However Japanese authorities have confirmed to the IAEA that they began to discharge 11,500 tonnes of low level radioactive water into the sea on 4 April. The operation is being conducted to create storage capacity for highly radioactive water pooled in parts of the reactor facility, hindering efforts to restore electrical power from the grid to the facility.
Japanese officials reported they plan to release 10,000 tonnes of water from a waste treatment facility and 1,500 tonnes from drainage pits around reactor Units 5 and 6. The operation is expected to last no more than five days.
Yesterday Japan also announced setting seafood radioactivity limits. The introduction of permitted level of radioactive iodine in seafood followed leaks of radioactive products into the Pacific Ocean.
Chief Cabinet Secretary Yukio Edano told a press conference – Japan Ministry of Health set the limit of permitted level of radioactive iodine in seafood and vegetables at 2,000 bequerels per kilogram.
Concern over the safety of seafood is growing as Tokyo Electric Power Co. announced dumping radioactive water into the sea to make room for highly contaminated water at the complex.
The decision to set radiation limits by Japanese authorities, followed the detection of radioactive iodine measured at 4,080 bequerels per kilogram in fish caught Friday off Kitaibaraki, Ibaraki.
Other young fish caught near Kitaibaraki found to have radioactive cesium at 526 bequerels per kilogram exceeding the legal limit of 500 bequerels.
Cabinet Chief Secretary Yukio Edano is said to denied a ban on marine products shipments from affected areas was needed. He promised tough inspections will ensure contaminated products will not reach markets.
But what are accepted levels of radioactivity in air, water and food?
Measuring radiation: 1 Becquerel = 1 disintegrations of particles / per second / per square meter
Measuring Cellular damage: 1 millisievert (mSm) = 100 Millirem (mR)
Effects of Radiation Levels on the Human Body
|5-20||Possible late effects; possible chromosomal damage.|
|20-100||Temporary reduction in white blood cells.|
|100-200||Mild radiation sickness within a few hours: vomiting, diarrhea, fatigue; reduction in resistance to infection.|
|200-300||Serious radiation sickness effects as in 100-200 rem and hemorrhage; exposure is a Lethal Dose to 10-35% of the population after 30 days (LD 10-35/30).|
|300-400||Serious radiation sickness; also marrow and intestine destruction; LD 50-70/30.|
|400-1000||Acute illness, early death; LD 60-95/30.|
|1000-5000||Acute illness, early death in days; LD 100/10.|
|Source: Nuclear Arms Race: Craig and Jungerman, 1990|
The IAEA website advices “Basic approaches to radiation protection are consistent all over the world. The ICRP recommends that any exposure above the natural background radiation should be kept as low as reasonably achievable, but below the individual dose limits. The individual dose limit for radiation workers averaged over 5 years is 100 mSv, and for members of the general public, is 1 mSv per year. These dose limits have been established based on a prudent approach by assuming that there is no threshold dose below which there would be no effect. It means that any additional dose will cause a proportional increase in the chance of a health effect. This relationship has not yet been established in the low dose range where the dose limits have been set.”
However CBS News which covered the topic of radiation advises us today that background radiation is 3 mSv a year and diverts our attention with statements like: “Getting the right dose of radiation” – CT scans regularly used, they say – exposes us to 3 to 10 mSv per scan and since this is administered by doctors in hospitals we should not worry ourselves about it too much…
I should think any radiations is undesirable. But then again what do I know…
Radioactive tap water has now been detected in the US, Richland, Washington and Boise, Idaho. according to ktvb.com Jonathan Edwards, Director of Radiation Protection Division with the EPA said: “These levels are very, very low, trace, minuscule amounts” The EPA claim they know the radiation came from the Fukushima nuclear plant because iodine-131 is not typically in the environment and it has a short half-life of eight days. The EPA insist no health risk exist.
INES – The international nuclear and radiological event scale
IAEA publishes a Fukushima Nuclear Accident Update Log where they write “Overall, the situation at the Fukushima Daiichi plant remains very serious.”
But how serious is very serious? A new analysis prepared for Greenpeace Germany, by nuclear safety expert Dr Helmut Hirsch, shows that by March 23 2011 Japan’s nuclear crisis has already released enough radioactivity to be ranked at Level 7 on the International Nuclear Event Scale (INES). This is the scale’s highest level, and equal to the 1986 Chernobyl nuclear disaster. INES – The international nuclear and radiological event scale
IAEA are also monitoring radiation in Japan and publish data collected on a daily basis
‘Radiation Map Tracker’ app
Black Cat System A software developer is offering a iPhone app ‘Radiation Map Tracker’ which monitors a network of radiation detectors, updating the readings every few minutes. A map of the world, with a number of circles indicates the location of sensors. You can scroll and zoom in and out to see the various site. The App requires access to the internet.