Japan Nuclear Crises: Radioactive Traces in Air, Food and Water. Potential Risks
By Mirna Santana
March 22, 2011. The World Health Organization (WHO) has recommended that the evacuation zone expand to 80 KM. Traces of radioactive compounds have been found in Tokyo's water as well as in the ocean water--and even in various US states (EPA). The latter was expected since water is being transported from the ocean to the plants risking contamination. Particles also travel through air and fall to the ocean. Food and milk in the closer perimeter 0-30Km from the plant has been found to contain radioactive traces.Outside that area water and some crops also shown higher readings of radioactive elements.
The Government of Japan has distributed iodine pills and also informed people to avoid drinking milk and eating potentially contaminated crops. The government also banned food from the area nearby the nuclear plants from being distributed to outside regions. Tokyo Electric Co.is willing to offer compensation to farmers. A Japanese scientist --suggested that Japanese people will not eat contaminated food. However, given the scarcity of testing and the low in food supplies in some areas, along with an increase number of homeless people-- and increase poverty levels-- it is expected that some people, specially in the disaster areas may override precautionary measures.
Water: According to the Japanese ministry of health, the levels of radiactive elements have been fluctuating. They are testing twice a day in Tokyo. On March 22, 2011--77 Becquerel per kilogram, reading for radioactive iodine-131 in water was the highest level reported (Tochigi Prefecture). Tokyo's reading was reported as low. On March 23, 2011- the public in Tokyo was informed that trace levels of radioactive elements were 2folds higher than those considered safe for infants ( Infant safe level is 100 beq). Later on the same day the government reported that water in Tokyo was around 77 beq thus safe. In theory human adults can intake as much as 300 beq.
I wonder if Tokyo's supply has a big input from underground water sources-- as to decrease the radiactive levels so fast, as the report stated. If there are chelating agents in Tokyo's water that can bind the radioactive elements, that would be fantastic news. Otherwise, with a continue input of particles falling from the air through rain or as dust particles the readings will be unstable/unsafe. Unfortunately, water supply from sources other than tap water are now scarce.
It is possible that water companies may speculate to benefit from the high demand. But lets hope that this will not be the case. Bottled water is less regulated than tap water (and companies are privately owned). There are cases in the US and elsewhere were bottled water has been found to be tap water placed in bottles. Underground spring water would be the safest, but perhaps would not met the demands. Underground sources of water also need to be tasted because the earth contains heavy metals and other elements that may be damaging to human health (it always depend on the location/type of soil and vegetation contributing to the water and serving as sources/filters ). People tend to complain about tap water but the truth is that there is more transparency and test for tap water than for any other supply. It is always safer to filter it through reverse osmosis to make it even safe. Private companies that supply bottled water don't disclose their procedures. Many times, harvesting of spring water compromises the ecosystems (see movie flow).
Food--Up to now reports of crops with high levels of either I 131 or Cesium include milk, fish, spinach. This is just because testing is limited to certain crops or products. The potential for pretty much any plant receiving particles/or contaminated water is there. Though, some plants or organisms biomagnify and may show higher levels that the ambient levels. Mushrooms are among the type of foods to be avoided.
The reports from food pollution near the nuclear facilities are consistent with particles traveling with air/dust currents. Most of the pollution traveled south half way Tokyo. The geography of the region appears to be a determinant of how far these particles travel on air. Atmospheric dispersion had been documented for Hiroshima atomic bomb (though a bomb disperses locally and on the upper atmosphere). In the present case, for the nuclear facilities, a level 5 indicating local dispersion appears to be the most prevalent said the UW-Madison nuclear engineers.
UPDATE: May 5th 2011 Seven weeks after the nuclear facility damage the Rating of the International and Radiological Event Scale (INES rating) is now 7. The rating indicates the impact on safety by any individual event on people and the environment (Agreement on the definition of INES was signed on 1992 by the International Atomic Energy Agency IAEA, and International Energy Agency, The Organization for Economic Development). This nuclear spill has released more contaminants to the air than any previous nuclear spill and all combined says the Union of Concerned Scientist Report.The assessment was conducted by the Japan Nuclear Safety Energy Organization and involves the current condition of the cores, the different type of radiactive spills at the facility, human risks and environmental pollution. Although this has reached the maximum number of the INES rate= 7, the same rating than Chernobyl, " the amount of radiactive discharge up to now is only 10% of that released by the Chernobyl reactors (source Japan Ministry of Economy,Trade and Industry http://www.nisa.meti.go.jp/english/files/en20110412-4.pdf--April 12, 2011). A Major Accident classified as 7 using the INES scale "is a major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended counter measurements"(INNES manual, 2008). The following agencies provide updates and summary of the event WHO, AIEA, and the Union of Concerned Scientist Report.
Food monitoring: 190 samples of vegetables, mushrooms, fruit/strawberries, beef, pork, poultry eggs, seafood, fresh milk, raw unprocessed milk and yoghurt were drawn and tested for I131, Cs 134/Cs137 (April 27-30). In most samples radioactivity was undetected or under acceptable levels (Health Ministry). Only in Fukushima prefecture where the damaged nuclear plants are located-one sample of bamboo, one sample of fern and 5 samples of shiitaki mushroom were above acceptable levels for Cs 134/Cs137. Three samples of fish from Ibaraki showed levels above the acceptable for Cs 134/Cs137. Areas previously considered safe for cropping and living --are now being evaluated. It is possible that the restricted area will be expanded and more people will need to be evacuated.
On May first some of the restriction on raw milk were lifted in Fukushima prefecture from the city of Minamisouma and Kawamata town. However within these locations, the following areas remain banned Karasuzaki, Ouchi, Kawago and Shionosaki &Yamakiya area.
Water: at this time,Tokyo's water is considered safe for drinking.Only in one village in the Fukushima shows levels of I131 above 100 beq in its water. This is the upper limit for infants-- and is thus not safe for them.
Marine monitoring: Monitoring of sea water is conducted near the Fukushima Daiichi plant by TEPCO and at off-shore stations by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT). Both deposition and discharge of contaminated water on the ocean contribute to sea water pollution. On April 25-30th water with high levels of radioactivity outflow from plant 2 to the Ocean.
In the close perimeter to the damaged reactors, however, conditions continue under constant monitoring. People are prevented from accessing those areas, except for the engineers/plant safety workers). Reactor #1 can only be accessed only using iRobots (restrict area around the plant is 20Km/12.4 miles). 70,000 tons of stagnant radioactive water are still on the nuclear facilities--and water continues to be poured at the cores for cooling. The risk for more releases to the ocean remains.
Update July 2011:
It is now know that an approximate of 600 cows feed with grass that contained high radiation levels --500 levels above standard--were slaughtered for meat. The meat was distributed in Fukushima Prefecture though it may have reached other location. The government will impose further restrictions to meat from that area (March 11-July, 16 2011)--even though there was a restriction concerning food safety in that region. After consuming feed stock cows the traces increase or are biomagnified in milk and to a lesser degree on the meat
Nuclear Power and Energy
More about Japan
INES Radiological Scale Manual 2010
How Radiation Harms: Simulation
Union of Concerned Scientist: Japan Nuclear Crisis briefings
- Japan Nuclear Power Crisis - Telephone Media Briefings | Union of Concerned Scientists
Audio links and transcripts of media briefings by experts from the Union of Concerned Scientists regarding the nuclear power crisis in Japan.