As the world waits to hear whether radioactive isotopes from the Fukushima reactor explosions have been released into the air, ecologists are becoming anxious about the environmental effects—and not just in Japan. Health officials from South Korea, Indonesia, Thailand, Malaysia, Singapore, and the Philippines are beginning to screen food imported from Japan for radiation , and several other Southeast Asian countries are expressing concern over the potential for contamination of soil and water that could affect food sources. No one has imposed restrictions on Japanese imports yet, however.
Could food be affected? "It's a reasonable question and one we should have a handle on," said David Schauer, executive director of the National Council on Radiation Protection and Measurements (NCRP) in Bethesda, Maryland. Unlike the Chernobyl disaster, which mainly affected small, self-subsisting farming villages in the Ukraine, the Fukushima accident could affect a larger population because Japan is one of the world's leading exporters of goods. "I can't think of anything that would not be contaminated if radioactivity passes over an area and lands on surfaces," he said.
One of the lessons driven home by Chernobyl, Schauer said, is that contamination of food products is a major human-health concern. Especially for children, consuming milk or meat from an animal that fed on radioactive grass could present health risks. Cesium-137, a radioactive product of nuclear fission, is one of the largest threats: it mimics potassium in the body and is taken up in the muscles. Because its half-life is 30 years, it is difficult to get rid of.
Whereas radioactive particles that fall on surfaces could be washed, cesium-137 that is ingested by a stock animal, a fish, or taken up from soil by a plant would lead to that product being condemned. A 2006 report  the International Atomic Energy Agency compiled after the Chernobyl disaster found that condemning contaminated food proved to be very expensive; tens of thousands of animals had to be slaughtered.
As radiation levels around the plants continue to fall , all are hoping that the question won't need to be addressed.