The operator of the damaged Fukushima nuclear power plant has confirmed that an underground wall is unable to keep contaminated groundwater from seeping into the sea. Officials of the Industry Ministry estimate that 300 tons of groundwater pass through the contaminated area before flowing into the Pacific Ocean every day. Engineers with Tokyo Electric Power Company have hardened the soil along the coast to create a 100-meter-long underground wall, NHK World reported today. They injected chemicals into the ground to a depth of 16 meters. But it is technically difficult to harden the soil up to 1.8 meters from the surface. The workers recently dug a well just inside the wall to see how the level of underground water has risen due to the construction of the wall. They found that the water level in the well was about 60 centimeters higher than the top of the wall. The operator began pumping up contaminated groundwater on Friday, as a temporary measure to lower the water level.