Although an American article the sentiment is the same for UK farmers. Seed stewardship is as important as the disposal of all pesticides.
As we are well aware the more pesticides that are thought to be polluting the environment; the greater the risk that they will be banned.
http://m.agrinews-pubs.com/mobile/articles/default.aspx?title=Official+emphasizes+importance+of+proper+treated+seed+disposal&id=4812&sid=50