I've heard that it takes 500 years to break down styrofoam?

Question

Has anyone actually done a study or did they just pick a random number? Does anyone know? If you do, please try and link some actual research. Thanks!

Answer 1

Perhaps someone else can find more details, but it's a rough estimate.  It does degrade very slowly.  In a landfill, without exposure to oxygen or other composting mechanisms, it could well last a lot longer.  But some bacteria can do it quickly, see the reference.  It can be recycled, but recyclers don't like it because of its bulk.  That doesn't mean it should be banned, especially not before proposed alternatives are demonstrated to be environmentally superior.

Answer 2

Styrofoam is made of polystyrene. This plastic is composed entirely of carbon atoms and hydrogen atoms.

The structure is fairly stable but will degrade with time.

I've used potting soil purchased at a hardware store that had Styrofoam bits intentionally mixed with it and after two years the bits had completely disappeared.