text: what does non-biodgredable plastic? explain.? plastic are non-biodgredable. explain what this mean, the problems this causes and other ways we can deal with plastic waste? it means it does not rot down into anything that can become incorporated back into the environment. this means that many plastics end up in landfill and may sit there for thousands of years.   recycled plastic is starting to be used in all kinds of products - anything from fence posts (where lack of rotting is a good thing) to kitchen worktops.