polystyrene peanuts

Just been talking to a friend who has bought a huge bag of what is claimed to be bio-degradable polystyrene peanuts which he is going to use in his sowing/potting compost. I've never come across these wondering if anyone knows about or uses them.

Do you have any more information about the ones your friend has bought ?  Are they these ? (scroll down a bit):

http://en.wikipedia.org/wiki/Foam_peanut

If they are then he may have been "had".  They are packing pieces made of starch that are used instead of polystyrene.  When they get wet the dissolve down to nothing and the residue is digested microbes.

http://www.starchtech.com/faqs/faq-dispose-of-packing-peanuts.html

and this:

http://www.livescience.com/21274-mushrooms-replace-plastics-nsf-bts.html

I just checked and they are the ones Aunt Sally's link led to- made from starch. £10 for 5 cubic feet that will dissolve in water, pity he didn't ask first!