generally speeking, urine is sterile unless you have a bladder infection so i would try not to worry. and if there is infected urine in the pool it would be pretty well instantly disinfected by the chlorine or other sterilizing methods that are more than likely required by law.
you shouldn't be worried about it. i pee in the lakes around here but thats a much bigger volume of water than a pool and much less people. also theres fish in the lakes to so your swimming in fish and bird scat anyways. oceans just filthy period but i swim in that to.
I stay out of the ocean, for a number of reasons! 
sharks are more likely to be cuious about you than to eat you. if i remember correctly shark attacks on humans are mostly surfers due to the fact there outline on the surface is like a seal with the board. also if your swimming in the beaches or bays here your not going to go deep enough to get eaten by a shark. besides. theres no dangerous sharks up where i live. the only kind we have is a smaller one that does not eat humans... prefers smaller stuff not to mention it stays in deep watters so you will only ever see them scuba diving.
Poll