Man, I love this issue.
Wading in the surf should be enough to make you wonder about water conditions.
I'm on a septic system where I live and I often think about what happens when I flush. Folks in other areas can't or won't be concerned with it.
Some of the local fish have even been given colorful nicknames due to their close proximity to sewage.
It's always been a simple solution to flush the toilet and imagine it just dissappears. If you spend any time on the ocean, it becomes pretty clear where that tainted water goes.
I don't want to become too Mother-earthy, but I've been looking at ways to keep the matter individual and not political.
For example, composting and incinerating toilets are an idea. Sure, it's an inconvenience, but if one person stops adding to the waste burden, that's a step in the right direction.