The Nuclear Regulation Authority said Wednesday that it is “strongly suspected” that highly radioactive water at the Fukushima Daiichi nuclear power plant is seeping into the ground and contaminating the Pacific Ocean, (Kyodo) Japan’s News Agency reported. “We must find the cause of the contamination…and put the highest priority on implementing countermeasures,” NRA Chairman Shunichi Tanaka told a meeting of its commissioners after they had studied recent surveys on the radiation level of groundwater at the plant, which has shown radioactive substances such as cesium and tritium existing in high density. Plant operator Tokyo Electric Power Co. believes the source of contamination to be a pit from which highly radioactive water was found seeping into the sea in April 2011, shortly after the nuclear crisis began at the plant, but the NRA said that toxic water in the area may not be the only cause.