Eco-Friendly Gifts Blog: Can Plastic Pollution Be Solved With Biodegradable Plastics?
Plastic pollution is one of the largest human made disasters ever, second only, arguably, to the climate crisis.
Because conventional plastics don't biodegrade, they can stay present in the natural environment for many years.
When they do break down via several mechanisms including heat and light degradation, they form smaller and smaller pieces of plastic instead of natural components.
In this blog, we are going to look at the premise of biodegradable plastics being introduced to replace non biodegradable plastics, in an effort to combat plastic pollution.
Plastic pollution is down to two main factors: the inability to process plastic efficiently enough that it won't end up in the natural environment, and that when plastic does end up in the environment, it doesn't biodegrade.
In order to stop plastic pollution getting worse, we need to stop making conventional plastic.
It's really that simple.
As soon as we stop making plastic, then we can focus on clearing plastic from the natural environment.
The only reason this concept isn't a widespread unilaterally agreed upon idea, is that since the 'Keep America Beautiful' campaign in the 1970s, the consumer has been made responsible for where plastic ends up.
This same concept still applies today with recycling.
If plastic that is recyclable ends up in the natural environment, then the companies producing the plastic in the first place can say "oh, nothing to do with us, you should have recycled it".
Imagine if you walked into your bathroom, and the floor was flooded because someone had left the tap on.
What would you do first?
You would turn the tap off. Only after you had turned the tap off would you start to mop up the floor.
This same principle applies exactly to the current situation we have with plastic.
There is no point investing millions in cleaning our oceans, when a garbage truck worth's full of plastic is entering our seas every minute.
Due to the current rate at which plastic is produced, 300 million tonnes a year, not likely to be changed due to the fossil fuel industry lobbying governments around the world, we have to think of other solutions to the plastic crisis.
One of these ideas is to use biodegradable plastic.
Let's get a few key points out of the way to address this suggestion immediately.
Biodegradable plastic has no set time frame on how long it takes to biodegrade.
This means that biodegradable plastics could still be present in the natural environment for many years, all the time being a threat to wildlife.
Biodegradable plastic can still form microplastics, and nanoplastics, from other forms of degradation.
Just because a plastic is 'biodegradable', does not mean it will only break down via biodegradation.
Biodegradation refers to the process of a material being broken down into natural substances such as CO2, biomass and water with the aid of microorganisms.
In the natural environment, there are a few other ways in which plastics can breakdown: thermal degradation (degradation due to heat), photodegradation (degradation due to UV light) and hydrolysis (degradation due to reaction with water).
If biodegradable plastics are degraded abiotically (not using microorganisms) with the methods above, then microplastics still have the potential to be formed.
Because plastics typically break down abiotically, before they break down biotically, it is likely that microplastics will be formed.
What Do Microplastics And Nanoplastics Do?
Microplastics (pieces of plastic less than 5mm in all dimensions) have been shown to have a negative effect on the immune system.
A study was conducted showing that immune cells that come into contact with microplastics are three times more likely to die than immune cells that had not come into contact with microplastics.
Microplastics accumulate up the food chain, through the trophic transfer of microplastics.
This process is from the predator ingesting the prey, when the prey contains microplastic content. This means that the predator has ingested all of the microplastic content that was inside the prey at the time of ingestion.
This process continues all the way up the food chain, to humans. So in effect, we are eating our own plastic waste.
Pieces of plastic below the size of 100 nanometers are called nanoplastics.
On a health level, nanoplastics are arguably far scarier than microplastics. Because of their size, nanoplastics have the potential to accumulate in organs, enter the bloodstream, and even pass through the blood brain barrier.
Nanoplastics have been studied to actually change the behaviour of animals in the study just linked, due to the tiny plastic particles having the ability to come into contact with the brain.
This is why we need to work on fool proof systems that work on an international scale, to ensure that plastics, regardless of their biodegradability, do not end up in the natural environment.
Examples Of Biodegradable Plastics
When we are talking about biodegradable plastics, we are referring to a group of plastics that come under the category of 'bioplastic'.
Bioplastics are similar to conventional plastics in terms of their characteristics, but they are produced from renewable resources, can biodegrade, or both.
To represent the wide range of bioplastics and their characteristics, we have picked two that account for different areas of the vast field: PLA and PHA.
Let's start with arguably the most well known bioplastic out of the three polymers - PLA.
Polylactic acid is produced from cornstarch in many of the western manufacturing methods. It is biodegradable and compostable under industrial conditions.
One of the main concerns over branding a material 'biodegradable' is that people assume it's ok for the material to end up in the natural environment.
As previously mentioned, this is not true. To achieve the full benefits of PLA, it must be composted industrially.
This means that the material will biodegrade to form compost in six months or less.
You can access industrial composting through our zero to landfill scheme LFHP Zero, to ensure that any used compostable items you purchase from LFHP will be fully composted.
If PLA is composted in a home scenario, it will compost, but at a far slower rate.
There is such a wide range of variables when it comes to home composting, that we can't really put an exact figure on how long PLA would take to break down in a home composting area.
We do know that it is almost certain to take far longer than in industrial conditions.
The reason for the difference in composting times between industrial and home, is mainly to do with temperature.
In industrial composting conditions, there is a constant high temperature, of around 58 degrees celsius. In home composting, the temperature will be roughly whatever it is outside, locally to the composting area.
Moving onto the next bioplastic: PHA.
PHAs aren't actually the bioplastic material, they are the polyesters that make up the material. When we are referring to the bioplastic polymer constructed by the PHA polyesters, we will call them PHA polymers.
PHAs are produced by bacteria, that metabolize different inputs to generate the PHA polyesters.
These bacteria then store the PHAs as carbon storage material and energy.
When there has been enough PHA produced by the bacteria, the PHA polyesters are then harvested, by cutting into the bacteria cells.
The polyesters are then manufactured to form the PHA polymers.
PHA has the main advantage over PLA of being able to degrade into non industrial composting environments such as freshwater and soil, within 18 weeks.
However, just because a biodegradable bioplastic such as a PHA polymer can biodegrade, doesn't mean that it will.
It still has the potential to degrade via other means, which means that potentially micro and nanoplastics will still be formed in the process.
Research has been carried out that shows PHA in freshwater can still form nanoplastics which have a negative effect on the local organisms.
Biodegradable Plastics Require Systems
From what we have seen from the facts about biodegradable plastics such as PLA and PHA polymers, it is clear that being biodegradable isn't good enough.
Biodegradable plastics still can form microplastics and nanoplastics due to other forms of degradation taking place in the natural environment.
Mechanisms such as heat, light and reaction with water are all potential ways in which biodegradable plastics could degrade in methods other than biodegradation.
What does this mean?
It means that just because a material is biodegradable, does not mean it should end up in the natural environment. Full scale, systematic processes need to be put in place to stop plastic pollution from occurring on a global scale.
Who should pay for it?
The producers of the materials, whether it be the retailers selling to consumers or the manufacturers selling to retailers. We recognise this, and it's why we put vast amounts of time and thought into LFHP Zero.
In the future, we believe that because of the terrible recycling rates that are currently being achieved by public services, the only way forward is to force producers to take account for their own materials and where they end up.
If producers started getting fines per every kilo of their products ending up in the natural environment, it wouldn't be a great shock to see multinational companies suddenly investing huge amounts of capital and time into cleaning their own mess up.
If you would like to read more about biodegradable plastics and the data behind plastic pollution, feel free to subscribe to our email list at the bottom of the page.