Green chemistry in practice - Anna Zhenova, Green Rose Chemistry

In this episode I speak with Dr Anna Zhenova of Green Rose Chemistry.

Green Rose Chemistry are a mission-driven consultancy applying the principles of green chemistry to help organisations to develop more sustainable products and processes.

Our conversation covers:

• What does Green Rose Chemistry do?
• Green chemistry as a grass roots movement - the need for education and champions within organisations
• How different sectors are at varying stages on the green chemistry journey
• The importance of language in communicating sustainability
• Examples of green chemistry solutions - chemical substitution vs functional substitution
• Reflections on connecting chemical safety with product development and other disciplines
• Avoiding tunnel vision and uncovering win-wins - a case with safer solvents
• What is green chemistry? 12 principles, 3 pillars
• On externalities - economic vs moral questions
• Chemicals in the environment, persistence, transformation products, and mixtures
• Dealing with overwhelm and working within your sphere of influence
• How do green chemists differ from traditional chemists

Green Rose Chemistry | Sustainable Chemistry Consultants

Beyond Benign

Green Rose Chemistry | Training

Advancing Safer Alternatives Through Functional Substitution | Environmental Science & Technology

12 Principles of Green Chemistry - American Chemical Society

Visit my website for more content and insights www.embarkchemical.com

Transcript

Chris: Hello everyone and welcome to the Chemical Journeys Podcast. Today I'm speaking with Anna Zhenova, who's the founder and CEO of Green Rose Chemistry, a company that helps clients to adopt safer and greener chemicals, to create sustainable products and processes. Anna, thanks for joining me.

Anna: Hi Chris. Thanks for inviting me to join the podcast. It's a pleasure to be here.

Chris: No problem at all. I originally came across you when I was doing some work with Peter Fisk, and he mentioned that you were somebody he had worked with and that I should get in contact with you. I think the first thing I did was look up your website, and I was really impressed with the way you'd laid it out. I thought the artwork was really beautiful, and there's obviously a lot of passion coming through in terms of the mission that you've got within your company. And it's also really nice to collaborate with somebody else who's in this world of solopreneurs. So yeah, it's great to have you on the podcast.

Anna: Well, I made that website myself, and I think graphic design is not often appreciated in the chemistry world, so it's nice to hear kind words about it.

Chris: No, definitely. It was really, really nice. I'd recommend anyone to go and take a look, because it takes you on a little journey through the website. I think we could start perhaps by you telling us a bit in your own words about Green Rose Chemistry — what kind of work are you doing, and who are the sorts of customers that you're serving?

Anna: Yeah, sure. So we are a very small consultancy, but we do a lot of different work actually. I sort of disregard the advice to focus narrowly that's often given to chemistry consultants, because I personally like learning something new all the time — every day if I can. While we do specialise in green chemistry, the principles of green chemistry are broadly applicable across basically every sector, every type of chemical manufacturing, chemical use, and chemical distribution. So we work with a really wide range of sectors and projects.

I always say we're a mission-driven consultancy. We aim to accelerate the sustainable chemical transition by lending our expertise to other companies that need it, and that takes a couple of different forms. One is the technical side of things — we provide technical R&D services in green chemistry. And the other is the communications side of things, which covers development of marketing content, advice on opportunities, and technology landscaping. And then also training courses, which is our most recent offering.

We've offered training courses on demand a few times in the past, going back to 2022 — so almost four years now — and they've gone really, really well. So this year we've taken on a consultant who actually has a background in education, and she's fantastic. She's helping us to spin it out into a proper offering where we say, okay, we do offer training courses, and we publicise that as part of our services now. We're already in quite a few discussions after having started to publicise that a couple of months back.

Chris: That's awesome. I think the education side is such a big part of this overall sustainability movement, isn't it? Because people need to retool in terms of how to approach things.

Anna: There's a wonderful nonprofit in the US called Beyond Benign, and they are trying very hard to get green chemistry integrated across the board into education — from primary school all the way through to university commitments to integrate green chemistry into their programmes. That's run by Amy Cannon and she's doing a fantastic job. But the problem that I've noticed is the professionals who are already in the industry. They might care very much about sustainability, they might have a lot of expertise in formulations or extraction, but getting the green chemistry expertise in order to take their company and make it greener — that is really challenging.

Once you're already in the industry, if you don't want to go back to get a master's or a PhD, there's not a lot of options out there. So that's the gap we're trying to fill, because we don't have much time left to make that transition happen, and we can't wait until the next generation of chemists comes into the workforce.

We need the chemists who are in the workforce now to understand the principles of green chemistry and be able to practically apply them — to understand what a lifecycle assessment is and why that matters for chemistry, to understand about environmental justice and the intersection of chemistry and environmental justice, and how their work is contributing to that. So we really need to retrain the chemists who are already out there — the ones who care and are convinced it's a thing worth doing, but just don't have the skills to actually do it themselves.

Chris: Yeah, I mean, it sounds like a really important role that an organisation like Green Rose Chemistry can play in terms of getting this knowledge distributed throughout the economy, right? Because the challenge is that it's difficult to do this in a purely top-down manner — you kind of have to do it through conversations.

Anna: Yeah. And that's the hope, right? We are a small consultancy, and initially I thought I'd grow the consultancy and we'd become really big and end up providing help to dozens or hundreds of companies at any time. But even if you imagine my company suddenly tomorrow had 50 employees, that still wouldn't be enough to meet the demand for green chemistry, even in the EU, much less around the world. And so I've realised that those kinds of training programmes — which I think we're uniquely positioned to deliver because we have a really good combination of technical expertise and communications expertise — are actually going to be more impactful if they embed those skills directly within the companies.

A, it's more consistent. B, they have a better understanding of the company's needs. And C, the company spends less money on green chemistry consultancy, so they're more likely to actually do green chemistry. The cost barrier can be hard to get over for a lot of companies.

Chris: Yes. And they need to integrate it as part of their DNA, rather than it just being something they purchase from a consultant, like you say.

Anna: Right. Because a lot of the time when we do projects, they're not always taken forward — for whatever reason. Either priorities change, or the employee who really believed that project was necessary leaves the company and nobody takes it forward. There are a lot of reasons that reports get dropped after they're commissioned, and that's heartbreaking for a mission-driven consultancy when we're trying to make an impact. So actually transferring those skills to chemists who are in the industry — and not just chemists, but sustainability professionals who need to understand a little bit about chemistry, and toxicologists who need to know more about process engineering — doing that sort of interdisciplinary skills transfer is really powerful.

Chris: Yes. It sounds like, in a way, within companies you need an advocate. Do you typically find that's at the ground level? Or do you tend to engage with companies higher up, with a view to getting things implemented in their day-to-day processes? Or do you find you need to work with people who are perhaps at the coalface and want to bring these concepts and processes into the company?

Anna: I mean, I think ultimately it has to be both, right? The coalface chemists — the ones who are making the decisions about choosing a solvent, choosing a reagent, trying this, trying that — they need to be equipped with the tools to make those choices in a greener way. But you also need support from the very top, because if you have managers or VPs or CEOs asking, 'well, why did you spend 10p more per litre on a greener solvent — that's not consistent with our cost-saving initiative', then even the chemist who cares and is equipped with the tools is not going to get anywhere in the end. It has to align throughout the company, all the way from the top down through the chemists who are doing the actual work.

But we most often work with somebody kind of in between — it'll be like an R&D manager or a formulation director or something like that, where they have enough decision-making ability and enough clout within the company to push and say, okay, we actually need to spend some money on this. We need to reskill our chemists, we need to reskill our biologists, et cetera. So it'll often be somebody with a higher-level title who has seen the light themselves.

Right now, we're actually not in the business of trying to convince companies that they should be doing green chemistry, because there are enough companies out there that understand they need to do it but just don't know how. So that's our sweet spot, our working space right now — companies who have seen the light but don't have the expertise to act on it.

Chris: No, that's really interesting — because that helps to describe the landscape where we are. And different companies are at different stages, I imagine, with different sectors in different stages of maturation in terms of adopting these principles.

Anna: Yeah. There is a huge sectoral difference, and some sectors are already so deep in that space that we don't even have anything to teach them — not sector-wide, but in general as a rule. Sectors where vulnerable populations are more affected — so like baby skincare, for instance. Anything that goes on a baby: parents care a lot about it being absolutely safe and as sustainable as possible. So that's a leading sector. Cosmetics and personal care in general already have this focus on natural, bio-derived, plant-based ingredients, because the customers who buy those products have feelings about those words.

And that's actually a really interesting thing. I know you work a lot in hazard and safer chemistry, and I also work with renewable chemistry and bio-based chemistry — making chemistry not from fossil sources, not mining it out of the ground in an environmentally destructive way, but ideally growing it in some way that locks carbon down, and then using that to make bio-based chemicals. The interesting thing about the bio-based chemical space is that nobody feels any feelings about the word 'bio-based'.

It's too technical, and yet it's the word that most of the bio-based chemical industry uses. The cosmetics industry and the personal care industry have stolen a march on other sectors by saying 'our ingredients are natural, our ingredients are plant-based' instead of bio-based, because that gets an emotional response from customers — that these things are natural. So they've done quite well with that.

But then companies like those in the automotive sector or the defence sector — these are sectors that are now starting to understand that this is really a problem for them. They've had other priorities until now. The automotive sector, for instance, has been very focused on better fuels and more lightweight vehicles, because that's where the bulk of their climate impact is. If the vehicles are lighter, you don't have to move as much weight, which means you save a lot of energy. There were a lot of savings to be had there. And if you use bio-based or alternative fuels, or even switch to electric vehicles, you open up the opportunity for renewables in that sector, and that makes a huge impact. Now they've made huge inroads in that direction, and we're starting to see demand from the automotive sector asking: what about the foam inside the car seats that we're still getting from a petroleum feedstock? How do we make that bio-based while keeping the car safe? In the event of an accident, you don't want that foam to catch fire — how do you do it using bio-based chemistries, and at the scale that the automotive industry needs?

In cosmetics and personal care, it's very easy to have a boutique brand — you can have tiny little bottles sold in packs of a hundred to the local organic shop and build a business that way. But you can't sell just two cars. So the scale of adoption for something like the automotive industry makes it much harder to change the materials going into it.

Chris: Yes. And it is still quite a nascent sector, isn't it — the bio-based sector? But it does seem that there's huge potential there. You've given an example around the foam in seats, and I guess it's an iterative process — we're going to need to solve for many, many problems individually, and each one is going to take time.

Anna: Yep. And there are often knock-on effects or synergies between the different individual parts. If you look at baby car seats, that's actually a pretty good example — the foam in infant car seats was impregnated with flame retardants that weren't chemically linked to the foam. You just take the foam and essentially dip it in a flame retardant bath, and then let it dry. So those flame retardants come out in the dust — they come out every time you put your infant in the car seat.

We're now starting to understand what happens to those additives to foams and furniture foams. What we've realised is they get into your bloodstream. Parents have now had the realisation that they don't want to put their child in a car seat that's full of flame retardant additives, because that is bad for the baby.

A company in the US figured out that instead of soaking the foam in flame retardants, they could use a cover for the car seat — the fabric covering the foam was inherently flame retardant, which meant they could remove all of the chemical flame retardants from the foam. And so they came to market and said: we have the first flame-retardant-free car seat. And they sold out their first production run basically immediately.

So it's interesting because you think: I need to replace the foam in the car seat, or I need to replace the flame retardant. But actually you can have a more systemic solution where you prevent the flame from reaching the flammable component. There's this concept in green chemistry of substituting not the chemical but the function of that chemical — that's called functional substitution, which is a term that Joel Tickner in the US came up with, I think in 2014 when he published that paper. It's really caught on since then, and now even in Europe people are talking about functional substitution — substituting what that chemical is doing, rather than substituting the chemical itself.

Chris: Yeah, that's a really interesting point. A lot of these chemicals we're using are delivering functions, and when we're looking to substitute a chemical determined to be undesirable, we can look beyond replacing it directly with another chemical and actually redesign the solution entirely.

One thing I've observed in my experience working with chemical hazard and risk assessment is that there was always a disconnect with product development. When we talked about driving towards safer and more sustainable chemicals, the understanding of technical performance always seemed to be a gap that was difficult to bridge. Are you seeing progress being made there? Do you have any experiences of connecting people to have more of those discussions between chemical risks and performance?

Anna: Not really — it is very much something that needs to be done. And this is something I've noticed in my own work: when we come into a company and start figuring out how to substitute a chemical for a greener one, we need to make sure that every relevant team is represented in the room. And not only that those teams are in the room, but that they're able to communicate with each other. Oftentimes the language they use is inherently different. You have your ESG folks, your sustainability team, who are talking about carbon footprint. Then you have your toxicologists who are talking about the inherent hazard of the chemical. Then you have your risk assessors who are talking about — not the hazard, but we need to look at the risk and how we can control it. And then you have your formulations or product design team who are talking about performance. If you're lucky, you have the marketing team in the room as well, there to talk about how they're going to sell this to customers. And maybe you even have your sales team reporting back on what it is that customers are actually asking about — do they care if something is Teflon-free, or do they just want it to perform?

If you have all of those teams in the room — which is rare, it's rare to even get full company commitment where every department sends a representative — even if you do get them all in the room, they're speaking completely different languages. So a lot of what we do is that sort of alignment work: trying to get people to communicate with each other in a helpful way.

We try to do it in quite a systematic way. Whenever we do an alternative assessment, we start by asking in quite a chemically technical language — what's the viscosity of this solvent, the boiling point, the auto-ignition temperature you can't go above? But we very quickly tailor it to who's in the room. Usually we'll have at least one chemist who understands most of those terms, but oftentimes they'll just say: we just need it to be non-flammable, and I'm not really sure about the exact auto-ignition temperature. And we say, okay, that's fine — just tell us in your own words what you need, and then we'll use our judgement to come up with a number that fits that.

A lot of that translation work is really critical to get the alignment you need in order to do a good alternative assessment and substitution work. Because otherwise you might think you understand what the company needs and come back with a solution, and they say: no, that doesn't suit us at all — weren't you listening? We've also had interesting cases where we come back with a solution that the company didn't realise they wanted, which sounds a little bit ridiculous.

But companies will sometimes have a laser focus, a tunnel vision on one thing. Sometimes it's cost, sometimes it's performance, sometimes it's carbon impact. And they lose sight of the bigger picture. We've had one case in particular where the customer was dead focused on cost. They were looking for an alternative solvent, and the one they had initially wanted to use was toluene — which is very, very cheap, but also very, very nasty. It has a lot of hazards including aquatic toxicity, and it's very volatile so it escapes into the air immediately if released. They were basically saying: if you can't find us something that's roughly as cheap as toluene, we're not going to be able to use it.

So I went and tried to find them something as cheap as toluene but without the flammability hazard, which was their main concern for insurance reasons. If something like that existed on the market, they would've already been using it and wouldn't have needed to come to me — because it would have been an easy choice. Normally, by the time a company comes to me, they've already explored the easy choices and are at a loss, needing help deciding about trade-offs rather than making an easy choice.

So this company was very, very convinced that it needed to be cheap, basically the same performance as toluene, and just not have the flammability hazard. I eventually came back with a solvent that cost ten times as much as toluene and performed much more slowly — it would do their cleaning process in, say, 24 hours instead of 10 minutes. But the company in the end was actually 100% happy with that solution — they were thrilled, even though it was the polar opposite of everything they said they wanted.

Because when we zoomed out and looked at the bigger system — and we actually brought in a risk assessment consultancy to do this, because we needed somebody well practised in systematic assessment and costing risk — we went through two scenarios: using toluene, or using the safe solvent. They actually found that, even in the immediate term, the safe solvent was cheaper. They would have to spend ten times as much to buy the same volume of solvent, but they wouldn't have to replace it very often. And the controls required for the safe solvent were so much lower. They could have a tank of it inside their manufacturing facility, the tools could be cleaned directly into the tank and moved back. Even if it took a full day to clean the tools, they would still have them on site, they would know exactly where they were, and they would know when they would be cleaned.

The other scenario — with toluene — would have to be external to the building. They would essentially have to build a satellite site on their manufacturing site, across a car park from their main building. They would have to train their employees to safely forklift their very expensive machined aluminium tools across the car park without hitting anybody. They would have to have not just a secondary control but a tertiary control in case of a release, because toluene was so hazardous and the site was next to a river — so if anything went down the drain, it would drain directly into the river. And toluene has high aquatic toxicity. There was also a residential property right next door, so it would have been really bad PR if their neighbours suddenly started smelling toluene and were exposed to it. They would have had to have multiple levels of containment, 24-hour monitoring in case of spills, volatile solvent pumps — which are very expensive — and they wouldn't have been able to put a heating jacket on it safely because of the flammability. It was just cost after cost after cost.

The choice was so obvious that the safer solvent was just cheaper — it was ten times the price, and it was cheaper. And so they went with that, and now they're building that system out. I really liked that case study because they had gotten so laser focused on the cost of the solvent, and it took zooming out systematically to convince them that actually safer is cheaper in this case — and in many cases.

Chris: No, that's a really good story of a win-win — improving the safety of the solution, and in the end it's better for the business as well. That's great. I realised we didn't really invite you to describe what green chemistry is, but I think with our discussion so far you've painted a picture that it actually has many, many different spokes in a wheel, and there are lots of different things to take into account.

Anna: There are parts of green chemistry that are already integrated into traditional chemical engineering. Efficiency is part of green chemistry because you don't want to waste resources — and efficiency is also part of traditional chemical engineering because you don't want to waste money. So the motivations are different, but in terms of the actual actions you take, they're very much the same. You try to reduce waste; if you can get value out of a waste product, you try to do that, sell it on to somebody who can use it. That's all green chemistry — and it's also standard process engineering.

But there are other bits that aren't standard. You have efficiency, and then there's safety, which is part of traditional chemical engineering — you try to minimise risk, control hazard as much as you can, put people in protective equipment, use non-ignition equipment with no open flames or sparks. So safety is in there. But green chemistry takes an approach of eliminating hazard rather than just controlling risk. In green chemistry there's a contrast to traditional process engineering: you don't accept that hazard is inevitable. You don't say, well, doing chemistry is just dangerous, so we just have to deal with it as best we can. With green chemistry you ask: why is it hazardous? Does it actually need to be hazardous? Is there a safer way we can do this? Are we maybe looking at the system costs wrong? Maybe we don't need a flammable solvent. Maybe it's actually cheaper to have a safer solvent when you zoom out and look at the whole system.

And that's something where, if you keep zooming further and further out, you get to where the environmental justice bit comes in — because the cost of pollution or chemical hazard is often pushed outside of the factory and not accounted for. You have communities exposed to chemicals that affect them in a very real way and create serious health problems. And the cost of those problems — to talk about it in cold financial terms — is real, and it's passed on to society. It's lost productivity, mental health challenges, actual medical costs for treating cancer and other conditions that come from hazardous chemicals. So that's where green chemistry, I think, diverges quite significantly from traditional chemical engineering — we don't accept that hazard is inevitable, and we ask: can we do this in a safer way? Because somewhere in the system, even if it's not inside your factory or inside the final product, somewhere in the system that hazard is going to have an effect and that's going to have a cost.

So that's the second pillar. There are 12 principles of green chemistry, but I like to split them into three pillars, which is much easier to remember. Efficiency, inherent safety, and the third one is renewable feedstocks. That's something that's not at all present in traditional chemistry, because traditional chemistry doesn't think at all about where the chemical is coming from. In green chemistry we want the feedstock or the raw material to be good for the environment. We've talked a lot about bio-based, but it's not just bio-based — it can be from CO2, for instance, pulling CO2 from industrial flue gases and reusing it, locking it away into chemicals. Also examples like just using waste feedstocks: if you can't go bio-based because you're talking about an inorganic chemical like a metal or a mineral, how can you do that in a renewable way, in a circular economy? The answer is usually you find waste from another process and repurpose that — which is also a type of circular, if not strictly renewable, feedstock.

And then recycling is the other big one — we're going to have to find better ways to recycle plastics and other materials in order to gain value out of them and move them back into the economy instead of throwing them away.

Chris: Thank you — that's a really nice overview of green chemistry, and you've actually covered a lot of the different facets of it, including the environmental justice and externalities component. You're right that we're not accounting for a lot of the potential externalities or impacts from some of these activities at the moment. Do you have any thoughts on how those could be better addressed?

Anna: I mean, if you think about it for long enough it becomes very clearly a moral question — or rather, if you think about it for the correct amount of time it becomes a moral question rather than an economic one. I've actually been doing more and more reading about economics lately, because that's what it always comes back to. People are saying that the cost-benefit analysis still makes sense. And if we were to stop using this hazardous chemical to protect, you know, a frog or a small community outside the factory, the cost would mean we couldn't make medicine that saves hundreds of thousands of lives, or we couldn't have non-stick pans. But ultimately economics comes down to a moral judgement, doesn't it? You have to weigh up one cost against another and say, which cost is worth more? Is it one human life, or is it a million eggs that come off the pan more easily? Somebody has to make that decision at some point.

And I'm starting to read more and more about different economic models, because the dominant economic model right now, I would say, is not a particularly ethical one. I've been spending a lot of time thinking about what the philosophical, ethical, and moral implications are of the cost decisions that we make — though that's actually fairly recent. If you go back a couple of hundred years, economists were kind of philosophers.

And I've started — whenever I go to a green chemistry conference — timing how long it is before I first hear 'well, capitalism is the problem, isn't it?' And that amount of time has been decreasing. I think the record was about three and a half minutes into a conference before somebody said, well capitalism isn't it? That's causing all of these problems. And it is, right? Fundamentally, capitalism is what's telling us that we can have externalities that happen to somebody else, somewhere else in the world, and it doesn't matter as long as we get our shampoo, as long as we get our vinyl floors. So there's something very, very wrong with the economic system, and I don't think there's an easy fix.

Chris: Yeah. No, I mean, it is really interesting, the points that you raised. The more work I've done on the issue of chemicals in the environment, the more philosophical questions it seems to raise. I think one thing's for sure — we've built a society on the basis of this system, and there have been a lot of benefits. But there are also some things to be concerned about, and then it becomes a question of how we begin to address that.

If I can zoom in on the topic of environmental persistence — because I've been thinking about this quite a bit. I feel that this is kind of a trigger point for some of these issues. For a long time we've performed risk assessments of chemicals with an assumption of a steady-state concentration in the environment, and we can kind of calculate that and feel pretty assured that the risks will be controlled. And then you see more recently people talking about issues like microplastic pollution and PFAS, where there's this extremely long residence time in the environment for these kinds of materials.

I'm seeing that this is challenging some of our paradigms. But in the end it comes down to: are we okay with there being chemicals in the environment? That's another point — I think the scientists who performed these risk assessments were generally okay with it, and they kind of gave a pass to allow the economy to develop in this way. But the public was not informed about it. And so now we see a lot of alarm in the media about chemicals — new chemical issues that we sort of learn about — and the public is continuously bombarded with this information and is frightened. And as a result we're getting quite reactionary responses in terms of policy. I think we do need to have a grown-up conversation about how we've got to where we are and what we can do thereafter to try to address some of these things.

Anna: Hmm. Yeah. I mean, in a sense, yes, somebody has decided that it's okay to release these chemicals into the environment. But in another sense, a lot of the chemicals that are in the environment were never approved for release — or if they were approved, it was without any significant data about their hazards.

I heard an interesting talk at a conference I was at in the US — the American Chemical Society's Green Chemistry and Engineering Conference, which happens every year and where there are really interesting insights shared. An environmental toxicologist was talking, and she said: I get phone calls from chemists who have discovered a chemical in the environment. They've gone out and sampled a stream or sampled the soil and found a new chemical they didn't expect to be there. When they Google it, they come up with no information about it, or very little. And then they call me and say, do you know anything about the hazards of this chemical? And she has to say, no, I've never heard of that chemical before, but I'll start doing research on it. So there are people who have this job: investigating the chemicals we have released into the environment, finding out about what hazards they have, and what implications that has for the people, animals, and plants exposed to them.

I don't think it's true that every chemical that's been released was put out there intentionally. A lot of it is inadvertent — whether it's done without full awareness, or whether it's well-intentioned and it's just chemical reactions producing chemicals that aren't anticipated once they're released into the environment. We don't necessarily know how it got there. There are definitely a lot of unknown or unexplored chemicals all around us. So I guess that's the other side of that point.

Chris: Yeah. You're right — there's a lot that we don't know about chemicals we use in day-to-day life. I think when I said we've used risk assessment, judgements have been made on a balance of risk and benefit based on the knowledge and information available at the time. And of course you also have regulatory systems and different regulations that have driven data generation and improvements in understanding with respect to chemical hazards and risks. But yeah, we've got to where we are.

And there's also where we go next and how we address this, because there is so much still to learn, especially on the topic of persistence. And a big emerging topic is transformation products — you put chemicals into the environment, and as they're being degraded they're turned into other chemicals. That's the nature of the environment.

Anna: And there's the question of chemical mixtures, right? Because when the hazard of a chemical is assessed, it's assessed for that one chemical in isolation. You model how that one chemical goes into somebody's bloodstream or into the environment and what happens to it. But then you have, say, flavour and fragrance formulations that have dozens or hundreds of chemicals mixed together and that have never been tested in combination. And we're starting to see evidence that, for example, quaternary ammonium compounds — which are used in cleaning products — on their own can be a little bit dangerous, but in combination they actually get much more dangerous. So if you use a cleaning product that has a few different actives in it, actually the hazard to you is a lot more significant than could have been predicted by the hazard or risk assessment performed for any of those individual chemicals.

So when these chemicals get out into the environment and react and produce new chemicals, and then mix with other chemicals that have produced yet more new chemicals — we literally don't even have a way to assess that. It's not possible for us to assess the impact of that. So how do we decide whether that's acceptable? That's a question I don't know how to answer.

Chris: Yeah, it's definitely a thorny issue, the question of mixtures. And to an extent there are always potential 'what if' questions — that's the nature of science and research. We ask the what-if questions and then we have to go and investigate them. But we don't have infinite resource to test every single mixture, so we have to try and make decisions as best we can.

But you're right that mixtures is definitely a hot topic right now. One of the regulatory measures being discussed is whether we need additional safety factors in our risk assessments to account for these co-exposures. So it'd be really interesting to see what happens with the update to the REACH regulation on that, for instance.

Anna: Yeah, it'll be interesting to see. Because I do not know how to account for co-exposure — I suppose you'd have to do it on a limited basis, not taking into account environmental reactivity.

Chris: Yeah, it is a big one. I just had a conversation on the podcast with Andrew Johnson, who's a professor at the UK Centre for Ecology and Hydrology. He just released a study looking at monitoring data for rivers in England, and using sophisticated modelling they were able to tease apart the variables linking to the macroinvertebrate biodiversity in those rivers. It seemed to show quite interesting insights — that the biodiversity within the rivers had increased since the 1980s to a plateau in the 2000s, and since then it's levelled off. And the metals were actually seemingly the thing that was driving a lot of the toxicity — and they weren't seeing wastewater inputs as a source of that toxicity.

That's a completely different way of looking at impacts in the environment and trying to connect them to human activities. It is a really complex picture, but if you follow the trail of breadcrumbs from our risk assessment processes in regulation, you end up in a place where we're overlooking mixture effects at the moment.

Anna: Yeah. A lot of the things I deal with on a daily basis, when you think about them for any length of time, you start to get very, very concerned. So you just kind of have to do the best you can and accept that there are things that aren't going to change immediately.

Chris: We've got to keep moving forward and doing what we can in our own domain. Not that we should keep to our domain, but—

Anna: No, and this is the situation of information overload, right? We live in a society where we're bombarded by information, by concerning information from every angle. And if you try to pay attention to all of it, you end up paralysed — basically cowering under your bed because there are so many horrible things going on that we have more information about than ever before. So you do, just by the nature of your human brain being limited in its capacity to understand and process upsetting information, have to limit the things within your sphere of influence.

I've been doing some reading about that lately, actually — there's a lot we can learn from political organisers, people who are very active in trying to drive political engagement. They talk about your sphere of influence: locally, you can have the most effect in your neighbourhood and in your community. Going further out, in your city you can still have a significant impact. Going further still, in your region, your impact starts to be more diluted. And then when it comes to nationwide, continent-wide, globally — there's very little that one person can do. The advice is: you have a limited amount of energy, so spend it as much as you can within your sphere of influence. Try to affect the things you can affect. Talk to your neighbours about, you know, the impacts of household chemicals, or not buying vinyl flooring. And when it comes to posting about it on social media, maybe that's not as important because it's not actually going to drive anybody to change.

I thought that was a helpful way to look at it — that you are allowed to limit what you think about and what you care about on a daily basis. Because if you dive too deep into that pool, you end up never doing anything and never making a difference because you're just infuriated or very sad or traumatised. I think for the sake of being able to make a difference, it's actually okay to say: I don't have the capacity to think about that right now. I'm going to focus on the thing I'm equipped to influence, and I'm going to try my hardest to influence that — and I'll set this other thing aside because it will overwhelm me. In the information age and the disinformation age that we live in, you have to set boundaries around your capacity to process information.

Chris: No, that's really interesting insight, Anna. And you're clearly somebody who's thinking a lot about these challenges. This isn't just a company for you — it's part of your life's work.

Anna: Well, this is true. I think for most people who are in the green chemistry space, we didn't get there by accident. It's not a normal career path for a chemist — still, unfortunately, though it's becoming more normal and more mainstream. But if you look back 20 or 30 years, green chemists were considered very strange, kind of the hippie version of a chemist, and they weren't taken very seriously. In some areas they're still not taken seriously — in the EU and in the US, acceptance of green chemistry is growing, but in other regions of the world it's still considered quite a strange thing to be concerned about doing chemistry sustainably.

Most of the people who have devoted their careers to green chemistry, you will find, have very strong feelings about sustainability and are very passionate about it, because they didn't get into that career by accident. I actually got into chemistry because I happen to be good at it, but what I care about is sustainability. Green chemistry is my outlet for: how do I make a difference in the world? How do I make the world a better place by using the thing that I happen to be good at, which is chemistry. Whereas most chemists I've found who are in academia — you could call them 'brown chemists' — they're kind of the other way around. They really, really love chemistry. Some of them love being in the lab and mixing things together and seeing what happens; they have that curious nature, and that's fantastic — we need those people. But green chemists are not necessarily there because they think chemistry is cool. They might think chemistry is cool, but they're also very passionate about making the world a safer and more sustainable place.

Chris: So, Anna, this has been fantastic. I was really happy to speak with you on the podcast — given that you're also trying to build something in your own area, in green chemistry. So thank you very much for spending your time to talk us through some of that and to discuss ideas with you. I normally ask my guests a couple of questions. I suspect we've already covered the big goal that you're working towards in the coming months?

Anna: So the training courses are one big goal, and then the other is we're actually going to be launching a software tool in the next few months, coming out of a collaboration we did with Cambridge that was funded by Innovate UK. It's about polymer solubility. You need to dissolve polymers, plastics, and materials in all kinds of applications, but it's actually a hidden bottleneck in sustainable innovation. Because we need plastics — we need packaging that enables us to have a sustainable lifestyle, we need wind turbine blades, we need lightweight vehicles, and we need drugs to be delivered in our bodies, which is also done with polymers. So there are all of these healthy and sustainable outcomes that are enabled by polymers. But currently we're not doing polymers in a sustainable way — we're making them from petroleum, and usually at end of life we just throw them away.

So polymer dissolution would enable not only more sustainable polymers — because we could make new bio-based and biodegradable polymers — but also polymer recycling for a circular economy. Because if you could selectively dissolve the nylon from your gym clothes and then move it to the next vat, and selectively dissolve the elastane, then you can recover all of that and reuse it again. So polymer dissolution is critical for recycling, for processing, for formulation, for cleaning. And right now we don't have a good way to predict it.

So we have this AI-powered software tool that's built on a huge database we made ourselves using high-throughput automated experiments. As far as we know, it's the most accurate software out there for predicting polymer dissolution — conservatively speaking, it can predict with 90% accuracy. We're really hoping it helps to accelerate the green chemical transition in a very material way. We have the algorithm, we have the dataset, and we're working on a couple of consultancy projects with our first clients to tailor it to their specific use case. Then within the next few months we'll hopefully be launching the software itself for beta trials, where you put in just the structure of a polymer and get predictions about what solvent is going to dissolve it, with 90% accuracy. So yeah, that's the other big project.

Anna: Thank you for having me on, and it's been really nice to have this conversation. Regulatory chemistry is something I'm always adjacent to, and I'm always grateful that there are people who are deep in that space, because we absolutely need people like you to understand the regulations and push them in a good direction. That's something I could never do myself, because just the level of focus on the details of regulation is something I couldn't do on a day-to-day basis. So I'm very glad that there are regulatory scientists out there who enjoy doing that and are good at it.

Chris: Oh, no — thank you, Anna. That's really nice of you. I think, as long as we all keep talking, then we should be able to move in a good direction. So, thanks very much for coming on, and thanks to everyone who's been listening — your time is really precious, and so I'm really grateful that you've spent it with us.

If you've enjoyed this podcast, please tell your friends and colleagues about it. We've got more conversations like this to follow. This has been Chemical Journeys. Thank you very much, Anna.

Anna: All right. Thanks so much, Chris. I'll speak to you soon.