A worker points to a pit near the Fukushima No. 1 Nuclear Power Plant's No. 2 reactor from which radioactive water leaked into the Pacific Ocean. Photo courtesy of TEPCO

TOKYO, April 15 (Kyodo) — The total level of radioactive materials in water dumped in the sea from the crippled nuclear power plant in Fukushima Prefecture earlier this month was lower than previously estimated, the nuclear safety agency said Friday. But the Nuclear and Industrial Safety Agency instructed the operator of the plant, Tokyo Electric Power Co., to study in more detail the impact on the marine environment of the move, which sparked concern among neighboring countries. … According to the safety agency, TEPCO released 10,393 tons of water (2,795,717 U.S. gallons) containing a total of 150 billion becquerels of radioactive materials from the plant into the Pacific Ocean between April 4 and 10. The operator, which earlier projected that the readings could reach 170 billion becquerels, said it had not detected any substantial changes in the levels of radioactive materials in seawater sampled off the plant’s shore and farther offshore since the release. The release of contaminated water sparked concern among China, South Korea and Russia over the possible impact on marine life and the environment, with Seoul complaining that it had not been notified in advance. … TEPCO threw three sandbags each containing 100 kilograms of zeolite, a mineral that absorbs radioactive materials, into the sea near the plant on Friday to reduce the levels of contamination. … The agency also said the top level of water in the vertical part of a tunnel connected to the No. 2 reactor had risen back Friday morning even though the utility pumped out around 660 tons of highly radioactive water from the tunnel. Removing the highly contaminated water that has flooded the basements of the Nos. 1 to 3 reactor turbine buildings and adjacent tunnels is seen as key to restoring critical cooling systems for the damaged reactors, which were lost in last month’s disasters. …

Radioactivity in water dumped from Fukushima plant lower than thought