This idea could be checked out in laboratories very quickly, and it might be more broadly applicable to other safe materials.

Coffee grounds could very well help remove radioactive iodine and other radioisotopes from the drinking water in Japan. EPA states that radioactive iodine

combines easily with organic materials in soil. This is known as ‘organic fixation’ and slows iodine’s movement in the environment.

That being the case, coffee would have similar properties because it has  a lot of organic material. I’ve cited references about this phenomenon in a previous post. This approach would only work for brewed coffee in which hot water passes through coffee grounds, not instant coffee.

This concept brings up some important issues. Babies don’t drink coffee, and what happens to the grounds that might accumulate adsorbed radioisotopes? To address the first issue, maybe there are other organic materials that could be used to get a similar effect…. ground up rice?

To address the second issue, it depends upon the half-life… iodine 131, the chief problem here as I understand it, has a short, 8-day half life, and it is chiefly its ingestion that is a problem.

Of course, babies and pregnant women should drink water from the best sources possible, and not rely on such methods. But, at the least, coffee brewers might take some heart in knowing that the coffee they make may well have reduced levels of radioisotopes.