Recent findings have shown high levels of radioactive contamination in Japan, particularly in the eastern and north-eastern areas, whereas the western parts have been sheltered by mountain ranges.
The results of the new research have been documented in the Proceedings of National Academy of Sciences (PNAS) journal.
As per the reports, large concentrates of radioactive cesium-137 (137Cs) have been found in the area due to the emission from the Fukushima Daiichi Nuclear Power Plant (NPP) following the massive quake on March 11, 2011.
This poses an urgent issue due to the hazardous effect of the radioactive material on agriculture and stock farming and, thus, on human life.
The researchers mentioned that this outcome is already identified in the country where there has been continuous and regular monitoring of food products.
As per the study, the soils around Fukushima NPP and neighboring prefectures have been extensively contaminated with depositions of more than 100,000 and 10,000 MBq km-2, respectively.
The BBC reported that under Japanese Food Sanitation Law, 5,000 becquerel per kg (Bq/kg) of cesium is considered the safe limit in soil (cesium-137 makes up about half of total radioactive cesium). The researchers estimate that cesium-137 levels close to the nuclear plant were eight times the safety limit, while neighboring regions were just under this limit.