Every additional source of radioactivity carries some additional health risk, but these risks vary with many factors, including the dose (how much a person is exposed to and for how long) and which isotopes you are exposed to, as well as individual sensitivities—there is a higher concern in children, for example.Fukushima will likely have the most significant long-term health impacts on those who had the highest exposures, so those living closest to the plant or in areas with higher fallout.
We should always be concerned, but we should also realize that different levels, time, and manner of exposure can have widely varying health risks.On March 11, 2011, a magnitude 9.0 earthquake—one of the largest ever recorded—occurred 80 miles off the coast of Japan.The earthquake created a series of tsunamis, the largest estimated to be over 100 feet, that swept ashore.Another radionuclide of concern, cesium-134, has a half-life of two years, which means that it is rapidly disappearing.Because of its short half-life, cesium-134 is the one isotope that, if we find it, could have come only from Fukushima.For the workers at the site, direct exposure from leaking storage tanks is of greater health concern because exposure from these concentrated sources is much higher.
For the general public, it is not direct exposure, but uptake by the food web and consumption of contaminated fish that is the main health concern from the oceans.
In the months after Fukushima, I also formed the Center for Marine and Environmental Radioactivity, in part to help share the most accurate, up-to-date information about radiation from human and natural sources and, when it became clear that there was no coherent and consistent source of government funding to monitor radiation in U. waters and to support public education, I formed a citizen-science/crowd-funding initiative called Our Radioactive Ocean at WHOI.
These are a few of the most common questions that people have been asking me.
Cesium-137 has a relatively long half-life (30 years), but it is also present in the ocean as a result of nuclear weapons testing in 1950s and 1960s.
Cesium-134 is much shorter-lived, which means that any detected in seawater samples must have come from Fukushima.
This change is measured in half-lives—the length of time it takes for the radiation to decrease by one-half.