Plastics and The Environment
Most people would agree that we need to look after our planet, so that we and future generations can enjoy it. I certainly feel that way and it is good to see so many articles bringing attention to the topic. They make people want to act. Our leaders, major corporations and even children are demanding action. But what actions are the wisest? How can we be sure that we are helping and not harming our environment? As a scientist, I wanted to see the facts, but I didn’t find any in the articles online. Hardly any of the articles referenced scientific studies. I began to realize that just about all we believe about the environment is based on LinkedIn headlines, YouTube videos and articles that are just opinion pieces, without any solid foundation. That made me uneasy.
This page is the culmination of my personal search for all the solid data I could find. To give one example, before writing anything on marine litter and microplastics, I read over 50 scientific articles and one book to get a balanced view of the topic. That’s the proper scientific way to approach a new topic. Collect all the evidence you can find, digest it and then form an opinion. It’s the opposite of what many people do. For the layperson, it can be tempting to form an opinion first and then look only for evidence that supports that pre-conceived view. People are welcome to do it that way, but that is not the path to wise decision-making. Our environment and our kid’s future deserve better than that.
Here you will find lots of data and links to the original sources so that you can read it all for yourself. That includes both articles that are for and against plastics. If you have information to add, please send it. I will try to keep the page updated, although I am doing this in my spare time, without any funding so, bear that in mind. I just put this page up in January 2019, so please bear with me as I improve and add content to it.
It all started with plastic bags
Why did I start down this path? I had been reading a lot of articles online about plastic bags and proposals to ban them. But I did not see a single piece of data to support that decision. It may surprise you to hear that I find plastic bags to be one of the ugliest things imaginable. However, I realise ugliness alone is not sufficient reason for a ban. So, with all the options including paper, cotton, conventional PE bags, reusable PP bags, biodegradable plastic bags and so on, how can we know which one is best? There are many different companies telling us their bags is green, but how do we know who is right?
It all started with a Google search. I looked for the terms “plastic bag lifecycle analysis” and “plastic bag LCA” because lifecycle analysis is the only internationally accepted standard to determine what is good and bad for the environment. GreenPeace uses it and so do governments and major companies. It’s expensive and includes everything from cradle to grave including all the “inputs” (raw materials and energy), and “outputs” (emissions to the air and water, by-products and wastes disposal) for making a product. Because it’s so expensive, I wasn’t sure I would find any, but I was happily surprised to find some right away. You can type “LCA plastic bag” into Google and find many of the same hits I did. These are all the studies I have found so far.
In the interest of fairness, these are exact quotes copy-pasted from the executive summary or conclusions of each study:
- Clemson University Study
- UK Study
- Franklin Study
- Reason Foundation Study USA
- Danish EPA Study
- Australian Study
- Californian Study
- Slovenian Bag LCA
- South African Study
- Swiss LCA Study
- Australian Study 2
- Indian Study
- Franklin Reviews LCA Studies
- Portuguese Review
- Canadian Bank Note LCA
- English Bank Note LCA
- McKinsey LCA Report
- Austrian Packaging Study
“A compilation of all of the statistically-based, scientific studies of litter in the U.S. and Canada over an 18 year period shows consistently that “plastic bags” (which includes trash bags, grocery bags, retail bags and dry cleaning bags) make up a very small portion of litter, usually less than 1%.”
“Our results also show that Paper bags, even with 100% recycle content, have significantly higher average impacts on the environment than either of the reusable bags or single-use plastic retail bags”
“Our results in this study show that these regulations and policies may result in negative impact on the environment rather than positive. Even though Paper bags come from a renewable resource and are easily recycled, it is likely that they are not the best environmental choice.”
In summary, they found that paper bags are much worse for the environment and that the best two choices were reusable polypropylene bags or single-use polyethylene bags.
“The conventional HDPE bag had the lowest environmental impacts of the lightweight bags in eight of the nine impact categories.”
“The paper bag has to be used four or more times to reduce its global warming potential to below that of the conventional HDPE bag, but was significantly worse than the conventional HDPE bag for human toxicity and terrestrial ecotoxicity due to the effect of paper production. However, it is unlikely the paper bag can be regularly reused the required number of times due to its low durability.”
“The cotton bag has a greater impact than the conventional HDPE bag in seven of the nine impact categories even when used 173 times (i.e. the number of uses required to reduce the GWP of the cotton bag to that of the conventional HDPE bag with average secondary reuse). The impact was considerably larger in categories such as acidification and aquatic & terrestrial ecotoxicity due to the energy used to produce cotton yarn and the fertilisers used during the growth of the cotton.”
They also found that plastics designed to degrade were worse for the environment. Non-woven, reusable polypropylene bags have least environmental impact if people actually reuse them several times but in reality, people forget to do so.
“The study results support the conclusion that any decision to ban traditional polyethylene plastic grocery bags in favor of bags made from alternative materials (compostable plastic or recycled paper) will be counterproductive and result in a significant increase in environmental impacts across a number of categories from global warming effects to the use of precious potable water resources.”
“This study supports the conclusion that the standard polyethylene grocery hag has significantly lower environmental impacts than a 30% recycled content paper bag and a compostable plastic bag.”
“Proponents claim that banning plastic shopping bags will benefit the environment. Yet, as this study has shown, there is very little empirical support for such claims. Indeed, the evidence seems to point in the other direction for most environmental effects. Some of the alleged benefits are simply false, such as the claim that eliminating plastic bags will reduce oil consumption.”
“Unfortunately, policymakers have been cajoled into passing ordinances that ban plastic bags. That is bad news for consumers. It is also bad news for the environment, since the public has been misled into believing that by restricting the use of plastic bags, the problems for which those bags are allegedly responsible will be dramatically reduced.”
“In general, LDPE carrier bags, which are the bags that are always available for purchase in Danish supermarkets, are the carriers providing the overall lowest environmental impacts when not considering reuse. In particular, between the types of available carrier bags, LDPE carrier bags with rigid handle are the most preferable. Effects of littering for this type of bag were considered negligible for Denmark.”
They found that single-use PE bags or reusable PP bags were better for the environment than paper, unbleached paper, conventional cotton bags, organic cotton bags, biopolymer bags or any other types of bag.
Once again, we see that PE and PP win over so-called “green plastics” or renewable options. This is a wake-up call that renewable or “green” alternatives can be much worse for the environment than the materials what we already use now.
- Reusable bags have lower environmental impacts than all of the bags with only 1–3 typical uses
- A substantial shift to more durable bags would deliver environmental gains through reductions in greenhouse gases, energy and water use, resource depletion and litter
- The reusable PET bag with 100% post-consumer recycled content was found to achieve the greatest environmental benefits, closely followed by the non-woven plastic (polypropylene) ‘Green Bag’
- The shift from one single use bag to another single use bag may improve one environmental outcome, but be offset by another environmental impact. As a result, no single-use bag produced an overall benefit
- Recycled content in bags generally led to lowering the overall environmental impact of bags
- From a climate change perspective the paper bags performed most poorly, due in large part to their relatively high weight
“Reusable plastic bags can reduce the amount of green house gas emissions, solid waste generation, and acid rain pollution than single-use polyethylene plastic bags. The plastic bag with the least amount of environmental impacts would have the following features:
• Made from recycled plastics
• Lightest weight possible
Currently, PP non-woven bags could not be produced from PCR due to the lack of recycling infrastructure in the Unites States. However, PE reusable bags could be made with PCR in concentrations of 40% to 100% PCR. Likewise, single-use plastic bags can be produced with 40% to 100% PCR. The use of PCR can offer significant environmental benefits for reduced carbon dioxide emissions, reduced solid waste, and reduced pollution.
The polyethylene based reusable bag with 40% PCR is the plastic bag with the least amount of environmental impacts. The reusable bags though will require more fresh water than a single-use polyethylene bag due to the washing requirements of the bags that carry meats and dairy products.”
“The studies show that bioplastic bags have some advantages in the production life cycle phase (from cradle to door), but can be questionable in the end of life cycle phase, if not properly disposed and/or composted industrially instead in domestic compost bins. It was shown that long life (PP) carrier bag is by far the best choice if used for five years as proposed by manufacturer.”
Another study showing that so-called bioplastic bags are not friendly and that reusable PP bags are the best choice.
“As a first order assessment, it can be reliably concluded that plastic bags have a smaller environmental footprint for use ratios of up to 2.5 plastic bags to one paper bag. Above this ratio, the uncertainty of data accuracy is too high to form reliable conclusions. Only for very high ratios of 7:1 and above does the paper bag begin to compete with the plastic bag.”
- The shopping bag ECOLOOP has in almost all examined areas the lowest environmental impact of the here examined shopping bag types.
- A shopping bag from ‘I’m green’ bioplastics has an overall ecological load that is between the results for the shopping bags out of primary plastic and the ECOLOOP bag; its result is however clearly lower (i.e. better) than the one from the biological degradable and the paper shopping bags.
- This fact is also visible in the table below; table that shows how many times a shopping bag has to be used in order to have a similar environmental impact (per use) like the model ECOLOOP.
“All in all and based on the detailed results shown in this report here, we can conclude that the shopping bag ECOLOOP – under the here used boundary conditions – is the ecological winner, followed by the ‘I’m green’ shopping bag.”
The ECOLOOP bag is made from recycled LDPE type polyethylene. The I’m Green bag is made from a renewable type of polyethylene which is commercially available (for example from Braskem). As with all the other studies, these plastic bags were far greener than paper, cotton or biodegradable plastic.
“The smaller reusable HDPE bag uses more material to achieve the functional unit, and as a result the reusable HDPE bag becomes equal to that of the PP Box. The next best alternative is the reusable PP bag.”
“In terms of primary energy used, the preferred option is still the reusable woven HDPE bag, followed by the PP box and the reusable PP bag.”
“In terms of global warming potential, the preferred option changes from the reusable HDPE bag to the PP Smart Box, followed by the reusable HDPE bag and the reusable PP bag”
After comparing cotton, paper, bioplastic, single-use and multi-use bags, they concluded the above. Namely, that the HDPE and PP materials gave the lowest environmental impact.
This study looked only at carbon dioxide emissions and concluded that all the plastics were far better than natural materials like jute or paper. Interestingly, they concluded that PLA was slightly better than PE, PP and PET. Other studies looking at all the other factors all agreed that PE and PP were a better choice than PLA or other biopolymers. I did not include a quote from the conclusions section in this case because there was no such section from which to quote.
This study reviewed studies to date on compostable packaging and also food service ware (FSW), which is unusual.
Summary of Compostable Packaging Studies:
“While compostable packaging represents a small share of the packaging market, consumer interest in sustainability has increased demand for it (Meeks et al. 2015). Unfortunately, the studies included in this review suggest that the use of compostable packaging has signficant environmental tradeoffs when compared with non-compostable materials and other end-of-life packaging management practices. Results suggest that other waste recovery strategies, such as recycling, may be preferable when considering the disposal of a specific compostable packaging material.”
Summary of FSW LCA studies:
“The available studies indicate that some, but not all, of the conclusions drawn from the review of the various attributes for packaging also apply to FSW. No LCA studies providing midpoint impact results for FSW with recycled content were identified. We found that recycling of FSW products generally results in lower impact potentials when compared with landfilling or incineration. Biobased FSW is generally not preferable to fossil-based FSW. This is because production impacts for biobased materials tend to be higher than for conventional materials. Compostable FSW is generally not preferable to non-compostable FSW, as they are generally biobased, resulting in higher production impacts than fossil-based materials, and receiving less credits at end-of-life than other waste management options.”
“The literature on LCA of plastic waste management systems is vast and the results reported are generally consistent, showing that recycling has the lowest environmental impact on Global Warming Potential (GWP) and Total Energy Use (TEU) impacts. On the other hand, the literature addressing the economic assessment of plastic waste, namely the various End-of-Life (EoL) treatments, is rather limited. Other methodologies, such as integration of LCA and Life Cycle Costing (LCC) of plastic products, are almost never addressed. In any case, the overarching conclusion is that plastic materials usually have environmental and economic advantages over conventional materials throughout their Life Cycle, with or without consideration of the EoL stage.”
They conclude based on a review of many LCAs that we should pay more attention to the end of life aspects but even accounting for that, plastics are usually better for the environment than conventional materials.
“For all indicators under study (Primary Energy Demand, Global Warming Potential, Eutrophication
Potential, Acidification Potential, Smog Potential, human and ecosystem toxicity ), most of the impacts
are associated with the distribution and use phase. The polymer substrate shows benefits over cotton
for all main phases of the life cycle:
- for the manufacturing phase, since it has to be produced 2.5
fewer times than the cotton paper bank note
- for the distribution, since it has to be distributed 2.5
less times and its weight is lighter
- for end-of-life, since the contained carbon in cotton paper bank
notes is released as GHG in the landfill.”
The polymer (polypropylene) bank notes are clearly superior to cotton. This LCA is not on grocery bags but I thought it important to see whether the LCA analysis changed when applied to other end products. It seems that the plastic is more friendly in bank notes too.
“When comparing substrates, it is seen that for a given mass of bank notes the paper substrate generally has slightly lower environmental impacts than the polymer substrate. However, because polymer bank notes are assumed to last 2.5 times longer than paper bank notes (the default assumption in this study) a significantly lower mass of polymer bank notes are required to satisfy the functional unit. Hence, overall polymer bank notes have lower environmental impacts than paper bank notes for all impact categories assessed except for photochemical ozone creation potential.”
“The sensitivity of the results to the default lifetime has been assessed. It was found that polymer bank notes need only have a lifetime 1.33 times greater than that of paper bank notes to achieve a lower global warming potential. Based on experience of from other countries that use polymer bank notes it seems very likely that this lifetime will be exceeded, indicating that the overall conclusions from the study are robust.”
This is another study showing that polymer (polypropylene) is far superior to paper in terms of almost every indicator of environmental impact.
“In other words, and compared to total global emissions of 46 GtCO2e in 2005, there would have been 3.6 to 5.2 GtCO2e, or 8 to 11 percent, more emissions in 2005 in a world without the chemical industry.”
and goes on to say…
“The biggest levers evaluated for emissions savings enabled by the chemical industry were:
- Insulation materials for the construction industry, which reduce the heat lost by buildings and thus the use of heating fuel. Insulation alone accounted for 40 percent of the total identified CO2e savings. This report did not address cooling applications where additional emission reductions in the building industry would be anticipated;
- The use of chemical fertilizer and crop protection in agriculture, which increases agricultural yields – so avoiding emissions from land-use change. Due to the uncertainties in land-use changes, yields, soil quality effects and modes of CO2-binding and assimilation in different conventional and organic agricultural processes, this study adopts two scopes, one with and one without this case;
- Advanced lighting solutions: compact fluorescent lamps (CFLs), with longer lifetimes and greater luminous efficacy than incandescent bulbs, save significant energy;
- The seven next most important levers in 2005 were plastic packaging, marine antifouling coatings, synthetic textiles, automotive plastics, low-temperature detergents, engine efficiency, and plastics used in piping.”
This report was performed by McKinsey but was funded by the chemicals industry. They found that overall, the chemicals industry saves carbon dioxide in large part due to plastics used as heat insulation, packaging, automotive plastics and piping.
” If plastic packaging would be substituted by other materials,
the respective packaging mass would on average increase by a factor 3.6
life-cycle energy demand would increase by a factor 2.2 or by 1,240 million GJ per year, which is equivalent 27 Mt of crude oil in106 VLCC tankers or comparable to 20 million heated homes
GHG emissions would increase by a factor 2.7 or by 61 million tonnes of CO2-equivalents per year, comparable to 21 million cars on the road or equivalent to the CO2-emissions of Denmark.”
They conclude that replacing plastic packaging would require vastly more alternative materials, far more energy and lead to far more carbon dioxide emissions.
Summary – plastic bags
Lifecycle assessments (LCA) are the only internationally accepted method for comparing the environmental impact of materials and products. They are used by governments, companies and environmental groups, including GreenPeace and are independently audited. The LCA method takes into account all the energy, materials, water, emissions and so on associated with the manufacture and disposal of a product. No tool is perfect, but LCA is by far the best, most widely-accepted way to see what is really green.
LCA analyses are done by government agencies in the US, Canada, UK, Australia and Denmark. They all agree that the single-use polyethylene bags we use today have much lower environmental impact than potential replacements such as bioplastics, paper, unbleached paper, cotton or organic cotton. The other leading green solution is reusable PP bags (think of the iconic blue Ikea bags). Those are actually the best option, as long as they are reused several times.
To replace plastic bags with paper bags requires 2.7x more energy, 1.6x more carbon dioxide emissions and 17x more water usage. It has also been estimated that replacing the plastic bags in the EU would require cutting down an astonishing 2.2 million more trees per year and require 60 000 Olympic swimming pools more water.
I believe this to be the largest collection of LCA studies on this topic. Why did I spend so much time to collect every study I could find? The reason is that this is an important topic and people are convinced that plastic is harming our environment. Because the findings go against popular opinion, there is an added burden of proof when trying to dispel the myth that has evolved around the topic. If I had found one LCA that said plastic was better, or if I had found only a couple of studies funded by the plastics industry, I would have been skeptical. Instead what I found instead was multiple studies from several countries and all of them funded by impartial parties. The conclusions are unanimous and solid.
What does this mean?
I was surprised to find that our traditional PE and PP bags are far greener than the alternatives that are being thrust upon us. That means that the bans being implemented are actually harming our environment. Plastic bags are being taxed to discourage use. That may be a nice source of revenue, but it is counterproductive. This is exactly why we need facts before we act. Without hard data, we end up doing harm instead of good. Governments, companies and the environmental groups have not done their due diligence. They are making statements and taking policy decisions without checking the data first.
This opened my eyes and showed me that it is not safe to trust what we’ve been told. We have to stop parroting the same old sound-bites and headlines from articles written by people who did not spend the time to check the veracity of their words. I was also deeply disappointed with the so-called environmental groups. I had assumed that they had done their homework and given us good advice. After all, they collect millions in donations and have had decades to find the best path forward. How is it that with all that funding they did not find ten minutes to type “LCA plastic bag” into Google? Why are they advocating bans that harm our planet? It makes me seriously question their competence and motives.
What about other uses for plastics? What do the lifecycle studies show for other applications of plastic versus renewable materials? I went looking for more information and found LCAs done by the Bank of Canada and the Bank of England. Both showed that polypropylene plastic bank notes were far greener than cotton notes. In fact, after several days of searching, every LCA I have found shows plastics to be the best solution.
Plastic food packaging
CNN featured news about the World’s first supermarket aisle free of plastic packaging. They touted the move to “new compostable bio-materials as well as traditional materials” such as glass, metal and cardboard.” That sounds admirable enough, but they presented no evidence that what they had done was actually green. So, is their idea environmentally sound or just a publicity stunt? The only way to be sure is to look for the evidence.
A good starting point is a leaflet called Preventing Food Waste from the American Chemistry Council. It shows that plastics are incredibly good at protecting our food and preventing waste. The food is protected during transportation and then it helps prevent spoilage. Cucumbers last 11 days longer, bananas last 21 days longer and beef 26 days longer. They showed that good packaging can save many billions of dollars and millions of tons of food.
Here’s a statement from the conclusions of a detailed report called Plastics & Sustainability published by the American Chemistry Council.
“Plastic packaging has many properties that are vitally important for packaging applications, including light weight, flexibility, durability, cushioning, and barrier properties, to name a few. This substitution analysis demonstrates that plastic packaging is also an efficient choice in terms of environmental impacts.”
“For the six packaging categories analyzed – caps and closures, beverage containers, stretch and shrink film, carrier bags, other rigid packaging, and other flexible packaging –14.4 million metric tonnes of plastic packaging were used in the US in 2010. If other types of packaging were used to substitute US plastic packaging, more than 64 million metric tonnes of packaging would be required. The substitute packaging would result in significantly higher impacts for all results categories evaluated: total energy demand, expended energy, water consumption, solid waste by weight and by volume, global warming potential, acidification, eutrophication, smog formation, and ozone depletion, as shown previously…”
From this we can see that plastic packaging is by far the best solution for our environment. In fact, another study showed that plastic packaging also leads to enormous reductions in CO2 emissions because they help food stay fresh longer. Food production is a major cause of carbon dioxide production and plastic packaging greatly reduces CO2 even accounting for the carbon dioxide from plastic production.
Then comes the question of litter
When I first wrote about plastics and how the evidence showed them to be the greenest solution, most people were glad to see an article that supported by extensive data. Probably the biggest pushback was from people saying something like, “even if plastics are the greenest solution, what about the litter and the oceans”?
Of course, litter is a separate topic and I didn’t have the answers, so once again, I had to go looking for them. There is a surprising amount of information about litter. For example, the EPA in the US have collected extensive data on all waste since the 1960s. It’s available for download but there’s so much that I could not make any sense of it. I had to ask a professional Data Architect to make graphs so that we could see the trends.
AnnaLytix™ did an outstanding job of making interactive graphics which allow me and you to look through the EPA data and apply filters (see below).
Data trends from 1960 onwards on US waste (source EPA)
AnnaLytix™ did an outstanding job of making interactive graphics which allow me and you to look through the EPA data and apply filters (see below). Unlike the old days where we just had static graphs, it is now possible to dig into the data using dynamic graphics as seen below.
What we see is that plastics waste grew rapidly at first, because it was a new material. However, in the last couple of decades, the growth of plastic waste has slowed and now follows population growth. Population growth rate passed through a maximum many years ago and has been decelerating ever since. We can expect waste generation to follow that trend.
Here is a quote from a peer-reviewed article written about this EPA data:
“A comparison of waste generation rates for each material category found in MSW reveals that plastics increased by nearly 84 times from 1960 to 2013 while total MSW increased only 2.9 times. The increase in plastic waste generation coincides with a decrease in glass and metal found in the MSW stream. In addition, calculating the material substitution rates for glass, metal and other materials with plastics in packaging and containers demonstrates an overall reduction by weight and by volume in MSW generation of approximately 58% over the same time period.”
They conclude that plastic dramatically reduced the amount of municipal solid waste (MSW). This is in line with the other studies that found replacing plastics would lead to far more material usage, waste and environmental burden.
Interactive data analytics on US waste (source: US EPA)
The graphs allow us to see more than that. I just read a post on LinkedIn saying that 90% of plastic waste has never been recycled. That sounds dramatic, so I went to the graphs and could see what that number means in context. We can see that 9% of plastic in the US is recycled compared to 5% of food waste, 34% of metal, 16% of wood, 15% of textiles, 67% of paper and 26% of glass. Why was only plastics mentioned in the post as though plastics were of special cause for concern? It is not productive to demonize plastics. Instead we should look at all the data to see that there is clearly huge room for improvement for all material types.
Plastics account for just 13% of all US waste by weight. Why is it then that people only talk about plastics waste? I have never in my life seen an article complaining about glass waste or metal waste. Why are people obsessed with 13% of our waste and disinterested in the rest? I think that there are several reasons. Firstly, plastics was something new and people saw its dramatic growth. Another reason is that much of the common plastic floats, so we can see it on the surface of the water. In contrast, metal and glass both sink. There are many sunken ships. The Titanic alone weighed over 50 000 tons but no-one talks about it in terms of ocean litter. In fact, it is common to intentionally scuttle ships in order to make for good diving sites. I have seen TV shows talking about how great sunken ships are in creating artificial coral reefs. The Gen. Hoyt S. Vandenberg, a massive World War II ship weighing 17 000 tons was intentionally scuttled for divers. Why is it that metal is treated as a delight to nature and plastics are vilified? It’s something to think about. I don’t think any kind of ocean litter is good and we should treat it all with equal disdain. It has been estimated that the Great Pacific Garbage Patch weighs 80 000 tons. That’s the same as the Titanic and the Gen. Hoyt S. Vandenberg combined. The patch is in the news all the time but the ships are not.
In looking for data on litter in the USA, I found the website of Keep America Beautiful who have studies and reported on this topic for decades. They actually study litter as it happens, noting the circumstances and whether or not the act was intentional. Here is a quote from their report:
Litter is primarily the result of individual behaviors.
- About 85% of littering is the result of individual attitudes. Changing individual behavior is key to preventing litter.
- Nearly one in five, or 17%, of all disposals observed in public spaces were littering. The remainder (83%) was properly discarded in a trash or recycling receptacle.
- Most littering behavior—81%–occurred with notable intent. This included dropping (54%), flick/fling of the item (20%), and other littering with notable intent (7%).
What does this mean? The conclusion is clear. People are responsible for dropping the litter and 81% of the time, it’s intentional. You can literally watch them do it on purpose. Of course, these are the same people blaming plastics for the litter problem. They are not honest enough to look themselves in the mirror and admit where the real problem lies. Instead, they drop the litter on purpose and then blame the litter. What is the consequence? People are pushing to ban plastics, conclusively proven to be the greenest option, when the problem lies with human behavior. As mentioned elsewhere, replacing plastics with other materials does about 4x more harm than the plastic does and creates 4x more litter as well. Is that what you want?
Marine litter and microplastics
Do you remember all the articles about the plastics beads used in facial scrubs and how they were causing huge problems? I decided to take a look at that subject. Another topic drawing a lot of attention is that of plastics in the ocean and microplastics, i.e. plastic particles formed as plastics break down. What do we know about them? What kinds of plastics are involved? Are animals eating them? If they are, is it causing any harm. As mentioned earlier, I read 50 articles and one book on this topic to work out the answers. Here is what I found.
You may have read about the great garbage patch. They analyzed its contents and found it was about half discarded nylon fishing nets. That’s something that should be addressed in particular, such nets have been shown to entangle and harm birds. Just as we saw for land-based litter, much of it is created intentionally. Education and heavy fines may be suitable actions to take. As for the rest of the ocean litter, it comes from 10 rivers in Africa and Asia.
“The 10 rivers that carry 93 percent of that trash are the Yangtze, Yellow, Hai, Pearl, Amur, Mekong, Indus and Ganges Delta in Asia, and the Niger and Nile in Africa. The Yangtze alone dumps up to an estimated 1.5 million metric tons of plastic waste into the Yellow Sea.”
Source: Stemming the Plastic Tide – 10 Rivers Contribute Most of the Plastic in the Oceans – Scientific American
Why are we banning plastic products in the US and EU when the litter doesn’t come from there? That seems nonsensical to me.
The countries involved are behind us in that they have not had time to get used to plastics and have not yet developed the infrastructure to handle their waste. The problem has been addressed in the US, EU, Scandinavia and other regions. The same measures need to be applied to the developing countries. We know the solutions, so this can be handled successfully.
Here’s an analogy to think about. If you saw clothes on your kid’s bedroom floor, would your solution be to ban clothes? That would be an outrageous overreaction. In fact, the correct analogy would be that you visit a friend in another country and see clothes on their kid’s floor and your solution is to go home and ban clothes at your house. I think everyone can see how silly that would be.
What are microplastics?
Microplastics are defined as plastic fragments of 5mm or less across. They first came to the public’s attention when articles started showing up about the polyethylene microspheres used in some facial scrubs as a mild exfoliant. There was a huge uproar, as this was perceived as a major problem and now the PE spheres are no longer used.
A recent report gives an excellent overview (see Primary Microplastics in the Oceans- a Global Evaluation of Sources IUCN 2017). The report says that the global release of primary microplastics in the oceans is estimated to be about 1.5 Mtons/year. So, we know that microplastics are real and the quantities are enough to be concerned about.
I looked for the data and it turns out that just 2% of the plastic particles in the sea were from in facial scrubs. I was surprised at how low the amount was, in light of the huge amount of attention the topic received. So, what is responsible for the microplastics in our oceans? Here’s the breakdown:
Microplastics are abundant – but are they causing harm?
For a substance to present a danger, it has to be toxic and there has to be an exposure route. For example, a bottle of poison on the moon would not be a threat to people on Earth so there would be no danger. In that example, there is toxicity but no exposure. Conversely, we may be exposed to something but if it turns out to be harmless, then there is no cause for concern.
I looked at many studies and we know for sure that birds and fish do eat plastic. Microplastics can be found in their digestive system.
“Plastic was detected in 49 out of 64 fish (77%), with 2.3 pieces on average and up to 15 pieces per individual” and “Most were polyethylene (52.0%) or polypropylene (43.3%).”
So, the exposure component is there. What about the toxicity aspect? Are these plastic particles harmful to the marine wildlife?
It is interesting to see that PE and PP are the main plastics. It should not be too surprising, as they are the two most commonly used plastics and they both float on water, making them more visible and more likely to be ingested by fish. PE and PP are also two very safe plastics that we use all the time to package food. PE is used for sealable food bags in the kitchen and PP is used for sealable food containers. Both have been used safely for several decades.
The press has drawn the public’s attention to studies claiming that plastics leach toxins, but when we look at those studies, it turns out that the plastic was shown to be safe and only released toxins after the plastic was intentionally soaked in toxins by the experimenters. These studies are not only misleading but irresponsible. We could soak more or less anything in poison and then show that it released some poison once placed in clean water. Interestingly, other workers showed that plastics absorb toxins from water and hold them tightly so that even when ingested by fish, they are able to protect the fish. Have you ever seen a headline highlighting those studies? I have not. Why is that?
So, it is a myth that microplastics are toxic. You can see details of the various studies in the myths tab in the section below. To summarize, having read many studies, here is what they say:
- Several studies show that microplastics are non-toxic to marine life
- Some studies show that microplastic soaked in poison are somewhat poisonous, but we could say that about any substance
- Some studies state that microplastics protect marine life by binding poisons from the ocean and preventing exposure
- Other studies claim microplastics cause harm but none of them are credible because they use the wrong type of plastic, they use the wrong shape of particle, they use 100-10 million times too much plastic and they use fluorescent colored plastic which is completely unrealistic
A very detailed review article entitled Deleterious Effects of Litter on Marine Life shows that plastics cause harm by entangling birds and other forms of marine wildlife. Much of the harm is caused by fishing nets and the blame lies with the people who recklessly discarded the nets. Interestingly, the review goes on to say that the problem of plastics entering the ocean peaked many years ago and declined after the issue was recognized and addressed. I was not aware of that because no-one in the media talks about it.
“Long-term studies on seabirds have shown that measures to reduce loss of plas- tics to the environment do have relatively rapid effects. After considerable atten- tion to the massive loss of industrial pellets to the marine environment in the early 1980s, improvements in production and transport methods were reflected in a visi- ble result in the marine environment within one to two decades: several studies from around the globe showed that by the early 2000s the number of industrial granules in seabird stomachs had approximately halved from levels observed in the 1980s (Van Franeker and Meijboom 2002; Vlietstra and Parga 2002; Ryan 2008; Van Franeker et al. 2011; Van Franeker and Law 2015). These examples indicate that it is possible to reduce deleterious impacts from marine plastic debris on marine wild- life in shorter time frames than the longevity of the material might suggest.”
This is good news indeed. We know that actions we take now can bring about a rather rapid improvement for the environment.
Conclusion – microplastics are not toxic
Careful consideration shows no credible evidence that microplastics are causing harm. Some of the data even points to a protective effect whereby the plastic particles absorb toxins in the sea and shield marine animals from exposure.
There is a shocking amount of bad science whereby the experiments were so poorly designed that they should never have been accepted for publication. I have refereed articles for major publishers and I would not have allowed many of the environmental papers to be released. I would encourage people to take the challenge of doing good quality research so that we can learn more about the facts and take appropriate action.
Myths about plastic
- The Black Plastic Can't be Recycled Myth
- The Plastic Lasts Forever Myth
- The Plastics / Microplastics are Toxic Myth
Articles state that black plastics can’t be recycled. That’s untrue. Most plastics like PE, PP, PET, PVC, polystyrene and so on can be recycled simply by melting them and forming them into a new shape. There are multiple reasons why black plastic often goes unrecycled but the point to note is that it’s a matter of choice. It can be recycled but people choose not to. Here are the main reasons:
- Black plastic is hard to sort because the sorting process uses infrared light to sense the plastic type. The black plastic prevents that from working. However, you can often sort it into the right pile by manually looking at each piece.
- Black recyclate is worth less on the open market, so there’s less incentive to produce it.
What can be done? The pigment normally used is called carbon black. It may be added simply for colour but often it is added to protect the plastic from degrading in sunlight (the same reason car tires are filled with carbon black). Recently, they have started marketing black pigments that give the required colour but without interfering with automatic sorting equipment. Using that allows for more recycling, thus helping the environment. Here is an article about BASF’s Sicopal and Lumogen blacks. This type of black masterbatch is commercially available from Ampacet.
I’ve seen so many articles stating that plastics are stable indefinitely and last for hundreds or thousands of years in the environment. Any competent plastic materials expert will tell you that’s just not true. Museums even struggle to preserve plastic items that have been kept indoors, protected from the elements. These museum items are just a few decades old and are already falling apart. Neil Armstrong’s space suit is just one example, but one of my good friends worked as a plastics conservator at a major museum and he saw similar cases every day.
Plastics are organic materials and like any material made of carbon, hydrogen and oxygen, they degrade with time, heat and UV light, including sunlight. Plastics experts know that you have to add stabilizers to protect the plastic and without stabilizers they would fall to pieces. Two of the most common plastics found in waste are polyethylene and polypropylene. Both degrade readily. Polypropylene (PP) is so unstable that it loses strength and degrades in just one year at room temperature. Does that sound like a material that lasts forever? I have added about ten peer reviewed articles to support what I’ve just stated. It’s common knowledge amongst plastic materials experts. In fact they spray stabilizer on PP the instant it’s made, to prevent instant attack by oxygen in the air.
So, what looks like a stable material in your hand, is only surviving because of added stabilizer. As soon as the stabilizer is washed out or used up, the PP becomes unstabilized again and will start to degrade in about a year. This has all been known since the 1950s and published widely. There’s even a journal devoted only to this (Polymer Degradation and Stability, Elsevier). Polyethylene is more stable than PP but it too has been found to literally fall apart, even at room temperature and without sunlight. At higher temperature and with sunlight, the degradation is much faster.
So, how long does it take for a plastic grocery bag to degrade? I looked for studies on that topic.
“This study shows that the real durability of olefin polymers may be much shorter than centuries, as in less than one year the mechanical properties of all samples decreased virtually to zero, as a consequence of severe oxidative degradation, that resulted in substantial reduction in molar mass accompanied by a significant increase in content of carbonyl groups.”
Source: Degradability of linear polyolefins under natural weathering, T. Ojeda, et al., Polymer Degradation and Stability 96 (2011).
So, the science shows that thin PE films degrade so much that they fall apart in about one year. Why are the environmental groups claiming again and again that they last 1000 years? If they want to make claims they should be truthful and should cite scientific studies to support them. Once again, it seems they are content to make outlandish claims without any evidence at all.
A review article talks about PE films used for greenhouses. Those are specifically stabilized to make them more durable, but even so, the authors state the following:
“Consequently, the life of plastic films used for protected cultivation varies from a minimum of one cultivating season to a maximum of two to three years, and, at the end of its useful life all this plastic is classified as waste.”
Contrary to the claims of environmental groups, the PE films are destroyed by exposure to the elements and teams of scientists are still trying to find ways to make the films last longer than a couple of years.
Source: Degradation and Stabilization of Low-density Polyethylene Films used as Greenhouse Covering Materials, P. A. Dilara and D. Briassoulis, J. agric. Engng Res., 76 (2000).
Articles also claim that conventional plastics do not biodegrade. That is not true either. Experiments show that they are attacked by bacteria. For example, PP film buried in a landfill.
“The results show that high-molecular-weight polyethylene can really biodegrade under bioactive circumstances if the test period is long enough.”
Polyethylene and polypropylene have been shown to biodegrade. Polystyrene is more resistant but does degrade in sunlight. As we saw in the interactive waste charts, paper makes up most of the waste (40% by volume) and it doesn’t degrade in a landfill because they are not designed to encourage degradation. The items get buried without enough oxygen and that slows down the process.
“There are the 40-year-old hot dogs, perfectly preserved beneath dozens of strata of waste, and the head of lettuce still in pristine condition after 25 years. But the hands-down winner, the one that still makes him shake his head in disbelief, is an order of guacamole he recently unearthed. Almost as good as new, it sat next to a newspaper apparently thrown out the same day. The date was 1967.”
Seeking the Truth in Refuse, New York Times
Environmental groups like to say that plastics and microplastics are toxic. I just read a Greenpeace page saying exactly that. It’s a bold claim. So, where is the data? There was not one piece of evidence presented. According to Wikipedia, Greenpeace collect $400 million dollars annually from donors. Surely, as their business is protecting us and our environment, they should have checked their facts. So, what are the facts? Here is a recent headline on this topic: “Microbeads are leaching toxic chemicals into fish, sparking public health fears“. The headline is wrong but that’s what the public sees. In the study they loaded toxic chemicals into the plastic on purpose!
Toxicity is a complex topic but for the purposes of this article, let’s keep it simple. Is plastic safe to touch with your hand and is it poisonous to eat? The answer should be obvious to most people. We store our food in polyethylene bags and polypropylene boxes. We have done so for several decades. The plastic used is food contact approved and tested very thoroughly to make sure that no harmful additives come out of them and get into our food. Those plastic contain extremely low levels of additives anyway, typically under 0.1% by weight.
I should point out that the effect of microplastics in the ocean is something I have only just started reading about. I will have to read many more articles before a firm conclusion can be drawn.
First comes this warning from scientists who point out that many of the studies are not done under realistic conditions.
R. Lenza, K. Endersa, and T. G. Nielsen, Proceedings of the National Academy of Sciences, 113(29), E4121 – E4122 . . DOI: 10.1073/pnas.1606615113
The authors warn that:
“Experimental exposure concentrations tend to be between two to seven orders-of-magnitude higher than environmental levels.”
Meaning that many articles are using 100x and 10 million times more more plastic and toxin than are found in the environment. Dose is very important for toxicity. For example, breathing 20% oxygen keeps us alive where 100% oxygen is lethal. Therefore, they go one to say:
“Microplastic research is an emerging field, and there is a lot of misunderstanding and in some cases over- reaction or misinterpretation of results from MP science in the public. We therefore strongly suggest that future studies of MP impact on marine ecosystems should also include concentrations that have been documented in the environment to yield more realistic estimates of sublethal effects.”
Another article points out that the studies are usually done on the wrong kinds of plastic. Many studies are done on polystyrene when that is not at all common in the ocean. Polystyrene is just 1% of microplastic in the ocean so why focus on that? The reason is that polystyrene particles are easily obtainable making it convenient for the scientists to order them.
“Analysis of the available data revealed that 1) despite their widespread detection in field-based studies, polypropylene, polyester and polyamide particles were under-represented in labo- ratory studies; 2) fibres and fragments (800–1600 μm) are the most common form of MPs reported in animals col- lected from the field; 3) to date, most studies have been conducted on fish; knowledge is needed about the effects of MPs on other groups of organisms, especially invertebrates. Furthermore, there are significant mismatches between the types of MP most commonly found in the environment or reported in field studies and those used in laboratory experiments.”
They correctly noted that studies are done on the wrong plastics and on the wrong shapes. In the oceans fibers and fragments are found, whereas all the studies are on perfectly round particles.
Now let’s look at a couple of studies that make plastics out to be a problem…
The abstract for the article states:
“This work provides evidence that microbeads from personal care products are capable of transferring sorbed pollutants to fish that ingest them.”
Later, the article says:
“The bioavailability of PBDEs sorbed to microbeads that did accumulate in the fish is of concern, considering the large volume of MBs (and other microplastics) entering the aquatic environment and their largely unknown environmental fates. Implications for the food chain, including the human diet, from this very fine fraction of plastic debris demand further investigation.”
That sounds like it could be a problem, so I read the article in detail. First, they showed that polyethylene beads from facial wash had no effect on fish that ate them. Then they soaked the beads in known toxins so that they beads absorbed the poison. They fed the toxin loaded beads to the fish and confirmed that a small proportion of the toxins was transferred to the fish.
What does this mean? Let’s picture what would happen in the ocean. The PE beads (proven to be harmless alone), will absorb toxic chemicals. That means less toxic chemicals in the water that the fish are in. That’s great news. What happens if the fish eat the plastic beads? Just 0-12% of the toxin is released by the beads because the toxic chemicals prefer to stay inside the beads. That’s more good news! The plastic beads are purifying the water and protecting the fish. The title of the article could have been “Microplastics miraculously effective at sequestering toxins and purifying seawater”.
I hope this shows you how desperate the environmentalists are to do studies that are unrealistic, improperly performed and incorrectly interpreted. It’s shocking.
In fact, at least two studies have proven that microplastics are very effective at binding toxins and protecting marine wildlife (polypropylene study, nylon study). Yet another study directly tested the hypothesis that microplastics (MP) would lead to accumulation of toxins in fish. What they found instead was:
“Contaminant concentrations in the muscle tissue were unrelated to the MP levels in fish, suggesting a lack of direct links between the levels of HOCs and MP ingestion. Thus, despite their ubiquity, MP are unlikely to have a measurable impact on food intake or the total body burden of hydrophobic contaminants in Baltic herring.”
Source: Hydrophobic organic contaminants are not linked to microplastic uptake in Baltic Sea herring, M. Ogonowski, V. Wenman, S. Danielsson and E. Gorokhova
Sussarellu et al., PNAS March 1, 113 (9) 2430-2435 (2016)
The authors state:
“This study provides evidence that micro-PS cause feeding modifications and reproductive disruption in oysters, with significant impacts on offspring.”
I then noticed this:
“analyses on extracted micro-PS particles detected bibenzyl and 1(2H)naphthalenone,3,4,dihydro4phenyl with >90% correspondences”
This means that the PS spheres they used contained toxins not found in household polystyrene. The beads used contain added surfactant and are cross-linked with divinyl benzene, which explains the toxic extractibles found (see manufacturer’s description).
In conclusion, this experiment cannot be trusted because it was not performed properly. They used polystyrene beads when only 1% of plastics in the ocean is polystyrene. They also used a special type of polystyrene that contains toxic chemicals not found in normal polystyrene.
Next is a study on worms that feed on sediment.
“Biouptake in worms was lower by 76% when PCBs were associated with polypropylene compared to sediment. The presence of microplastics in sediments had an overall impact of reducing bioavailability and transfer of HOCs to sediment-ingesting organisms. Since the vast majority of sediment and suspended particles in the environment are natural organic and inorganic materials, pollutant transfer through particle ingestion will be dominated by these particles and not microplastics. Therefore, these results support the conclusion that in most cases the transfer of organic pollutants to aquatic organisms from microplastic in the diet is likely a small contribution compared to other natural pathways of exposure.”
Another study states the following about microplastics (MP):
“Thus, despite their ubiquity, MP are unlikely to have a measurable impact on food intake or the total body burden of hydrophobic contaminants in Baltic herring.”
Both polyethylene, and polypropylene, by far the most abundant microplastics in the ocean, have been proven to absorb toxins from water and sequester them, thereby protecting marine wildlife. Nylon has been shown to do the same, the PA (polyamide) particles were themselves harmless and reduced the amount of BPA in the water:
“The PA particles themselves did not induce negative effects, while the effects of BPA alone followed a typical dose-dependent manner. Sorption of BPA to PA particles prior to exposure led to a reduction of BPA in the aqueous phase.”
For the next article, I did a search of the title to find a link to share here and Google revealed this hit, which was quite a surprise:
“We wish to report a strong suspicion of research misconduct in the following study by researchers at Uppsala University, published in the journal Science on June 3 2016:
Lönnstedt OM and Eklöv P (2016) Environmentally relevant concentrations of microplastic particles influence larval fish ecology. Science 352: 1213-1216. doi: 10.1126/science.aad8828
“Regarding point #4 above, we have evidence including witness reports, photos of the experimental setup, and email correspondences that the experiments reported in the paper were not performed as described by the authors. To be clear, there is a significant mismatch between what is described in the paper and how the experiments were actually performed. Examples include:
- The exposure times of eggs and larvae reported in the paper are longer than the actual duration of the experiment at the Ar research station in Gotland, Sweden.
- The actual number of replicate tanks and fish is lower than what is stated in the paper.
- Aquaria maintenance and monitoring were not conducted as described in the paper.
For these and other reasons, we strongly suspect that this study constitutes a case of research misconduct.”
You read that correctly. Apparently, these researchers were so desperate to make plastics look bad that they falsified their results. After an investigation, the article was retracted.
I have many more articles that I will be reading and commenting on here.
There is one meta-analysis on this topic but unfortunately, they did not properly screen the articles they included. I checked with the lead author and she admitted that even the studies where they intentionally soaked the plastic in toxins were included. I hope that they do a new meta-analysis only on articles that have been conducted properly. Even with the inclusion of those suspect studies, the meta-analysis showed surprisingly few adverse effects.
One may wonder whether creatures containing plastic could be eaten by people and whether any harm would result. I found one detailed report on that topic and they concluded:
“As an example, a worst case estimate of exposure to microplastics after consumption of a portion of mussels (225 g) would be 7 μg of plastics. Based on this estimate and considering the highest concentrations of additives or contaminants reported in microplastics, and assuming complete release from microplastics, the microplastics will have a negligible effect on the total dietary exposure to PBTs and plastic additives. These contaminants are estimated to contribute only <0.1 percent of the total dietary exposure to these compounds.”
I am still reading but so far, I have not seen a single credible article showing microplastics to be toxic. When reading such studies we should ignore studies based on polystyrene, ignore studies using 100-10 million fold more particles than are actually present in the ocean and ignore studies where the plastic used was intentionally loaded with poison. Realistic, professionally designed experiments are needed if we are to draw meaningful conclusions.
Most articles show that microplastics do no harm. Some articles actually show that microplastics help aquatic life by soaking up and holding toxins from sea water and preventing them from harmed the fish. A few articles claim to show harm but of all those I have read, not one was credible.
So, we have learnt a lot. Let’s look back and summarize what all of this new information means.
- Plastics like PE and PP are far greener than cotton, paper or biodegradable plastic (as proven by LCA)
- Replacing them with sustainable or biodegradable options like paper, cotton or bioplastic harms would do significant harm to the planet (more CO2, more warming, more chemicals, energy and water used)
- Reusable PP bags come out as the best solution, assuming they do get reused several times
- Litter is a totally separate issue
- Using plastics has significantly reduced the overall amount of waste
- Only 13% of municipal waste is plastics but inexplicably, it commands 100% of the media attention
- Ocean plastics are eaten by fish and birds but the PE and PP are non-toxic
- In fact, both PE and PP have been shown to absorb toxins from the ocean and thereby protect marine wildlife
- Of course, we still need to dramatically reduce the amount of litter going into our oceans
I hope that you found this page of some use. Some people will be happy to see so much solid, independent data. Other people will remain skeptical. If you are skeptical, I would ask you to try and remember how you formed the view you have now. Was it from some LinkedIn headline, YouTube video or FaceBook rant? If it was from an online article, did they quote a multitude of peer-reviewed scientific studies as I have done? Remember, what you read online is just an opinion unless it is backed by data. What you read here is the truth because it is supported by a great number of independent studies from around the world.
Disclaimer: I have made every effort to ensure that the content provided here is accurate. Please inform me if you find an error and send me any data you think should be included. It is the reader’s responsibility to look at all the evidence available here and form their own opinion.
References (many more in the text and more to be added soon)
Plastics Reduce Waste Helping the Environment
Role of plastics in decoupling municipal solid waste and economic growth in the U.S., D.A. Tsiamis, M. Torres, M. J. Castaldi, Waste Management 77, 147–155 (2018)
Life Cycle Impacts of Plastic Packaging Compared to Substitutes in the United States and Cananda – Theoretical Substitution Analysis – Franklin Associates, A Division of Eastern Research Group 2018
Plastics Degrade Rapidly
Handbook of Fiber Chemistry, 3rd Edition, M. Lewin Editor, CRC Press, NY, p174 (2006)
The long-term stability of polyolefins, P. Gijsman, Technische Universiteit Eindhoven (1994)
The Deterioration of Polypropylene By Oxidative Degradation, H.J. Oswald & E. Turi, Polym. Eng. and Sci., July 1965 p152-158
Polypropylene Handbook, E.P. Moore Jr., Hanser/Gardner Publications Inc., Cincinnati, Ohio p177 (1996)
Manufactured Fibre Technology, V.B. Gupta & V.K. Kothari, Springer p465 (2012)
Handbook of Fiber Chemistry, 3rd Edition, M. Lewin Editor, CRC Press, NY , p175 (2006)
A study of the oxidative degradation of polyolefins, A.J. Sipinen et al., Environ. Polym. Deg., 1(3) (1993)
Effects of high oxygen pressure and temperature on the aging of polypropylene, D.L. Faulkner, Polym. Eng. Sci., 22(8) p466-471 (1982)
Polypropylene stabilization by hindered phenols – Kinetic aspects, E. Richaud, B. Fayolle, J. Verdu, Polymer Degradation and Stability 96 pp 1-11 (2011)
On a transition at 80°C in polypropylene oxidation kinetics, L. Achimsky, L. Audouin, J. Verdu, J. Rychly, L. Matisova Rychla, Polymer Degradation and Stability, Volume 58, Issue 3, Pages 283-289 (1997)
Effect of temperature on the lifetime of stabilized and unstabilized PP Films, F. Gugumus, Polymer Degradation and Stability, 63 pp 41-52 (1999)
The influence of temperature and catalyst residues on the degradation of unstabilized polypropylene, Pieter Gijsman, Jan Hennekens, Jef Vincent, Polymer Degradation and Stability, 39, pp 271-277 (1993)
A study of the oxidative degradation of polyolefins metal stearates, A.J. Sipinen, D.R. Rutherford, Journal of Environmental Polymer Degradation, Vol. 1, No. 3, (1993)
Isotactic polypropylene biodegradation by a microbial community – physicochemical characterization of metabolites produced, I. Cacciari et al., Applied and Environmental Microbiology, 59(11), p3695-3700 (1993)
Induced Degradation of Polypropylene with an Organic Pro-Degradant Additive, L. S. Montagna, M. M. de Camargo Forte and R. M. Campomanes Santana, Journal of Materials Science and Engineering A 3 (2), 123-131 (2013)
Debunked Microplastics Articles
Here is a partial list of articles claiming that microplastic is toxic along with the reasons that they are not valid experiments. The main reasons these studies are invalid include: using the wrong polymer type, using particles that are the wrong size, the wrong colour, particles that contain toxins and particles that are made artificially to be fluorescent. Many studies use thousands or millions times more microplastic, compared to actual amounts in the ocean.
Single and combined effects of microplastics and pyrene on juveniles (0+ group) of the common goby Pomatoschistus microps (Teleostei, Gobiidae)
They used round, red, fluorescent PE particles that must have had surfactant added. They were much smaller with much higher surface area than found in the ocean. They showed that plastics can help the fish by protecting them from toxins.
The correct size of particles to use, i.e. the size of actual ocean microplastics is stated as follows:
“The size range 800–1600 μm, the most commonly reported from field samples of biota represents a very small fraction of the sizes used in the laboratory”
Source: Studies of the effects of microplastics on aquatic organisms – What do we know and where should we focus our efforts in the future?
Microplastics cause neurotoxicity, oxidative damage and energy-related changes and interact with the bioaccumulation of mercury in the European seabass, Dicentrarchus labrax (Linnaeus, 1758)
In this article the scientists state:
“Fluorescence red polymer microspheres, 1–5μm diameter (lot number: 4-0906-0661), purchased from Cospheric − Innovations in Microtechnology (USA), were used as microplastics model. According to the manufacturer, the particles are spherical, red opaque, 1.3 g/cc density, and can be detected by spectrofluorimetry (excitation wave- length of 575 nm and emission wavelength of 607 nm).”
It is clear that they don’t even know what kind of plastic they used! From the description, we can deduce that they were cross-linked polystyrene which are totally unlike any known ocean microplastics. This invalidates their work.
Evaluation of the impact of polyethylene microbeads ingestion in European sea bass (Dicentrarchus labrax) larvae
They used red fluorescent PE (which is not realistic) but found no harm and that the PE passed right through the larvae.
Uptake and Accumulation of Polystyrene Microplastics in Zebrafish (Danio rerio) and Toxic Effects in Liver
Used cross-linked PS that was 5 microns in size which is far too small and with far too high a surface area. As mentioned above, polystyrene is not the correct plastic to use.
Microplastic ingestion decreases energy reserves in marine worms
They claimed reduced energy in the worms due to PVC exposure but all effects were within the error bars of the experiment, meaning no detectable effect.
Early warning signs of endocrine disruption in adult fish from the ingestion of polyethylene with and without sorbed chemical pollutants from the marine environment
This study was done quite well but still has some issues. Firstly, they used a polyethylene that was not characterized in any way. They do not state the grade, the manufacturer or what additives were in it. Furthermore, they did the study by replacing 10% of the fish food with plastic. It is well-known that reducing the food given (10% of the nutritional value was removed) can induce physiological changes by itself.
Altered behavior, physiology, and metabolism in fish exposed to polystyrene nanoparticles
This study is meaningless. They used polystyrene, which is not a common plastic in the ocean. They chose nanoparticles, which are far smaller than microplastics in the ocean. Nanoparticles have massively more surface area, so they can interact much more than is realistic. Crucially, they used sulfonated polystyrene, which it utterly unlike real polystyrene used in commercial products.
Size‐dependentproinflam‐ matory effects of ultrafine polystyrene particles- a role for surface area and oxidative stress in the enhanced activity of ultrafines
They used polystyrene particles, i.e. the wrong kind of plastic and did not specify exactly which type (no product number was given). The particles were from Polysciences, meaning they are cross-linked, probably coloured and unlike real polystyrene. Another invalid study.
Physical Adsorption of Charged Plastic Nanoparticles Affects Algal Photosynthesis
They used nanoparticles which are far too small to be realistic. They used polystyrene particles which were synthesized and unlike the kind found in the oceans. Crucially, they used surface modified particles that had a charge added to their surface in order to make them stick to the algae in a way that real plastic particles do not. They concluded that the plastic particles stick to the algae and affect photosynthesis. Of course, if you modify a plastic to stick to the algae, they will block some light. Not a valid or worthwhile study. They might as well have put the algae in a black box and noted that photosynthesis was affected.
Impact of polystyrene microplastics on Daphnia magna mortality and reproduction in relation to food availability
The workers found no effect on health except at exceptionally high microplastic concentrations far above those found in the ocean. They used “2 μm carboxylate-modified polystyrene, fluorescent yellow-green” particles. Meaning that they used the wrong polymer, with the wrong surface chemistry, the wrong size and the wrong color compared to real plastic microparticles.
Polycarbonate and polystyrene nanoplastic particles act as stressors to the innate immune system of fathead minnow
This study used fluorescent nanoparticles unlike any plastic found in the ocean. Not a relevant piece of work.
Microplastics as Vector for Persistent Organic Pollutants In Urban Effluents: The Role Of Polychlorinated Biphenyls
This study actually isolated polyethylene microparticles from commercial facial scrubs,. They showed that the particles can absorb toxins and implied that they could transport toxins. As shown elsewhere in this page, what actually happens according to several studies, is that the PE absorbs toxins from the ocean and protects fish from exposure.
Toxicity of Microplastics to Aquatic Organisms – Clemson Thesis
This study was performed on synthetic fluorescent blue polyethylene microspheres from Cospheric. The spheres are made by a different process than real PE in the environment, are the wrong colour, are fluorescent (real PE is not), they are the wrong density, the wrong shape and surfactant needs to be added to disperse them in water (the potential toxicity of surfactant, if used, was not accounted for). The PP fibers used were taken from a marine PP rope that had been on the ground outdoors for three years. The brand of the rope and additives in it were not analysed. We do not know whether the rope had absorbed toxins while lying on the ground. It is not good science to perform studies on poorly characterized materials.
Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum
This study looks at PMMA and PHB microplastics, neither of which are in ocean water, making the study irrelevant.
.Microplastic leachates impair behavioural vigilance and predator avoidance in a temperate intertidal gastropod
This study is quite different to others. They exposed gastropods to commercially available PP pellets and polymer pellets randomly collected from a beach. They found that the plastics were non-toxic but the gasptrods were slower to respond to a threat when they were in water exposed to the plastic pellets. Beached plastics had a larger effect than virgin, clean PP pellets. It seems that somehow the chemicals from the plastic confuse the ability of the gastropod to sense danger. The study was done well but the conclusions were incorrect. To understand the relevance of this, we need to consider the whole picture. In the real ocean situation the gastropods would be in water containing toxins that confuse them. Adding microplastics to that system would absorb those toxins and potentially help the gastropods sense chemical danger. Therefore, this experiment was not designed in a way that tells us what would happen in reality.