Wednesday, April 13, 2011


Since the Japan disaster, we have been hearing a lot about radiation exposure in the news, including about the isotope cesium-137 . Several recent posts on this blog have also mentioned it. But what is it? And, how does it affect us? I am not an expert on cesium-137, so I did some research using reliable websites, including those of the U.S. Environmental Protection Agency (EPA) and the National Institutes of Health (NIH). This is what I came up with.

Cesium 137 is a common radioactive form of the metal cesium (cesium 134 can be present in food, but is less common). It can be in a lot of other places as well. Cesium 137 is used in some industrial processes and in certain treatments for cancer. It can be found in hospital and research laboratory waste, which is usually safely disposed of. But, as we know, it is also released into the environment by nuclear reactor accidents. This happened at the Chernobyl disaster, and has also been occurring over the past month at the Fukushima power plant.

From the environment, cesium-137 can enter growing food. Leafy vegetables and grass tend to pick it up first from the air, helped by wind currents and rain. Cattle and other animals eat grass, and from there it gets into our milk and meat. Some is also absorbed by soil and water and enters root vegetables and fish. Unlike iodine-131, which can last as little as 8 days, cesium-137 has a half-life of about 30 years. Cleanup of soil or lakes or rivers is very difficult and costly. It also creates a high level of risk for the workers doing it.

The problem is that you cannot feel, smell or taste cesium in your food or water. Unless you use special equipment to check for it, you don't know if you are being exposed. If you do ingest it, this metal is apparently easily absorbed by the GI system. Some would be excreted through urine, but a portion would build up in your body, especially in the muscles. The cells lining the intestine and stomach are particularly vulnerable.

Exposure to enough cesium 137 can raise your lifetime risk of cancer fractionally, for example, from 20% to 24%. It can also cause genetic and developmental problems or result in other damage to organs. In the short term, sizeable exposure (unlikely with food or water) may give you headache, diarrhea, bleeding gums, nausea, vomiting and even fever. The size of the dose, and how regularly and how long you keep eating the contaminated food will determine how much you are affected overall.

As with almost all contaminants in food, health effects of radiation will partly depend on who you are: your age and general health, although case studies have documented mysterious exceptions to the rule. Again, as with many contaminants, if the doses are few and small, the cesium-137 will not affect your health. But if your consumption of cesium-contaminated food is "acute" or regular over a long enough period of time, especially if you are also getting radiation from other sources (such as the environment, X-rays, your occupation, international flights, or whatever), it can add to these other sources of cesium and damage your health.

Yes, there are several tests for cesium-137, that can measure levels of it in your urine, blood, bones, feces, hair or skin. But don't expect such tests to be widely available. Most medical laboratories don't do them. If diagnosed with dangerous levels of cesium-137 in your body, treatments are available.


1 comment:

Anonymous said...

This would suggest that in continental US, we are not immediately at risk unless we live in the immediate radius of a nuc plant which melts down. Those folks in Japan living near the fukishima plant, though, have a problem, but more long term than their immediate challenges.