A detectable amount is not necessarily a dangerous amount. While minuscule amounts may not be good, they does not mean they should cause excessive worry.
"Repercussions of Japan's triple disaster came into clearer focus Monday after the World Bank said the earthquake and tsunami caused up to $235 billion in damage and health officials reported more cases of radiation-tainted vegetables and tap water.
The announcement by Japan's Health Ministry late Sunday that tests had detected excess amounts of radioactive elements on canola and chrysanthemum greens marked a low moment in a day that had been peppered with bits of positive news: First, a teenager and his grandmother were found alive nine days after being trapped in their earthquake-shattered home. Then, the operator of the overheated nuclear plant said two of the six reactor units were safely cooled down."