Radiation reality

A UC Davis professor sets the record straight on Japan’s nuclear-power disaster’s repercussions

As the situation with Japan’s Fukushima Daiichi nuclear power plant continues to deteriorate following the one-two punch of an earthquake and a tsunami, many Sacramento residents—and people around the world—are worried about the effects of radiation leaking from the damaged facility. It’s even led to a run on potassium-iodide tablets, as people stock up on a medication known to be helpful when exposed to radiation.

SN&R wanted to get the facts on radiation from Japan and on potassium iodide as a solution, so we asked an expert: Dr. Jerrold T. Bushberg, clinical professor of radiology at the UC Davis School of Medicine. Bushberg trained as a health and medical physicist, and he specializes in the biological effects of radiation. He’s also worked with several government agencies on issues of radiological emergency response, so we were pleased when he agreed to answer a few questions.

Is there a general risk from ambient radiation, the stuff that’s just there all the time anyway?

If there are any risks for normal levels of ambient radiation, they are too low for us to measure epidemiologically. In theory, there could be a health risk from background radiation because it is ionized radiation, which can damage DNA. However, we’ve also got a number of systems that work to keep our DNA in good repair. The amount of risk from ambient radiation and from small exposures, such as those for X-rays, has been debated for many, many years, and it’s one of the reasons that we always seek to minimize exposure to radiation.

Is there a reason to be concerned about fallout or radiation from Japan?

The websites of the Nuclear Regulatory Commission and the World Health Organization both have up-to-date information that is readily accessible by laypersons, and I’d recommend that anyone with concerns consult that information.

The exposure limit for anyone using radiation or radioactive materials is set by law, and we are required to manage that use so that people who are not radiation workers are not exposed. There are legal limits in levels for food and water, and the law requires that, if radiation exceeds those legal limits, we have to take action. None of the levels that have been measured in the United States since the earthquake and the tsunami have come anywhere near the action levels.

They have reached those levels in Japan, of course, which is why they have set aside some crops until that issue is resolved.

A lot of people in this area have been concerned and have been stockpiling potassium iodide. Is this a good idea?

People should not do that. The use of potassium iodide is one of those things that is often misunderstood. It is not a radiation pill that will protect you from radiation in all circumstances. It has a specific use for when people are exposed to radioactive iodine, when exposure exceeds the levels for which intervention is required.

Potassium iodide saturates the thyroid with non-radioactive-form iodine, and it will fill up all the binding sites in the thyroid so that the radioactive iodine can’t bind to it. The non-radioactive iodine eventually will be flushed out through urination, but it will keep the thyroid from radiation damage.

But potassium iodide doesn’t help with other types of radiation—any radiation other than radioactive iodine—nor does it provide any protection for organs other than the thyroid. So except in particular circumstances, where the risk is from radioactive iodine, the risks of using potassium iodide really outweigh the benefit.

The [Environmental Protection Agency] monitors radioactivity through a national network of monitors, and there are scientists who are tracking the releases, and meteorologists who are tracking the weather and dispersion patterns. They are following this, and there has been some elevation in radiation, but it seems to be much lower than needed for any kind of intervention. There really isn’t much likelihood of enough radioactive iodine coming to the West Coast to warrant potassium-iodide tablets.

Radiation is used for treating cancer, right?

Yes, and we also treat thyroid disease with radioactive iodine, and we treat a number of other noncancerous thyroid diseases. It’s also used in a number of diagnostic tests, so that we now get a great deal of benefit from nuclear medicine.