Chemicals, waste, untreated water, fertilizers, other stuff that gets dumped into rivers and oceans,... It all ends up in there. It's not just this.
Fukushima does concern me as I live in Tokyo but it doesn't worry me that much. We all get exposed to natural and minimum levels of man-made radiation levels everyday. Our bodies have ways to deal with it. People expose themselves to high levels of radiation everyday: x-rays or taking an airplane. Etc...
Don't get me wrong, there is a real risk with the plant in Fukushima and it's lie to believe everything is under control.
But I feel the most sympathy for the people living in Fukushima prefecture as they get much higher levels of exposure with no or little (financial) way of escaping as no one will help them.
My point is: pollution and radiation is everywhere. Get informed, live a healthy life, help support our environment and don't get stressed. I think smoking and obesity will kill people in developed countries more likely then this crisis. Have a look at those numbers.
Now excuse me while I finish my sushi.