Oral evidence: Environmental impact of microplastics, HC 179Wednesday 8 June 2016
Oral evidence, 8 June 2016.
Witness
Professor Richard Thompson, Professor of Marine Biology, Plymouth University, gave evidence.
Chair
Professor Thompson, sorry to keep you. We were having a very interesting discussion. Professor of Marine Biology at Plymouth University. Thank you for taking the time to be with us today. I know it is quite a journey from Plymouth, so thanks for being with us. In 2004, your team described the impact of microplastics on the marine environment. You coined the phrase; you are perhaps the godfather of microplastics. How far has our knowledge developed in the 12 years since then, and what level do you think our knowledge is at now, compared to those times?
Professor Thompson
In 2004, we knew already that there were small pieces of plastic in the ocean, and our paper really described pieces that were truly microscopic, less than the diameter of a human hair, and that is what started this trend of researching what is now described as microplastics. I have listened to the earlier evidence sessions, and I think is important that we think about the definitions and what we are talking about. The most broadly accepted definition is now pieces less than 5 millimetres, which is not what you might consider to be truly microscopic, but that was brought in by NOAA. It is more or less universally acknowledged, but there would be some that would say maybe less than a millimetre would be a better recognition. There are some issues with definitions. A lot of what I have heard in terms of the discussions by this panel have related to microbeads, which of course is something that you might or might not want to legislate about, but they are an aspect, a subcategory, of microplastic, and sometimes I have heard the words used a little bit interchangeably. Microplastic is small bits of plastic. Microbeads from cosmetics are one contributor to that. To answer your question of what we have learnt, we have learnt that microplastics in general are widely distributed in the marine environment. They are present on shorelines across all of the continents. They are present in remote regions, including the Arctic. They are very abundant in remote habitats such as the deep sea. They are widely distributed in marine organisms. In some populations, we are talking about 85% to 90% of individuals containing microplastic, but at relatively small quantities. We have a fair picture of distribution. Our understanding of sources is patchy, and I think it is based largely on estimates of what might be their relative importance. We could certainly weight the likely importance of fragmentation of larger items, which are progressively breaking down into these smaller pieces, against, let us say, microplastics from cosmetics, which I would perfectly agree is a smaller proportion of the total. In terms of the harm that the microplastics might cause, we know from laboratory experiments that creatures will ingest this material quite readily. There is some evidence of retention. There is some evidence of physical effects. There has been concern raised about the possible transfer of chemicals from plastics to organisms on ingestion. At the moment, the evidence base there is less certain, in my view, and it may well prove that its physical effects are the ones that, going forward, are more definite and categorical ones relating to harm, or it could be that it is some combination of the two, its physical effects and biological effects. Our scientific understanding of the harm is in its infancy, I would say, and a lot of the laboratory experiments, even some of the best ones, are probably using doses that are higher than you would find typically in the natural environment. That is not an unreasonable way to proceed but it is the state of the evidence at the moment.
Chair
When you came in 2013 to the Science and Technology Committee, you said the evidence is still relatively new and our knowledge is limited. Why do you think our knowledge is progressing so slowly in this area? Is it just that 2004 was when we realised it was an issue, and then we are just 10 years in, which means effectively it is in its infancy?
Professor Thompson
I think there has been a lot of experimental work done. It is quite a challenging issue. It depends also to some extent on the interplay with the policy need: what kind of evidence is there that is required from this perspective? Obviously a greater understanding of harm, but then if you consider that a lot of the microplastics are resulting from larger items that are fragmenting into smaller pieces, we already know that some of those larger pieces are causing harm, and what you are talking about is a continuum of litter from very big pieces down to pieces that may be smaller than a few microns in diameter, and you are talking about a complex mixture of many different polymers, different shapes, different sizes, possibly with different additive chemicals. It is quite a complex thing to try to disentangle. You also have the possibility of co-contaminants attaching to the plastic and then potentially being released. The number of permutations here in terms of understanding harm is quite substantial. It maybe has not helped the science that there are so many different possibilities. There is considerable concern that you could give an all-clear when there was not actually an all-clear; it was a question of the few examples that you had chosen to look at. It is a question of trying to study things in the round and consider all the possibilities. Certainly a lot more work has been done. If you look at the scientific publications since 2004, it is an exponential curve, so there is a lot more known but maybe not as categorical as you might like in terms of hard and fast evidence. One of the questions that policymakers often put to me is: is plastic causing a population-level negative effect? That is going to be almost impossible to answer because there are so many other environmental challenges that face the natural environmental that isolating the effect of plastic on its own, let alone microplastic, is going to be almost impossible and I would argue perhaps prohibitively expensive. In the context of MSFD, where we are wanting to move towards a status of no harm, what is the definition of harm that we are working to? To some extent there is a question of: what is the evidence that is needed? I think that discussion with scientists would be useful in terms of what are the critical tipping-points from a policy point of view. Certainly we realise there is a need to gather more evidence on harm, and that is what we are trying to do, but if there was an aspiration to get evidence at a population level, then that is going to be almost impossible to obtain.
Chair
You talked about physical and biological effects. When you talk about biological effects, is that the bit where the chemicals accrue into the plastics and then potentially harm the fish?
Professor Thompson
Sorry if there was confusion there. We have physical effects from the mere presence of the plastic itself, and there is also concern of chemical toxicity associated with the transfer of chemicals from the plastics to the organisms after they have ingested them.
Chair
From the plastics to the organisms. That is the biological, chemical—
Professor Thompson
I would say they are both biological. We have physical and chemical toxicity. At the moment, the evidence is clearer in terms of harm from the physical presence of plastics. The issue with the chemical toxicity is not that the chemicals will not transfer; it is a question of trying to set that into a wider context. Of course, the environment is heavily contaminated with all manner of chemicals, including some of the chemicals that are latched on to the plastic, so separating the additional role of the plastics as a vector in the transfer is the challenge there. It is not challenging to establish that plastics can transfer. They do. What is challenging is to understand exactly how much worse does the presence of plastic make things in terms of chemical transfer.
Chair
Thank you for clarifying that.
Peter Heaton-Jones
I want to go back, Professor Thompson, to the terminology stuff that we talked about to start with, the very basic stuff. Forgive me for the simplicity of these questions, but what proportion of all the plastic that is washing around in our oceans is microplastic?
Professor Thompson
It depends whether you want to do the sums by abundance or by weight.
Peter Heaton-Jones
Which would you prefer?
Professor Thompson
If we take them by abundance, which is particularly important if we are thinking about a risk assessment because it will link to encounter rate—the more of something there is, the more likely are these creatures to encounter it—then there is clear evidence that microplastics are the most numerous fraction. If you take that by weight, then you will get a different answer because there are still some very large items of plastic that might only be one or two in number but they are weighing a lot. A lot of the data that we have on marine litter in general is by numerical abundance rather than by mass. There are complications with mass because some of the litter is wet, some of it is fouled by marine organisms, so it is harder to get that data. It is not impossible, but in terms of routine monitoring it tends to be done by count. Microplastics can be very numerous. On some shorelines, we know that they far outnumber the larger items, but if you looked at it by weight, you could get a slightly different picture.
Peter Heaton-Jones
Understood. Of microplastics, what proportion of those are microbeads found in cosmetic products?
Professor Thompson
We can only hope to try to estimate that. If we look at data from the industry, that suggests that 680 tonnes of microbeads are used in cosmetics every year. I obtained permission to bring some microbeads in, if you wish to look at them, because I was not sure if you had actually seen them. With your permission, Chair, I will circulate these. Each of these jars matches one of the containers it has come from. That is number 3, which matches that one. There was a paper relating to these published in 2015. Some of these manufacturers may have taken steps to remove the particles since then, and I do not think that it is a case for trying to name and shame particular manufacturers because, as you have heard already, they are widespread. These pairs match up. These are widely used in the industry. The container that you have over there, Carolyn, contains about 3 million particles of plastic. It is not about naming and shaming necessarily individuals, but their use is quite considerable—
Peter Heaton-Jones
Professor Thompson, sorry, I do not want to pin you down necessarily, but what proportion of microplastics would be microbeads from cosmetic products?
Professor Thompson
If we say that 680 tonnes a year, which is an industry figure, is used as microbeads in cosmetics, some of that is going to pass through sewage treatment and into the marine environment. Some of it is going to be captured in sewage treatment. There are uncertainties about how much might be captured by sewage treatment. However, there is a residual question there of what happens to the material that you do capture in sewage treatment, and I have been trying to obtain reliable data from the water authorities as to what proportion is incinerated and what is returned to the land. If it is returned to the land, then the total emission to the environment is going to be equivalent to the total production. A worst-case scenario: let us assume that all of the tonnage of microbeads that are produced each year for the UK use, the 680 tonnes in the UK, is potentially going back to the environment. That puts it in the region of 1% or so of the total marine litter to the environment based on estimates of marine litter entering the marine environment from the UK. Those estimates of the total marine litter to the environment in the UK are quite noisy. They are ranging from 10 tonnes to 250,000 tonnes. We have no clear figure on what the total emission is of all litter in the UK to the environment. The figure of the relative proportion of microplastics is dependent on two things: first, the data on the microbeads, which I think is quite reliable because we know the production statistics, the 680 tonnes. If you want to look at it as a percentage, it is more dependent on our uncertainty over the other. Having said all of that, 680 tonnes I do not think is a trivial amount. If you want to compare that to the mass of litter that is removed by the Marine Conservation Society in their annual beach cleans, we could be talking up to 70 times the amount of litter that is removed from beaches by volunteers in beach cleans. It might be small in percentages, but to me what that illustrates is the scale of the wider problem, rather than trivialising the issue relating to microbeads as a source.
Peter Heaton-Jones
It is perfectly legitimate, in your expert opinion, to be focusing on microbeads in cosmetic products as being a problem that is—if I can put it like this—worth tackling? It is not so trivial that we should be looking elsewhere?
Professor Thompson
I think it is worth tackling, and I think particularly in my view it is worth tackling because I see it as an unnecessary and an avoidable emission to the environment. What we need to be clear on is that any action on microbeads on its own is not going to solve the problem. While I was delighted to see a number of nations introducing legislation, and I see that as a positive move, I have a concern in the back of my mind that I would not want that to be seen as a tick in the box that marine litter issues are now solved because 1% or 2% of the problem has been solved by eliminating microbeads from cosmetics. I have a concern there that we must recognise that this is only part of the problem, but it is an important part and it is something that action could be taken on, yes.
Geraint Davies
If I can take you forward then, what do you think can be done to deal with the existing plastics in the ocean? We are talking at the moment about not making the problem worse, but there is all this plastic, as you said. What can we do about that?
Professor Thompson
My view is that the appropriate place to take action is stemming the flow. If I had an amount of money to invest as a philanthropist, I would be spending at the moment 99% of it on stemming the flow and 1% on clean-up. As I started to move towards stemming the flow, I would increase my expenditure on clean-up, but we need to recognise at the moment that it is going in far faster than we can attempt to clean it up. It is present in the deep sea, thousands of metres beneath the sea surface. It is present in coral reefs. It is present in a wide range of marine organisms. The idea that we would want to invest money in clean-up in perpetuity seems to be the wrong way to go. We need to think about stopping the input. I could expand that more as to what you might do, if you want me to, in terms of action to stop inputs, but that is where I would place my emphasis.
Geraint Davies
On stopping the flow. If we do not have a ban and there is an ongoing flow, albeit diminished, is it the case that water and sewage plants are able to trap these particles before they go into the sea, so they do end up going down the sink? What is the situation there?
Professor Thompson
It would depend on the efficiency of the sewage treatment plant, and there is evidence that some sewage treatment plants will potentially trap more of these particles than others. If you use a sound filter, there is a need for some kind of back-flushing, which may then result in an emission. There is also the question of whatever solids you separate from the sewage, what do you do with those solids? If they are incinerated, then I suppose everything that is there is removed from the equation. If they are spread back on to land, then they are spread back on to land with the plastic contaminants. It is quite hard to separate the plastic from all of the other solids that you have in a sewage treatment plant.
Geraint Davies
Really you are saying we should put a full stop to the flow of more of this stuff into the environment. I think you are saying that. You did not have any particular solution for the current stock of contaminants. Are there ways to clean up our oceans, or not really?
Professor Thompson
To be clear, I think it is far simpler to eliminate the microbeads at source, rather than try to develop an expenditure on more sophisticated sewage treatment. Elimination at source is the way forward. In terms of litter that is already in the ocean, it is completely worthwhile to try to remove it. Voluntary beach cleans are very important. However, it is not a long-term answer. We will be cleaning up in perpetuity unless we take action to stem the flow, and that relies on taking action across a range of different inputs. We need to recognise there that there is not a single solution. With microbeads, it may be a question of introducing a ban. If you look at the types of litter, larger litter that are fragmenting into smaller items, about 40% of it is single-use items of plastic. We have already—and I think very responsibly—taken action on single-use plastic carrier bags because they were seen as being largely unnecessary. We could take a plastic bag with us. Some of the things that we do with plastic—plastic is not the enemy here. Let us be clear on that. It brings many societal benefits. It has the potential to reduce our footprint on the environment, but there are a lot of things that we do with plastic that cannot be solved by a ban. What we need to achieve is a much more systemic thinking. I caught the end of the session from the cosmetics manufacturers earlier on, and some of your questioning drove towards that when you were asking, “What happened 20 years ago when these materials were being phased in? Was there no precautionary principle?” Maybe there was, maybe there was not, but that is what is absolutely needed, in my view: a recognition at the beginning, at the design stage of a product, of what is its fate at the end of its lifetime. If we are thinking of introducing legislation—and I heard you grappling with whether or not there should be a ban, and what that would do to small industry or not, and what the message would be from a ban or not—it is about trying to give a message to industry that what is needed is to take that precautionary principle right at the outset when you are starting to think about a change. In my view, we did know about marine litter 20 years ago. We knew quite a lot about it. The first scientific paper on microbeads in cosmetics was back in 1996. It is not a new thing. It may be new in the wider public interest, but this is not a new problem, the likelihood that they would pass to the environment.
Geraint Davies
You are talking about microplastics, but you also said 40% of plastic is single-use packaging.
Professor Thompson
Yes. Single-use items of packaging, yes.
Geraint Davies
Yes, so what do you think should happen about that?
Professor Thompson
What should happen?
Geraint Davies
Yes. Do you have any particular idea on policy? Should it stop altogether?
Professor Thompson
I will give you an example here.
Geraint Davies
I know what you are talking about, but what should we do about it?
Professor Thompson
Let me give you a simple example relating to policy. These are PET bottles. If I talk to a recycler, these are the low-hanging fruit. These are the most widely recyclable polymer that we have, PET. They are both delivering a soft drink. They both weigh the same amount. The introduction of colouring in this one means that from a recycler’s point of view there is almost no economic incentive to recycle it because it limits the applications that they can use the recyclate for. This one is potentially worth five times more to them. What is the colouring doing? It is not to do with getting the goods safe to the consumer or extending the shelf life. It is to do with marketing. If I look at these bottles in Japan, I will find that the same brand that is green here is clear, because the association have got together to move towards clear PET, which has a higher value. Where we need to go is to make sure that at the design stage we incorporate value for recovery at the end of the life, because it is that value that will make sure that the material gets collected, rather than wasted into landfill or into the environment.
Zac Goldsmith
I am going to be very quick. I just want to go back to the ecological impacts briefly. We heard at the last session from the Marine Conservation Society that they believe that the microplastics have had the effect of reducing reproduction in oysters by 36%. I am interested in very briefly knowing whether you accept that figure, if that is something you are familiar with, and what you believe the impact will be more widely on the fishing industry.
Professor Thompson
The figure is true from those experiments. Those experiments, however, are relatively high-dose compared to what an oyster might encounter in the natural environment. I do not think that that is a widespread phenomenon with oysters. I think that the high-dose experiment has yielded those results. There is at the moment a discrepancy between linking some of the lab evidence, where, by necessity, you are maybe using a single polymer of a single size in a particular dose, whereas in the natural environment you are faced with a heterogeneous mixture of different sizes and different types of polymer. That makes that particular lab experiment, in my view, a very high-dose experiment.
Zac Goldsmith
We also have heard that microplastics can be inhaled by humans. Can you elaborate on that? Can you tell us what you believe the impact of that would be, what the implications are?
Professor Thompson
If you have fine dust particles that are airborne, of course there is the potential for them to be inhaled, as there is with a range of other particulates. We hear about it from exhaust fumes. The potential for small particles of plastic to be inhaled is certainly a real one, but I do not think that that is an issue that relates to marine litter. I do not think we are going to be inhaling dust that has come back from the sea or that has come back from seafood. I think that the environmental exposure to most humans is probably going to be in and around the home, the office, the workplace, rather than coming back from the environment. As to what the consequences of that might be, we really do not have any clear understanding. There is some data from high exposure, chronic exposure in factories of effects on workers there, but that is very different to what you might encounter as an average citizen.
Zac Goldsmith
In a line, we have heard from almost every panel that we do not know everything there is to be known about the harmful impacts of microbeads and microplastics, but surely it is also the case that we know enough already, even though we do not know it all, to apply something more than the precautionary principle, that there is enough evidence there to justify a phase-out or a ban, depending on your politics and where you are coming from. Would you accept that?
Professor Thompson
That would certainly be my opinion.
Zac Goldsmith
There are no doubts in your mind; we know enough already to justify—
Professor Thompson
We know enough already. When you consider that there is 4% of oil production going into making plastics, if we recovered those plastics at the end of their lifetime, we could use that to recycle. If we consider that we know that there is harm from large items of plastic, and that is very clear, a list of over 700 species that encounter large items of plastic, that large items of plastic are one of the main things that are fragmenting into smaller items, along with the microbeads in cosmetics, and the plastic in the oceans is going to be cumulative. It is not going to biodegrade. At some point, we are certainly going to reach a perspective where your oyster example maybe is more environmentally realistic. In my view, yes, we are at that position where there is enough evidence to take action. Of course, we could always ask for more evidence.
Zac Goldsmith
Thank you.
Caroline Lucas
We were just touching on the issue of ingestion. Is it your view that that is an area that just needs far more research before we can even begin to decide what the balances are in terms of the need to raise awareness and the need to develop policy responses to it?
Professor Thompson
It is similar to Zac’s question. In my view there is already a substantial body of evidence. Of course it would be desirable to collect more evidence, but particularly when we start to think about the quantities of larger items of plastic that are fragmenting into microplastics—and this inquiry is about microplastics in general, and cosmetics are part of that—then we have a lot of evidence already about the harm that those larger items of plastic can do. Microplastics are part of the picture that we are starting to understand, but I would not necessarily consider—put it this way—that an absence of knowledge about the full extent of any problems to do with microplastic is a reason to delay on action relating to larger items of litter that we already know quite a lot about. It is a part of the picture, I would say.
Caroline Lucas
It was human ingestion in particular. That was the missing word, sorry, in my question.
Professor Thompson
Sorry. We know very little about that. It would need to come from laboratory experiments, not with humans, and that may be an area that requires more work in the future. It depends a little bit on whether or not the emissions of plastic to the environment can be stemmed, because if we can solve the problem in other ways then the human exposure pathway that you are talking about may not actually be realised.
Carolyn Harris
Last question. Do you believe that the insufficient evidence is allowing manufacturers to get away scot-free, or a get-out-of-jail card?
Professor Thompson
No. I do not think that manufacturers are going out of their way to do harm to the environment, but there is a question about being aware of what the end-of-life fate of a particular product is. In the case of the microbeads in cosmetics, it seems inevitable that they are going to pass, or a proportion of them, into the environment through sewage, and we have a growing body of the evidence that that might cause. I do not think the lack of evidence is a reason not to take action and I do not think it is a reason for manufacturers not to take action.
Carolyn Harris
What about funding for research? Is that easy to come by, or is it more difficult to get funding?
Professor Thompson
Funding is challenging at the moment, I have to say, but our research has been funded. It has been funded by Defra, it has been funded by the Leverhulme Trust, it has been funded by the European Union. We have an ongoing study that is funded by NERC. There is funding, but of course, depending on the rate at which these questions are to be answered, it is going to be limited by available funding, yes.
Chair
Thank you. Professor Thompson, thank you for taking the time to be with us today. We have had a bit of a gallop through the science, but that has been very interesting and I am sure you will await the conclusions of our report with interest.
Professor Thompson
Thank you very much. Oral evidence: Environmental impact of microplastics, HC 179 2