One of the issues related to the use of plastics in society is the creation of microplastics.
In the guide below, we outline the different aspects of microplastics, such as what they are, where they come from, their different potential effects, how to potentially avoid them as an individual, how to potentially address them as a society, and more.
(Note – this guide contains general information only. The information in this guide is not professional advice, and is not a substitute for professional advice)
Summary – Microplastics
In the guide below, we’ve included information on the following aspects of microplastics:
– What microplastics are
– There’s different types of microplastics (microfibres, microbeads, pellets, and so on)
– Primary vs secondary microplastics
– Difference between microplastics and nano plastics
– Detecting microplastics vs nano plastics
– Where microplastics come from/the range of sources that microplastics come from
– How microplastics are spread across the different parts of society and the environment
– Where microplastics are found across society and in the environment
– The potential effects of microplastics
– Whether microplastics are harmful or not
– Microplastics in humans
– Microplastics breaching/infiltrating the blood-brain barrier
– Microplastics in food
– Microplastics in water
– Microplastics in soil and on land
– Microplastics in the air
– Microplastics in the ocean
– Microplastic pollution
– Microplastics in the environment
– Microplastics in wildlife, fish and marine life
– How to avoid microplastics as an individual
– Microplastic filters for washing machines
– How to address microplastics as a society
– Statistics on microplastics
What Are Microplastics
According to multiple different publications that provide definitions of microplastics, microplastics are micro sized pieces/fragments of plastic that measure less than 5 mm in diameter (0.2 inch)
Microplastics are smaller plastics than macroplastics
Types Of Microplastics
Something we have outlined elsewhere on the site is that there can be different types of microplastics
As just three examples:
– Microfibres can come from some textiles and clothing that use synthetic plastic based fibres
– Microbeads are included in some cosmetic and personal care products for the function of scrubbing or exfoliating
– Plastic pellets are manufactured for a range of potential uses
How Are Microplastics Created? – Primary vs Secondary Microplastics
There might be two main ways that microplastics are created …
Primary microplastics are microplastics that are manufactured as a product for a primary use i.e. they are purposefully manufactured.
Plastic pellets and nurdles are examples of primary microplastics
Some reports have a different definition of primary microplastics, defining them as any plastic that is the size of a microplastic at the time of manufacture. They can be standalone products like nurdles/plastic pellets, or they can be parts of other products, like microfibres that are a part of an overall textile product
Secondary microplastics come from the break down other primary plastic products
The first secondary source of microplastics is when they break off from plastic products whilst in use.
One example is microfibres breaking off from synthetic fibre textiles and clothing in a washing machine
The second secondary source of microplastics is when plastic is sent to landfill or ends up in the environment as plastic pollution, and plastic waste breaks down into microplastics over time
You can do an online search for largest sources of both primary microplastics, and secondary microplastics.
Difference Between Microplastics & Nanoplastics
Nanoplastics are even smaller than microplastics
They are in the nanometre size range
According to a range of publications that define nanoplastics, nanoplastics are tiny particles of plastic that are less than 1 μm (i.e. 1000 nm) or less than 100 nm in size
Difficulty In Detecting Nanoplastics Compared To Microplastics
A potential issue with nanoplastic issues might be how difficult they can be to detect compared to microplastics.
While microplastics can be seen under the microscope, nanoplastics are very difficult to detect, particularly in biological tissues (ec.europa.eu)
Where Do Microplastics Come From? – Sources Of Microplastics
There are a range of sources for microplastics/places that microplastics commonly come from across society
We provided a comprehensive list of those potential sources in this guide about plastic pollution on land.
A dot point summary list of those sources includes:
– Primary microplastics like plastic pellets (and other primary microplastics) – one example of where pellets are used is at some waste water plants and some waste treatment plants
– Clothing and textiles that contain synthetic plastic based fibres, such as acrylic, nylon, spandex, and polyester (according to plasticsoupfoundation.org: ‘… wearing polyester clothes releases as many microplastic fibers in the air as through washing’)
– Cosmetic and personal care products
– Plastic packaging
– Plastic items flushed down toilets and washed down sinks
– Industrial discharge
– Car tyres
– Road markings and plastic pellets and additives in asphalt (and most recently, they might come from some roads that use plastic construction or technology)
– Plastic in sewage sludge
– Plastic in sewer overflows
– Artificial turf
– Shoe soles
– Agricultural plastics
– Water bottles, and baby bottles
– Lids and caps of bottled water
Other sources not listed in that guides might include:
– Fishing sources (such as fishing vessels)
– Face masks
wikipedia.org has a comprehensive list of of the sources that microplastics can come from in their resource
How Microplastics Get Into Soil, Water & Other Parts Of Society
We’ve explained the various ways microplastics get into soil, water and other parts of society in this guide
A dot point summary list of those ways includes:
– Water run off
– Drains & outlets
– Air (air and wind can transport microplastics long distances, and microplastics in the air can land on the surface of food)
– Sewage sludge, biosolids & organic waste used for fertilizer
– There’s some evidence that microplastics can become involved with the Earth’s water cycle, and be evaporated with water, and then come back down in precipitation
Where Are Microplastics Found Across Society?
Because of their size and the ease with which they can be transported and move across society, microplastics can be found in a wide range of places.
Some of the notable places that microplastics are found are:
– In humans
– Inside wild life and marine life
– In tap water
– In bottled water
– In the food supply
– In the air
– In dust
– In snowfall
– In rainfall
– In the soil and in sediments
– In freshwater sources like rivers and lakes
– In the ocean
– In ice cores
– There’s also theories that microplastics end up as in the deep sea as sediments and washed up and buried on coastlines and beaches around the world
Effects Of Microplastics
We’ve previously discussed the potential effects of microplastics across different parts of society in our guides on the potential negative effects of plastic, plastic pollution on land, plastic pollution in the ocean, and the general impact of plastic.
We’ve also pointed out that it may be hard to truly quantify the economic cost or impact of microplastics now or in the future.
In the sections below, we’ve provided further information on the potential effects of microplastics across specific areas.
The information is not intended as definitive, but rather a summary of some the available data on effects right now.
Are Microplastics Harmful?
There’s different data suggesting that microplastics may have the potential to be harmful in different ways for all three of:
– Wildlife, marine life and living organisms
– The environment (microplastic may have the potential to act as a long term stress factor on different parts of the environment for example)
Microplastics In Humans
Potential Effects On Human Health
There’s differing and perhaps conflicting information available on the potential effects of microplastics on human health across society (other points like the current exposure level to microplastics, the link between microplastics and human health effects, and more can also be contested)
Some reports might indicate microplastics are only of low concern to human health at current exposure levels, some might indicate we simply don’t know the full impact of microplastics on humans, and, some indicate that we might know of some specific effects microplastics might have on humans and human health.
We provide more information on each of these stances below …
– Microplastics Are Only Of Low Concern For Human Health
[Right now, it’s thought plastics are inert when ingested andpass through the body without uptake]
[There appears to be] no reliable information at this time that would suggest any overt health concerns associated with microplastic particles … and there low concern for human health
The impact of microplastics and nano plastics in the human body right now has limited information available, but, it’s believed the health risk to humans is low or no risk at current levels, according to most sources (euronews.com)
From wikipedia.org: Mean/median intake of microplastics in humans are at levels considered to be safe in humans
… microplastics larger than 150 micrometres are not likely to be absorbed in the human body and the uptake of smaller particles “is expected to be limited.” (euronews.com)
– There’s An Uncertain Impact Of Microplastics On Human Health
… science still lacks evidence about how microplastics and nanoplastics are affecting the human body … [and there’s] limited data on exposures and risks, which makes risk management a challenging task
[A 2019 ‘WHO’ report on] the effects of microplastics on human health … concluded that there is not enough data yet on humans to know if microplastic particles are hurting us [… and there needs to be] more research into microplastics
There are a lot of analytical constraints when analysing microplastics and we lack the standardised methods and reference materials
[There might particularly need to be more research on microplastic particles in the air, and the impact of them crossing the] placenta barrier and directly [exposing foetuses in pregnant women]
[Right now, it is considered there is insufficient information to make firm conclusions on what plastics do to the human body …]
[There appears to be] no reliable information at this time that would suggest any overt health concerns associated with microplastic particles … and there low concern for human health
… [it is also not known] what effect microplastics are having on our agricultural ecosystems
[When individuals exceed mean/median intake of microplastic levels …] the effects, if any, of this is unknown
It is unknown whether and to what degree microplastics bioaccumulate in humans
… the degree of absorption and retention [of microplastics in humans] is unclear
… It is as yet unknown if exposure to microplastics at the levels found in the environment represent a “real” risk to humans; research into the subject is ongoing
… little is known with respect to the human health risks of nano- and microplastics, and what is known is surrounded by considerable uncertainty
Also from wikipedia.org:
Nanoplastics are thought to be a risk to environmental and human health. Due to their small size, nanoplastics can cross cellular membranes and affect the functioning of cells.
Little is known on adverse health effects of nanoplastics in organisms including humans.
Even though MP exposures are ubiquitous and toxic effects from such exposures are a concern, systematic studies on this topic remain urgently needed (frontiersin.org)
From time.com: … [it’s] “completely unknown” what happens once [microplastic] particles enter the human body
There is, currently, very little evidence of the impact of microplastics in humans.
Despite having no clear evidence of health impacts, research on potential exposure is ongoing
… levels of particles found in drinking water varied so widely between the different studies that no conclusions could be drawn (euronews.com)
– Specific Effects Of Microplastics On Humans & Human Health
There are three main areas of potential concern with microplastics: the plastics themselves may have some effect on human physiology, microplastics might complex with heavy metals or other chemical compounds in the environment and act as a vector for bringing them into the body, and it is possible that microplastics might serve as vectors for pathogens.
[Potential risks from microplastics in the human body are toxicity of the particles, plastic additives, pollutants that accumulate on the plastic, biofilms, and the spread of pathogens and antimicrobial resistance]
Research has shown microplastics can alter the shape of human lung cells
[Experiments on human microglial cells also suggest that microplastics might have the ability to impact and change human microglial cells, and can cause change to the immune system]
[Microplastics may get into the airways, and causes swelling or damage to the windpipes or tissue in the lungs]
[Microplastics may damage the air sacs in the lungs, and may increase the risk of developing lung condtiions]
[Microplastics get into the bloodstream, and may contribute to artery issues and heart conditions]
[Microplastics in the air that carry pollutants on their surface may also be inhaled by humans and there’s a range of health conditions they may contribute to]
… microfibres are more likely than other types of microplastic to absorb toxic chemicals, which may be injurious to health (wwtonline.co.uk)
[Although] exposure to MPs itself is a concern, MPs can also be sources of exposure to plastic additives and other toxicants
[frontiersin.org also discusses other potential ways microplastics may impact humans and human health in their resource]
How Humans Ingest & Inhale Microplastics
Some of the main ways humans might either ingest or inhale microplastics might include:
– Inhaling through the air and dust we breathe in
– Eating food that has had microplastics from the air settle on it’s surface
– Eating food from animals that ingest microplastics. Some reports debate this as we don’t often eat the digestive systems, lungs or other organs of some of these animals. However, wikipedia.org notes ‘Microplastics can become embedded in animals’ tissue through ingestion or respiration’, and humans eat animal tissue
– Ingesting microplastics through the water we drink (bottled and tap water)
Available information suggests that inhalation of indoor air and ingestion of drinking water bottled in plastic are the major sources of MP exposure (frontiersin.org)
[Humans ingest microplastics from food and water, and from plastic utensils, and from breathing] (abc.net.au)
How Much Microplastics Humans Ingest & Inhale
We outlined some different stats on how much microplastic humans might consume or inhale in this guide.
The range of estimates of the number of microplastic particles humans consume and inhale each year might be between 70,000 to 121,000.
Although time.com indicates that ‘… the true number is probably much higher, because for some likely sources of microplastics, there was no strong data available’
Microplastics Breaching/Infiltrating The Blood-Brain Barrier
The blood-brain barrier is a semipermeable border that acts as an interface, and surrounds most of the blood vessels in the brain.
The main purpose of the blood-brain barrier in humans and some animals is to prevent foreign substances (especially solids, but also toxins, bacteria, fungi, viruses and parasites) from entering the brain from the circulating bloodstream.
Some people want to know whether microplastics have been studied to cross the blood-brain barrier.
There is research that suggests that microplastics may have crossed the blood-brain barrier of some animals.
The observed impact of these microplastics and the number of particles that reach the brain might be less definitive though between different sets of research.
[Scientists found that microplastics made their way through the blood-brain barrier of mice that were orally administered microplastics of two micrometers, over the course of seven days]
[The microplastics impacted the ability of microglial cells to proliferate, and contributed to other changes too]
Current evidence indicates that micro- and nanoplastics can be taken up by aquatic organism as well as by mammals.
Upon uptake, micro- and nanoplastics can reach the brain, although there is limited information regarding the number of particles that reaches the brain and the potential neurotoxicity of these small plastic particles.
Currently, a systematic comparison of the neurotoxic effects of different particle types, shapes, sizes at different exposure concentrations and durations is lacking …
Microplastics In Food
What Foods Contain The Most Microplastics?
Seafoods might contain some of the most microplastics, but air and bottled water might contain as much, or more.
Aside from seafood, other foods have had microplastics detected in them.
The microplastics ingested by fish and crustaceans can be subsequently consumed by humans as the end of the food chain
Microplastics are found … especially [in the seafood that humans eat]
[Researchers analysed 26 studies that] measured how many microplastic particles were in the foods people ate or the air they breathed.
They found acceptable data on plastic concentrations in seafood, added sugars, salts, beer, water and air, but none on grains, vegetables, beef and poultry …
Air, bottled water and seafood were the biggest sources for ingested microplastics.
Added sugars accounted for less, and salts, tap water and beer contributed minimally [to ingested microplastics]
These estimates are conservative, the researchers note, since the included foods only make up about 15% of the average diet. It’s not yet known how much plastic is in the remaining 85% of the typical diet
[Microplastics] have already been detected not only in fish and seafood, but also in salt, sugar and beer
… tiny fragments of plastic can be accumulated in yeasts and filamentous fungi
How Much Of A Problem Are Microplastics In Food?
Some reports indicate that microplastics in food might not be as much of an issue as other sources of microplastics such as household dust, or microplastics that land on food from household sources of microplastics.
… ingestion of microplastics via food may be relatively minor; for example, while mussels are known to accumulate microplastics, humans are predicted to be exposed to more microplastics in household dust than by consuming mussels
… we are likely to ingest more plastic through household dust from textiles than through mussel consumption … research found out that the microplastics in wild mussels were low compared to household fibers ending up on the surface of the food
Microplastics In Water
Microplastics may get in a range of water sources such as:
– Drinking Water
Such as plastic bottled water, and also tap water
Recent studies into water contamination have found microplastics in 83% of tap water samples from major cities around the world and in 93% of samples from the world’s top 11 bottled water brands.
… our drinking water supply is heavily contaminated with microplastics.
wikipedia.org also notes that different bottled water brands lesser quantities of plastic particles in their water compared to others, and the bottling and packaging of bottled water may contribute to the microplastic contamination
– Fresh Water
Such as rivers, lakes, and other fresh water sources
– Ocean Water
In surface water, but also deep sea and below the surface of the water
Microplastics In Soil & On Land
We wrote about microplastics in the soil and on land in this guide.
Microplastics In The Air
Microplastic particles have been found in the air in many locations across the world, and even in remote locations away from cities.
Once in the air, these particles can be transported long distances.
Aside from microplastics in the atmospheric outdoor air, microplastics can also be found in the air indoors.
Overall, some reports indicate that more microplastics enter the human body from the air than from the tap and bottled water we drink.
Microplastics In The Atmosphere
It’s estimated that about 10 million metric tons of microplastics are emitted into the atmosphere each year
[These] microplastics are being emitted into the atmosphere, mainly from roads, the ocean, and agricultural practices
Microplastics Found In The Air Indoors
From from accuweather.com:
Although recent studies have shown that microplastics have been found in our bottled and tap water, additional research now reveals that the majority of microplastics in our bodies comes from the air we inhale each day
The fragmentation through friction, heat or light of plastic objects found indoors can introduce microplastics into the air inside
Research shows that most of the microplastics found in the air indoors comes from plastic fibers released from synthetic clothes as well as textiles used in furniture
Microplastics In The Ocean
Microplastic particles might be found mainly on surface water in the ocean.
There are also reports or theories on microplastics finding their way to the deep sea, inside marine life, and also washed up and buried on coastlines and beaches.
Read more about plastic and microplastics in the ocean in this guide.
We’ve previously written about microplastic pollution in our guide about general plastic pollution.
What we also mention in our guide on plastic pollution on land is that microplastic pollution on land may be 4 to 23 times the extent of microplastic pollution in the ocean.
Microplastics In The Environment
– Have the ability to carry organic pollutants around in the environment
– Have potential to be vectors that carry diseases around in th environment
– Have potential to be a long term stress factor on the environment
Similar to some reports on the impact of microplastics on humans, the impact of microplastics in the environment may not be conclusive at this stage.
– Uncertainty Of Impact Of Microplastics On The Environment
The intake and uptake of small microplastics could turn out to be the new long-term stress factor for the environment
… [but, right now] there is a lack of standardized methods for determining microplastics in terrestrial ecosystems in order to produce an accurate assessment [of their impact on these ecosystems and the environment] (sciencedaily.com)
Also from wikipedia.org: While there is no evidence of widespread ecological risk from microplastic pollution yet, risks are likely to become widespread within a century if pollution continues at its current rate
– Specific Effects Of Microplastics On The Environment
[Degradation of plastics leads to micro plastic particles that] act like sponges and soak up persistent organic pollutants (POPs) around them
… some plastics accumulate more pollutants than others
… the surfaces of tiny fragments of plastic may carry disease-causing organisms and act as a vector that transmits diseases in the environment (sciencedaily.com)
Microplastics In Wildlife, Fish, Marine Life
We mentioned the potential effects of microplastics on wildlife in this guide, and wild life as well as marine life in this guide.
Some of the extracts from those guides, and additional reports can be found below.
A range of reports indicate that microplastics may have a range of potentially negative effects on a range of living organisms in the environment.
There might be toxic effects, hormone disrupting effects, inflammation, interference with gene expression, and a range of other explored and unexplored effects.
General Impact On Wildlife & Living Organisms
Generally speaking, when plastic particles break down, they gain new physical and chemical properties, increasing the risk that they will have a toxic effect on organisms. And the more likely it is that toxic effects will occur, the larger the number of potentially affected species and ecological functions.
Chemical effects are especially problematic at the decomposition stage … [where] additives such as phthalates and Bisphenol A leach out of plastic particles. These additives are known for their hormonal effects and can potentially disrupt the hormone system not only of vertebrates, but also of several invertebrates
… nano-sized [plastic] particles may cause inflammation; they may traverse or change cellular barriers, and even cross highly selective membranes such as the blood-brain barrier or the placenta. Within the cell, they can trigger changes in gene expression and biochemical reactions, among other things.
The long-term effects of these changes have not yet been sufficiently explored. However, it has already been shown that when passing the blood-brain barrier nanoplastics have a behaviour-changing effect in fish.
– sciencedaily.com, and unenvironment.org
Although plastics were once perceived as inert materials, MP exposure in laboratory animals is linked to various forms of inflammation, immunological response, endocrine disruption, alteration of lipid and energy metabolism, and other disorders (frontiersin.org)
wikipedia.org lists some other potential effects of microplastics on living organisms and wildlife
Impact On Mammals
From newatlas.com: [Scientists in Korea found that microplastics may act as toxic substances towards mammal brains]
Impact On Soil & Land Based Organisms
Microplastics can also interact with soil fauna, affecting their health and soil functions … [like for example the] earthworm’s fitness and the soil condition (sciencedaily.com, and unenvironment.org)
Impact On Freshwater Aquatic Organisms
[Some research indicates that] 50 per cent of freshwater insects tested in South Wales has microplastic inside of them (wwtonline.co.uk)
… earlier studies have demonstrated that microplastics might be harmful to ecosystems when ingested by aquatic key organisms … [and it is thought that there could be a similar impact on land based organisms] (sciencedaily.com, and unenvironment.org)
Impact On Marine Life
[Studies have found that some of the threats that microplastics may pose to marine creatures might include] weakening the adhesive abilities of muscles, impairing the cognitive ability of hermit crabs and causing aneurysms and reproductive changes in fish]
Microplastics have turned up in the guts of sea turtles all over the world and have been discovered in seal poo …
Some evidence indicates microplastics hurt sea life and slow down growth and reproduction rates in fish (businessinsider.com.au)
[Polystyrene nanoplastics can induce stress responses in, as well as affect the growth and reproduction of several fish species] (wikipedia.org)
How To Avoid Microplastics As An Individual
Because of the extent of microplastics in society, and the number of ways humans can both ingest and inhale microplastics, it may be impossible to 100% avoid them in everyday life.
It may be possible though for individuals to reduce their exposure to microplastics, or reduce their ingestion and inhalation of microplastics.
Some of to do this might include:
– Filtering tap water for microplastics
– Drinking from water bottles that aren’t made from plastic (such as steel/metal, glass and other types of water bottles), or don’t have plastic lids. Plastic bottle liners should also be checked in any water bottle
– Drinking from tap water over bottled water. Time.com outlines one report that indicates ‘… when people drink their water only from bottled sources, they ingest about 90,000 microplastic particles every year from that water, but people who drink only tap water get 4,000 of such particles a year’
– Cleaning the house, car and working environments more regularly so that there is less dust build up (microplastics can be found in dust)
– Substituting products containing plastic for products made of other materials where possible and reasonable to do so. This can include furniture, clothing and textiles, and more
– Being aware of the foods that show higher rates of microplastic accumulation than others, such as some seafood
– According to iqair.com, either a high performance air purifier, or for heavier microplastics, high performance centrifugal fans are designed to trap and collect large and heavy microplastics in the air
Microplastic Filters For Washing Machines
There is a range of microplastic filter products on the market that capture microplastics in the washing machine when doing the laundry
How To Address Microplastics As A Society
Filtering Water & Other Potential Solutions
Filtering tap water and other sources of water for microplastics may be one of the main ways that humans can ingest less microplastics on the society wide level. In some countries though, filtering drinking water for harmful bacteria and pathogens may be a bigger priority (in countries where it’s a bigger public health and safety risk).
Other potential solution on a society wide scale might involve:
– Filtering and capturing microplastics in waste water, storm water and sewage
– Setting up microplastic collection devices and systems in places where microplastics are known to travel or accumulate in, such as in the ocean
– Clean ups of plastic already in the environment to prevent further breakdown of these plastics into microplastics (which will spread throughout the environment and across society)
– Changing activities or substituting products that lead to the release or run off of microplastics into water sources – such as washing textiles with plastic based fibres, plastic wash off from cosmetic and personal care products, flushing plastics down the toilet, the use of primary plastic pellets, plastic packaging, plastic from marine sources like fishing vesels, and more. Realistically, the sources of microplastics and the ways that microplastics get around can be addressed on a society wide level
– New technology and developments such as enzymes or microbes that only eat microplastics and nanoplastics in certain environments, or, new plastics that biodegrade or compost under specific conditions instead of breaking down into microplastics
Reducing Microplastics, & General Solutions To Plastic Problems
Part of the solution to addressing microplastics might be to reduce microplastics in the first place.
There’s various ways we might be able to reduce microplastics and also better manage plastic across society in the future.
Statistics On Microplastics
There’s a range of reports that provide different statistics on microplastics.
Rather than link to one or two reports, we’ve provided a range of topics you might like to do your own research on that might be relevant to the microplastics issue:
– Number of microplastics particles that humans ingest and inhale every year
– Number of microplastics particles in the food supply
– Number of microplastics particles in drinking water sources (tap water and bottled water)
– Number of microplastics particles that wildlife and marine life ingest and inhale every year
– Number of microplastics particles in the air
– Number of microplastics particles on dry land in the soil and in freshwater sources
– Number of microplastics particles on the surface of the ocean (some estimates range from 15 to 51 trillion particles)
– Total number of microplastics particles in the ocean (on the surface and below the surface), and in marine environments on beaches and coastlines
– Number and types of health cases, health conditions or mortalities with a link to microplastics
– How much microplastics cost the economy each year
– Potential cost to address microplastics problems across society
1. Various ‘Better Meets Reality’ resources
4. Prüst, M., Meijer, J. & Westerink, R.H.S. The plastic brain: neurotoxicity of micro- and nanoplastics. Part Fibre Toxicol 17, 24 (2020). https://doi.org/10.1186/s12989-020-00358-y. Accessed from https://particleandfibretoxicology.biomedcentral.com/articles/10.1186/s12989-020-00358-y
11. Kannan K and Vimalkumar K (2021) A Review of Human Exposure to Microplastics and Insights Into Microplastics as Obesogens. Front. Endocrinol. 12:724989. doi: 10.3389/fendo.2021.724989. Accessed from https://www.frontiersin.org/articles/10.3389/fendo.2021.724989/full
18. Hannah Ritchie and Max Roser (2019) – “Plastic Pollution”. Published online at OurWorldInData.org. Retrieved from: ‘https://ourworldindata.org/plastic-pollution’ [Online Resource]
20. Forschungsverbund Berlin. “An underestimated threat: Land-based pollution with microplastics.” ScienceDaily. ScienceDaily, 5 February 2018. <www.sciencedaily.com/releases/2018/02/180205125728.htm>