Climatide

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In 1986, reactor 4 at the Chernobyl nuclear power plant exploded, creating the worst nuclear accident in history. Today, Japanese officials upgraded the Fukushima crisis to a level 7 rating - matching Chernobyl.

The big news from Fukushima today is the fact that officials are upgrading the disaster from a 5 to a 7 (out of 7) on the international rating scale for nuclear accidents. Chernobyl was also a level 7 “major accident,” while Three Mile Island was rated a level 5 “accident with wider consequences.” But that may be the end of the similarities, according to Hidehiko Nishiyama, spokesman for Japan’s Nuclear and Industrial Safety Agency.

“It is quite different from Chernobyl,” said Mr. Nishiyama. “First, the amount of released radiation is about a tenth of Chernobyl,” he said, adding that while there were 29 deaths resulting from short-term exposure to high doses of radiation at Chernobyl, there were no such deaths at Fukushima.

There are fundamental differences between the two incidents. In the case of Chernobyl, a reactor actually exploded:

… a graphite fire burned uncontrolled for days, spewing out radioactive smoke that spread around the world. Fukushima, unlike Chernobyl, has a containment structure, which, even if damaged, has meant that the Japanese accident has shown “much, much, much lower” traces of far-flung radiation, Wolfgang Weiss, chair of the United Nations Scientific Committee on the Effects of Atomic Radiation, said in Vienna last week.

Geoff Brumfiel points out that the timescales of the two crises are totally different. Nearly a month after the earthquake and tsunami that crippled the Fukushima plant, steam continues to rise from the reactors, contaminated cooling water is still leaking and flooding some parts of the facility, and experts say it could take months to staunch the flow. So the total radioactivity released by Fukushima could eventually surpass Chernobyl.

And then there’s the fact that highly radioactive water has been flowing directly into the adjacent ocean, resulting in levels of radioactive iodine and cesium millions of times over the legal limit – and thousands of times higher than seen in the Black Sea after Chernobyl.

So Fukushima’s impacts on marine life will be more severe:

“Given that the Fukushima nuclear power plant is on the ocean, and with leaks and runoff directly to the ocean, the impacts on the ocean will exceed those of Chernobyl, which was hundreds of miles from any sea,” said Ken Buesseler, senior scientist in marine chemistry at the Woods Hole Oceanographic Institution in Massachusetts. “My biggest concern is the lack of information. We still don’t know the whole range of radioactive compounds that have been released into the ocean, nor do we know their distribution. We have a few data points from the Japanese — all close to the coast — but to understand the full impact, including for fisheries, we need broader surveys and scientific study of the area.”

It’s entirely possible – indeed, likely – that radioactive material from Fukushima will make it’s way around the ocean, traveling on ocean currents and falling to the seafloor. In fact, it’s precisely the ocean’s vast size and capacity for distributing and diluting the radioactive contamination that has kept experts downplaying the likely ecological and public health impacts.

But with skyrocketing concentrations of radioactivity in seawater reported by Japanese officials have come renewed concerns about seafood safety. Some fish in Japan have been found to contain radioactivity in excess of newly enacted safety guidelines and scientists estimate that fish, shellfish, and especially seaweed in the area surrounding the plant are likely to carry significant levels of radioactivity. Still, while experts caution it’s probably a good idea to avoid fish and seaweed from the affected area for a few months (not hard given that much of the fishing industry in the region was decimated by the March 11th earthquake and tsunami), they still say that seafood in most of the world is safe and that major, long-term ecological impacts are not expected.

Does that mean we’re in the clear? Not exactly. Even basic questions – how much and what kids of radioactivity? and where? – lack detailed answers at this point. Many scientists, like Buesseler, are increasingly saying initiating long-term research needs to be a top priority. But here’s a catch:

“Any survey would be welcome,” says Ulf Riebesell, a biological oceanographer at the Leibniz Institute of Marine Sciences in Kiel, Germany. “But I certainly wouldn’t ask my students to do field work off Japan amid this ongoing crisis.”

Of course, even after the crisis is over, officials and workers at Fukushima face a clean-up effort of gargantuan proportions. It’s expected to take decades. In that one regard, at least, Fukushima and Chernobyl are similar.

Share your thoughts and get your questions answered by Dr. Ken Buesseler tomorrow morning at 9:30am on WCAI’s The Point.