Nuclear fallout is showing up in U.S. honey, decades after bomb tests

sciencehabit writes: In the wake of World War II, the United States, the former Soviet Union, and other countries detonated hundreds of nuclear warheads in aboveground tests. The bombs ejected radiocesium—a radioactive form of the element cesium—into the upper atmosphere, and winds dispersed it around the world before it fell out of the skies in microscopic particles. The spread wasn’t uniform, however. For example, far more fallout dusted the U.S. east coast, thanks to regional wind and rainfall patterns.

Now, researchers have shown that that fallout is still showing up in honey from the region. 68 of 122 samples of locally produced, raw honey from across the eastern United States tested positive for radiocesium--at levels above 0.03 becquerels per kilogram, roughly 870,000 radiocesium atoms per tablespoon. The highest levels of radioactivity occurred in a Florida sample—19.1 becquerels per kilogram.

Radiocesium levels in plants have declined sharply since the 1960s. “Cesium levels in honey were probably 10 times higher in the 1970s,” one of the authors speculates. “Because of radioactive decay, what we’re measuring today is only a whiff of what was there before.”

Still, those numbers are nothing to fret about, says the U.S. Food and Drug Administration. The radiocesium levels reported in the new study fall “well below” 1200 becquerels per kilogram—the cutoff for any food safety concerns, the agency says.

The findings, however, do raise questions about how cesium has impacted bees over the past half-century, says Justin Richardson, a biogeochemist at the University of Massachusetts, Amherst. “They’re getting wiped out from pesticides, but there are other lesser known toxic impacts from humans, like fallout, that can affect their survival.”