In article , Huge wrote:
(dmc) writes:

Had a couple full of gravel at the bottom of the garden for a few years.
Both have gone very brittle - the one I attempted to empty and move just
crumbled.

That's not biodegrading. The UV in the sunlight has destroyed them.

Hmm. Good point. They had turned to dust though. Nasty poisonous dust
maybe

What actually has to happen to something in order for it to have "biodegraded"?
Break down into component chemicals?

Darren