Not if it's from lakes in Gunma!
Seriously, though, I really hope that's right. I'm not into scaremongering. People in Japan have enough problems. However, even in fairly optimistic pieces such as this, you have the final two paragraphs:
"The authors use a computer model of the local currents to figure out how much radioactivity must have been discharged to produce the pattern they see. The answer turns out to be on the high side of estimates (22 PetaBecquerels), indicating that the direct discharge was a significant route for contamination, accounting for about two-thirds of the total radioactivity release.
Nevertheless, the isotopes that landed on the ground have stayed there, creating a serious contamination problem that may take years to resolve. Although the seas in the immediate vicinity of Fukushima probably experienced a very high dose of radioactivity during the months immediately after the disaster, as long as none of the isotopes accumulate in any organisms, the effects are unlikely to be long-lasting.
This is the piece that reminded me that the problem is still really bad: