Minute amounts of radioactive strontium have been detected in soil at 11 locations in Fukushima prefecture, including the city of Fukushima located 62 kilometers from the crippled Daiichi nuclear power plant, according to the science ministry.
The Nuclear Safety Commission said they are unlikely to pose an immediate threat to human health but warned people about the intake of radioactive strontium into their bodies.
According to the Government 54 becquerels of strontium 89 per kilogram were detected in soil collected in the city of Fukushima on April 27.
The highest amount, 1,500 becquerels of strontium, was detected in soil collected on May 6 in the town of Namie located 24 km northwest of the nuclear plant, which was severely damaged by the March 11 earthquake and tsunami.
The ministry also detected 1,000 becquerels of strontium in the village of Iitate, 220 becquerels in the town of Kawamata and 30 becquerels in the town of Hirono
The commission said it will investigate to see if the strontium has been released into the air from the soil.
Strontium tends to accumulate in bones and is believed to cause bone cancer and leukemia.
The ministry was investigating samples of soil collected in the prefecture from March 21 through May 6.