Tecnologico

FISH
The  Nuclear  Accident  in  Japan:   Impacts  on  Fish
hen an earthquake and subsequent tsunami devastated Japan’s northeastern coast on March 11, 2011, a nuclear crisis began unfolding at the Tokyo Electric Power Company’s (TEPCO) Fukushima Daiichi plant.1 The Japanese government estimates it could be several months before the cooling systems, damaged by the natural disasters, are fullyfunctional.2 In an effort to thwart a nuclear meltdown at the plant while the cooling system is damaged, hundreds of tons of water has been sprayed into four of the six reactors to cool fuel rods and spent fuel.3 The radioactive water is pooling in various locations around the plant, inhibiting work to bring the damaged cooling systems back into operation.4
Releases to the Environment
Asexplained by the Japanese Chief Cabinet Secretary Yukio Edano, “…the longer this continues, the more radioactive particles will be released and the greater the impact on the ocean.”5 To clear the way for workers and create more storage room for highly radioactive water, TEPCO pumped approximately 3 million gallons of water contaminated with 6 The water that was dumped contains about 100 times the legallimit of radiation, while the highly contaminated water remaining in the plant contains 10,000 times the legal limit.7 On April 2, 2011 workers discovered a nearly eight-inchlong crack in the side of a pit holding water in reactor two at the plant8 and found that radioactive water leaking from
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It is estimated that 1,680 gallons of highly radioactive water rushed out of the crack everyhour, directly into the ocean.10 On April 5, 2011 attempts to plug the leak were reported to be successful.11 Several types of radioactive materials are being released into the environment from the damaged Fukushima Daiichi plant. The different types of radioactive material degrade at various rates; some persist in the environment longer than others.12 Degradation of radioactive material is measuredusing its half-life, which is the time it takes for half of the material to degrade.13 Radioactive iodine (iodine-131) has

photo courtesy of NASA/Goddard Space Flight Center, SeaWiFS Project and ORBIMAGE

a half-life of eight days.14 Radioactive cesium (cesium-137) has a half-life of 30 years.15 Scientists are voicing concern about the potential longterm impacts from the cesium-137 beingreleased from the plant, as well as the risk that contact with the most contaminated water would lead to “immediate injury.”16 One expert, Kenya Mizuguchi, professor emeritus of Maritime Science and Technology at Tokyo University, said, “We’re seeing the levels of radioactive materials in the water increase, which means this problem is going to continue to get worse and worse.”17

least sixmonths.29 Knowing this biological half-life, researchers are able to determine where an individual animal has traveled and eaten prey from contaminated waters.30

Food Chain Accumulation
Direct contact with water is a factor in the uptake of radioactive material for all seafood. But in addition to taking up

No Safe Level
While much of the coverage of the impacts from the nuclear disaster areaccompanied by reassurances about low levels of exposure, there is no “safe” level of radiation exposure. The full impact of the Japanese nuclear crisis remains to be seen, but the health risks posed by radioactive contamination are well-documented. In 2006, the National tion exposure that concluded that even low levels of radiation can cause human health problems, including cancer, and called forfurther investigation on potential links between low-level radiation exposure and heart disease and immune disorders.18 Children are especially susceptible to the impact of foodborne exposure to radioactive materials, making safeguards for food and water particularly critical.19

material in its body.31 The discovery of radioactive material higher up the food chain, like tuna.32 native to Japan...