Hi RebbecaJane,
I paddle in the river from the Jindalee boat ramp. Always head into the current so you have a shorter easier paddle back if something goes wrong/wind gets up.
There is a creek straight across, if the boat traffic gets bad.
Yes it's dirty but it sure beats driving for 50min each way to clean water.
Where in Brisbane are you? I'm wanting some paddling buddies for the river.
PM me if you want a casual easy paddle.
As far as bull sharks go, they only nibble you in the brisbane river.
Down the gold coast they actually kill you!!
However I did get a dead leg from a kamikaze mullet.