10) Fish pee in it.
9) Things die in it.
8) Jellyfish
7) Shipwrecks
6) Corpses, the results of shipwrecks
5) Seaweed
4) People puke/pee/poop in it
3) Sharks
2) Companies and power plants dump chemical waste into it
and.....
1) All of the above can make you violently ill
