Tokyo - High levels of radioactive materials were detected in sediment in rivers near a crippled Japanese nuclear power plant, local government officials said Tuesday.
Of the 72 rivers in the Fukushima prefecture, radiation levels of more than 10,000 becquerels per kilogram were found in seven rivers, a survey showed.
Up to 54,500 becquerels per kilogram of radioactive substances were found in Maeda River in Futaba town, located 2 kilometres from the Fukushima Daiichi complex.
A level of 10,000 becquerels is considered the safe limit for radiation in drinking water, according to the World Health Organization.
The survey covered river sediment only, and the readings did not indicate possible risks for the safety of agricultural produce.
The central government is not required to conduct decontamination work in rivers, as they are not residential areas.
The survey was conducted by the Fukushima prefecture in January and February.