Radiation in Seawater near Fukushima

Radiation levels in seawater near the Fukushima reactor are still 1,550 times higher than the legal limit. TEPCO published data that the I-131 radiation south of reactors 1-4 was 62 Bq/cm3 on April 15, 2011. The legal limit is 0.04 Bq/cm3. 

Perhaps more troubling, TEPCO published data that the CS-134 and CS-137 radiation levels in seawater are 56 and 57 Bq/cm3 respectively. 

While I-131 has a half life of 8 days, CS-134 has a half life of 2 years and CS-137 has a half life of 30 years. The CS-137 radiation will be affecting life in the ocean for at least 600 years. 

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110415e8.pdf

I-131 radiation levels in the seawater near the Fukushima reactor peaked at 1,300 Bq/cm3 on April 8, 2011. That is 32,500 times the legal limit. 

TEPCO announced that they are now planning to take steps to address this by dumping a mineral into the ocean that has the effect of absorbing radiation. 

The Japanese operator of a stricken nuclear plant said Saturday it has started dumping a mineral into the sea that absorbs radioactive substances, aiming to slow down contamination of the ocean.

Tokyo Electric Power Co. (TEPCO) said it had begun dropping zeolite near a water outlet from the Fukushima Daiichi plant -- which has been leaking radiation since it was crippled by a March 11 quake and tsunami -- from Friday.

The mineral has wide-ranging industrial applications, including nuclear waste processing.

Officials hope it will help to reduce the spread of radioactive materials from the plant into the Pacific, though the effectiveness of the measure was not yet clear.