A consensus opinion seems to be 10,000 bpd. I put no credence in the "estimates" by NPR and others. They have no data to work from. BP and the Coast Guard do.
"Oh? What chemicals does fractionation result in?"
Uh, the same ones that came out of the well. All "fractionation" does is more or less separate them somewhat by density. However, the more fractionation and dispersion that happens, the less toxic the oil is, and the easier it is for the naturally-occurring bacteria who can metabolize it to do so.
Not quite.
The concensus keeps rising - as more if found beneath the surface. A third large plume was found yesterday - six miles wide from the surface down to the floor.
Moving beneath the surface it is harder to contain and collect. There is a great deal of life in this zone.