Types of plastic
This page goes more deeply into all the different types of plastic that exist.
The Plastic Soup Foundation believes that we should always look critically at which potential uses of biodegradable plastics are desirable and which are not.
Bioplastics and biodegradable plastics
Organic vegetables and fruit in supermarkets are often packaged in biodegradable plastic. Plant pots and magazine wrappers are also often biodegradable. The logo of a sprouting leaf on the packaging shows that this plastic is compostable. The definition of the logo is that the material should disappear completely within seven weeks in an industrial composting unit which runs at up to 65 degrees Celsius. The material is broken down into natural resources by bacteria. But if you add this biodegradable plastic to your own compost, the natural biodegrading process can take two years.
The term bioplastic is used for plastic that partly consists of natural materials such as sugar cane or starch. This means that these bioplastics ultimately have the same characteristics as regular plastic and, despite their name, are not biodegradable.
Biodegradable plastic – so not bioplastic – that can be put into the vegetable/fruit/garden bin for collection can also be put in the compost. If biodegradable plastics are mixed with conventional oil-based plastics, they will negatively affect the quality of recycled plastic.
Composting at sea – is that possible?
The conditions required at sea for ‘composting’ barely exist. The temperature is lower so no heating takes place, and there are no bacteria of the type needed to break down the plastic. This means that the animals that swallow the biodegradable plastics or get entangled in them face the same fate as they would with ordinary plastics. Simply put, the breaking down process in animals’ stomachs takes so long that they do not have a higher chance of survival swallowing biodegradable plastic as they would ordinary plastic. This has been proven by research into sea turtles.
Sea turtles are the victims
While manufacturers assume that biodegradable plastic bags are 100% compostable in industrial composting units within 49 days, it appears that if these bags remain in the stomachs and intestines of sea turtles for 49 days, they would only disintegrate by between three and nine percent. Ordinary plastic bags even remain completely intact. The researchers then concluded that, while the speed of breaking down of biodegradable polymers may be higher than ordinary plastic bags in the stomach and intestines of sea turtles, it is still not fast enough to prevent the animals dying from ingesting plastic. Sea turtles unfortunately do not see the difference between a jellyfish and a plastic bag floating in the sea, whatever it is made of.
Click here (pdf) for the sea turtle research.
Be critical about packaging
The Plastic Soup Foundation believes that we should always look critically at which potential uses of biodegradable plastics are desirable and which are not. Some uses are preferable, such as making fishing nets from biodegradable plastic instead of from nylon or plastic as they will eventually break down. They are also heavier and will therefore sink to the seabed more quickly.
Much packaging is completely unnecessary. Why should vegetables and fruit that have a natural protective layer such as pumpkins and bananas still need to be wrapped in plastic? Even packaging them using biodegradable materials is redundant.
There is much confusion about biodegradable plastic and bioplastics. For example, Coca Cola’s Plant Bottle is presented as sustainable because 30 percent of its components are natural resources (sugar cane). The production of the bottles may need less energy, but the bottles themselves are not biodegradable. Another objection is that the resources used to produce bioplastics could also be used for food instead and the clearing of land to make room for plantations for the bioplastics industry could lead to further deforestation.