People are becoming increasingly aware of the problem with plastic. Increasingly, alternative plastic products are sought to solve these problems. Biodegradable plastic is often espoused as a greener alternative to other plastic products. But what is biodegradable plastic? And is it really a great solution?
Plastics are usually made from finite and polluting fossil fuels. And yet more fossil fuels are used for the energy required for manufacture. The plastic industry is responsible for high emissions of greenhouse gases, and often uses a lot of fresh water too. But the problems don’t end there. Most plastic products also pose a problem at the end of their useful life. They persist in the environment for a very long time before they break down. This means that they pose a threat to our planet’s ecosystems and its wildlife – and even to human health. Only a small proportion of plastics can actually be recycled. And even those which can be recycled often are not.
What is Biodegradable Plastic?
Biodegradable plastic is plastic which, unlike traditional plastic polymers, will degrade (break down) over time. Those plastics are broken down through mainly bacteria, the agency of living organisms. There are two types of biodegradable plastic: Bioplastics – plastics made from renewable raw materials, and Biodegradable synthetic polymers. (These are plastics made from petrochemicals which contain biodegradable additives which enhance bio-degradation.)
It is necessary to understand that not all biodegradable plastics were created equal. Certain bioplastics break down completely into natural, harmless materials and can be almost carbon neutral. But others are not so beneficial for people and our planet as they may at first appear. Remember, just because something is biodegradable, that does not automatically make it an eco-friendly material.
The pros and cons of biodegradable plastic will depend on whether we are taking about bioplastics or biodegradable synthetic polymers. Bioplastics are generally a better option that biodegradable synthetic polymers. The latter category will often biodegrade to a degree, but still leave behind toxic substances that can harm our environments.
But even bioplastics are not all ideal. It is nessasy to focus to the processes of biodegradable plastic creation and the energy, land and water use that they involve, before deciding whether or not it is a viable, sustainable alternative.
Alternative Plastics That Are Compostable as Well as Biodegradable.
Many people get confused between the terms ‘biodegradable’ as well as ‘compostable’ plastic. A biodegradable plastic like material will break down, but only the compostable material will go though a process that breaks a material down into compost, or humus – leaving only natural, harmless materials behind.
Certain alternative plastics labelled as biodegradable will not decompose in a traditional aerobic home composting system (an oxygenated environment). PLA, for example, is a popular biodegradable plastic. But it will only decompose when composted in a special facility where very specific composting conditions can be provided. It will not readily biodegrade in a home composting system.
Under the right conditions, however, certain bioplastics can be metabolised by micro-organisms entirely, reduced to just carbon dioxide and water. They are therefore compostable as well as biodegradable. Starch based bioplastics are a example of this. They are fully compostable at home.
Care must be therefore be taken over the term ‘biodegradable plastic’. Certain bioplastics made with natural materials from sustainable farming can be an excellent environmentally friendly choice. However, these are only ever likely to be a partial solution, at best, to the problem of plastic.