Evaluating the Risks of Fukushima-Derived Radionuclide Concentrations in Pacific Ocean Seawater and Biota

Here’s a paper I wrote this quarter for an Ocean Environment class that I’m taking. I thought it might be cool to share! It was a fun research project. References are at the end (sorry, I didn’t link them in the body of the paper/post).

Evaluating the Risks of Fukushima-Derived Radionuclide Concentrations in Pacific Ocean Seawater and Biota

Ryan Gratzer
UCLA Extension: Z3892: Ocean Environment
Fall 2013

On March 11, 2011, a 9.0 earthquake off the coast of Japan triggered a tsunami that flooded the Fukushima Dai-ichi Nuclear Power Plant, resulting in a meltdown. During the meltdown, large amounts of freshwater and seawater were pumped through to cool the overheating reactors, and in the process 3 million gallons of contaminated water from the damaged reactor buildings were released into the ocean. There has been much concern over whether these radionuclides in the ocean will adversely affect both ocean and terrestrial life. Will they bio-accumulate up trophic levels in marine biota, and how may that affect humans who consume fish from the Pacific Ocean? The data so far seems to show that while radiocesium and other radioactive elements are certainly making their way around the Pacific Ocean, they are not concentrated at levels that present health concerns, and are, in most places, continually diffusing rather than accumulating.

Some context: Earth currently contains naturally-occurring stable isotopes (ex. carbon-14), naturally-occurring unstable (radioactive) isotopes (ex. potassium-40, uranium), and anthropogenic unstable isotopes (ex. cesium-137). We constantly expose ourselves to naturally-occurring radioactive materials (NORM) through mining, drilling, burning coal, building materials, flying on airplanes, food, sleeping next to people, the sun, and much more (many of these exposures are referred to as “background radiation”).[1] Radiation can damage DNA, and damaged DNA can lead to mutations (such as cancer, or aging). The isotopes we are exposed to are constantly decaying into other forms and thus becoming more stable, and so, barring an event that introduces a relatively large amount of radioactive materials into the environment, the radioactive level of our bodies stays pretty stable and our bodies are effectively handling damaged DNA.


The public has been very skeptical of the scientific and government reports about Fukushima. TEPCO and the Japanese government took two months to communicate to the public that a meltdown had occurred; and TEPCO did not admit until recently that 300 tons of contaminated water was leeching out into the ocean every day (though scientists had suspected it for a while, due to the concentrations of fast-decaying cesium-134 that was still present); and it is still unclear exactly how much radiation has entered the atmosphere, ocean, and land. There are also a lot of questions about “safe levels of radiation,” and the safety of nuclear power in general.

The Navies, scientists, and government bodies are doing their best to analyze and respond to the event given the uncertain data coming from TEPCO. But they’ve been slow to release their reports, and speculation abounds about “what is being hidden from the public,” and what the possible global ramifications could be. The bulletpointed conspiracy-laden articles are vastly more popular with the general public than, say, the scientific reports that focus on just one facet of the effects of the meltdown. The sensational “28 Signs That The West Coast Is Being Absolutely Fried With Nuclear Radiation From Fukushima” has gone “viral,” while the responses – “28 fallacies about the Fukushima nuclear disaster’s effect on the US West Coast“ and “More Fukushima Scaremongering Debunked“ – receive far less attention.[2, 3, 4]
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