Does it feel like everything is “biodegradable” these days?
Maybe it’s because the term reached an all-time level of popularity last summer, according to Google Trends. Meanwhile, its more humble cousin, the term “compostable”, hasn’t seen much uptake in the last five years.
So what’s the difference between “biodegradable” and “compostable”? Both biodegradable and compostable products can be broken down by naturally-occurring microorganisms such as bacteria, fungi, and algae.
The real difference comes from how well, how quickly and without harm to the environment a material will break down:
The term biodegradable is heavily misused and leads the average consumer to believe that the product will degrade in a timely manner after disposal. However, biodegradation may take many years and depends on where the product is disposed of. Since everything will eventually biodegrade, even if it takes hundreds of years, it becomes meaningless to say a product is biodegradable, unless it biodegrades in the normal disposal environment in a timely manner.
Even something as simple as a newspaper may not fully biodegrade in a landfill - rolled up newspapers have been found intact after several decades in the landfill. Since it can take hundreds of years for something to biodegrade, products which are marketed as biodegradable do not solve the problems of litter unless they take into consideration the disposal environment and the time for biodegradation. They may also contain toxic chemicals, which are released and enter our soil and waterways as the product degrades.
On the other hand, a compostable product needs to biodegrade within 180 days in a composting system and leave no toxicity in the soil. Any compostable product is biodegradable, but a biodegradable product may not be compostable, since it may not biodegrade within 180 days. Unfortunately, the term “biodegradable” has been heavily misused on product labels, leading to greenwashing, consumer confusion, and contamination at composting facilities.
Oxo-biodegradable is a term for petroleum-based plastics with small amounts of heavy metals or other catalysts. The metals speed up the decomposition process, but the material only breaks down into small pieces that turn into microplastics. Studies have not been able to show that it can fully decompose into biomass, carbon dioxide and water within a reasonable time frame.
Municipalities across the country are starting to take a stand on which terms can be used on packaging. In fact, the State of California has restricted the use of the terms “biodegradable,” “degradable,” or “oxo-degradable,” and similar terms.