Set the parallelism level for all collections in Scala 2.10?

Question

I understand how to set the parallelism level for a single parallel collection, via the mutable tasksupport field (c.f. https://stackoverflow.com/a/5425354/82970).

How can I set the parallelism level for all new parallel collections in Scala 2.10?

A subsidiary question --- is the tasksupport associated to a parallel collection 'inherited' by new parallel collections built out of it? (e.g. with take, map, etc.)