Transcript
Speaker: Hello and welcome to Pardon My Planet. I'm Anne -Charlotte, your host. This episode is part of our series on soil health. We've explored ah what healthy soil, really is, how scientific knowledge travels from research into real -world decisions and today we turn into one of the most pressing and often invisible threats to our soil's pollution.
Speaker: Soil contamination affects wide areas in Europe, from former industrial sites and mining areas to agricultural land exposed to pesticides and heavy metals. It threatens biodiversity, water quality, food safety and human health. And yet,
Speaker: it remains one of the least visible environmental challenges of our time. To explore both the diagnosis and the solutions, I'm joined today by two researchers who work at the frontline of this issue. Virginie Derrick is a geochemist and expert in contaminated and land management at BRGM, the French Geological Survey. She is also a contributor to the Eastlander Project, a European research initiative developing new approaches to guide remediation strategies for polluted sites. Michel Chalot is a professor at the University of Marie and Louis Pasteur, specializing in the development of nature -based solutions using plants and microbes. Organisms to Remediate ah Polluted Soils is also the coordinator of the EDAFUS project, a European research initiative exploring how soil can be restored and monitored through those nature -based approaches, working with the biological processes that make soil come alive. Together, we look at what soil pollution actually means in the European context, how contaminated sites are detected and characterized, and what science and nature can do to help restore what's been damaged. Virginie? michel welcome to pardon my planet hi hello thank you ah for for joining us today
Speaker: When we talk about soil pollution, it can feel like a distant technical problem, something that happens to former factory sites or mining the zones.
Speaker: But the reality is more... widespread and more complex and than that. Virginie? How do you define salt pollution simply and why does it matter so much in Europe today?
Speaker: I would define soil pollution as um human activity. um impact on the environment. So it can be on soil, but it also... go from Seoul to...
Speaker: groundwater, surface water and impact ah many ah media. in the environment It matters because ah human activities...
Speaker: There are so many ways to... impact the environment. with the specific threat that is pollution. That was mentioned from...
Speaker: very historical activities where pollution was not acknowledged at all. was not an issue, actually. So this...
Speaker: is from many, many years of activities to impact. in many ways. Ziaria. that is potentially contaminated is very large, very wide. so The challenge is in. So very different kinds of pollutants that can be included in that historical activities. And it can be very... Invisible like chimneys dust.
Speaker: from the chimneys, so very invisible but also very big. and that you cannot ignore. So there are many forms, like um what we call hotspots of pollution. That can be very visible.
Speaker: But the risk associated with this pollution can be also very diverse to the human and the environment. That was the topic from... the historical activities throughout throughout your Europe.
Speaker: is um an issue for... for all. When we even try to define what counts as polluted it isn't from what i understood always so straightforward as well because Why is it so difficult to talk about a polluted soil without well taking a local and geological context also into account? This is also a question ah for for you, Michel.
Speaker: Yeah, I would say that. There are so many situations. diverse situation in terms of pollution. in France, but not only in France, in Europe also. depending on the type of soil, depending on the climate, depending on the on the type of land use. on the type of pollution or so when you try to look at solution or the impact of pollution, it's very complicated to have an homogenized, let's say, type of actions. It's so very diverse in Europe.
Speaker: And yeah. It is very... um I would say unrealistic to see a kind of standard. solution that could be applied in ah in in different countries. so Even within France, I mean, there are so diverse situations that it's difficult to have a generic solution.
Speaker: we need to go for a specific solution and that's why usually soil policy has always often be competence at national level, not at European level. which is not the case, for instance, with air or water, air and water.
Speaker: usually have been competent at the European level, but not so because of the difficulty of harmonising. diagnostic solution etc is it also linked to the different types of soil because as we've heard also in previous episodes in this series the diversity of the types of soil add another layer of complexity about defining for you know this this ah type or this type is it also part of why maybe it's difficult to harmonize.
Speaker: Yeah, because I mean, ah the same pollutant in a sandy soil or in a clay soil will be will have a different behavior. So it's very difficult to have a solution that apply a different. to different type of soil. So it adds a level of complexity to the situation for sure. Once we understand what pollution is, the next question is what it does. to the soil itself.
Speaker: also to the living organisms that depend on it and beyond. What are the pollutants you're the most concerned about in European soil today and how do they affect the biological life? of the soil There is no generic.
Speaker: way to say this this is the one. Like this pollutant will always be the one that I'm most concerned about. But... What? What I like that has been developed in contaminated land management is more questions. that You need to have answers too. It's like. What is the source of the pollution?
Speaker: How does it transfer in the environment? What is the risk related to this presence? So the answer to these questions will drive... The... management of this pollution and we allow for a side -by -side adaptation of pollution.
Speaker: Now, the concern... related to the present of a pollution. will ah depend on where it is. For example, if I have a very heterogeneous soil, for example, um organic solvent that will go in the environment, if the soil ah has a lot of heterogeneous parts,
Speaker: it will be more difficult for it to know where it goes. if it lasts long and is very toxic. it will be a concern. If this contaminant degrades in more toxic components, it will also be a concern. And if it is...
Speaker: ah volatile and it poses problems to the indoor air, it will also be a concern. concern So the concern about pollutants is very different in many aspects and we will need to um categorize.
Speaker: the the kind of ah concern it poses. Does it pose ah a w risk to the indoor? Does it pose a risk to the underground water? Does it pose a risk? so I wouldn't give one pollutant to be most concerned with. But let's say if it spreads largely in the environment, is highly toxic and is volatile, you've got a a winner here.
Speaker: ah Of ah concern, obviously. you Have we noticed? Let's say, do you do you happen to have winners in these ah very dangerous categories? Well, ah in the Icelander project, i actually, we did that kind of exercise. Bye.
Speaker: prioritization of contaminants of emerging concerns. which um kind of aggregated the quantity of each substance that can be released in the environment. How does it move in the environment? ah does it Is it toxic? Does it have toxic, degraded products, et cetera, to end up with a top list of ah contaminants of emerging concern?
Speaker: as kind of a checklist at national level of... do I manage this so substance correctly ah in my country? Do I need methodological ah tools, regulation tools? Do I need to do something for this substance? so it's a Yeah, really a checklist for decision making to know if...
Speaker: You want to have more tools for these emerging contaminants.
Speaker: And. This Icelandic work that has been developed by my colleagues and others from the Icelandic Consortium. um did also another checklist for more like a ah research roadmap or agenda for Let's check these substances that we cannot prioritize because we don't have enough data.
Speaker: Because when you... arise ah new substances that you don't have this historical data that For pollution, we have we know how to sample them in soil and water. We know how to analyze them, sample, know how they move in the environment, in different media, soil, water, air. We know how to degrade them and how to...
Speaker: to decontaminate and how to evaluate risks. So when a new substance arises and we don't have any data on this substance, you have many, many information to have.
Speaker: Two. be able to reach this good management. of this substance. Michel, on the biological life also of the of the soil, what are usually let's say the most concerning consequences or the ones that you see the most often in the type of let's a very ah problematic ah pollutants?
Speaker: I would say that whatever the the contaminant... they have a huge effect on the quality of the soil. A few examples for incentive pH. pH is something it's a very important parameter in the soil. It should be stable.
Speaker: to ensure ah plant nutrition, to ensure that most microorganisms can survive in this in the soil. It can also affect the the nutrients. availability and if you are blessed nutrients but then There will be. an impact on crop production, for instance.
Speaker: or even sometimes. the pollutant can replace the nutrient. and instead of potassium for instance in the leaf of a plant you will find zinc or you will find cadmium So this is niverggen this is a very important impact.
Speaker: so fertility may decline after we we find the the after the soil is polluted. And then... If fertility is declined, then biodiversity also will decline. And this is also an important issue in the management of polluted soil.
Speaker: how the biodiversity is affected, microorganisms may just disappear or at least the microbial communities will be reshaped. and sometimes not with the most interesting microorganisms. That's really a problem. also earthworms.
Speaker: which are very important in the living soil, may disappear and this is a real indicator of wilted soils. We often measure ah the... the number of first ones so the the pollution um will have some kind of cascading effect.
Speaker: And at the end... the the pollution may affect. the production of Crops. And then... affect the food that we consume, not affect on the or the yield that are produced, but also the quality.
Speaker: We often talk about the cadmium contamination of cereals. or chocolate. We found some calmium in chocolate recently. So this is a major concern for for the population.
Speaker: especially because pollutants can stay in the soil but also can migrate in the groundwater. So... you can find the pollutant far away from the original source so that's That's another concern. And another challenge, I guess, as well, too, when you want to know if an area is is polluted and you want to know where it's coming from and so on, it becomes challenging because...
Speaker: it's spreading and you were ah mentioning just a moment ago that we were talking a lot about kenyon recently, right, in the in the news, especially ah in France also, it's been a huge topic of discussion. Usually when we talk about pollution, there is a sort of perception gap there.
Speaker: What do you feel? people most commonly misunderstand or underestimate when we talk about polluted soils. in in fact the the point is that The problem is that soil pollution is something invisible.
Speaker: It cannot be seen, it cannot be... smelled it. And the the effect is usually very slow. So you will ah be impacted. I mean, we we talk about calmium, but calmium has been applied. to the agricultural soil in France and in Europe for for decades.
Speaker: But... Now we... Only now we we we see the effect the near back the impact of um on crop production and on the quality of crops. and this is uh This is an old pollution.
Speaker: but the effect is just emerging. and This is the same for a number of other contaminants. It's not like an oil ah spill where you see the immediate... impact on the on the environment for soil pollution. Diffusal pollution is very different.
Speaker: And we... We need to better communicate with the public. That's what we do within the EDAPOS project, trying to go to the... to the young generation to this problem ah of pollution.
Speaker: and to sensibilize the young. people to what we call the Invisible pollution, not only the visible pollution but also the invisible pollution. such as Calmium, PFAS, etc.
Speaker: As you've been saying before, both of you, it's it's such a complex topic. It's so wide and it depends so much on the context of the the land at this moment precise moment and its topology and so on. um I guess it must be challenging also on the science part to explain all of these complexities. When you address such a...
Speaker: a wide topic that makes also such strong reactions from the public. Hmm. Yeah. um So difficulty with... ah contaminated land management is that It can be so sensitive. especially when it is present where People are already in contact.
Speaker: is the pollution that is the most sensitive. then suddenly you realize that you are at risk from this pollution. so So this is very sensitive. And ah in France, we have this very immediate... ah um kind of methodology to evaluate very rapidly if there is a risk. and This communication is very different from a communication with um a site that is polluted.
Speaker: But... to... the pollution is not in contact contact with the population. And you can do some... um some works You can work the pollution to make it to make it good for further uses. So there is this two kind of communication, I guess. We already have tools and the soil monitoring law is giving a lot of triggers to value communication.
Speaker: regarding souls in the soul monitoring law communication is very present both at the monitoring and a lot ah in the part dealing with contaminated land management. We will have communication better communication in contaminated land management in Europe.
Speaker: thanks to this soil monitoring law. Let's say in France we... kind of already has it. Information on potentially. Uh. on sites that can potentially have an impact on soul.
Speaker: And we already communicate on the area where we know we have pollutions and where um some ah remediation has occurred.
Speaker: And we communicate. after remediation? Does this residual pollution need to have a kind of a follow -up? after that you have residual pollution following ah um a remediation but you need to have a follow -up because that was an industrial site and maybe if there is a school or ah houses that are being built then you need to make sure ah the soil the project is okay with the quality of the soil so
Speaker: We have the... whole um
Speaker: kind of roadmap. to this communication. Actually, in the Iceland project was developed a roadmap to contaminated land management, which was a step -by -step what tools you need to um to have. at each step of the kind of life cycle of a site. You need to do these inventories that is asked in the soil monitoring law. If you're in a remediation process, here here are the building blocks you can use. And if you are in a follow -up, then you want to monitor. Maybe. yeah this soil quality and how it evolves following remediation.
Speaker: So yeah communication is key. But. Let's say... It's... has to be practical. got to communicate to say here are some historical activities and we are not certain that The quality is good, but we don't have measurements yet. So this um communication about uncertainty.
Speaker: Do we know how... Do we not know? Kind of. It must be pretty when you say, well... we don't I don't know. It may be. But... um Yeah, communication is is really key in in that aspect.
Speaker: if i may add just something about uh yeah the the soil quality because this is important. indeed to to evaluate and This is part of the diagnostic phase ah of ah of any project. when when it comes to the remediation of a polluted soil.
Speaker: you need to put the diagnostic on the soil. and for that we need the to to sample the soil and then to measure. some indicators. And...
Speaker: the indicators that we are that many ah researchers are many people are using is the what we call the bioindicators which are living organisms.
Speaker: that may be sensitive to the pollutant. It can be plants, it can be microorganisms, algae, etc. And these are usually part of a battery of of the tools.
Speaker: that we use to evaluate the impact of pollutants on the soil health before any restoration. so we need to diagnose the soil at let's say at the t0 when nothing is has been done yet and then We'll talk a little bit later about this solution. but after the solution has been implemented it's important to apply again these tools to be sure that what we have been implementing has indeed a positive impact on biodiversity.
Speaker: on the more generally on the soil on the health of the soil. so There are a number of tools that we are applying within the the EDAFOS project. to evaluate both.
Speaker: The... the state of the the biodiversity. and the state of the health of the soil. before any any intervention. We just talked now about the the different types of tools that we use to diagnose a contaminated site.
Speaker: Do you have a particular challenge? ah When you have to analyze an industrial or mining site and when you have to characterize what type of contamination we are talking about, is it specifically ah challenging when we talk about mining or industrial sites?
Speaker: Hmm. Yeah, as we were saying, there is no general approach, so it must be a side -by -side approach. And... You have...
Speaker: many challenges because If you aim for ah industrial sites, you might have many, many substances including ah substances of emerging concern.
Speaker: on which sampling and analysis is not yet very ah mature because There is some...
Speaker: ah research ah going on. But on, let's say, historical substances that have very different behaviors, this is a challenge because they will ah ah have effects on one another. So it's not like you're taking taking one substance and another one. So when they are together, whether their behavior is more difficult to predict.
Speaker: So that's for industrial. And my insights, well, they are the... So... mainly in France, at least, the historical aspect. And that works also for... historical activities. that you may not have the memory of everything that you're looking for. So you you have... That kind of... of challenges. and For some more... um Not.
Speaker: hotspot and maybe medium Contamination is ah to know where does the source comes from, if you have very diverse activities that can have impact with the same pollutant.
Speaker: So to know... ah which is responsible for this pollution. And. For metallic contamination like arsenic, lead, it can be ah naturally present. in the environment. So it's the impact. um ah from the mining or the industrial activities, or is it naturally?
Speaker: present in this environment. And if the environment is very homogeneous, this is might be easy but if this environment is very heterogeneous and the the um metallic content um has a wide variation. this This is a real chat.
Speaker: So. yeah many challenges and and that's that's indeed a very important issue because usually when we when we do research on polluted soils we start with experiments in laboratories We test. in laboratories and then when we want to implement in let's say real world situation or condition then we faced as you said.
Speaker: heterogeneity of the pollutant. and heterogeneity in the soil structure, heterogeneity of the microbes present, of the vegetation present at the site, so it's very... it.
Speaker: And in those solutions you were mentioning, traditionally while cleaning up a contaminated site, it can mean ah excavation, chemical treatment, so heavy machinery, for example. But there is a growing body of research exploring a very ah different approach, one that works with nature, rather than, let's say, against it.
Speaker: Michel, how can plants and microorganisms help clean up a polluted soil? And what in what situations are these approaches?
Speaker: let's say, the most relevant. so So when it comes to... a solution to manage the poll the pollution. Of course, there are traditional ah solutions such as excavation or soil replacement or ah cleaning the soil with... ah with different solutions, but it's very expensive.
Speaker: It's very rapid. That is very expensive. and it only applies to very small area. I mean, it's very costly, so you cannot apply this traditional solution to a larger space, large field.
Speaker: maria So to treat contaminated soils, then you can paste your technology on on living organisms. especially plants and microbes.
Speaker: uh the advantage of plant it's is that they will stabilize the pollutant in the soil. more one of the most important effects of the vegetation. a soil without vegetation that is polluted by a metals or any other type of pollutant.
Speaker: is a real concern because the pollutant will migrate more freely. Whereas when there is vegetation, The plant produces a number of chemicals that will attract that will fix the pollutant.
Speaker: and then some of the plants may also take up Metals. we have isolated among europe a number of plum that are able to capture zinc. can we um arsenic, for instance, or this type of of metals. Nikkei?
Speaker: and then you can also ah combine a plant with microorganisms because the plant will stimulate the microbial communities. and within these microbe communities you may find some microbes that are able to degrade.
Speaker: organic contaminants such as hydrocarbons or chlorinated compounds. So there are solutions. And if you combine... these plants.
Speaker: with microbes and you can also ah select organic amendments, for instance. that can help. the plant to to grow or to develop. the microbial communities. You can also mix different types of crops, and that's indeed what we are doing in the EDAFOS project.
Speaker: trying to mix popular with some type of other type of vegetation that are able to capture metals and the idea is to optimize the colonization of the soil by the vegetation.
Speaker: So the advantage is that these solutions are at lower cost. They are usually environmentally friendly and also there is usually a better acceptance by the public.
Speaker: the limit The limitation is, of course, the long time frame because you cannot... That's what I was about to ask you. Yeah, it must take a long time. Yeah, because, you know, I always said ah human activities have...
Speaker: generated pollution for decades. And we cannot expect. uh to find solution to restore the polluted solids in just a few months. I mean, it's unrealistic. So we need years and decades to to decontaminate solids, at least.
Speaker: Stabilize a solid is very rapid. In one, two years you have the vegetation thats stabilized the that will help to stabilize the the pollution. but to decontaminate it would take much longer.
Speaker: and But it's visible. and Which is a great news for for for sure, because it's a challenge that we have on our let's say all parts ah of our daily lives. But indeed, ah this ah this ah longer long is to take into account. And I guess also, as you mentioned, it's also the type of use that you will do of this ah soil in which ones are the priority as well ah to decontaminate and which are the ones that could, let's say,
Speaker: take the time to be depolluted based on their on their uses. On the other aspect, even though we've explained it a little bit, Virginie... Islander helped move from, ah let's say, contamination diagnosis to an actual remediation strategy. How does it look on the on the ground?
Speaker: Um, If you're referring to the roadmap that Icelander has produced, um it It really focuses on... different Kind of a journey if you have one site. you're dealing with from. the inventory of activities, the inventory of the soil quality, to remediation, to follow -up, to tools if you have a portfolio of sites which are different. front
Speaker: kind of side what can be done in that aspect on ah the whole process of remediation including financial ah tools. What we have worked also is on remediation itself to put forward what was called low input remediation techniques. in order to set
Speaker: to ah put forward. techniques that have low input both in um energy, so so as to have this input in any remediation.
Speaker: you have this cost -benefit analysis which aims to choose a remediation technique that is most fitted to the site.
Speaker: Let's say that you compare different kinds of techniques that aim to the same objective of remediation and you have different kind of techniques including for fetal remediation, bioremediation, which takes longer time and can be chosen if the site can be remediated. What we added also, apart from consideration to low input,
Speaker: is also the integration of soul health. from the beginning to the end. that says that We added information that...
Speaker: So how should we consider it? at the start so what Do I want to do... with this side? Do I want to to have a school there? In that case, you want to have very low residual contamination, but do do I also want this salt to be functional in terms of carbon, in terms of water, in terms of biodiversity? So it's kind of...
Speaker: saying, okay, you have a soul at the start. and to ah inquire about the history of this salt. Where does it come from? has Is it a technosol, what we call a technosol, which is also soil -built? a built soil, let's say. If you are in an urban area, it's usually a soil that has been moved a lot. And.
Speaker: What do you want? of the soul after the remediation. which will ah ah allow you to choose this technology. from very slow, but... Maybe your technology can ah remediate and improve your soil quality in the same time.
Speaker: or you want to have ah this remediation very fast. I say fast and furious. Fast, furious and probably a bit costly, probably.
Speaker: But like with ah heat or with well so thermal remediation or chemical remediation, but that leaves your soil... barren and if your objective is to have a functional soul then you have to take into account further Regeneration.
Speaker: technologies. in the process. So it allows you to choose In knowing knowing that, okay, I will choose this pathway. This salt pathway, remediate fast, but but because maybe this site has...
Speaker: to be remediated very fast because there it is an urban site that you cannot have pollution.
Speaker: which poses risk to people around. I don't know. So it's not to have on one side thermal remediation and on the other side fetal remediation, but kind of choosing them choosing them side by side. In Iceland, we try to put soil health consideration at each step. If you want to really go deeper in that knowledge, you acquire information in a stepwise approach. But at least have this...
Speaker: question which way I was ah saying in the beginning. ah Now it's not only what is the source, what is the transfer, what is the risk, what is the sole function and what is the objective in soil health aspect I want to. And even if the answer at first is not very precise, at least you have the answer which gets progressively, stepwise, precise. And this ah conversation, again, just reinforces the fact that the better you know about the soil and all its functions and so on, the better as well you can take ah decisions. And this is ah both ah those projects also, ah what they are contributing to.
Speaker: Thank you Virginie and Michel, thank you very much for this conversation. You've given us a clear picture of what soil pollution really means, the scale of this challenge as well, the complexity of the diagnosis and the real promise of solutions that work with ah with nature. This series is produced through several EU -funded projects mobilized on soil health, islander, EDAFOS, bioservices and in base soil. You can find all the details at lgi .earth .com. You can also listen to all episodes of Pardon My Planet on Spotify and Apple Podcasts.
Speaker: Thank you for listening. Until next time! Bye -bye! Thank you.
