The Ministry of Agriculture, Forestry and Fisheries has embarked on the mammoth task of measuring radiation levels of all forest areas in Fukushima Prefecture, sources said.
The Ministry of Agriculture, Forestry and Fisheries has embarked on the mammoth task of measuring radiation levels of all forest areas in Fukushima Prefecture, sources said.
The area in question covers 970,000 hectares, or 70 percent of the prefecture's land area.
Until now, the focus has been on specifying residential areas and roads to be decontaminated. Decontaminating forest areas will likely be far more difficult.
Radiation maps on soil contamination released and updated by the science ministry since early May were created on the basis of data collected by aerial surveys.
But the new measurements by the forestry ministry focus on identifying concentration levels of radioactive cesium in the soil and airborne radiation levels.
The investigation, which started in late September, covers 400 locations in the prefecture. Measurements are being taken for each 4-kilometer-square within an 80-kilometer radius of the stricken Fukushima No. 1 nuclear power plant, and for each 10-kilometer-square beyond an 80-kilometer radius of the facility.
The airborne radiation levels are assessed 1 meter above the ground surface, while soil contamination levels are measured by collecting topsoil up to 5 centimeters deep.
The soil will be sent to the Kyushu Environmental Evaluation Association, a Fukuoka-based research foundation, for analysis.
The results will be released in map format by the end of February.
The central government, complying with basic guidelines for urgent decontamination established in late August, outlined steps to remove fallen leaves from within 20 meters of the edges of forests close to residential areas.
However, the government has not come up with any plans to decontaminate all forest areas in the prefecture.
One reason for this is that it would involve a huge amount of soil for disposal.
The forestry ministry will use data from the on-site investigation to determine areas in need of decontamination and set priorities on areas where work must be carried out.