I've been reading up on the Fukushima nuclear meltdown and its effects it had on the environment. The iodine-131 initially released from the incident decayed after 8 days, but other isotopes such as cesium-137 and strontium-90 have a half-life of 28.7 and 30.2 years (about 300 years to completely decay).
Apparently, large quanties of cesium-137 were found in neighbouring countries as well as in seafood near Japan.
Now, for something like nuclear isotopes, not having the required knowledge can lead someone to fear something that might be harmless (or confirm some doubts about the issue), hence why I am here.
From my research on scientific websites and different governmental regulations, I found out that food and water in Japan have a legal limit as to how much cesium-137 a food item can contain. Especially since cesium-137 ressembles potassium and therefore being easily taken up by the body, this is worrying.
To my understanding, the way a radioactive isotope creates havoc in the body of an individual is that:
- It ressembles a normal element we usually consume, like iodine, potassium for cesium-137 and calcium for strontium-90.
- The body digests it and it is stored in the body.
- It emits radation for a certain period of time, anywhere from 8 days for Iodine-131 to years for cesium-137.
- The prolonged radioactivity from these isotopes causes cancerous cells to occur.
- A tumour or other form of cancer develops.
If this is what happens for isotopes like cesium-137, how can it be possible to eat food or drink water containing ANY cesium whatsoever? Sure, the radiation isn't so bad, but what is important to take into consideration is that this is internal and highly centralized radiation. This is a completely different thing to external radiation.
For my questions about the topic, I would like to know three things (which could really put many doubts to rest).
The first is, is my understanding described above correct?
The second is, how does this affect us healthwise? We are stuck with these debris of cesium-137 and strontium-90 for the next 30 or more years, but what effect do they have on us?
If someone ingests an atom (or a small amount) of cesium-137, what affect will this have on this person's body?
Finally, for someone living in North America, how much of these debris are there, either that got here from the wind, products, food, water, etc.?
EDIT: If someone knowledgeable on the subject could answer the questions directly (highlighted by means of italics), it would be very much appreciated.