The company said the radioactivity levels are within the range of normal variation, The Japan Times reported. It said its scientists are unsure if the radiation is linked to leakage from the plant.
Tepco and the Japanese government are also trying to deal with groundwater buildup in the plant, Kyodo News Service reported. The company has constructed storage tanks, and a government committee is reviewing a plan to build wells around the plant to stop groundwater flow.
About 400 tons of water leak in every day.