- The "usual suspects" of dangerous radioactive contamination
- Recently reported incidents of contamination
- How bioaccumulation and biomagnification exacerbate the impact of contamination
- Prudent advice post-Fukushima
If you have not yet read Part I: Fukushima's Legacy: Understanding the Difference Between Radiation & Contamination, available free to all readers, please click here to read it first.
Sources of Radioactive Contamination
As mentioned in Part I, polonium provides an excellent and dramatic example of something that is perfectly safe on the outside of the body and perfectly deadly on the inside. That's the difference between radiation and contamination.
"Radiation, just like with any toxic chemical, is related to dose," said Cham Dallas, a professor and toxicologist at the University of Georgia's Institute for Health Management and Mass Destruction Defense. "If you get a big dose, then you'll die sooner."
And with polonium-210, a dangerous dose can be a matter of micrograms: smaller than a single speck of pepper, he said.
If you ingest polonium-210, about 50% to 90% of the substance will exit the body through feces, according to a fact sheet from Argonne National Laboratory. What is left will enter the bloodstream. About 45% of polonium ingested gets into the spleen, kidneys and liver, and 10% is deposited in the bone marrow.
Radiation poisoning from polonium-210 looks like the end stage of cancer, Dallas said.
Liver and kidney damage ensue, along with extreme nausea and severe headaches. Victims often experience vomiting, diarrhea and hair loss. The alpha particles emitted from the decaying substance get absorbed in the body, which is what causes harm. Death may come in a matter of days, sometimes weeks.
Yes, polonium-210 is highly radioactive – a half gram of it in a vial will heat itself up to 500 degrees Celsius all on its own just because of radioactive decay – but it is not at all lethal until and unless it is ingested. Once it gets inside, then a fleck the size of a grain of pepper is lethal.
The much-feared plutonium-238 is also an alpha emitter. On the outside of your body it is not much of a problem. Inside it is extraordinarily harmful.
Iodine-131 (I-131) is another "fairly harmless on the outside, but deadly on the inside" sort of substance. Even a vastly sub-lethal dose of I-131 in terms of your whole body load will be damaging if not deadly, because iodine is viewed by your body as a delicious and rare treat, with your thyroid gobbling it up, radioactive or not, and storing it for future use.
As the thyroid does this, the I-131 gets concentrated into a very small body mass where the radioactive load experienced by the thyroid is far higher than any surrounding tissues. At a high enough dose, the thyroid will be destroyed which is a survivable experience, as anybody who's had their thyroid removed can attest.
The real difficulty actually comes with…