Likely Japan Produce Problems for 3 decades

http://www.automatedtrader.net/real-time-news/72472/japan-update-tokyo-tap-water-radiation-upsmoke-at-no-3
Around the Fukushima Daiichi plant itself and in the surrounding four prefectures radiation levels are reporting lowering somewhat.
Warnings about consumption of produce grown in the generating plant area may be in place for some time, an expert on NHK TV said, given that cesium-137 remains present in the soil for three decades.end quote.

So, vigilance not only by the Japanese public but also vigilance by people who import any Japanese food grown or processed in Japan is likely to be an ongoing problem at the very least for 30 years or more.

next quote from same article:

With nightfall, it has become more difficult to determine the color of the smoke coming from reactor No. 3, the most dangerous of the six since it is the only one containing plutonium. Authorities earlier said they have been unable to find the cause of what was black smoke and as a precaution evacuated plant workers for a time.
The smoke later turned white and radiation levels have not worsened. Sixty more tons of water was sprayed on No. 3 in the past 24 hours.