Hi YEG, Buzz here. When i've seen fuel dumping, the fuel atomizes , well it sure disspates shortly after leaving the airplane. I haven't seen a jet fuel slick from low altitude dumps.
Let's see, 737's and 757's and A320's don't dump fuel, they land overweight (hopefully gently) and then guys like me do an overweight landing inspection.
Some towns might get touchy about the jet fuel dump issue, but then i'll let the office workers in Chicago deal with that. I'm the kind who belives in a certain kind of noise abatement: the sound of an airplane crashing.
Buzz Fuselsausage: Line Mechanic by night, DC-3 crew chief by choice. g'nite