The aftershocks of the 2011 Fukushima Daiichi nuclear disaster are still being felt to this day: Although the Japanese government has lifted eviction orders for the more than 100,000 individuals evacuated during the power plant's meltdown, many are reluctant to return home, citing concerns over radiation, ongoing dismantling of the nuclear power plant and radioactive wild boars that roam the region’s abandoned streets. Across the Pacific Ocean, Fukushima’s fallout is also apparent, albeit in a wholly surprising source—northern California wines, from rosé to cabernet sauvignon.
Last January, researchers at France’s National Center for Scientific Research, or CNRS, chanced upon a series of California wines dating between 2009 and 2012. Inspired by similar tests conducted in the aftermath of the 1986 Chernobyl disaster, the French team decided to analyze the California wines for traces of radioactive particles, specifically cesium-137, a man-made isotope.
Their findings, newly published in the pre-print online journal Arxiv, suggest that currents and atmospheric patterns carried radioactive particles across the Pacific, where they settled on grapevines growing in California's wine regions. The team writes that bottles produced following the nuclear meltdown contain increased levels of cesium-137, with the cabernet revealing double the amount of pre-Fukushima radiation.
Luckily for wine lovers, however, the New York Times’ Mihir Zaveri reports that enjoying a glass of post-2011 Napa Valley red poses no discernible health risk (at least not from radiation).
“These levels are so low, way below the natural radioactivity that’s everywhere in the world,” study co-author and CNRS physicist Michael Pravikoff tells Zaveri.
According to Alix Martichoux of local news outlet SFGate, physicists initially attempted to analyze the 18 bottles of rosé and cabernet sauvignon with a gamma detector. This method, which allows researchers to conduct tests on unopened bottles, is a key tool in detecting wine fraud, or the mislabeling of newer wines in order to inflate their prices. To determine the actual age of a bottle, scientists scan the wine for traces of cesium-137, which only shows up in wines produced after the world’s first nuclear tests and explosions.
MIT Technology Review explains that French pharmacologist Philippe Hubert developed the fraud detection tool in 2001. Thanks to his efforts, “dating wine is a a simple process of matching the amount of cesium-137 to atmospheric records from the time the wine was made.” Following Chernobyl, levels of radiation in wine spiked, and, as the new study shows, a similar phenomenon occurred after the Fukushima disaster.
Still, it took more than a gamma detector to uncover the California bottles’ secrets. After failing to detect cesium-137 in the unopened bottles, the physicists vaporized the wine. The subsequent ashes contained twice the amount of radioactive materials as pre-Fukushima wines, SFGate’s Martichoux reports. The amount found in red wine was higher than that of rosé.
Although ingestion of cesium-137 can elevate individuals’ risk of cancer, the World Health Organization states that levels of Fukushima radioactive materials found in food and drink outside of Japan are too low to pose a public health hazard.
In lieu of the new findings, the California Department of Public Health reiterated these reassurances: There are no “health and safety concerns to California residents,” spokesperson Corey Egel said in a statement provided to the New York Times. “This report does not change that.”
To study co-author Pravikoff, the study is more about scientific curiosity than a tangible threat to public safety.
“I just bought [the wines], just to see,” he tells the New York Times' Zaveri. “It is more for the pure scientific aspect that we were interested in measuring them.”