Radiation dose higher than 1000 mSv was measured at the surface of water ac ulated
on the basement of Unit 2 turbine building and in the tunnel for laying piping outside the building
on Mar. 27th.
Plutonium was detected from the soil sampled at Fukushima Dai-ichi NPS site on Mar. 21st, 22nd, 25th and 28th.
The amount is so small that the Pu is not harmful to human body.
Radioactive materials exceeding the regulatory limit have been detected from seawater sample collected in the sea surrounding the Fukushima Dai-ichi NPS since Mar. 21st.
On Apr. 5th, 7.5 million times the legal limit of radioactive iodine, I-131, was detected from the seawater, which had been sampled near the water intake of Unit 2 on Apr. 2nd.
It was found
on Apr. 2nd that there was highly radioactive (more than 1000mSv/hr) water in the concrete pit housing electrical cables and this water was leaking into the sea through cracks on the concrete wall. It was confirmed on Apr. 6th that the leakage of water stopped after injecting a hardening agent into holes drilled around the pit.
Release of some 10,000 tons of low level radioactive wastewater into the sea began on Apr. 4th, in order to make room for the highly radioactive water mentioned above.
Regarding the influence of the low level radioactive waste release, TEPCO evaluated that
eating fish and seaweed caught near the plant every day for a year would add some 25% of the dose that the general pubic receive from the environment for a year.