Bioplastics are often being touted as eco-friendly, but do they live up to the hype?
The world has produced over nine billion tons of plastic since the 1950s. 165 million tons of it have trashed our ocean, with almost 9 million more tons entering the oceans each year. Since only about 9 percent of plastic gets recycled, much of the rest pollutes the environment or sits in landfills, where it can take up to 500 years to decompose while leaching toxic chemicals into the ground.
Traditional plastic is made from petroleum-based raw materials. Some say bioplastics—made from 20 percent or more of renewable materials—could be the solution to plastic pollution. The often-cited advantages of bioplastic are reduced use of fossil fuel resources, a smaller carbon footprint, and faster decomposition. Bioplastic is also less toxic and does not contain bisphenol A (BPA), a hormone disrupter that is often found in traditional plastics.
Kartik Chandran, a professor in the Earth and Environmental Engineering Department at Columbia University who is working on bioplastics, believes that compared to traditional plastics, “bioplastics are a significant improvement.”
How Biodegradable are Bioplastics?
- Since there is often confusion when talking about bioplastics, let’s clarify some terms first.
- Degradable – All plastic is degradable, even traditional plastic, but just because it can be broken down into tiny fragments or powder does not mean the materials will ever return to nature. Some additives to traditional plastics make them degrade more quickly. Photodegradable plastic breaks down more readily in sunlight; oxo-degradable plastic disintegrates more quickly when exposed to heat and light.
- Biodegradable – Biodegradable plastic can be broken down completely into water, carbon dioxide and compost by microorganisms under the right conditions. “Biodegradable” implies that the decomposition happens in weeks to months. Bioplastics that don’t biodegrade that quickly are called “durable,” and some bioplastics made from biomass that cannot easily be broken down by microorganisms are considered non-biodegradable.
- Compostable – Compostable plastic will biodegrade in a compost site. Microorganisms break it down into carbon dioxide, water, inorganic compounds and biomass at the same rate as other organic materials in the compost pile, leaving no toxic residue.
