Ep. 164 Urban Agriculture & Soil Contamination with Zack Grant Part I | #GoodGrowing

Welcome to the Good Growing podcast. I am Chris Enroth, horticulture educator with the University of Illinois Extension coming at you from Macomb, Illinois, and we have got a great show for you today. We're talking about soil contaminations and and kinda dealing with that. What does that mean? And the research that goes into that here at U of I Extension.

We're gonna be talking with Zach Grant here in just a second. But you know I'm not doing this by myself. I am joined as always every single week by horticulture educator Ken Johnson in Jacksonville. Hey, Ken.

Hello, Chris. How are you?

I am doing fantastically speaking. How about yourself?

Not bad. Can't complain.

No complaints here. Exactly. Have you tasted your soil lately? I have not. Don't know if I wanna taste my soil.

You have a you have a dog. I have two dogs, so this is probably a really bad idea. Maybe one day we'll do a show about pets in the landscape because they just destroy everything. But yeah. But how how would you say your soil is in your your home, your property?

I think it's pretty good. We got nice black soil. We do live behind a historic house, the Duncan Mansion in Jacksonville, which used to be governor Duncan's house. And I think we may have been part of their trash pit because every time we dig, we get China and random pieces of stuff in in the yard. So it's it's like being an archaeologist every time you dig a hole sometimes.

Mhmm. Yeah. Well, I I would say because your house your house itself, where you live, is also an older home. So whatever construction disturbance that occurred there happened decades, if not a hundred years ago. Is that correct?

Yeah. I think the house was, yeah, nineteen teens, '19 twenties when it was built. Depending on who you talk to, we get different dates, so I'm not entirely sure.

Yeah. Well, old. Yeah. And leaky is that I I've heard people often describe houses of that age. So yeah.

Yeah. Yeah. We get some nice nice drafts.

The curtains flutter sometimes when it's nice and windy and cold out stuff. Mhmm. Well, I I guess I would classify my home as more of a conventional suburbia type home built mid seventies. You can definitely when I'm I'm digging outside and planting things either near the house, and then as I move away from the house, there's definitely a gradient of of soil texture differences. I mean, near the house, it's just a mishmash of stuff, from, like, I'll I'll put the the shovel on the ground, then it'll go right in.

I'll put the shovel in the ground right next to it. It'll be like hard clay. Little bit farther, there's a rock or concrete. And so that's up against the house. You get farther away, it gets a little bit better.

So but, yeah, here in Illinois, we do have nice deep soil, at least here in Central Illinois. So I guess we're lucky enough for that.

Yes. Looks like chocolate cake.

That's right. Yes. Well, I I think it is time to introduce our special guest because his soils might be a little bit different where he's growing. I don't know though, so we better we better talk talk about it. So let's introduce local food small farms educator, Zach Grant in South Suburban Cook County.

Zach, welcome to the show.

Thanks, Ken, Chris, for having me. Longtime listener, first time first time caller, first time guest. This is great. Super excited.

I'm I'm glad you broke through our outer circle to make it onto this illustrious podcast. You broke through. Way to go. By breakthrough, we we had a conversation last week at a conference. So Absolutely.

Yeah. But no. Zach, I I mean, honestly, I've been a fan of yours for a while watching the stuff that you do. So, I mean, how would you classify the soil that you grow in? Because you're located in in in Cook County.

Do you have, Ken, the soil like Ken and I have, like like chocolate cake?

It depends. And this is that was a really great intro you all did because I think we can refer back to it as we get into this conversation. So where I'm at, and you can actually see I have a little background of of Sosuko, the South Suburban Cook County Extension Research Urban Ag Demonstration Farm. We we just call it SOSUCO for short. I'm always trying to find an acronym for everything.

Right? So think Tribeca or those neighborhoods in New York that have those those really catchy acronyms. It always seems like when you see big grants that the university puts together, they also come up with really excellent acronyms for the grants. So I I was I was trying to find one, and and so SUCA was kind of the the best possible one that I could come up with. So so we are located in in south more suburban, rural fringe, kind of para urban Cook County.

So this site actually has kind of a mixture of what I call native soil types that were developed through normal kind of soil formation processes over millennia, right, and potentially influenced by agriculture but we we can kinda get into that. Kind of versus what I think you're getting at which is the more properly termed anthropogenic or technosol type soils which are heavily influenced soils which when we talk about urban areas that pretty much is is is what they're classified as. You don't we can, you know if you've ever looked at the NRCS soil map, the digital soil map, the physical soil maps, the soil orders, there there's always some sort of classification whether it's a Flanagan silt loam or or something very specific. But up here in Cook, it's really a black it's really a black box. In fact, if you look at the NRCS, they have a not only the the digital soil map, but they actually have posters that you can purchase.

And there's a couple of really great posters. I have a couple of them looking at the soil orders for all of Illinois. Mhmm. And and most of the the soils, as as Ken referred, these black chocolate cake soils are in that sort of mollisol prairie soil or the the forest type soils, which have thinner topsoils but are are still, you know, pretty rich, well defined topsoils. But if you look at Cook County primarily and especially the city of Chicago, it's completely grayed out.

They don't have any sort of proper soil order classification for really anything. In Chicago, there's a little bit in kind of the suburban areas of Cook County and in particular Sosuko behind me, they actually still have some classified soil. So we have two different I think an Elliott silt clay loam and and one other type of kinda silty clay loam. So most of our demonstration farm actually does have native soils that are classified, But we treat part of the demonstration area, and I can show an image here in a moment, like we would a proper urban soil that doesn't really have classification. So before we get into the contamination just in general, that's kinda they're really urban soils are generally unclassified, which is interesting because there likely are some spots.

Right? Like when I look at the soil map, the NRCS soil map, if you look at like Humboldt Park or Garfield Park, right, which have been green spaces since the beginning of Chicago's formation, some of those park soils actually have classification because they're undisturbed, never been touched. But the rest of the developed part of of urban areas, like, they just don't go out and take the soil cores and do the, you know, whatever they they do. The the soil mappers, however they develop the soil maps, they just haven't done it in in the urban areas. But I've actually heard whispers that the NRCS is interested in maybe taking a second look at that.

Maybe to seeing if there are some actual classifiable soils in urban areas even though by and large we kinda treat it as unclassifiable non native soils essentially.

That's interest yeah. So like when the NRCS sent out their surveyors across the country, Chicago probably was not a priority for them. But I have heard, you know, so one soil scientist, he's he's joined our our ranks as a volunteer recently. He talked about he was one of them in the the seventies and eighties in Iowa that helped classify those soils. And we've actually recently had NRCS does update those soil maps.

And so as you mentioned, there is a new push to update some of these to make make them a bit more applicable to urban farming. So we didn't get touch on that yet, what Suzuco does and what it grows, and maybe your background in that that urban agriculture. Could you just maybe touch on that just a little bit? Like, what what's urban agriculture and what are you growing at Suzuco?

Sure. Sure. So I mean, a little bit my background, you know, I come from I don't come from a farming background but I've been involved in what I kinda call small scale diversified like intensive vegetable farming, year round vegetable farming with high tunnels even for about twenty almost twenty five years now as crazy as that is to say for me. And I used to manage the student farm project on campus, on U of I's main campus. Maybe some of your listeners have heard of that.

We used to manage that. So I was kinda doing this sort of what I would call medium to slightly large compared to urban agriculture, diversified vegetable production at that site. That was like a seven acre, pretty intensively mechanized kind of vegetable operation. But I I always had a passion for like the sort of micro farming scale, what the Europeans call market gardening, what we call here market farming in a lot of sense. There's some discrepancy over the European definition and The US definition between what's a garden versus what's a farm in terms of direct marketing specialty crops.

Mhmm. So that kind of led me down this path of interest in urban agriculture. I I kind of come from the Chicagoland era, although I didn't grow up in Chicago proper. Grew up just South of of the city. So I I just had an interest in it and this extension position opened up to kind of focus on urban agriculture a little bit more within our local food small farm team.

So I I just jumped on it. And in terms of definition, I mean, there really isn't a proper like specific definition. I mean, in general urban agriculture is more or less the growing of specialty crops in urban settings at a variety of different scales or typologies as as I like to refer to it sometimes. So urban ag can refer to, you know, really even backyard kind of urban home food production or urban homesteading all the way up to, you know, multiple acre market farms in urban settings. But in general, most of the farms we see are kind of in the, you know, several thousand square feet up to half acre, two acre, couple acres in size.

So Sukho behind me is is about 10,000 square feet. And just for visual purposes, I'll share my screen and show you an overhead shot of what that looks like. So that's kinda what it looks like above. This is a drone shot. We did this really cool three d mapping.

I won't go into it today, but essentially all those arrows you see, you'll be able to click on those and it turns it in, you know, like street view in Google Maps, how you kinda go on the street view. All those arrows will be street views essentially of the farm and you can kinda navigate around our demo farm. So here you can see this is about, again, about 10,000 square feet inside of the fence. In total, you know, we have maybe closer to like five to 6,000 square feet of of bed space. We have a high tunnel as you can see in the upper left hand corner, a little storage container, a little seasonal washpack up there.

So most of the outdoor areas that you see at the bottom, those are all kind of native soils that we manage kind of like a traditional market farming system. And then in the upper right hand corner where you see those raised beds and there's three beds just south of that that we call berm bed systems, which we can talk about a little bit later. And there we have this the the native soil capped. So our soil isn't contaminated, which we'll talk about in a minute, but we sort of treat it like it is contaminated. And to kind of mimic and mirror and demonstrate what a lot of these urban farm practitioners have to do where they can't use the soil, they essentially just use landscape fabric like you can kind of see in the path there, put maybe a layer of wood chips down and then build beds, structured or unstructured beds, burn beds on top of that with soil and compost.

So we grow, I mean, we grow, you know, a diversity of crops anywhere from, you know, just like cooking greens. In this image you can see things like kale and collards, a lot of the fruiting crops in the Southwest corner there, that's a lot of just the cucurbit and solanaceous family fruiting crops. In the High Tunnel we primarily do fruity and vegetables. We're actually gonna do some of the the ginger trial work with with you all this year in that tunnel as well as winter salad greens. So so very similar crops to rural market farms.

Kinda the scale and size and scope are just a little bit smaller and a little bit more intensively focused. So I mean in the tunnel for instance, typically we'll grow anywhere from three to four different crops per per bed in a year. Outdoors, you know, we sometimes get to two, maybe three crops. So a lot of double, triple cropping, which is a hallmark of a lot of urban ag systems.

So this is is this a drone image? And then you have within that, you now have kind of linked to a three d camera that's on the ground. So aerial drone, and now then there there's buttons you can push linking the three d imagery of the farm on the ground.

Exactly. Exactly.

Okay.

It was a it a project we did this past summer with Ohio State University. I'm a part of this urban ag integrated pest management working group, and it was just a a project that we worked on. And it's really cool. There some Cornell folks did this several years ago, and then there was a IPM professor at Ohio State University that did this with a bunch of Ohio urban farms a couple years ago. And I I just love the concept so much, not only, you know, for our teaching and kinda demonstration purposes, but just yeah.

Mean, but mainly to connect people, you know, via Zoom or things like this with Mhmm. You know, urban farm tours so they don't have to physically go go in. We can I can just zoom in on one? Let's just click on one of the arrows really quick. So there, it just went from that overhead image, so now you're kinda looking down this this area right here where we had, you know, one bed of kale and, you know, a bunch of tomatoes and peppers outdoor.

We're doing a little bit of unreplicated trial work with different organic fertility treatments outside. We're actually kinda starting to limit what we do at Sosuko, so rather than trying to grow like 35 different crops that a lot of urban farms and community gardens try to do, we try to do our farm a little bit more like it's kind of a commercial urban farm. So we're gonna start focusing on like the higher value cash crops. And that's gonna be easier for us to do replicated work. So you know, we're just looking at one crop to track, like, yield or productivity, it'll be easier to assign different, you know, fertility treatments or, you know, mulching regimes or whatever we wanna do, irrigation regimes, so we can actually get some good replicated data versus just, like, doing observational side by side comparison.

So we do a little bit of it all here in our own replicated work, just traditional Extension demonstration stuff. We donate everything from this site too, you know, all of us in Extension who are involved with donation garden projects. I think we did about 4,000 pounds of produce from this site last year, so we've averaged around that for the past few years. We donate it all to a couple food pantry locations in South Suburban Cook. Yeah, that's a little gist of the site.

We use it also for training was the last thing I'll mention about this particular site, our Master Urban Farmer Training Program. We use this for a lot of the content for the course, but also we have some workshops here with the students who take that kind of hybrid online online training with us as well.

Yeah. They can get some like physical, like hands on demonstration work here. So yeah. Very cool. Yeah.

So Succo, hey. I've never been there, and and maybe I I can go visit virtually. So very very neat to have this And

here's another picture just inside the high tunnel so you can kinda see what that looks like. In here we actually have we we did kinda we started building some structured raised beds. These are six inch raised beds built with cedar five quarter or essentially one inch one inch decking boards. It's a little bit cheaper to do it that way versus like the two by dimensional cedar lumber which is more rot resistant. We would grow in ground here.

Again, this soil isn't contaminated but we're we're actually replicating a little bit of what they do at the Dixon Springs Ag Research Center in Southern Illinois. It just makes it easier to do like different replicated work, and it's definitely easier to like transition like from the crops you see in this image to winter crops. Because if you can imagine, like, pulling all this out and trying to get the beds ready for winter crop planting in September, it can be a real challenge. So that was one of the issues with that. So so, yeah, we once this is available to the public, we'll get the link out so people can come, you know, see what we're actually talking about here in this in this podcast interview.

Yeah. And and are you still pretty active on the

Local Foods YouTube channel? Do you still post updates? I I try to. So, you know, much like yourself, Chris, who kind of experimented into the sort of vlog space in in in on YouTube, I've got this vlog series I call the Urban Egg Connect vlog series. It kinda corresponds with our Urban Egg Connect newsletter we put out quarterly up here in Cook.

And you know, I have I don't know. I've got maybe like 30 or so video vlogs on there. And as you both know well with the kind of post recording edit process, like it just it is fun to do. I like doing it just like you guys love doing this. But it it was taking a little bit more time than I anticipated.

So I'll probably continue to do it in some format. But what I'm actually trying to do this year, I'll definitely get you the links for to push this out, is I have a new I have an Instagram channel for Sosuko. So I wanna start doing more of their, like, video reels and just, you know, images I post and and talk about there. Because a lot of farm farmers, small farmers, and I'm sure a lot of gardeners, they they tend to gravitate towards Instagram, it feels like, for the visual aspect of it. So I don't know if you all are into Instagram at all for for anything you do extension wise, but I'm gonna try to start doing more of that this year.

So so and that way, just easier for me to do while I'm there. If there's an idea, I can make a quick little, you know, two minute video, post it on Instagram, and share it while I'm there versus, like, going back into the office, editing, posting, trying to promote it, blah blah blah.

Oh, cool. Yeah. And we'll put those in the show notes. I'll I'll say Ken and I are working on our dance core coordination so we can become TikTok stars. But in in seriousness, what was the the statistic I heard?

The majority of people 25 are using TikTok as their news source. So instead of going to Google and typing in, you know, urban farming, they're going to TikTok and they're typing that in. So it's another just another platform for us to get on, Ken.

It is. It is. It's challenging in Extension because we we do our best as educators to, either do some of the research ourselves or work with faculty members or try to mine that literature for that good data to share. And it's so hard for us to share that good information whereas in the pop what I call the popular media in gardening and horticulture, you know, mean there's countless examples on YouTube and Instagram. People have millions of followers and their followers just listen to everything they say even if it's not really well validated growing information.

Not to say they're not good growers and it's not good material and education to share, but it's just maybe not as rigorous in terms of the the the sort of work that we try to do in Extension. Yeah. All a perennial challenge for us.

Forever. Yeah. That's that's job security. Right, Ken? Exactly.

Yeah. Well, let's TikTok our way over to talk about soil contamination. Ken, could you get us started in this line of questioning, please?

Yes. I think we we've touched on this a little bit. But how do urban soils kinda differ from our our quote unquote normal soils? You talked about, you know, don't necessarily have soil classifications, for urban soils, are there other ways that we could kind of differentiate them from our maybe less more undisturbed type soils?

Yeah. Absolutely. So, you know, I mentioned that terminology, the anthropogenic techno soil. There is actually a whole kind of soil science involved in anthropogenic soils. But in general, yeah, I mean it's just it really is highly disturbed soils.

Right? So if you look at if you think about a traditional soil profile where you have the a horizon, b horizon, c horizons, and like the regolith or the, you know, the the actual material maybe that the soil was formed from. You know, in urban soils, it tends to be situations where you might dig down a foot and it might kinda look like a a rural soil, but it also you might dig down six inches and there's a bunch of like rubble or fill from a building that was there or material that was scraped from one location and deposited there. You kinda never you don't know what you're gonna get. It's a it's a bit of a grab bag in terms of the actual soil profile.

So to our you know, kinda adding on to what we were talking about earlier. Interesting. I'm actually looking at a paper right now. I don't know that I need to share an image of this. And they actually were looking at and this is something I thought was intriguing.

Some of the initial classified anthropogenic soils, you can probably imagine they were looking at in in Italy, in Rome, right, where they were kinda excavating ruins. They would actually dig out and they'd they'd find like, you know, Roman walls or or fences that they would build or old floors or even situations where they would find like kinda like what they're what they're they're calling it, vegetable mold in quote or like vermicompost or dark earth that they had deposited for growing on top of what they found was like the actual native soil, you know, before the Roman times. So I I think I'd all that to say, maybe, you know, you mentioned earlier, Chris, talking about your both of your sites where you're just kinda digging down. That's something that I would recommend everyone, whether you're in an urban area or wherever you're at. You can look at these soil maps.

Right? But I think the first thing you gotta do is get out there and just dig down and see what you're you're you're working with. Right? Dig maybe you don't have to dig a full soil pit like some soil scientists do, but you certainly wanna dig down and see what you're working with. Right?

And and you're gonna get some idea right away whether or not you have kind of an urban heavily transformed anthropogenic soil or something that's kind of native and and and was there in the first place. So I bring that up again, Ken, with your question only to say that assessment of your of your site or your soil definitely if you're in urban areas important, but even maybe some of the suburban kind of rural fringe areas. Especially in your case Ken where you said you have an old house really close by. Right? So if you're thinking about doing any food production gardening in and around like, you know, a century old house, you know, lead contamination might be the big priority.

So you'd you'd maybe even wanna dig down and see what's going on, but then also kind of cordon that area off for a separate what we'd call a composite soil sample because that area might be high risk. Right? And then maybe in an area where in especially maybe in a rural setting where you know there wasn't an old house, maybe that can be kind of your low risk sample. So, you know, I think a mixture of the actual physical structure of these soils and the profile it definitely differentiates and is something you need to start with because even if you find out that your soil isn't contaminated, it may be primarily rubble or it may be super compacted or there may be an an old parking lot, you know, a few inches down. So you really need to figure those things out first before you really worry about contamination.

But then, yeah, I would say that the thing that sets urban soils aside from rural soils is the higher risk of contamination. And, you know, one thing I I've learned, I'm not a environmental engineer or an, you know, proper EPA environmental assessment expert, But there are some basic things you can do in terms of assessing your site. I mean, if if you know that a neighborhood or your site was primarily residential and there was no industry or it's maybe not next to like a super heavily trafficked road, then the primary potential contaminant would still be heavy metals and primarily lead. Right? Because of for the old house example, you know, most of the paint up until the seventies was lead based paint and pretty much all the gasoline up until that same era was lead based gasoline.

So high traffic lead deposition is a problem and lead paint is a big problem. So old homes, proximity to high traffic areas, lead's gonna be your your big number one factor. And that and that gets most of the attention when it comes to contaminate environmental contamination in urban soil. Certainly, there's other things like, the other polycyclic aromatic hydrocarbons and there's a new thing with biosolids now, well it's not a new thing but a new interest, PFAS compounds like per and polyfluoroalkyl substances, the forever chemicals. There's all sorts of stuff popping up all the time that you might have to be concerned about depending on on how the site was used.

But but I would say heavy metals is probably gets the most attention, and lead, which, you know, we've done some work with research with with campus faculty and the the work has been done elsewhere too, has has been the primary focus.

What about say like arsenic or something like that? Maybe more rural areas.

So yeah. I'm glad you brought that up. So the the one heavy metal contaminant, at least that I know of in in looking into this, is if you are in a rural area that and you had maybe like a very old orchard that was managed maybe with very old, now outdated unlabeled pesticides, arsenic was a common active or maybe, you know, inner ingredient in those pesticides. And so if you know that you have an area like that where arsenic was used as pesticide, you might want to do some heavy metal testing for arsenic. So that's a great example of doing what the EPA calls that phase one risk assessment where you're just kind of figuring out what happened with that soil or that area before your new intended use of growing food in it.

And, you know, sometimes that might be easy to figure out. You might have neighbors who know, like, oh, yeah. That was an old orchard. They used to spray all sorts of crazy stuff. So that might be a clue.

Like, okay. Yeah. We should probably test for arsenic. But if you're in an urban area, it's like, oh, yeah. If it's just an old neighborhood with old historic housing stock, then maybe lead's the big concern.

But I'm actually working with an an a group. Was just doing a technical assistance with MEFTP participant, and they're building an urban farm site right next to an old EPA Superfund site and across from another brownfield. So it's not on that site, but it's adjacent to it. So in that case, that opens up a whole other can of worms like, you know, lead could be a problem, but there could be all sorts of other potential environmental contaminants that you don't know about. And even if you can test for some of those things, there's not a for some of those contaminants, there's not always like a really good one to one, oh, we know it's here at this level.

Here's what you do about it. Right? We're starting to learn more with lead, which we we can discuss here as we move along, but it's not always straightforward in terms of what we do with remediation. But we have some tactics that we can we can talk about that work and that definitely work really well for urban ag because of the small scale footprint. We can do a lot more what we call in situ remediation versus like anything having to do with like removing soil, cleaning it, bringing it back, which there are examples of people doing that.

Like some of these EPA Superfund sites that have very expensive ex situ remediation is to literally clean the soil, which I I can't imagine the cost or the all the heavy equipment you need to do something like that. But but certainly, you know, for rural areas, heavy metal contamination isn't as big of a concern unless, like you said, Ken, there might be historic, like, pesticide usage in in an area that you know about.

So how do you clean a soil? I'm assuming it's not like you just don't put it in the dishwasher. You it's

That's that's I don't I'm not

I'm not fully up to speed on it. When I look in the literature and the research on this, they they talk about all these ex situ and in situ methods. So in situ is like in place there, not removing. Ex situ is removing it. And when they talk about Ex situ, they talk literally about like washing the soil, different things they can do after removing the soil and then bringing it back which I, you know, I'm not that's kind of beyond my expertise or anything I'd be familiar with.

But in situ in situ for some of these metals, particularly lead, think is a viable remediation strategy. And I kinda hinted at it earlier when I was describing some of our demo growing areas at Subsuko where you can literally some people call it capping and filling where you just kinda cap off what might be contaminated and you fill in on top of that. So I mean, obviously for big acreages, that's not practical. But if we're talking about, you know, a few thousand square feet, couple acres, that that's probably more doable.

Well, in Macomb, they had a superfund site in the middle of town that they cleaned up and there I mean, there was a pit 30 foot deep that they dug out. Oh, wow. And it was it was just kind of this empty pit for months. I don't know what they did with the soil. I don't know if they cleaned it or if they landfilled it or brought in fresh stuff.

I I I don't know. All I know is it was maybe an acre big, probably less than that, and it was a huge project. Tons of equipment, tons of earth moving. It had to be pretty costly. And they filled it all back in now.

It's just a turf grass. So it's

yeah. One thing I will touch on before we get into any other more details about this in situ remediation or talking about lead in particular is bioremediation. Because we get a lot of questions about that and We do. It's one of those things where, you know, this happens a lot when we're trying to do this knowledge translation from research where it's like there has been research done on it and shown that there are plants that are bioaccumulators of certain metals, right? But that doesn't always mean that there's a practical application for it.

So on the subject of that, there certainly is plenty of research and data out there to show that certain plants can be bioaccumulators of some metals, not all in all contexts. But in order to truly remediate the soil to those geogenic or background levels, the the timescale when they model this out is it's just not practical. I mean, we're talking hundreds if not thousands of years of constant bioremediation and uptake. And then you even if you're doing that, have uptake of a known environmental contaminant into biomass, and then that biomass needs to be disposed of properly. So while that sounds like it could be a promising strategy, in terms of practicality, it it just doesn't seem like there's much water there in terms of application.

I mean I mean certainly if there's like a super fun site like you're saying, Chris, and you wanted to just to put it into a forever perennial bioaccumulator, right, that's that's it's all maybe that's an application for it. But if you're trying to grow food on a site and you're like, oh, my levels are maybe a hundred part per million higher than what they need to be, Let me try to reduce it with bioremediation. That it just doesn't seem like it's practical, unfortunately. And that also goes for there's interest in, like, micoremediation with mushrooms. It's kind of the same concept.

Certainly, it it does happen. Right? You can replicate it in laboratory and maybe some field settings, but in terms of applicability, it really just isn't practical from from from what

we can tell. Let let's bring in some of your research that that you've done. Now I remember, oh my gosh, how long ago was this? It was you and doctor Andrew Margino showed up to a a team in service on campus, and you were talking about lead contamination, and and you brought out this this is, the second time we've referenced Star Trek in a in a month here on the show, but you brought out what I'll call a tricorder. And it's it's a portable X-ray.

You know the words I don't, Zach, but it it astounded me. Could let let's tie in some of your research here now with some of the soil contamination. So what did your research entail, and was it looking specifically at lead? And what the heck is that triforda thing?

Yeah. Yeah. Yeah. So I'll talk about it a little bit, then I can I'll share one image and this will there's also a link to one of our extension articles on on the subject. So yeah.

So when doctor Margino came on campus several years ago, was already maybe three years into my extension transition. He had some interest. He's a soil scientist by trade. He'd done a lot of really interesting work in in Africa with soils. But he he had an interest environmental contamination, particularly with lead, and and I had never heard of I I knew about what I'll call wet chemistry for for lead testing, for traditional and same thing with traditional soil testing, we'll get into in a bit.

But he brought up this idea of what he called in let's use the term again, in situ, in place dry chemistry involving the portable x-ray fluorescence device or PXRF device. I mean, essentially, you know, it's exactly what it is. It's it's a handheld scanning device that emits a low dose of radiation. Again, to handle the machine and operate it, you do need to get a little bit of training. I actually am not a certified operator of one.

Was him and his lab students, his grad students that were doing most of of the actual scanning. But essentially, yeah, it's a it's a portable machine and you literally can in place scan any sample. Right? Geologists use it quite a bit to look at chemical composition of different rocks or even maybe anthropologists do it when they're excavating sites to try to figure out what the chemical makeup is of something in place without having to remove it. I think that's where the large application of that technology is.

But Andrew had the idea, which wasn't a new idea, other people have been doing it, to apply it to soils. So essentially scanning the soil in place with an x-ray and it gives you kind of a a a readout of the chemical makeup of that sample. The challenge with it, because it sounds nice, well, there's a few challenges. One is the handheld devices are anywhere from 8 to, like, $20,000 apiece. So it's not necessarily a piece of equipment that, like, you know, even an extension office could necessarily budget for.

Certainly, we would love to have one. Some of the I'm trying to get some of the NRCS offices up here to get to get one, and maybe there's gonna be a new researcher at UIC who I've worked with who might get one in their startup package. Andrew has one on campus, and for that particular project, we were he partnered with Extension to what we did is, like, we had a bunch of different, you know, either conferences or workshops or things where we had a bunch of people coming to an event. Right? So we essentially just advertised it, bring in a sample, right, and come in, we'll scan it for you, give you the initial results, and I was there to kind of help them interpret that and tell them what that meant.

So that was the primary kind of extension facing citizen science interaction piece. But all that data kind of got molded into a prod, a couple research projects that him and his grad student worked on, and I'll just share screen share just really quick. Here's the article that was published on our website that Emily Steele wrote a couple years ago now that kinda highlights most of it. And I think there's a link here to the open access research project for the lead map. And then Andrew and George Watson, his grad student at the time, further did a little bit of work in looking at lead uptake mechanisms with different types of well, one particular crop in contaminated urban soil.

So they looked at uptake into tomatoes, you know, both in greenhouse studies and in field studies in contaminated soils to see what the uptake mechanisms are. So, you know, we did we collected maybe like a I don't know. It was, like, two to 300 samples with the extension events, and here's a picture of of myself and I think it's I think it was Elizabeth was her name. That was Andrew's, I think, research assistant at the time. You can literally see her pointing the gun.

That's the PXRF device right there. So we'd had people coming in, scanning it live. But then his grad student actually went through, and this map that you see right here, this color coded map, his grad student went and did a, like, kind of a cross sectional survey of all the soils in Chicago. So he went into, like, like, public ease you know, any public easement that he could access from the sidewalk or, you know, parkways, parks, and he just did this, like, kind of gridded PXRF scan of the entire Chicagoland area. And this map right here, I think, is all the individual samples, but we worked with kind of a geospatial geography expert on campus to create a heat map.

So somewhere in this, and we can share this with the listeners, there's a heat map where you can kind of look at your area of Chicago, and it kinda takes all these individual data points and creates a heat map so you can see, oh, yeah. I'm in this neighborhood, and it looks like the lead levels were a bit higher than they are in other areas.

It's not

super it's not super granular and accurate, but at least it gives you an idea of like, oh, yeah. Maybe my neighborhood might have been a little more contaminated, so maybe I should look into this further before doing anything more extensive with that soil. So that was kinda the extension facing slash research part of that particular project. And then, yeah, then then Andrew went on to do some a little bit more work with the tomato uptake.

Sure. And and the heat map, that's essentially it takes those individual data points and creates gradients so that it but, yeah, I will say on this, at least the lead soil image here that they have of this data set of points Mhmm. Red is a high lead levels, green is low. The map has a lot of red and orange on it. Not much not as much green, I would

say. Definitely. Definitely. The the levels that they found that we found with the study, this says average, but it was actually the median number was around 220 part per million, which is 11 times higher than the geogenic levels of 20 part per million. Mhmm.

So this is where it gets a little murky though because right below that, you're seeing they're they're saying that it's above the 400 part per million threshold that the EPA established a while back. But the problem with that 400 part per million level is that that was established as a risk assessment for essentially children playing in and around contaminated soil. So that's really about breathing in dust or in you know, indirectly consuming soil with dirty hands.

Yeah.

It's not a level that was really hyper focused on can I grow safely in that soil?

Yeah. So that was Can I work that soil every single day? Like, can I be in it every day for a job? Yes.

Yeah. So that 400 part per million level is is maybe more accurate for that. The California EPA, as California often does, they have slightly more stringent standards that are more akin to what European standards are for this a lot of times, and their cautious rate is is slightly under a hundred part per million or 80 part per million. So I've kind of my new recommendation, just in general based on our work and the work of others and other recommendations, is if you do a lead soil test, right, whether it's PXRF or like a wet chemistry analysis that the lab does, there is some difference with that, which I didn't quite get into in terms of calibrating that PXRF machine. But in general, if it's if it's less than a hundred part per million or in that kinda 80 to a hundred part per million range, you're probably okay.

I mean, that's definitely above background levels. But in terms of, like, growing in it, working in it, it's likely okay. It's when you get above a hundred part per million and then the EPA, four hundred part per million is another threshold. It starts to get murky in terms of, like, the risk of of that soil, right, with lead in particular. I've seen ranges all the way up to 1,200 part per million that that Andrew and George looked at where depending on what you're growing, that there might not be any uptake.

Right? So tomatoes are a good example. In this study in particular, they found that if soils were contaminated up to 1,200 part per million and they grew like a fruiting crop like tomatoes in them, there there wasn't any detectable lead in that edible portion of the fruit. Now maybe in a carrot crop in a 1,200 part per million soil, that might be there might be a little bit more uptake, more accumulation, more risk with in actually consuming those vegetables. So there's still a lot of gray kind of uncertainty with recommendations for growing and and what your lead levels actually are.

With some research like this, we're starting to refine it a little bit more. But again, you know, back to what with Ken's question earlier, it it it's all gonna come back to what's the quality of my soil anyway. Right? Does it drain well? Is it even actually a native soil?

So if it's even if it's not contaminated or kind of in that gray area of contamination, you might not wanna grow in that soil anyway, right, because of other factors. So capping it off, bringing in new soil, compost and and topsoil mixtures, You might end up doing that anyway. So and when you do that, you kinda negate growing in the soil and and there's less concern about the levels of of contamination in your soil, if that if that makes sense. And and the last well, not the last thing, but the one thing I do want to mention that is pretty clear with this work as well as when you look at the literature, you know, because when you're thinking about growing in contaminated soil, your first concern, and you were just kind of alluding to this, Chris, is, oh, I'm growing in it. The plants are gonna take the lead up.

I'm gonna eat the plant, and then I'm gonna get the lead in me because of that. I would what I would call that is an indirect or secondary pathway for exposure. It certainly can happen and there are groups like especially young children that are really sensitive to lead for cognitive development that it's really important to pay attention to that. But the primary concern pretty much for everybody is that direct lead exposure to what you were saying, working in the soil all day, breathing in contaminated dust, not washing the produce, and and actually ingesting the soil itself. That is likely the bigger risk factor by far.

And we've known this for a while, is why that EPA four hundred part per million threshold has been around for a while because children living in old public housing stock that are exposed to, you know, lead paint dust or contaminated soil in their playground, like they're getting they're getting exposed to to lead that way, and and it was causing cognitive issues with with small children. So we've known that that direct exposure was was a big problem. So for growing in it, for farmers and gardeners, the one thing you can do to kinda knock that off as a best practice is just to, you know, not have any exposed soil. Right? So we're putting down landscape fabric.

We're putting down mulch. You know, we're we're not working the soil too much when it's dusty and dry. So or maybe we're even wearing masks. Right? We talk about PPE with handling pesticides.

But what about, you know, breathing in dust and soil and and those issues? We we often overlook that. I mean, think even wearing n 90 fives if you're in a super dusty potentially contaminated soil is probably a good idea. So it's it's little best practices like that in conjunction with testing your soil that kinda lead you down a path of like what should I do if my soil is contaminated?

We'll we'll link to this article that you've you've shared with us, Zach, and it it looks at lead. Is there another soil dataset? Is there other contaminant datasets out there that people can can see online, or have those not been developed?

Good question. This one is for for lead, what I just showed you. That was just for lead. There may be so there's the published work, and then there was a couple links in the article. I think it was the mapmyenvironment.com, I think, that they'll find, where there may be other contaminants from other research where you can kind of they have, like, GIS files like that to overlay it to show you maybe there's other contaminants.

I mean, that's like an open source thing. It's welcome to map my environment, visualizing urban environmental health around the world. So, yeah, you can actually view the map or you can actually contribute like, soil samples to it, and that's it's like an open source mapping project. So that just looking at that map, you might be able to find other things of interest, but certainly it doesn't have, you know, every known possible contaminant and what the potential exposure levels are. I mean, lead, again, back to our site assessment, I mean, lead lead is very much tied to historic, you know, use.

Right? Whether it's housing stock, automobiles. Well, Andrew, in his lectures, he gives a great example of of the Romans. We were just talking about the Romans. You know, every a lot of people know that story.

Right? Like, the aqueducts, they're they're so innovative, but all their piping was made out of lead. So it was it was malleable. It was easy to make lead piping, and, you know, they were inadvertently, you know, poisoning themselves with with lead, and they didn't know it. So it was it was, like, a good idea at the time, but in retrospect, it turned out that it wasn't such a great idea.

So lead lead, we can really tie that to historical site use and and maybe like the arsenic example with pesticides. But some of these other environmental contaminants with industrial use and brownfield sites and and and contamination like that. That's there's there's research, there's study, there's work done in that space, but it's not super clear. Like, I'd like, I have some checklist I've developed for urban farmers that wanna develop a site, but I it certainly is not exhaustive. I can't you can't think about every possibility, which again ultimately leads us down to this in situ remediation where we end up just kinda capping the soil potentially if if we don't know for sure and and kinda bringing in a new media that we make, another type of technosol or anthro anthro sol, but a beneficial one that we use to kinda grow in.

So it it's complicated. It's it's it's you know, there's a lot of potential for urban agriculture. We're seeing it now. There's a lot of interest in it, but there certainly are significant upfront considerations you need to think about before just, like, starting to throw stuff in the ground and and growing it.

Well, that was a lot of great information about urban farming and dealing with soil contamination. We had a great conversation with Zach and we are going to split this into two parts. So next week, look for, part two as we continue this conversation with Zach about remediating contaminated soil kind of in a urban vegetable or farm situation and some of the pitfalls that we run into, especially when it comes to soil management and all that compost we wind up throwing on the ground, which, you know, some people say compost can do no wrong, and as you'll find out next week, oh, it kind of can. So stay tuned for that. Check us out next week.

One of Good Growing podcasts is a production of University of Illinois Extension edited this week by me, Chris Enroth. And a special thank you to Ken Johnson and Zach Grant for hanging out and chatting with me about urban farming and soil contamination, and look for that conclusion next week. Well, listeners, thank you for doing what you do best and that is listening, or if you're watching us on YouTube watching. And as always, keep on growing.