20 Oct

Video transcript
- [Acoustic Guitar]

So this version of the EPA'S online fourth and final Environmental Science Series event, 2021, which is on microplastics knowledge, measures and solutions. First of all, I'd like to thank all of the staff in the backroom from the EPA and our supporters who helped bring this topic to life and is helping us deliver it to the audience. My name is professor Mark Taylor. I'm the chief environmental scientist at Environment Protection Authority Victoria. First of all, I'd like to begin by acknowledging the Aboriginal people as the first peoples and traditional custodians of the land and water in which we live, work and depend. I am speaking to you from Dharug country in New South Wales. We pay respect to Aboriginal Elders past and present, as Victoria's environmental regulator. We pay respect to how country has been protected and cared for by Aboriginal people over the many thousands of years. We recognise the unique spiritual and cultural significance of land water, and all that is in the environment and the continuing connection and aspirations for country of Aboriginal people and traditional custodians. So just a few notes about this livestreamed event, as with all of our modern lives today, being disseminated during the COVID period by the internet, please be patient with any technical difficulties, they're likely to happen. We will be fixing them as fast as possible. So the structure of today's event will focus on this brief introduction by myself, followed by the presentation of the most important people of today, our guest speakers. And so there'll be some time for questions and answers, and a summary conclusion. The event will be recorded. So if you need to leave early and miss parts of this session, you can always watch it later on EPA's website. The session also has a live closed captions to ensure that it's accessible for all persons. We will open the question and answer now, but we will respond to the questions after the presentations. Please provide your questions at the icon with the question mark on your screen. We will get to as many of the questions that you present as, as we can, but not all questions may be answered today, and will be responded to via email. Please, when you do submit your questions, please provide your contact details so you can be responded to. So today we're here to talk about microplastics. As most of you will know, microplastics are small pieces of plastic, less than five millimetres in size that are becoming an increasing concern for our environment, and human health. Microplastics can range from small pieces of plastic that can be seen by the naked eye to tiny micro-sized plastic pieces and particles that requires specialist equipment to be detected. As you all know, we use plastic in our daily lives. It's everywhere, it's pervasive, but where does it microplastics come from? Well, research tells us that they come from many different sources, such as litter, clothing, wastewater, dust, car tyres, to name, yet, just a few. So microplastics are intentionally manufactured, so they're small size, for example, microbeads in products, such as toothpaste, facial scrubs, body washing, cosmetics. Fortunately many of those micro breeds- microbeads are now being removed from production and use. Other are the result of larger plastics breaking down into smaller pieces. For example, a drink bottle that fragments into many little pieces over time. Unfortunately some drink bottles will fragment and we will consume those microplastics during use. The sources and size of these plastics make the issue of microplastic pollution, highly complex, and the solutions to the problem and not straightforward. It is clear that there is evidence that microplastics are a concern for the oceans and our aquatic ecosystems. Plastics are being found in the guts of seabirds and some of the planet's most remote locations, such as the Arctic and in deep sea sediments, such as in the Mariana Trench, which is the world's deepest ocean trench. They are now one of the most pervasive pollutants as symbol of our consumerism. Perhaps the most famous example of the scale of plastic pollution is the "Great Pacific Garbage Patch" of plastic waste in the Pacific Ocean. The patch covers an area three times the size of France, and is one of five ocean gyres where plastics, including microplastics have been collected. Microplastics have direct implications for humans because they carry them, they can also carry a range of cold contaminants, such as trace metals and some potentially harmful organic chemicals. A recent study that I was involved with and my student at Macquarie University, and a colleague, which was published in Environmental Pollution showed that 39% of all indoor deposited dust particles were microplastics. Roughly a quarter of the fibres recorded were less than 250 microns in size, meaning that they can be inhaled and easily ingested. The risks of exposure were calculated to be greatest for children, but presently there is not enough data to say exactly how they're affecting human health. Nevertheless, as collectively, we need to address the problem through taking personal actions, as well as expecting regulation and intervention by our governments to help reduce plastics in the environment. We can as individuals, for example, use refillable water bottles, keep cups, reusable shopping bags, and avoid single use plastics such as straws, but these are only part of the solution. Having hard floors, using more natural fibres in clothing, furnishes and homewares, along with vacuuming, at least weekly can help reduce your personal exposure to microplastics. If you use synthetic or wear synthetic clothing, such as a fleece jumper, you might be surprised to find that that will contribute microplastics to your environment and the broader environment. Our speakers will expand on this topic shortly. As Victoria's environmental regulator, EPA's role is to protect the environment and human health from harm due to pollution and waste. EPA supports Victorian government's ban on single use, lightweight plastic shopping bags, as well as the introduction of a container deposit scheme and other circular economy initiatives where plastic waste can be minimised in the future. There is still much we do not know and EPA is pursuing research into the impacts of microplastic pollution. We are examining the risk of harm posed by different types of microplastics. Microplastics are typically found in complex mixtures of different polymer types with various shapes and sizes. There is no standard method for the measure of microplastics and no standard instrumentation. This makes the issue of the measurement and quantification of microplastics challenging and problematic. Understanding the dynamics of where microplastics come from and how they are transported in the environment will help guide appropriate action on this complex and diverse pollutant. Discussing this important topic and its effects on the environment and public health is also key to building our understanding and our knowledge. Importantly, this includes research here, conducted in Australia as well as overseas to help inform, actually on that note, it is with great pleasure that I introduce our two guest speakers for today, Dr. Mark Browne of the University of New South Wales in Sydney and Dr. Denise Hardesty from CSIRO, our National Science Agency. Dr Mark Browne has over 15 years of published groundbreaking research on global contamination of marine habitats by microplastic pollution. His research team has demonstrated that an abundance of plastic pollution is from clothing fibres, and that washing a single garment adds thousands of fibres to wastewater. Mark's research was the first to show that ingested microplastics accumulate in the gut of marine invertebrates, such as muscles, and that ingesting microplastic can transfer other pollutants and plastic additives. Through new research, Mark has shown that policy about plastic debris is scientifically outdated. And if countries classified the most harmful plastics as hazardous, their environmental agencies could conserve greater levels of biodiversity by having the power to restore affected habitats and prevent more dangerous debris from accumulating in those places. Our second speaker is Dr Denise Hardesty. Denise is a senior principal research scientist at CSIRO's Oceans and Atmosphere, leading a portfolio of plastics related projects. Denise's current work, focusing on plastic pollution, and Marine monitoring and surveillance to reduce illegal fishing. Denise's research looks at the drivers for litter losses into the environment. What rubbish ends up where, including how much and what types, and the effectiveness of interventions to reduce plastic into the environment, including from losses through gear use in fishing. Denise and her team published the first global estimate of microplastics on the sea floor, Denise promotes the role of science in underpinning policy and decision-making, and regularly provides science evidence to governments and international panels. She believes strongly in the contribution of communities, having worked with more than 8,000 citizen scientists to help tackle global challenges. On that note, it's with great pleasure that I hand over to the two most important people of today. The first of which will be Dr. Mark Browne. All yours, Mark.

Thank you very much for the introduction. I'd like to pay my respects to people past, present and future. I'm speaking from the Gadigal country in New South Wales today. I started on this project, on this work, a while ago in 2003, after about three years working various national and international agencies about pollution. And at that point we didn't really know much about micro plastic, but our understanding has expanded rapidly. I'm just trying to see the, don't seemed to have access to be able to move the slides on, sorry, people.

[Mark Taylor] Mark, you can just ask Blair to turn the slides. Just say next slide and she'll do it for you, I think.

Next slide, please. This work is done by a range of collaborations, it's got lots of people who range from their scientific disciplines to their engineering disciplines, a range of volunteers and helpers. And you need those different insights to be able to really understand and resolve particular problems. And that's really where we're coming. We have a range of scientists, biologists, engineers, physicists, and they help to understand and resolve these particular problems. Next slide, please. We've also got a range of partners. The partners range from the Australian research councils to various water utility firms, to various companies that produce and make various products. An important thing to realise is that humans over millennia have been making a range of different products in a range of different polymers. These range from animals, to plants, into more recently, petro-chemical products. Next slide, please. These range, obviously, from things like textiles, all the way through to packaging, to wetsuits that I was wearing this morning when I went for my daily swim, all the way through to child and children's playgrounds, to AstroTurf pitches, to the carpets we have in our houses, right the way through to the tyres we have on our cars, to the roads made from plastic, to the solar panels that we have on top of our roofs, right the way through to cleaning products that we use for our teeth, for our face, but also for cleaning infrastructure. Plastics has a wide range of uses, but also, so do a range of natural polymers themselves. Next slide, please. The main issue that we have is that the way that we design these products, and the way that we manage the waste themselves, isn't particularly great at the moment. So a large number of these polymers contaminated the environment. Next slide. We see these types of contaminations stretching right the way from the poles to the equator, from the very tops of mountains, all the way through to the depths of our oceans. We're finding these range of types of polymers. And it's really important to understand what types of processes are actually going on to cause these types of contamination. Next slide. The major problem we have with these, with these microplastics, these are micrometre sized particles of plastics that work done by Richard Thompson in 2004, demonstrated there been a 450% increase in the quantity of these micrometre sized particles of plastic in the oceans around the Northeast Atlantic. These were sort of samples taken by a silkscreen that was dragged behind boats, and that allowed them to demonstrate that these particles are actually accumulating in the oceans. The problem we have with microplastics are this, is that they can be ingested by a wide range of organisms, and the wildlife themselves, as well as humans are able to ingest these particles where they can transfer from the point of entry in the stomachs of the organisms, and transferred to the actual blood cells themselves. And the smaller these particles are, the greater the rates of transfer. So a material that fragments into lots of smaller particles causes major problems, and we know that it bio accumulates in humans, and also in wildlife. For humans, we've known this for some time, which is why many medicines use these sorts of types of polymers as mechanisms to be able to deliver them. But it wasn't really known for the wildlife until the study that we did in 2008. Next slide. Another problem that we have with microplastics are that if you look at the types of chemicals that we find either used in the production of these types of plastics or found sorbed to these polymers, and if you cross-reference that with the most important pollutants that we have to measure both here in Australia, but also in the European Union, and in North America and the U.S., it's well over 60% of our most persistent bioaccumulative and toxic chemicals are found at concentrations on these polymers at a hundred times greater than what we find in sediments and a million times greater than what we find in the water. So to understand whether or not these additives absorbed, contaminants could transfer, we did a study that looked at an important worm that holds about 30%-40% of the biomass of many shores around North America, and in Europe, it's called Arenicola marina. And then what we did is we wanted to understand, does this material sorb onto the plastics? Can it transfer into the organism? And can it cause a range of biological impacts? Next slide. So what we did is that we put these various types of worms in different treatments, and we added treatments that had sand and plastic. And then we analysed in those, what was in their body wall of the organisms, and what was in the gut tissues of them after a period of time. And for all four candidate chemicals, they all showed increasing concentrations of bioconcentration occurring in the actual organism, indicating that the contaminants were passing from the plastics themselves through the gut and into the organism. If the rates, if the process was actually occurring through the body wall of the organisms, the concentration in the body wall would be greater than what was actually found in the gut. Next slide. The other bit that we wanted to look at is whether or not the physiology of the organisms themselves could be impacted. So nonylphenol is a known immunosuppressant and sure enough, when you add it to plastic particles, and in also to sand and you give it to organisms themselves, it actually reduces the ability of their white blood cells to be able to phagocytose bacteria. Then when you look at the oxidative stress issue, any of the worms actually exposed to plastic treatments themselves, irrespective of whether or not the chemical was actually present or not, all showed a reduction in their capacity to deal with oxidative stress. Now, oxidative stress is very important in places like Australia, whereby where you have a low tide during the afternoon when the sun is warmest, the organisms themselves build up vast quantities of hydrogen peroxide in their tissues. And they use vitamins in their tissues as antioxidants to be able to metabolise that and turn it into water. But here, it clearly shows that when the plastic articles are present, it actually reduces the capacity of these molecules to be able to deal with that stress. Another issue that we had is that when you actually give the worms plastic particles with the antimicrobial present, triclosan, which is in many clothes and chopping boards, it reduces it's capacity fee, but it also causes substantial mortality. So these experiments demonstrates quite well that chemicals can transfer from articles in microplastic when ingested, and they can cause a range of biological impacts to the organisms. Next slide. So how important are the microplastic particles? So what, we did a study a while ago that looked in a particular estuary and we counted every single particle of plastic and measured every single size of it as well. And it clearly showed, in the best possible scenario, over 65% of the plastic counts themselves were composed of these micrometre sized particles of plastic. And in downwind areas, you get substantially more of these microplastic particles, and they're principally made up of these plastic fibres. So if you're an organism in those areas, you're going to be exposed to substantially more plastic particles, in particular fibres, compared to upwind. A range of studies demonstrated that organisms across terrestrial marine and freshwater habitats can suffer quite important lethal and sub lethal biological impacts when exposed to these types of plastic particles. Next slide. So the work that we did, we wanted to understand, well actually, how widespread are these plastic particles? So we collected some samples of sand from shores, from the poles to the equator, and we quantified the quantities of plastic fibres that we're finding in our samples. And we use something called Fourier transforming infrared spectroscopy, essentially we're treating the global environment as a crime scene, and we're trying to identify what types of polymers are actually found. And this work demonstrated, it was the first work to actually demonstrate that microplastic particles were found in Australia. What we actually did when we looked at the patterns of abundance is actually, places where there are more people have more of these plastic fibres, and it's principally composed of polyester, acrylic and nylon fibres. Next slide, please. Then what we wanted to do is understand the possible source of these. So we went to places around the UK, where they had conveniently discharged of sewage sludge in these neat locations, and we compared what was in these sub tidal disposal sites compared to other sites that hadn't had any sewage sludge added to. And even though the sewage sludge disposal grounds hadn't been used for over a decade, they still contained over 250% more plastic fibres than reference sites. Then we looked at sewage treatment plants here in Sydney and demonstrated the same types of plastic fibres were actually found in the affluent, acrylic, nylon, and polyester. And when we looked at the proportions of polymers actually found, i.e. dominated by polyester with smaller amounts of acrylic and nylon, it seemed to match those used in textiles. Next slide, please. These fibres themselves are actually twisted together to form yarns, and the yarns are normally put together to form fabrics, and the fabrics are stitched together to make clothes. So it was reasonable that these actual fibres, one possible source was actually from the washing and wearing of clothes, but we needed to test it. Next slide, please. Then what we did is we, we've got independent washing machines at different people's houses, we then put different types of clothes in those, and then we washed those. And then we compare different types of garments that were made from polyester, because that was the dominant type of polymer that we were finding, things like the blankets, fleeces, and work shirts. And then we looked at the numbers of fibres actually coming off per litre. And the interesting thing that we found was that the poster child for sustainability at the time, were things like fleeces, which is made up of recycled fibres from bottles themselves, was actually shedding nearly 200% more of these fibres compared to anything else. So what can we do to actually mitigate that? So we've set up a range of different facilities at our water research laboratory in Manly Vale, in New South Wales, under the provisor of trying to understand how can we mitigate this? Do we need to avoid certain types of polymers? Do we need to intersect them with better forms of filtration, or do we need to re-engineer the actual garments themselves, or the appliances, or to actually try to improve, reduce the amount of emissions coming off? Next slide please. So to do this, what we've done is we've set up what we believe is the world's largest scientific laundromat. It has 40 front-loader washing machines, and we're able to do what would normally take us years in about a week. We can test a range of different types of clothing, and we wanted to hear-test whether or not some of the filters that are actually on the market to reduce the emissions of fibres into the environment actually worked. Next slide, please. So there are a range of different types of filters on the market, ranging from balls that you put inside the washing machine that are supposed to collect the fibres, through to bags that you're supposed to put the garments into, through to inline filters that are essentially on the exhaust pipe of the washing machine that are designed to try and filter it much like many scientific aquaria. Next slide please. And then we convinced one of the manufacturers of the existing filters that were on the market. This one was called Lint Lover, with support from a local council. We got them to re-engineer the actual filter itself. So we had two different types of pore sizes. And then we tested that with cotton, and also with polyester clothes. So separate experiments for each type of polymer. We then ran those experiments. Next slide please. And then we looked at the amount of fibres themselves that were actually trapped by the actual filter. So each of the washers had a mass balance done and we looked at proportion of fibres on the filter itself compared to what's actually on the garments to begin with. And you see, when you use no filter, it doesn't catch anything. Obviously when you use the two millimetre size, core size, it collect some of it, but you get substantially more when you get much smaller pore sizes being used. So re-engineering the filters themselves can improve it. The important thing here to look at though is that, whilst the filters worked very well for natural fibres, they didn't work quite so well for the polyester garments themselves, which is what they're specifically designed for. Next slide, please. Ongoing work is looking at comparing natural versus plastic, versus recycled, versus virgin polymers, and seeing how the rates of emissions from the garments actually varies. Next slide please. But what we've done so far is we've been deploying fibres in the environment and actually looking at rates of survival and fragmentation of those. And we've demonstrated that the plastic fibres themselves actually lasts substantially longer compared to animal, and much longer compared to plant. And this was work done by PhD student, Charlotte Bellow, and also our current researcher, Bella Charlesworth. We've also got a textile engineer on our team, Marina Tedesco, who's got over 15 years of experience working in industry, re-engineering garments, and she's looking at how we can actually improve the types of fibres, yarns, and fabrics, and clothes, by re-engineering those to actually reduce emissions. Next slide, please. One of the aspects that we've been also wanting to improve on is the methods of quantifying these actual fibres in the environment. Obviously the fibres aren't just made of plastic fibres, they're made up also at the range of mineral, plant, and actual animal fibres as well. So we've been looking at those particular aspects. Next slide please. And just the next bit, so that Marina's photo can come in. What Marina Tedesco has actually done is that she's looked at some of the methods that they use for crime scenes for actually imaging fibres themselves, and been able to actually combine methods that they normally used in textile engineering to identify the types of polymers for individual fibres. So here she uses laser confocal microscopy to image the fibres. She's then able to build up a three-dimensional picture of each and every single fibre. Next slide, please. Next slide. And through that, she's been actually able to get really reliable estimates of the mass of the individual fibres themselves, and shown that many of the cylindrical methods that people are using at the moment are very inaccurate in terms of actually how they do that. So the idea is, here is rather than just doing counts, what you try to do is look at mass of fibres. So you take measurements of the fibres and then you combine those to be able to estimate the volume and information about the density of the polymer itself, you can work out the mass, and she's shown that the elliptical methods are actually substantially better compared to the cylindrical ones. Next slide, please. Other work that we've been looking at is that the plastic fibres themselves can be really easily identified using spectroscopy. However, cellulosic fibres don't work well under spectroscopy. A range of different methods of input forwards by people to actually be able to identify different types of cellulose. So we put them to the test, there's particular wavelengths that people suggest, we've got white and black versions of different types of cellulosic fibres. And then we then actually looked at their capacity to be able to actually identify those and find differences. And actually there's more differences between the different colours and types than there were consistent differences for actual particular types of the cellulose themselves. And this was the same for both of the wavelengths widely put forward in the literature to actually work. Next slide, please. Here's some of the images that you get with the confocal method, and with the cotton method, you can quite clearly see that it's got the kidney shaped cross section at the bottom left-hand corner. The linen, just go back to the last slide, please, sorry. The linen, you can see the bamboo type structure for ramie, you can see the pause in the middle, and for jute, you can see the multi pores in that cross section. So this provides a quick, easy method to be able to quantify and identify those based on the morphological features of the fibres, which hasn't been able to be done before. Next slide, please. One of the problems that we have is that when we've actually systematically, critically reviewed the literature since this work has been done, is that most of the surveys and experiments that people are doing don't actually allow us to provide robust data about the spatial quantities of the material in the environment, how much they're actually increasing, or to be sure about the actual quantities that organisms would encounter. And that's a major problem for risk assessment. However, if you can actually use linked surveys and experiments to actually focus in on understanding patterns and processes of contamination and pollution, we believe it will be possible to actually understand and manage these particular issues. And there's a recent review by Underwood at how that's looked at that, which you can read. Next slide, please. So the approach that we suggest is that we really need to be starting to look at what are the scope of the problems, doing systematic and critical reviews to understand the quality of the data that's actually out there, the types of work that's being done, then we need to identify what are the options for actually managing a particular problem for textiles. So either avoid, intercept, or re-engineer, and that's the same for most types of polymers. And then, when people pose an action to actually solve it, we need actual managerial experiments before and after control impact to determine for certain whether or not they actually work. And if we do that, we think those types of approaches will actually allow us to understand and manage these types of problems, and prioritise those in relation to other forms of pollution and environmental impacts. Thank you very much.

Thank you very much, Mark. And we'll move on to our next speaker, Denise. If your slides are ready.

Thanks so much. I think they're, will just be coming up. I'm just trying to click as well. I don't yet seem to have access, but I'm sure it's coming. I still am unable to drive. There we go. Thank you so much. And we'll see how this works. I'll just ask for someone to slip to the next one, if we need to. And I'd also like to start by acknowledging the Muwinina people of Hobart, Tasmania, who have been the traditional custodians of land and sea country from the area that I'm ringing in from today, which is in Hobart, Tasmania. I want to acknowledge their continued custodianship over their country and to acknowledge the elders past present and emerging. And I would also like to acknowledge that this photo that you show here actually looks pretty unlike most of our beaches and coastal areas in Australia, which means we are incredibly fortunate. However, these images are taken from Christmas Island, which is obviously within Australian national territory waters. Next. I'm going to be talking today, sort of from a stepped back perspective. I'm not going to walk you through, you know, Mark has talked about this fantastic research that he and his team and collaborators have been doing. And I'll talk a little bit about some of our research. I'm also going to shift gears a little bit and step back in scale to talk about solutions and approaches towards helping to resolve the issue. You know, so if you want to call it plastic, microplastic pollution management, and looking at policy responses, and regulatory instruments that are being developed and being implemented here in Australia and beyond. Next. And I think we're all incredibly aware that public perception and interest in this topic has grown exponentially in the last 10 or 15 years since I've been working on this topic, Next slide, or next click, rather. We know that we now have a federal government mandate that says that we will not be exporting all of our waste into the future. Next. And actually we, that is creating new opportunities for domestic businesses and partnerships to look at creative, new opportunities and means for helping to resolve what is typically perceived of as waste. Next. We know that plastic pollution, whether it's large items, huge items, or teeny tiny items, or objects that are either intentionally developed or designed to be microplastics, or if they are resulting from the breakdown of really small objects, we know that overall, we really need to have integrated responses, that there's not going to be a silver bullet solution to this. It's going to take the will of the public governance, producers, research scientists, such as, you know, those of us who are here today, as well as the frontline workers, waste management responders, consumers, and business enterprises as well. Next. So people often ask me what, if anything has changed, and has anything changed over the last decade? And my answer is always a resounding, next, it's a little awkward when I can't do these, but that's okay, is always a resounding yes. Next. I think one of the core things that has changed or is changing in today's society is that consumers are speaking loudly and clearly, consumers are voting with their purchase power, and we are seeing a significant or substantial shift in requiring or requesting change. And that means the social licence. So are we allowed and supported to do some of the things that have been supported within the past? You may liken it, to if any of you are old enough to remember when people could smoke on aeroplanes , that's what we call social licence. Once upon a time you could smoke on an aeroplane. Now you're best not to hardly smoke in public, much less, even on your own property, given the way that the social licence has changed. So consumerism has really shifted at the same time. We're seeing huge increases. Ah, perfect. Great. Thank you again. So what have we seen in terms of change through time? Well, we're seeing a huge increase in the amount of plastic that's being produced, whether it's from primary microplastics onto larger objects with a variety and an increasing suite of different polymer types. We know that we're seeing an increase in the amount of plastic pollution that is ending up in our oceans, and we know that that is tracking how much plastic has been made through time. We estimate that around a third of all single use packaging escapes from current collection systems. And while this number is a bit outdated, that says there is 8 million metric tonnes per year of plastic leaking to the environment. That number is only growing. When we look also at the trends, what we see is that continued increase in focus of plastic production for packaging itself. And so what that means is that we're turning our polymers into more and more opportunity to package the world. And so these figures here show how many metric, how many millions of tonnes per year of different types of waste are lost to the environment, and in the upper figure, it shows by different sector. And it shows the overwhelming amount by packaging as well as by coastal waste mismanagement. And I think it's really important as people in communities, and governments, and industry talks about the cost of action. How much does it cost to create the change? It's just as important or relevant to consider the cost of inaction, which is also estimated to be in the tens if not hundreds of billions of dollars. So Mark has talked about some of, a great deal about what we know about the impacts of plastics. We know that there are potential chemical or toxicological effects. We also know that there are economic costs and consequences, that our plastic pollution can be a navigation hazard, that it can transport invasive species that our wildlife, and sometimes threatened species may be caught up in it, or they may mistakenly eat it. And we also know that people want to spend their time and their money going to places that are viewed or seen as cleaner. And I realise that that's really tricky when we talk about microplastics, because we've also seen and heard, and we understand that our microplastics are in the air that we breathe, they're in the sediments, they are often on children's playgrounds, they're in the carpets, they're in the sippy cups, you know, that children are drinking from. So we acknowledge that plastics are everywhere and pervasive, and then it's really time to think, or to talk about what are we going to do to help manage some of the issues that we're seeing today? I think it's also worth noting that often, particularly in such developed, incredibly well-managed countries, such as Australia, we tend to think that our trash is coming from someplace else, that what we see on our shores, what we see in our communities, that it's, you know, that it's come from elsewhere. But what we've seen from analysis domestically and globally is that most of what we find in our coastal areas actually stays quite local in origin. We estimate that over 92% of the debris that's found in coastal areas actually remains on our coastlines. We also know that, as Mark pointed out earlier, that what we may find are higher concentrations, where we have more people or areas that are downwind. And what we find from large scale national analysis is that we tend to find whole consumer items near our urban centres, and that we tend to find more fisheries objects or marine type recreational objects in our very remote areas away from our city centres or urban areas. And if we want to understand how to manage this issue, whether we're talking about the large stuff or the small stuff, it's really useful to understand what's causing, or what's behind the patterns that we observe. And what we know is that while today, we certainly don't have crowds like this anywhere in Australia at the moment, such as here at the Sydney Opera House, we know that our urbanisation, our city centres are areas where we find much more litter waste, large and small, lost to the environment. And we know that some of the key factors are how close we are to roads and to infrastructure and networks, as well as how many people live within a particular region or area. We also know that how the land is used in that area is incredibly important for the amounts and types of waste that we see lost to the environment. And we know that people value different areas differently. We value our beaches, we value our parks, we value nature reserves more than we tend to value agriculture areas, industrial areas, and transportation areas where people are moving through without spending much time. And so we tend to find more litter in areas where people attribute it to less, attribute less value to them. I think the other thing that is often uncomfortable to talk about and may not be that popular to consider is one of the key drivers, is actually far beyond how many people live in the area. It really often has to do with the socioeconomic advantage or disadvantage of an area. We find more debris, more litter lost to the environment in areas where there are lower education and employment levels, where there's higher economic disadvantage, and where economic resources are simply lower. Now, of course, these things vary in time and space, but these are some good guidelines and can really help us to target policies and practises appropriately and effectively if we want to change the game substantially, I also think it's worth us to kind of consider, what do we know, you know? Mark did a fantastic job of highlighting so much of the research that's been done in what we know, you know, and it's also worth considering how much more of different types of studies do we need. What do we, what more do we need to know to be able to effect change and to create the actions required if we want to substantially change the game? You know, we know a fair bit about the types of plastics that result in more harm. We know about the overlaps between the types of waste that we find on land and on the seabed floor and where they overlap in terms of small particles and food components, and things like that. We also know that there are particular types of items and objects that typically result in more harm to taxa of concern, whether it's balloons, or soft plastics themselves. The upper picture just shows a balloon release, which is hard to see the purpose of in many instances, and the lower figure shows the amount and types, and sizes of a variety of soft plastics that were found in the digestive track of a single turtle. You know, we've also shown and known of the numbers and types of microplastics that we find in seabirds. Some previous work that we did, however, when we fed virgin plastic pellets, microplastic pellets to multi-generations of birds using button quail, we actually found very, very little or limited toxicological, demonstrable impact on those individuals. Although we did find a slight reproductive delay, which could have large-scale consequences in potentially, population level effects. As we've discussed, we know that microplastics happen in many products. We're starting to see a substantial change in that, in those consumer and, you know, face or personal care products. And we know that there are major efforts afoot, including domestically in Australia, to sign on to a potential international marine plastics treaty. Now, there has been some consideration of whether or not that would be something that is a binding agreement among the multitude of countries that would be signing on, but it is, again, a tremendous step forward, and a show of leadership and engagement within Australia to be considering our country's position or engagement with such an international agreement. We also know a fair bit about the changes and increase in science, so that we have, we have a federal threat abatement plan here in Australia. We know that there has been national surveys. There has been a number of different risk analysis and risk assessments for the impact or the exposure rate of major marine taxa to both entanglement and to ingestion. You know, there have also been some focus projects within Australia that have been supported to look at what should the emerging priorities be within the government and within the research, within the research component of the country. So this figure up here shows the amount of plastics, which tend to be microplastics, they're mostly microplastics, that are found floating on the ocean surface around Australia. And what we find here is the highest concentration is within the Great Barrier Reef region. So, you know, that may be because of a large number of factors or reasons, not just due to population density and runoff. And this is even when you correct for the potential for contamination due to contamination from clothing or fibres that may get in and may not always be considered in studies and surveys. I also show this image here, which is a combined set of information from CSIRO, from cleanup organisations, such as Clean Up Australia, and a small amount of information that was shared from Tangaroa Blue Foundation that allows us to understand some of the locations and sources or hotspots of littered waste or lost items to the environment. And these include everything from microplastics on up to quite large objects. And I think the other point to note here, in terms of where do we act and how can we act, this figure in this lower corner really talks about where along the plastics use and supply chain, where we can have implementation of policies or practises, and where they may be more or less likely to be effective as we go from implementing bans in items prior to their production and being used, through to bag bans and those sorts of things once an item is produced, and on through to where waste or litter is lost into the environment, and how it gets transported along its route where it often or can certainly end up out in the ocean. And I think that really comes, as I talked about, social licence, about human values, and how do we decide when and where we are going to act? Because I realise as a scientist, that my role and my area of engagement may be around the data, around the information. However, I'm equally aware that when and how people act isn't necessarily all based upon data and information, we actually start to act in, when we see that there is actually something that aligns with our values. So we have seen a huge influx and focus on plastic straws, which was, you know, and we've seen some voluntary actions and measures from industry partners or from industry groups such as Starbucks who've stopped selling, or sharing, or providing plastic straws after a video of a turtle with a plastic straw in its nose went viral. At the other end of the spectrum, you know, we also find legislation may come into place when there's actually the loss of human life. That's when we actually may move from voluntary measures to compulsion or to mandatory measures such as legislation. And this here is an example of plastic bags that were clogging drains. I think seven people died in this flood as a result, which results in a very quick and highly effective presidential decree that had an immediate impact. And so, where we as people and communities, and as different cultures decide that we value particular lives in different ways, becomes really important to consider in terms of when policies are implemented and how they may be enforced or mandated. So for this, I don't know if many of you have seen, there was a recent paper that came out that talked about microplastics in faecal material of infants, and then they compare that to adults. And I guess my question here is when, and where do we base our policies? Do we focus it on microplastics exposure where we find that sort of thing, or when we see that demonstration of impact? In the European union, for example, they have developed environmental quality indicators. In one instance, they use a species of bird that is known to ingest plastic, and when particular policies have come into play, what they have found is that there's been a substantial decline in the number of plastic pieces that are found in this particular species of animal. And so what they've done is actually set allowable limits for plastic particles in major marine taxa, for example. So that is one thing that can happen or an approach that can be taken. And to go back to, you know, understanding the risk of microplastics in infants versus adults. If you think about the number of, you know, the number and the weight of the microplastics that have been detected, if you want to understand, this is, the amount is presented in the number of nanograms per kilogramme, per body weight of exposure for each day. And if you think about how much a nanogram, it's a billionth of a gramme, and to give the audience a sense of how much a gramme is, a $2 coin in Australia weighs about 6.6 grammes. And so if you think about the weight of the, you know, of the items that we're talking about, having been ingested, those amounts are actually quite small, and we still, as has been highlighted, we don't have a clear understanding of the actual harm to humans and how much has actually passed through, versus resulting in harm to growth or to some particular aspects of human health. That said, we do know that many types of plastic can act as endocrine disruptors and are hormone mimics. However, it's very tricky to carry out some of these experiments, because it's incredibly difficult to find anyone who doesn't have some level of exposure to plastic, given the pervasity through the environment today. I do think the op, you know, the place that most of us stay or consider, is that we actually want to operate from the precautionary principle, and to think about how much knowledge do we need to have about particular topics before we start to take measures for something that we presume may not be in the best interest or the health of humans, wildlife, or the planet in general. And so when we also consider monitoring how much waste is getting out there into the environment and how we evaluate responses, I think it's really important to consider, what are opportunities for standardisation and for consistency? We know a lot about information today. We know a lot about the science. We know that incentives work, we know that consistent approaches and data sharing are really important. We've done work that's evaluated how effective different policies and practises, and outreach activities can be. And we have quantified how much waste is leaking through particular land sources, through stormwater drains, or through sewage outfalls, as has been done by some projects, and those sorts of things as well. But there are a number of emerging issues, some of which Mark touched on today. And I think a couple of those really relate to the ways in which some of the assets that we have in Australia are managed, or can potentially be managed to help stop pollution from getting out into the environment before it results in potential harm for ecosystems, for environments, for wildlife, or for humans. You know, we are going to be starting to look at post-COVID recovery within the nation. And we know that there is a waste export ban that has already been enacted for some material types, and is soon, and increasingly going to be enacted for other material types. It's really appropriate for us to be considering what are the relevant and timely solutions and how those may be scaled up so that we can reduce plastic leakage, and we can consider, through design principles, the products that may be less harmful and more appropriate in terms of longevity while still doing their job and being food-safe for humans. So within CSIRO, one of the key components that the institution has been focusing on is one of a number of initiatives to really tackle major social economic and environmental issues. And plastic pollution is one of those. So there's actually a mission which is focusing on ending plastic waste. And we really try to think about, how are we going to reduce up to, or more than 80% of the waste that's entering the environment in the next four or five years. These are the five main or core components of that work. And I'm just going to talk you through it because I think it's relevant for audiences here. And because this is really an integrated, collaborative effort, because it's certainly not something that one institution could do on its own. It's something that involves the public, involves community, involves state agencies, involves local councils, involves, you know, industry and everyone else. And when we, the way that we try to really describe it is we're really looking at, what are revolutionary approaches that can be taken within the packaging industry? How do we engage in behavioural change to really shift our relationship with plastic? And I see that using incentives and treating plastic as a commodity, as an actual product with value rather than waste, is going to be fundamental to shifting the dial on that. I think there are also real opportunities for engaging in novel approaches to waste management, including trying to incorporate longer length changes, change, and more circularity into the plastics production use and reuse game. I think that there's also, you know, as Mark touched on earlier as well, Mark Taylor talked about the role of standards and what do we need to see to change best practises and standards domestically and internationally, so that we're using products for their intended purpose without potential unintended consequences or harm. And then the other main sort of pillar or focal area is really on information. So how do we make sure that we have the best available data and information to support the decisions and the tools, and the policies that are going to be important to really change the relationship and to change the game with plastics, now and into the future? Not just domestically, but internationally. So there are a couple of technology approaches that we're taking on this. And one of those is actually involving using cameras and artificial intelligence to build an automatic litter detection monitoring approach. And so we actually use an inexpensive camera, just posted under a bridge, and something like this, we're working with local councils in this, we have a pilot project in Hobart, and we're using machine learning algorithms to identify those objects that are floating down our waterways, which is a really exciting opportunity to bring technology to bear on a problem that we simply need to be able to manage better and more effectively. And here, this image shows one of many different types of gross pollutant traps or stormwater assets, which are really important in stopping waste of all different types and sizes from metal contaminants, to microfibers, to a large number of other types of items, including plastic that can otherwise overflow, during floods in particular, and be lost into the environment. And given that there's such an incredible array of those different types of assets within the country, within even, in particular, individual council. What we've been doing is actually working to develop a small sensor or suite of sensors that can measure how full a trap is, and so that we can then build in an electronic signal that goes to the local council member, to the waste management team that says, "Hey, these traps are full, they're about to overflow, and this is the most effective, cost effective, and safe, smart way to clean out these assets and save the council's money." So we're working on a project with this, within the city of Hobart. This map here just shows the location of some of those assets, which is a really exciting opportunity to engage with local councils. And we're also looking at expanding that and doing some work in New South Wales, and other jurisdictions as there is interest. And I think as well, there are, based on the data and based on the public appetite, I think there are a substantial number of opportunities for success, if we want to really change the game. We know how to target or that we need and want to target particular sites that tend to have really high debris loads. And those are sites that tend to have high debris loads for microplastics, for larger plastics, for everything. We also know that the employment or initiation of incentives tends to be highly effective and that different incentives work in different contexts. And so really looking at whether you employ the carrot or the stick, it's really important to think about your context. And I think that, that comes through from a number of different projects and areas of research that we have seen. We also know that there are opportunities to spend less money and to get higher returns on our investment in terms of reducing waste and stopping it from being lost into the environment. And so considering those and looking at cost effective ways to reduce litter tend to be really, really important opportunities right now. And I think that there will and can be an increased focus on how effective different policies are and at what different local scale. So whether it's at the council, the state, the national, or international level as well. Ultimately I think, ultimately I think that if we start to measure, as Mark Browne was talking about earlier today, you know, we can start to manage and we can better understand the risks and the consequences to natural and human integrated systems. So, you know, if we start to understand the problem better, I think we can then be better poised to change our design principles into design for longevity. I think as well, that as we are participating, each and every one of us, in society through our purchase power, we can also start to influence the changes that we want to see, and that as we use particular products, as we have our say with our wallets, I think there are real opportunities to look at new, not only new designs, but to look at improved opportunities to circularise the plastics economy. And overall, I think that those differences and those understandings can really help to provide a springboard for improved policies, for better evaluation tools, and as Mark Browne was mentioning, looking at before and after there are interventions, or policies and controls that are happening. So looking at some of those and looking at a national consistent approach may yield substantial insights to help us to resolve this issue. And what I'm really heartened by today are the number of fantastic ways and means which people in communities, and businesses are starting to engage. Many of you may be familiar with AUSMAP, which is a citizen science microplastics assessment project, which has been underway, and which is helping to yield good insights from stormwater outfalls. Many of you, I'm sure most of you, have heard of Boomerang Alliance who, it takes a different approach in tact and is engaging with stakeholders and government to lobby or to encourage change at a number of different levels and different means. I think there's a hugely important role for a variety of different types of partnerships, such as, you know, Ocean Protect is a stormwater asset company that makes these assets and is very deeply and closely engaged in environmental stewardship and local custodianship. And so I think we're starting to see a wide array of players and partnerships developing that are taking into account the different viewpoints and perspectives, and different leavers that can be pulled to help resolve the issue from a variety of different approaches or perspectives. And I think it's, I'll leave it here and just say that, I think, now is a really good time and opportunity. I am, in spite of the work I've been doing on this topic and the over abundance of plastic, I am actually heartened by the ability of individuals and consumers, and governments to make change. And for that change to end up being reflected rather quickly within our natural and human managed ecosystems. And I will leave it there. Thank you so much for your time.

Denise and Mark, thank you very much for a really interesting set of talks, which provided, really, insight into the fact that plastics themselves are complex. And the issue, the problem of plastic pollution is complex in terms of the sources, the distribution, the cleanup, and the resolution of that problem. But we've got a range of questions. I've got one question, I've got actually two questions. One question for Mark that I would like to ask, is there any evidence to suggest that the microplastics are contributing to biodiversity loss in the oceans?

There is some, we've done a systematic review on the evidence and that's by, lead author was Chelsea Rochman on that one. For the microplastics themselves, there's less evidence compared to the larger bits of plastic, that microplastics have issues of trying to actually identify patterns in the environment and then relate those to the actual quantities. So I think there's more evidence for the larger bits of plastic than there is for the smaller bits. The concern that we have with the microplastic, in particular, fibres, are they the new asbestos? You know, in terms of actually the types of issues that they can cause, if you look at the evidence of what's been done so far, inflammatory responses, fibrosis, which is consistent with the asbestos. The bit we don't know about is whether or not the fibres themselves can go from the fibrotic stage, which is the scar tissue to the cancer stage. And that would be a concern. If you do give these fibres to organisms, they do suffer mortality and they can have reproductive issues. Again, it's the environmental relevance of those studies and trying to get at, you know, are you doing it on the main quantities you find in the environment, have you got blanks when you're doing that. So sampling, if it's like a storm water discharge, is that varying over time? Is there a first flush? Is there an end flush? So there's regimes of exposure are incredibly difficult things to, to investigate if you don't have the resources, but there are methods to do that with structured surveys and experiments. It just requires those sorts of studies to be supported.

Thank you. That's a good answer. Denise, a quick question for you before we move on to the long list of questions that we've received. Wouldn't it just be easier, and is it possible for us just to stop using plastic?

That is quite thorny question. Sure. So I hear the question and I appreciate it. I guess I'd ask every single person, you know, including ourselves, what are you going to replace those artificial heart valves with? What are you going to replace your chair with? What are you going to replace your mobile phone, your computer, your, you know, any of the number of products that we use that have quite long and useful lifetimes? You know, so are we just going to get rid of plastics in society? No, we're absolutely not going to. I don't think it's realistic and I'm not sure that we really want to. I mean, Mark I see you, like myself, wear glasses, many people also wear contact lenses. All these things are made of plastic. So there are many, many really useful, functional ways in which our lives are enriched through the use of plastics. However, I think that none of us want to be mistakenly eating plastics or getting tangled up in them or having the potential toxicological effects of plastics. So I think that becomes, you know, a bit of a two-edged sword, our convenience, and you know, the potential harm. I see you took your glasses off now.

I did. I decided I might be able to see without the glasses, but I'm enlarging the screen. I think the issue is a bit that, you know, it's the dispersal. If the plastics are contained, if it's not that, it's not the problem. It's the unbridled dispersal of microplastics into the environment, which is causing significant concern.

It is. Yes.

And I would like to move on to some of the audience's questions 'cause there's a raft for both of you. I'll start with the first one. These are directed to Mark. So the first question is, do natural fibres absorb contaminants the same as synthetic fibres?

Yes, they can absorb contaminants, The comparative studies across the range of different types of natural fibres and whether those are vegetable, animal, or plastic haven't been done. So that, to answer that question, you need a well replicated study that has replica types of each of those classes. Then within each of those classes, you need replica polymers within each of those. And then you need a nested design to be able to do that. And then you look at, need to look at rates of absorption, and then you need to decide which environment you wish to investigate that on. And at what stage is it? You know, if it's storm water treatment process, is that during a storm, is it after a storm? So those types of studies can be done, but it requires a greater level of support than we've previously been able to do. And mark, you'll appreciate this, that chemical analysis isn't particularly cheap to do with certain types of contaminants. It's quite, it's relatively cost effective, but for others it's a bit more expensive. And so painstakingly doing those types of studies, you know, first of all you need to look at the particular fibres in the environment, see what's absorbed to those, find a pattern, then investigate that with an experiment. So link pattern with process. So, can be done, just requires the necessary support to be able to do it.

Yeah. And obviously there's the challenge of time and spending the, finding the right team to do that and getting it done in a timely fashion in order to have findings that then can be acted upon.

I mean, the one thing I would say is that the study that we did, with the lugworms whereby we gave them chemicals that have been sorbed in parallel treatments with sediment, sand particles and plastic particles that were the same size range. What went on easy on to plastics was quite difficult to come off for some of those. It was still able to cause a toxicological impact. So it's, it can be done, but what comes on easy doesn't necessarily mean that it comes off easy. So it's a bit of a difficult thing to look at.

And if I can move to the next question, since you, the best washing man I've ever met in science, this question pertains to that. He says, "are there differences between top loader washing machines and front loader washing machines in relation to the generation of fibres?"

So there has been a study that's done now, but they're one of the cardinal rules, the problems in environmental science, something called pseudo replication where you don't actually have the necessary levels of replication in the tests that you want to do. So they compared one top loader with one front loader and found a difference. Well, within my 40 washing machines that we've got, we'll find differences between individual ones. So you, again, you need the proper replicate study and that's not been done yet, surprisingly.

So could I ask, was the difference, was the difference between your washing machines greater than the difference between the top loader and the front loader in the other study? Have you looked at that, just as an aside?

We have looked at the variation for particular types of garments to see if their block effects with our; I think the effect size was smaller in terms of the variation that we had to compare to the reported in the study, but there are reported studies using parametric statistical tests that require independent data. And if you've not got independent data, they're not reliable estimates because of the way the P values are calculated. So it's a slight problem. It'd be great to look at. We just need some appliance manufacturers to come on board and help us.

Well. I'm sure we can find some of those to supply a few washing machines for testing Of course, I'm sure some manufacturer would be keen so say "we have a washing machine that produces less microfibers that get discharged into your wastewater stream." And so on the third question I have for you, is microbeads have been phased out of cosmetics, but these have been replaced by acrylite cross polymers in some products. Are they just a different type of microplastic? And are they just as harmful, is the question.

Well, plastic comes from the Greek word "plastikos", which means capable of bending during the production process. Some of the other replacements for microbeads, others are some of the minerals that people have problems with when they cut kitchen tops and when people breathe those in. So there's this idea and I think Denise touched on it, that you demonise a particular class of polymer. I think it's a problematic one. We should be trying to understand, what are the features of polymers that cause the problems and then trying to remove those features from those particular types of polymers, you know? And I don't think those studies have been done so lots of calls to action to switch to particular types of materials, but not really the toxicological evidence that actually needs to be done, to be able to underpin those choices.

Sounds like the untested chemical assumption to me.

A very homoeopathic argument, isn't it? That you replace a natural something with something else.

So I'll ask some questions for Denise from the crowd. The first one I have is, and I think you've kind of touched on it, and both of you have touched on it in different ways, but the question is, is there any evidence that microplastics are causing health issues? And I'm assuming, human health issues in this question. So Denise, would you like to answer that?

Sure. So I think that, there isn't, you know, a finite answer that says X number of microplastic particles results in Y harm to humans. Now we know that really, really small microplastics nano plastics, they can cross cell walls, or they can be transferred, you know, through the bloodstream, they can, you know, they can move throughout the body. And Mark even talked about the fact that we actually use some of the knowledge that we have about that for drug delivery systems. So, you know, what we know less about, or what there is less finite knowledge of is what is the actual harm caused by microplastic ingestion, I believe, or presume, you know, or inhalation, as the question. And we don't have that crisp, clear answer that says "this harm to humans is caused by, you know, this plastic or this suite of plastic polymers." You know, as I mentioned that we know that they, some plastics can be hormone mimics or endocrine disruptors again, though, it's really hard to quantify, what is that potential impact? Because we simply don't have an audience or a group of people to draw from that don't have the exposure that, you know, may be anticipated. And as we spoke about earlier, you know, at the same time we are seeing an increase in human longevity overall. One argument that people also talk to at times is that the decrease in male sperm count has paralleled or has tracked the increase in global plastic production. And so people look to that as an indication at times of the rise of plastics in our environment, around us, whether it's being ingested or not, is having, obviously, what would be a sub lethal impact on humans. Mark, do you want to add to this, to that comment at all.

Denise, I would just say about that correlate, as you would know better than anybody, as would Mark, correlation is not causation and it may be the case, but we do not know. I mean, it could be from pharmaceuticals in our drinking, from recycled drinking water, or water, which, you know, blended water, sorry.

I suppose, I can agree with what both of you have said. I suppose the issue there is that if you have a correlation, you then got to propose possible explanations for that, and then go through in a falsificationist procedure for necessary experiments to actually try to disprove those. And if the industry was very confident that produces the polymers, that their particular polymers aren't causing those problems, those sorts of studies won't be supported. The issue is I think at the moment, they haven't been. So, you know, we've seen the argument changing from plastic's an inert substance that doesn't cause any problems. And then we demonstrated quite clearly that it can bio accumulate, it can have toxicological damage. Now the argument is about the risk of it, you know, what's the rate of exposure. And then people say, "well, actually you have not been exposed to enough based on some surveys". Well, the problem is when you look at those surveys, the types of surveys that you need and support to be able to do them just to distinguish procedural and environmental contamination is really difficult to do. You need a lot of support. So I think the argument that when we don't know that we're not being exposed to enough, therefore it's not a problem, I think has the problem that we've not done good enough surveys yet to be able to identify what those exposure regimes are, to be able to do the proper experiments. And until we do those, we're going to have problems. Certainly the biomedical sector has long known that polymers cause problems, which is why they continually test implants and to make them more durable and less toxic over time. And maybe if a similar approach was used for polymers, we might be able to sort of have a way forward.

Yeah, that's a really interesting set of comments. I think it's probably fair to say, the world's too full toxicants, to which no lower stage threshold could be identified. And that's largely because we don't have those controls that you've mentioned. We don't have the true blanks and toxicants could include particulate matter in the air, would include lead, benzene, mercury. There's a tonne of chemicals that are in our environment now, and we're industrial animals, from which we can identify a safe, lower threshold and no data doesn't, you know, the absence of evidence, isn't evidence of absence. And you know, where at the beginning of this programme of trying to identify what is, yes, we've been exposed and what is, what can we; can we identify a safe level of risk and for whom is that for? Cause not everybody will respond in the same way, as we know, to exposures to different chemicals. So another, I've got some more questions that have come through. Some questions in regard to the EPA. Will we be conducting any work in this space. And I think what I can tell you is that the EPA is pursuing research into the impacts of microplastic pollution to address current knowledge gaps. We're examining the risk of harm posed by different types of microplastics. We know as has been detailed in exquisite detail by Mark and Denise, that microplastics come in complex mixtures of different polymer types, sizes, and shapes. Unfortunately, so far, there's no standard method for their measurement or no standard instrumentation, that makes that difficult an issue to measure and quantify. However, understanding the dynamics of where microplastics come from will help us guide regulatory action on this complex and diverse pollutant. So in addition to doing that work, were facilitating these forums, to get the issues out in the open and for the community to understand what the problem is and what sort of interventions can be undertaken. So moving back to guest speakers, I know there's another question here for Denise, with the focus on circular economy, it's now evident that roads contain significant recycled inputs, including plastics, as these were, are microplastics, or plastics being released back into the environment. And if that is the case, should we continue doing this?

So the very short answer to that is yes, you know, roads are going to slough off plastics if they're constructed of plastics, as well as other, you know, tar oil from cars and all sorts of things. We also know that tyre wear, so rubber from tyres is also a growing increase, or growing in, you know, increase or concern. So the short answer is yes, as roads degrade, they are, if they are made of plastic, that to shell degrade and end up in our waterways, coastal or otherwise, and to what should we do about it? You know, as a research scientist, it's not my place to tell the government what government should do. What I would say is it's really worth thinking about unintended consequences and thinking about, you know, making the best decisions that we can with the knowledge we have at the time, and then to not, you know, I think it's really easy to look back and say, "well, that was really dumb", with hindsight. You know, if we have evidence or knowledge now though, that says, "Hey, this is a problem in our waterways." Then we may really want to rethink or to be, have quite strong conversations about what are the products that we're using to make things such as roads, such as, you know, rubber mats or artificial turf, which are being looked at for playgrounds, for schools. You know, as we look at and think about that, very young children put everything in their mouth. You know, when you look at the, even the wood chips that have gone into playgrounds, if you look at those, those in many places can have quite hard high levels of arsenic or other contaminants, you know? I was talking with Jenna Jambeck earlier today, and we were talking about that. So, you know, we should use the knowledge that we have to make the best decisions we can at the time. And if we are increasing our knowledge of dangers or risks of particular items, then we would want to be mindful about where and how we use those products and what we, what we use to construct them with, if that makes sense, and I'll pause there.

And so there's some more questions relating to this broader topic. And some of them relate to citizen science. One of the questions is raised and I'll put it out to the speakers to answer, can citizen scientists assist with sampling and monitoring in the local environment.

100%, yes.

Could you alert us, I mean, I'm aware of AUSMAP and he's a colleague of mine, I don't want to, I don't want to be selling his words too hard, but that's one...

You know, I mean, and so everybody in the audience knows, I actually have nothing to do with AUSMAP. It's not a programme or project it's, you know, led by Scott Wilson and others doing a great job. It's an opportunity for citizens to get out there and to help collect information about the amounts and types of microplastics that are in the environment in different areas, and to help the country develop maps of that. What we tend to find, however, is that citizens, like when we go and do clean-ups, when we engage in those types of projects, we tend to find that people go to places that are quote, unquote "dirty". And so that gives us a really biassed sample or estimate. And I also know that people will absolutely criticise citizen science programmes for being less precise and less accurate. However, if we have enough data, there are actually statistical tools that we can use that take into account some of the variability in skills and attributes that people may bring to bear. You know, we can measure particular components to allow us to understand, what are those differences, and to tease out the reliability and the importance of those results. So I would give a resounding yes to citizen scientists, certainly can have a substantial, positive role to play in data collection exercises. And the better we train our citizen scientists, our volunteers who contribute to and participate, you know, the better off we are. So I've worked with programmes with Earthwatch Australia, where we actually have worked very deeply with teachers, with industry partners around the country and provided training so that they could also help and contribute, and collect data. We're actually embarking on work, and you know, we've worked with Conservation Volunteers Australia and Clean Up Australia. And I think there are tremendous opportunities for community members, particularly if they're willing to undergo training, to really contribute and to collect data that is meaningful and valuable and can be used in an appropriate way. I mean, we've actually just analysed a couple of major global data sets, one from PADI AWARE, so from, which is part of their dive against debris programme, where people recorded from their scuba dives, they undertook surveys and transects. And we also analysed a global, international coastal clean-up data set. And while yes, some of those data are messy and not all of it can be used, we can actually tease apart some really important patterns. So that's my answer to that question.

Yeah, look, I'm a supporter of citizen science. We have citizen science at EPA and I had, I've got, still got two programmes at Macquarie University on citizen science. And there's a range of literature that shows that the data from citizen science is, that some, some studies show it's just as good as normal scientific data, as long as you give the right instruction and you keep it simple and straightforward. And without a doubt, citizens can add to our knowledge and understanding about the risks. So I'm with you, completely with you, I mean, completely in your camp, so.

I'm not a particular fan of it, I have to admit. For the types of microplastic work that we do and the patterns of variability in space in time, I have some reservations. I mean, a colleague once described it saying, "well, she doesn't prescribe to it because of the same reason she doesn't go to a citizen dentist or a citizen engineer." For the types of issues with procedural contamination, for microplastic, it would cause major, major issues. And I think whatever technique you do, whatever people's personal beliefs are, you need to be able to provide, provide the quality assurance and quality control. So if there is some data to say, well, actually a particular technique works and it's using citizen science, that's fine. It's just provide the methods so that someone can actually test it. And that's what any validated technique would need. It's the same with using a new instrument, isn't it, to be able to quantify polymers in the environment, whatever, as long as there's robust evidence to support it, I have no issue with it, but for the microfibers and for the microplastic stuff, procedural contamination is so easy to do that I would find it difficult to support it for that.

I think I would say there's still some value in understanding, using citizen science. You may want to treat the data with caution, but it's certainly a platform to educate the community about the prevalence and harm, that it made microfibers. Yes, having worked with my students, I collect microfibers in homes and the difficulty making sure that Petri dish is clean, you know, this is, there are limitations, and that as long as you understand the limitations, I think you can use the data. I don't, I take that view. And sometimes it's the only way to collect a very large sample and to understand, you know, the prevalence of a contaminant in the environment. I mean, for example, if you wanted to find out how prevalent microplastics were in people's drinking water in their homes, to get a really decent sized sample of 500 plus, let's say, it would be very difficult to do on a personal level. I don't know if you've ever gone to somebody's home, but everybody will want to give you a cup of tea and tell you their life story, and a biscuit. You know, you might get one sample a day, if you're lucky. Anyway.

I do like tea.

So I've got some more science-y questions that I think you would like to chip in on. People have identified a, some on additives one question is, polymers contain a wide range additives, including antioxidants, UV stabilisers, flame-retardant, anti statics, et cetera. Many of these were not designed for ingestion and the body of knowledge is limited. What do we know about plastic additives? And obviously their effect?

Well, when you give them two organisms sorbed to particles of plastics, they cause large rates of mortality, particularly anti-microbials, the flame retardants, we didn't see so much evidence of toxicity, but it might be that they're causing reproductive issues. I mean, the difficulty of all of this is trying to get environmentally relevant polymers with environmentally relevant concentrations of additives on them, and because of the legislative requirements, they aren't really there, it's very difficult to get that from industry, to asking industry to provide these types of things. Even polymers for libraries, the only polymers for libraries that we've been able to get are from the South African plastics industry or the one in Taiwan, the ones from the European and U.S. have been really resistant to do it. So I think policy has a really important play here. And I'd like to see it that, if someone releases a product in a particular country, that they have to provide the actual polymers or the particular chemicals to go, to look at it. I mean, with regards to chemical rates of production, 15,000 new chemicals go on the market every single day. If you look at the actual CAS numbers that each of them have, so that's an incredible amount and less than 0.3% of those have any form of safety testing on and done. So I think there's a real black hole here.

I also think it's worth noting that, you know, something that causes mortality in some organisms may not show a demonstration of harm in other higher organisms. So, you know, we actually used environmentally soaked virgin pellets and fed them to button quail. And again, we were not finding mortality due to plastic ingestion or, you know, when we looked at cellular and tissue level disruptions, and those sorts of things. And that's really different than the findings that you have, Mark Browne, from lugworms and things like that. And so, you know, different taxa are going to respond and behave in different ways. And granted, we weren't using a seabird species because we have ethics permissions and approvals that don't permit that, you know, but we have recently, with collaborators, looked at preen gland oil for, you know, a number of different seabird species around the world. And you do find flame retardants, you do find plasticizers, so softener agents and things like that, in these taxa in different species that are feeding in different ocean basins and, you know, different areas of concern around the world, but we're not seeing mortality from those. And I realised that we don't tend to see mortality because those animals die. But you know, there are also a number of studies that, that are not showing the types of mortality for higher organisms from some of those plasticizer or from some of those additives. And it doesn't mean that they're good. I'm not saying that those additives do not result in sub lethal impacts, but not everything that's harmful is going to result in death. And I'll pause there.

I think I'm Denise raises a very valid point.

Since you talked about additives. Carry on Mark, sorry.

I think it's about the aim of the study. The study that we, that the aim of this study is to try and look at whether or not there was capacity to plause, plausibility to be able to cause something. And I think with seabirds, there is an issue. If you look at the rates of mortality, in terms of the population modelling, more die from being caught up in fishing gear than they do from plastic ingestion, in terms of the autopsy reports, where they have done it with controlled experiments, feeding birds bits of plastic, they've not used in those studies in Hawaii and places, they've, and some of the other islands, they've not used the particular types of plastics that have been found in the organisms where they've established some of the correlations. And so the experiments aren't environmentally relevant. The other aspect they don't look at is the indirect effects. So, a bird has plastic in its stomach, it goes out, it gets dehydrated, or it gets malnourished because it can't fit as much water or food in its stomach. And then if you look at the rates of mortality from dehydration and malnutrition, there could be evidence that it could be plastic being caused there, but that requires proper experiments, like what Denise is saying, to be able to look at that. And then we come across ethical issues that, in some countries, particular experiments on particular birds are allowed and other ones they aren't. So fitting a correlation from a survey with an experiment becomes a bit more difficult.

Thank you. Since Denise was talking about additives, I want to ask about the additive effects. And if, particularly, Mark has looked at that, where you've got multiple chemicals associated with a type of polymer, cause obviously there's multiple types of polymers, and that would make your problem more complicated in terms of doing experiment. But have you looked to the additive effects of chemicals attached or associated with microplastics, as opposed to singular? So you might, you might look at antioxidants or anti-microbials on its own, but have you looked at it with plasticizers attached to it and trace metals for example, or have you just done single contaminant study.

That for Denise, or for myself?

I think for you, I'll put it to you, Mark, and Denise can also answer.

Yeah. So we haven't done those types of studies. That lugworms study took about a year to do. So you have to get the husbandry and everything right, and then sorb the contaminants on individually. Yeah, so it can take a bit of time to sort of do those types of studies. We would like to be able to do multiple chemicals. It's just gets a bit more complex. You know, those designs had about four or five factors in them already, or five factor anova. If you get much more, it gets a bit more complicated, but it can be done, it just requires a support to be able to do them.

Yeah, I think Denise, do you want to say something on this?

Well, I would just add that, you know, there is a new paper that we had, but it wasn't, you know, a designed experiment, it's actually on wild-caught, live seabirds. And so there, we did find a whole mix or a suite of flame retardants, of additives, of UV stabilisers, of polychlorinated biphenyls, and pesticides, and DDT's, and all sorts of things that were detected from, you know, the preen gland oil of a seabird is actually going to, for people who don't know what that is, it's actually a little gland above the tail. And it's, if you've ever seen a bird preen its feathers, it's actually reaching back to that spot and using that. And it's using that oil to waterproof itself and to waterproof its feathers. And so anything from a little songbird in your yard to the biggest albatross has this similar gland. And what was done was to take an extract from that, you know, very cleanly, very cautiously, and then using incredibly careful laboratory methods, because it's easy to get false positives, you know, looked at that in wild caught birds and found a whole plethora of different chemical additives in these birds that, you know, breed on uninhabited islands and those sorts of things. Again, as Mark would say, that's not a controlled experiment. However, it does show the uptake of different chemicals or the integration of those chemicals through one particular gland across a whole suite of taxa from, you know, Northern and Southern hemisphere and across a multitude of different taxa.

Well, I think, thank you very much for your answers. And I think we're sort of coming to a close here now at 10 past three, but before I wrap things up, the speakers, would you like to say any final comments?

It was just really nice to be able to talk to everyone about some of the work that we've been doing. And we're looking forward to being able to advance our understanding and management for this important problem.

And for me, I'd just really like to thank everyone for taking the time out of your day, for engaging on this topic, and, you know, I think there's real opportunities to engage with and to collaborate with state, community, you know, and local council governments to help address some of these issues in areas that are meaningful and are relevent to you. And that I think it is important for us, as scientists, to have the opportunity to engage with you. So again, a huge thank you to everyone for participating in this.

Mark and Denise. I'd like to thank you very much for your lucid and very interesting comments on this pervasive problem. I'd like to thank everybody else who's attended today's live stream seminar. And for the interesting questions submitted. Please keep an eye on your inbox for a short survey where you'll be able to share your feedback on today's session and any ideas you might have for future topics in our seminar series in 2022. If you've enjoyed the presentation, please let us know on Facebook, LinkedIn, or Twitter @EPA_Victoria. We look forward to seeing you at our next seminar series in the new year. And so with that, thank you very much again to our speakers. Fantastic and interesting science, continue with that work. It's really important stuff. And thank you very much to our audience.

Download the slide pack from the webinar (PDF 5MB)

In this seminar we learnt how science is increasing our understanding of microplastics and the potential solutions to their management.

The ocean is a source of food, oxygen, inspiration and jobs. It connects all continents and regulates our climate. Despite its vital importance, large volumes of plastic waste enter aquatic ecosystems every year. A recent study found that emissions of plastic waste to the environment are predicted to rise, and may reach up to 53 million metric tons per year by 2030.

Small pieces of plastic, called ‘microplastics’, are increasingly becoming an environmental challenge. Microplastics can be found across the globe: in the gut of seabirds and the planet’s most remote locations, such as deep-sea sediments. A survey of plastic debris in Australian coastal waters estimated that more than 4000 pieces of plastic per km2 littered the ocean surface. These plastics were predominantly small fragments resulting from the breakdown of larger plastic items.

As Victoria’s environmental regulator, EPA’s role is to protect the environment and human health from harm due to pollution and waste. Solutions to the issue of microplastic pollution are highly complex. Understanding the dynamics of where microplastics come from and how they are transported in the environment will help to guide the regulation of this complex and diverse pollutant.

EPA's Chief Environmental Scientist, Professor Mark Patrick Taylor, hosted special guest speakers Dr Mark Browne of the University of New South Wales and Dr Denise Hardesty from CSIRO to further explore the challenges of microplastics. Our guest speakers outlined the issues, presented their research and highlighted the importance of science to enhance our understanding and response to these microplastics.

Host: Professor Mark Patrick Taylor, Chief Environmental Scientist, Environment Protection Authority Victoria 

Professor Taylor’s research expertise has a special focus on ‘human environments’ including analysis of blood lead levels in children, firefighter chemical exposures, trace metals in bees, chickens, wine, honey, residential veggie patches, household dusts, microplastics and drinking water. He designed two national citizen programs measuring thousands of samples for trace metals in garden soil and house dust (www.360dustanalysis.com; www.mapmyenvironment.com) Topical research includes assessment of atmospheric trace metal emissions from wildfires and microplastics in Australian homes.

He has completed several commissions for government in recent years:

  • a review of the NSW EPA’s management of contaminated sites for the NSW Minister for the Environment, focusing on perfluorinated chemicals (PFAS) and their management;
  • a review of lead in plumbing fittings and materials for the Australian Building Codes Board; and
  • a science review for NSW EPA’s Broken Hill Environmental Lead Program regarding childhood lead exposures.

Special Guest Speaker: Dr Mark Browne, Senior Lecturer, University of New South Wales

Over the last 15 years, Mark has published ground-breaking research on global contamination of marine habitats by microplastic pollution. His research team has demonstrated that an abundant type of plastic pollution is clothing fibers, and that washing a single garment adds thousands of these fibers to wastewater. Mark’s research was first to show that ingested microplastics accumulate in the gut of marine invertebrates (mussels) and that ingesting microplastic can transfer other pollutants and plastic additives
Through his research he has shown that policy about plastic debris is scientifically outdated and, if countries classified the most harmful plastics as hazardous, their environmental agencies could conserve greater levels of biodiversity by having the power to restore affected habitats and prevent more dangerous debris from accumulating.

Special Guest Speaker: Dr Denise Hardesty, Principal Research Scientist, CSIRO Oceans and Atmosphere

Dr Denise Hardesty is a senior principal research scientist for CSIRO Oceans and Atmosphere, leading a portfolio of plastics-related projects. A broadly trained ecologist, her current work focuses on plastic pollution and marine monitoring and surveillance to reduce illegal fishing. Denise’s team takes a risk-based approach to addressing plastic impacts on wildlife, people, and economies. Her work also focuses on drivers for litter losses into the environment, how to identify and implement effective policies to reduce plastic entering the environment, and gear loss from fisheries. She promotes the role of science to inform policy and decision-making, and regularly provides science advice to governments and international panels. She believes strongly in the contribution of communities, having worked with more than 8000 citizen scientists to help tackle global challenges.  

Reviewed 28 October 2021