Ick!
With all that said...a whale tank with a dam good saltwater filtration system should be the least of your worries. The trainers are healthier and in a lot better shape than most of us are. Get over it, enjoy life and get a little wet.
By the way, lets not forget about those who want to go to Discovery Cove or those who have been there...Guess what...the were swimming in a "tank" with EWWWWW...dolphin and fish poo too.......like I said, GET OVER IT!
Cold salt water laden with fish oil (and who knows what else - you know what fish do in water)...not my idea of a fun time!