their pet cats outside.
David Fair: Well, I am always fascinated with the scientific mind, and I'm glad I got to know yours a little bit. Thank you so much for taking the time and sharing the information, Dorothy!
Dorothy Zahor: Yeah, thank you for having me!
David Fair: That is Dorothy Zahor. She has coauthored a research study published in the journal Urban Ecosystems. It's entitled, "You are what you eat: Urban soil lead predicts American robin blood lead in Flint, Michigan." This research was conducted while Dorothy was a master's student at Eastern Michigan University and published in 2024. She's now a doctoral student in integrative biology at Oregon State University. For more information on the research and the article, simply visit our website at wemu.org. Issues of the Environment is produced in partnership with the office of the Washtenaw County Water Resources Commissioner. And you hear it every Wednesday. I'm David Fair, and this is your community NPR station, 89 one WEMU FM, Ypsilanti. Celebrating 60 years of broadcasting from the campus of Eastern Michigan University!
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