Sunny,
Depends on the type of foam. A lot of foams are protein based and make excellent biodegradable fertilizer. AFFF is another matter.
I believe the chemicals are ones that date back to the 70's. They have contaminated multiple sites at each airport due to the various locations that fire fighting practise facilities have been shuffled around the airports over the decades.
I think the time for a Junior Minister for Aviation is long overdue. Minister farm boy is out of his league and depth, and the issues keep growing and growing and growing - just like the depth of a politicians trough!