Concentrations of radioactive cesium from the nuclear plant that were detected in the tissue of bluefin tuna, which migrate from waters near Japan across the Pacific to the coast of California and Mexico, were very low to begin with and have been falling since , said Nicholas Fisher, a professor of marine science at Stony Brook University. The California Department of Public Health sent inspectors to the beach shown in the video, and their tests found similarly elevated radiation levels.
But their analysis indicates they are naturally occurring — probably from minerals in the sand — and not associated with Fukushima. Kim Martini, an oceanographer at the University of Washington, noticed a surge in outrageous worries about radiation in Seattle last fall, including people who were afraid to go to the beach and stopped eating seafood.
A magnitude 9. Studies show that leaks from the facility continue to send radionuclides into the sea. But they dilute quickly in ocean water, scientists say. Once those contaminants disperse across the Pacific Ocean and reach the West Coast, their concentration will be many thousands of times lower and not of concern, according to an online FAQ by Ken Buesseler, a marine scientist at the Woods Hole Oceanographic Institution.
This level of radioactivity does not represent a health hazard for people who want to fish or swim in the area, said Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institution in Massachusetts, who helped analyze the seawater. Buesseler is leading a crowdfunded citizen science program to track cesium levels from the meltdown by collecting water samples along the U.
A swimmer who spent 6 hours every day for a year in water with 10 Becquerels per cubic meter of cesium would still receive 1, times less radiation than the dose from a single dental X-ray, Buesseler said. To date, no cesium has been found at Canadian or U. The short-lived isotope has only been detected offshore. Cesium does not occur on its own in nature — only forming in nuclear reactors — and it has a short two-year half-life.
Nuclear Regulatory Commission to see what your personal exposure is. Radioactive decay is defined as the process by which a radionuclide releases energy in the form of alpha particles, beta particles, or gamma rays over time, transforming into a different state until the element is stable again. As they decay, radionuclides may transform into different elements completely. The half-life is the rate at which a radionuclide decays to half its original atoms and is measured as time, ranging from mere seconds, minutes, or millions of years.
The severity of the impact of radiation depends on the exposure, either chronic continuous exposure over a long period of time or acute short-term exposure.
Radioactive materials that release energy in the form of ionizing radiation may cause damage to living cells by changing the state of atoms inside genetic material, in turn causing mutations to DNA. However, type of exposure is important internal vs. Experts disagree on the exact definition and degree of "low-dose" exposure, but the protection standards for the U. However, the accident in supplements these established sources, and the long half-life of Cs Now in a new preprint study , Michael Pravikoff and Philippe Hubert at National Center for Scientific Research and University of Bordeaux in France show the radiation from the disaster at the Fukushima Daiichi nuclear plant made its way into California wine.
Radiation detection has been used for decades as a way to verify the age, or vintage, of a wine. Wines from to the s, for example, have much higher radiation levels due to above ground nuclear testing. As for Fukushima, other studies have found increased levels of radiation in the ocean and marine life off the Pacific coast of North America after the incident. But this study is the first to examine how the cloud of atmospheric radiation traveled across the ocean to affect grapes in the Napa Valley.
More than 20 years ago, Hubert pioneered a non-invasive method to confirm the approximate vintage of a wine. The method involved looking at gamma rays emitted by cesium, a radioactive element that first appeared on Earth in Shielded from cosmic rays and other forms of radiation in an lab built specifically for low-level radiation measurements, Hubert was able to detect gamma rays from cesium Luckily, the process of glassmaking evaporates any cesium from bottle glass, so all the radiation must come from the wine itself.
An unopened bottle of wine sits next to a germanium detector. Gamma rays from radioactive cesium in the wine are quantified by the detector, giving researchers an approximate year the wine was made.
Photo by Michael Pravikoff. Hubert and Pravikoff subsequently tested dozens of wines certified to be genuine, and were able to correlate the level of radiation with the year the wine was made.
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