Thursday, April 22nd 2021, 2:46 pm - While not harmful to humans, more research is needed to see if the fallout is damaging to bees.
There are traces of radioactive fallout from nuclear tests conducted in the 1950s and 1960s in American honey, a new study has revealed.
The presence of a radioactive isotope called cesium-137 has previously been documented in fruits, vegetables, and nuts but it is found in higher concentrations in honey, a revelation that was made by chance.
Jim Kaste, an environmental geochemist at William & Mary University in Williamsburg, Virginia, made the discovery while reviewing a spring break assignment with his students in 2017.
Kaste says he asked his class to bring back locally-sourced foods when they returned from break, and he used his gamma detector to test for the presence of cesium-137. When they tested a jar of honey from a North Carolina farmer's market, they discovered isotope rates more than 100 times greater than the other sources, prompting Kaste to begin a formal investigation.
Upon deeper analysis, Kaste found that 68 of 122 honey samples from Maine to Florida contain varying amounts of cesium-137, although all were found to be far below harmful levels.
“I’m not trying to tell people they shouldn’t eat honey. I feed my kids honey,” Kaste said in a statement.
“I eat more honey now than I did when I started this project.”
Cesium-137 is a by-product of uranium-plutonium fission, part of the fallout from nuclear tests conducted at several U.S. and Soviet sites during the Cold War era.
Particles that didn't fall to Earth during explosive tests drifted high into the atmosphere, Kaste says, sometimes even reaching the stratosphere.
Winds pushed isotopes east and brought them back down to Earth through rainfall.
Honey samples from the Virginia Piedmont area were "virtually cesium-free," Kaste says, with areas from North Carolina southward commonly showing its presence.
Strangely, honey from regions that experience higher-than-average precipitation wasn't necessarily the most cesium-laced. It was found the composition of the soil plays a larger role in influencing concentrations, with the most cesium-laced honey coming from areas with low-potassium soils.
“Potassium is an important nutrient for plants,” Kaste explained, “and potassium and cesium atoms look very similar.”
Kaste says plants searching for potassium are taking in cesium instead, a phenomenon that doesn't occur in potassium-heavy soils. The plants then pass the isotope along to bees through their nectar, which then makes its way into the honey supply.
Experts say the findings are yet another example of damage inflicted on the environment during the Cold War era. And while the isotopes are not potent enough to affect human health, it's unclear if the cesium is detrimental to bees.
"Given that pollinating insects provide vital services to the world's ecosystem and are essential in maintaining global food security, more research is needed to help us better understand how ionizing pollution threatens their health and survival," researchers say.
Thumbnail image courtesy of Getty.