For something to be considered biodegradable it must completely break down and return to nature in a reasonably short time. The difference between biodegradable and compostable items is that when the latter breaks down it turns into compost, which can provide valuable nutrients to the soil. Different materials take different periods of time to biodegrade. Paper could take 2 to 5 weeks while plastic might take 5 years. Or even 100 years! There is now an array of biodegradable plastics on the market, including PLA. But not all bio-based plastics biodegrade. Just because something is biodegradable doesn’t mean it’s good. Some things that break down are hazardous.