Radiation will hit release life

Brown seaweed, usually off the coast of Japan (above), PRESS / AFP/Getty Images is harvested radioactive Jod.JIJI absorbent

Radioisotopes in the sea of the crippled nuclear power station Fukushima Daiichi pour, a calming message over and over again listened to: the Pacific is a great site.

That the isotopes will be diluted strongly is not in question. Still call for scientists to as soon as possible start a marine survey, assess damage to ecosystems in the area of Fukushima. Although the contamination unlikely, that marine organisms do immediate damage is long-lasting isotopes to accumulate in the food chain and possible problems such as such as increased mortality in fish and marine mammal populations.

"Only, because you can measure it, doesn't mean that it is dangerous," says Ken Buesseler, a marine geochemist at the Woods Hole Oceanographic Institution in Massachusetts. "However, this is the largest man-made release ever of radioactive material in the oceans." "We have on not yet seen enough data to assess what is going on, so that everything can be done, would be very welcome to more monitoring."

Seen extremely high concentrations have the last two weeks of radioactive iodine-131 (with a half-life of 8 days) and caesium-137 (with a half-life of 30 years) in samples of sea water collected in the vicinity of Fukushima reactors and even as far as 30 kilometers off the coast. By the end of March, tens of thousands of times higher than before the accident were (see ' radioisotope contamination '). Many other radioisotopes, both long- and short-lived, should also have been released.

But the total amount of radioactivity that has entered the ocean, is unknown, and further flows – accidental or deliberate – and can even significant should further problems at the site of Fukushima (see page 146 occur).

These uncertainties are scientists at the National Institute of Radiological Sciences (NIRS) in Chiba, Japan, studies to monitor design accumulation of radionuclides in the muscles, organs, eggs and bones of marine animals. You schedule the long-term behaviour of radioisotopes in the marine environment and the total will be exposed to the marine organisms radiation doses, also model. "We need certain levels of caesium and iodine isotopes get their impacts are in various marine organisms,", says Tatsuo Aono, expert in marine Radioecology in the NIRS.

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A team led by Dominique Boust, Director of the French Institute for radiation protection and nuclear safety (IRSN) in Cherbourg, the level of contamination is now marine organisms and in sediment with estimates of the amount of radioisotopes forecast published by Fukushima, and the relationships of these isotopes from available sea water measurements calculated.

The team calculated that about 50 Radio-isotopes to a total concentration of about 10,000 becquerels per liter seawater for 300 meters Fukushima contribute. Before the accident caesium-137 concentrations there were about 0.003 becquerels per liter, and iodine-131 was not detected. From these numbers, the IRSN, researchers suggest that now 10, since million could contain sediments in the region of becquerel per kilogram; Fish help could 10, 000-100 000 becquerels per kilogram; and algae, that that some of them particularly prone to iodine are recording may contain up to 100 million becquerels per kilogram. Japan has legal limits of the radioactivity in fish for human consumption of 500 becquerels per kilogram for caesium-137 and 2,000 becquerels per kilogram for iodine-131.

"Cans very quickly with time and distance from the plant, will reduce, if not further leaks occur, but it could remain a persistent low-dose component in the local marine environment for many years," says Thomas Hinton, Deputy Director of the IRSN, laboratory of Radio?kologie?kotoxikologie and environment modeling in CadaracheFrance. "The effects are handled best by international long-term evaluation."

Ward Whicker, expert in environment and radiological safety at Colorado State University in Fort Collins, agrees that a survey would pay. He says "It much sampling effort, near the discharge as in locations further away, would require". "Concentrations of radionuclides in water, sediments, plankton, molluscs, crustaceans, algae and fish would have to be measured and monitored the health of the ecosystem."

Although concentrations in fish, shellfish and algae for weeks could exceed radioisotope borders for human consumption, Whicker thinks that it is unlikely, that scientists recognize would be no genetic effect on marine life. All affected creatures would probably dissipate into the Pacific Ocean or die more quickly, he says. Moreover, would be that tsunami tease radiological impact of other stresses, such as conventional water pollution and the damage, extremely difficult.

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An alternative approach could be to an appropriate proxy types. "My opinion, Brown seaweed the research priority number one should", says in Cherbourg from Bruno FIEVET, a Radio-ecologist at the. The Brown seaweed Laminaria Digitata, omnipresent in the coastal Pacific waters off Japan, absorbed iodine to help against environmental influences such as air pollution through to defend. It can be about 10,000 times larger than the surrounding sea water iodine concentrations. "The world champion in iodine intake is such, and it would be a good indicator for the Radiolabelling other sea animals," says FIEVET.

But sampling can be hampered by the danger that stays at the location of Fukushima. "Every survey would be welcome,", says Ulf Riebesell, a biological oceanographer at the Leibniz Institute of marine sciences in Kiel, Germany. "But I would certainly not questions, my students at field work on the Japan in the middle of this ongoing crisis."

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