Eco-Friendly Gifts Blog: What Are Microplastics?
Plastic pollution is the result of incorrect disposal methods used to deal with plastic waste.
The obvious signs of plastic pollution are floating pieces of plastic debris in the ocean, such as single use water bottles, coffee cups and single use carrier bags.
A less well known consequence is microplastic pollution.
In this blog, we're going to discuss what microplastics are, how they get into our water systems, and reasons why we should be concerned over microplastic presence in the natural environment.
What Are Microplastics?
Microplastics are pieces of plastic less than 5mm in all dimensions.
Primary microplastics are microplastics produced to be less than 5mm, and include nurdles, clothing fibres and pellets.
Secondary microplastics are pieces of plastic less than 5mm that have formed from larger pieces of plastic breaking down.
They can be formed from any piece of plastic that breaks down, with main examples being the aforementioned carrier bags, water bottles and coffee cups.
Types Of Plastic
Let's go into the detail of exactly what 'plastic' is. Plastic, in the common use of the word, refers to conventional plastic.
Conventional plastics are materials consisting of polymers, which are produced from fossil fuels, and do not have the ability to biodegrade.
A polymer is a chain of repeating monomers bonded together. Monomers are a group of atoms bonded together chemically.
To explain this, let's have a look at a common plastic: polypropylene.
Polypropylene is a plastic composed of polymers, made from the repeating monomer propylene.
When the process of polymerisation is carried out, these propylene monomers form the polymer, polypropylene.
This is what 'plastic' is, with each different type of plastic being built from different monomers to form polymers.
As well as these polymers, different additives are used to give certain characteristics. Plasticizers and antioxidants are common additives used to give flexibility, and prevent the reaction with oxygen respectively.
There are seven different types of plastic today in mass production, with all of them being assigned a number from 1-7. The number is given based on the ease at which each type of plastic is recycled.
PET is number one, meaning it is the easiest plastic to recycle. In number two and three are high density polyethylene and polyvinyl chloride.
In terms of production volumes, the largest volume by resin type was polypropylene, with 19.3% of the 359 million tonnes of plastic produced in 2018.
In second was low density polyethylene, making up 17.5% of all plastic produced. In third was high density polyethylene, with 12.2% of all plastic produced in 2018.
Let's now compare these volumes with the volumes of microplastics found in a study based in the mediterranean sea.
The most abundant microplastic by resin type was polyethylene (we assume both high density and low density, but it is not clarified. We have asked for a clarification from the study group).
Polyethylene made up over half of all microplastics found, with 54.4%. In second and third were polypropylene and polyester with 16.5% and 9.7%.
We can see that the two lists are not directly correspondent. The most produced plastic is polypropylene, whilst the most abundant microplastic found in the study is polyethylene.
However, there is a rough correlation, with the two most widely produced plastics coming in the top three most abundant microplastics.
From what we've looked at, we could draw an extremely rough conclusion that the volumes of plastic produced, do correspond to the abundance of each type of microplastic.
From this, we can say that if the volume of plastic being produced each year is reduced, the amount of microplastics formed every year, whether primary or secondary, will also be reduced.
Primary microplastics are formed as such.
Common entry points into freshwater environments for primary microplastics are washing clothing, the abrasion of vehicle tyres when driving and microplastics used in cosmetics.
Primary microplastics make up from 15-31% of all microplastics in the oceans.
Many of the clothes we wear are produced from synthetic materials, such as polyester.
Polyester is estimated to make up 60% of all clothing produced internationally.
Every time a piece of synthetic clothing is washed, microplastics are released into the water system.
An estimated 35% of all primary microplastics produced arise from washing synthetic clothing.
When vehicles are in motion, tyres are abraded on a very slow but steady basis.
As a result, 28% of all microplastics produced come from tyre abrasion. As the road is rained upon, these microplastics are carried with the surface runoff into the drainage system, and from then on into freshwater environments.
The third most prevalent source of primary microplastics is from cosmetic products.
In 2018, the UK put a ban on microbeads, which are primary microplastics no larger than 1mm. Commonly found in shampoos and other cosmetics, they were a large source of primary microplastics.
The UK ban is not yet international, with some countries still producing microbeads, hence why microbeads are still a source of microplastics entering the ocean.
Secondary microplastics are microplastics formed from larger pieces of plastic breaking down.
They are estimated to make up 69-81% of all microplastics in the ocean.
As previously mentioned, secondary microplastics can be formed from essentially any plastic that breaks down over time. Fishing nets, coffee cups and plastic bags are all plastic items that break down.
The Problem With Microplastics
Microplastics have been found to pose a risk to the immune system.
A study carried out found that immune cells attempting to attack microplastics died three times more quickly that immune cells that had no contact with microplastics.
In a twenty-four hour period, 20% of immune cells died in a culture dish with no microplastics present.
In the same time period, 60% of the immune cells in a culture disk including microplastics died.
The effects of microplastics on a wider scale are being researched, and are not fully understood yet. It is crucial we know what risks microplastics pose, as they are now present in essentially every water system the world over.
In the marine environment, microplastics enter the food chain at the lower trophic levels, often starting with zooplankton.
Zooplankton ingest microplastics, and then are themselves ingested by the animal on the next trophic level. The predator of the zooplankton ingests all the microplastics that were present in the body of the zooplankton at the time of ingestion.
This process is called the trophic transfer of microplastics, and continues all the way up into the higher rungs of the marine food chain. Microplastics have now been found in seals, cod and us.
It is easier to say that seals and cod ingest microplastics through this process, but harder to say where exactly humans ingest microplastics.
This is due to humans being exposed to far more sources of microplastics, such as the aforementioned reasons including drinking water and airborne microplastics.
The future, if plastic is entering into our bodies at the current rate, could leave mass segments of the population unable to deal with common colds through their immune systems being compromised.
Ultimately, the poorest in the world will suffer the most, and the quickest. Developing countries will be unable to deal with microplastics in water, unable to remove microplastics from drinking water.
Developed countries will have to create entire new systems to remove microplastics from drinking water, in order to protect the population.
In a hundred years from now, we could have a situation where food chains that support us are being damaged to the point of no return. Food supplies that we rely on such as fish could begin to die in mass from the effects of microplastic toxicity, throwing the marine eco system off balance.
Not only will this result in food supplies being cut short, reduced fish numbers will cost jobs in the fishing industry, causing economic damage.
The environment is actually very closely linked to our modern economy, with the economy essentially reliant on a healthy environment.
Solutions To Microplastic Pollution
There are a few viable solutions, but all of them come down to the basic premise: Reduce the amount of microplastic polluting sources.
This can be achieved in two ways.
Either replace microplastic polluting sources to materials that can biodegrade, or just stop producing microplastic polluting sources altogether.
Consumerism dictates that whilst there is a demand for a product, it is unlikely that companies producing microplastic emitting materials will stop to doing so, unless enforced by laws.
Therefore, the best way to reduce microplastic pollution is to swap non biodegradable plastic to plastic that can biodegrade.
A crucial technicality to get down, is that biodegradable plastics can still form microplastics, due to other abiotic forms of degradation occurring in the natural environment.
Bioplastics are plastics that are produced from renewable resources, that can biodegrade, or both.
In this blog, we will be focusing on the bioplastics that can biodegrade, as the source material is not directly relevant to reducing microplastic emissions, at a rate comparable to non biodegradable plastics.
There are two groups of bioplastic that can biodegrade: fossil based bioplastics, and bio based bioplastics.
A key point to get across here is that just because a plastic is produced from fossil fuels, does not mean it can't biodegrade. This is shown in the bioplastic PBAT.
This works the same with the other side. Just because a plastic is produced from biomass, does not mean it automatically has the ability to biodegrade. This is shown by the non biodegradable bio based bioplastic bio based PE.
We should also clarify what we mean by 'biodegradable'.
If a material is biodegradable, it can break down into CO2, biomass and water with the aid of microorganisms.
This does not mean that biodegradable plastics will break down in all environments such as the marine environment and landfill, due to the necessary microorganisms not being present to aid in the biodegradation.
There is also no time frame on biodegradation, meaning that a biodegradable coffee cup could still break down into biomass, CO2 and water in 1,000 years, and it could still legally be called biodegradation.
The only reason why biodegradable plastics are being talked about in this blog as a solution to reduce microplastic pollution, is that they don't break down into smaller and smaller pieces of plastic all the way to fragments.
Instead, they break down into CO2, biomass and water, hence stopping the creation of microplastics entering the food chain at the lower trophic levels.
Removing Microplastics From Water
Microplastics are notoriously difficult to remove from water, both drinking and fresh. This was until a few years ago, when a young scientist developed a method involving a NASA invention.
Fionn Ferreira was 18 when he won the google science fair in 2019.
Ferrofluid is a magnetic liquid, created in 1963 to make rocket fuel able to move in zero gravity situations, in particular for the apollo missions.
Ferreira, using this knowledge, created his own magnetic liquid by suspending mangenite powder in vegetable oil. By placing a magnet in a mixture of this liquid and water, the microplastics in the water can be removed.
An average of 80% of microplastics can be removed using this method.
With this blog, we've talked about what microplastics are, what risks they pose, and possible solutions to microplastic pollution by using biodegradable plastics over non biodegradable plastics.
As more research is carried out, we will have a better understanding of what microplastics can do to humans and organisms alike. Hopefully, the worry that microplastics can have long and damaging effects on immune systems are overstated, and we will have nothing to worry about.
However, by the current research, this does not look likely.