It only took one year for radiation from the March 2011 Fukushima Daiichi power plant disaster to reach the coast of British Columbia, reports Discovery News, and the radiation has continued to drift on down the North American coast, carried by the ocean’s currents.
On December 3, scientists from Woods Hole Oceanographic Institute (WHOI) issued a press release saying they have found an increase in the number of sites off the California coast that show contamination from Fukushima.
One sample collected 1,600 miles west of San Francisco gave scientists the highest recorded level of radioactive cesium to date. According to the WHOI report: “The level of radioactive cesium isotopes in the sample, 11 Becquerel’s per cubic meter of seawater (about 264 gallons), is 50 percent higher than other samples collected along the West Coast so far, but is still more than 500 times lower than US government safety limits for drinking water, and well below limits of concern for direct exposure while swimming, boating, or other recreational activities.”
Measuring radioactive cesium in the Pacific
Ken Buesseler is a marine radiochemist, and the director of the WHOI Center for Marine and Environmental Radioactivity. He was among the first to begin monitoring radioactivity in the Pacific Ocean, taking his first expedition into the Northwest Pacific just three months after the Fukushima disaster.
Buesseler launched Our Radioactive Ocean, a citizen science sampling effort in 2014. In 2015, using sophisticated measuring sensors, Buesseler’s own expeditions and citizen scientists added 110 new samples to the 135 previously collected samples posted on the Our Radioactive Ocean website. Buesseler will be presenting his findings at the American Geophysical Union (AGU) conference in San Francisco being held December 14 through Dec. 18.
Why is this new data important?
Buesseler says there are two reasons we need this information. “First, despite the fact that the levels of contamination off our shores remain well below government-established safety limits for human health or to marine life, the changing values underscore the need to more closely monitor contamination levels across the Pacific,” He says.
Cesium-134 has a half-life of about two years while cesium-137 has a half-life of a little more than 30 years. Buesseler says knowing this is the second reason for keeping track of the data. “These long-lived radioisotopes will serve as markers for years to come for scientists studying ocean currents and mixing in coastal and offshore waters.”
The Woods Hole data agrees with the findings reported by the group Kelp Watch and by the team of Canadian scientists working under the InFORM umbrella. While Buesseler’s data concentrates of ocean chemistry and does not involve itself with biological sampling, InForm scientists have done sampling of fish and have not seen any Fukushima cesium in fish collected in British Columbia.
Buesseler is also working with Japanese scientists, taking samples as close as one-half mile from the Fukushima plant. He says the radiation levels are decreased from after the initial event in 2011, but radioactive levels still remain 10 to 100 times higher than the levels off the U.S. coast.
Fukushima Watch is reporting Buesseler says, “Levels today off Japan are thousands of times lower than during the peak releases in 2011. That said, finding values that are still elevated off Fukushima confirms that there is continued release from the plant.”
In the meantime, according to Bloomberg, TEPCO is still trying to make their ice wall, a barrier of soil 30 meters (98 feet) deep and 1,500 meters long which are frozen to -30 Celsius (-22 Fahrenheit) that is supposed to prevent groundwater from flooding reactor basements and becoming contaminated.
Bloomberg also quotes TEPCO spokesperson, Yukako Handa as saying that since January, a little “slightly-tainted” water has spilled from a drainage system into the ocean nine times.
So what are we to believe? Will the ice wall work? How worried should we be about the ocean’s waters? These are some interesting questions, especially in light of a large number of sea creature die-offs over the past few years.
