Fukushima & Our Oceans – Part 1

Written by on December 9, 2013 in Other News, Physical Oceanography

Editor’s note — Kristen Spruill is a graduate from the University of North Carolina at Wilmington with a B.S. in Marine Biology and is a frequent contributor to MST. The following article has been split into two parts. The first part addresses the initial disaster and the extent of the radiation. The second part, which will be published tomorrow, deals with the safety of our oceans and what we can expect in the future.

Fukushima & Our Oceans – Part 1
By Kristen Spruill

On March 11, 2011 the earthquake (9.0mag) and subsequent series of tsunamis inundated the nuclear reactor facility in Fukushima, Japan causing a loss of power and cooling function for the reactors. Since the initial meltdown, radioactive material has been leaking causing “the largest single contribution of radionuclides to the marine environment ever observed.” This article aims to take a brief look at some of the current news, science, and reports behind Fukushima and our ocean.

The International Nuclear & Radiological Event Scale (INES) was introduced in 1990 by the International Atomic Energy Agency (IAEA) to properly communicate the level of a nuclear accident. The severity of nuclear and radiological events is 10x greater for each level increased (Image 1). The Nuclear and Industrial Safety Agency assigned level 7 on the INES for the Fukushima accident. Level 7 indicates “A major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures”. The Chernobyl disaster of 1986 is the only other accident listed as a level 7.

What are some of the Radionuclides to be concerned about?

Strontium-90:

  • Half-life of 29.1 years
  • Mimics calcium and is taken up and concentrated in bones
  • Byproduct of the fission of uranium and plutonium in nuclear reactors
  • One of the more hazardous constituents of nuclear wastes
  • 20-30% deposited in bones; 70-80% passes through the body
  • Internal exposure linked to bone cancer and leukemia. Cancer risk increases. Also depends on the environment/exposure
  • Everyone is exposed to small amounts because of wide dispersion in the environment/food chain. Dietary intake has steadily fallen over last 30 years with the suspension of nuclear weapons testing
  • “The greatest concern would be the exposures from an accident at a nuclear reactor, or an accident involving high-level wastes”

Cesium-137

  • Everyone is exposed to small amounts as a result of atmospheric fallout.
  • Half-life of 30.17 years
  • Can be ingested (food/water), inhaled
  • Distributed uniformly throughout the body’s soft tissues
  • Remains in the body for a relatively short time
  • Increased risk of cancer

Polonium-210

  • Naturally occurring in extremely low concentrations
  • Half-life of 138 days
  • Direct damage occurs from energy absorption into tissues
  • Radiation hazard only if taken into the body. Does not represent a risk to human health as long as it remains outside the body
  • Can enter the body through contaminated food, breathing contaminated air or through a wound
Fukushima Daichi Nuclear Power Station.

Fukushima Daichi Nuclear Power Station. Photo credit: IAEA Imagebank via photopin cc.

Is Radiation Reaching U.S. Shores?

To many, it looks like it is. A post by Ukiah Community Blog reports on increasing radiation levels along the west coast. The blog provides a map of the west coast that displays various radiation levels across the United States. In California, the map shows radiation levels to be “elevated” with a few locations listed under “concern/watch.” Along the coast of Japan, radiation levels are “normal”. In addition, the article cites 28 “signs that the west coast is being absolutely fried…” with radiation, with examples from along the coast of California to Alaska. Some of these include the mass stranding of California sea lions, high levels of cesium-137, Herring bleeding from their gills, and more.

The examples provided have not been directly linked to the Fukushima disaster, but have been compiled to show the current trends in the US west coast ecosystem. Also keep in mind that the post was written by a former attorney, not a researcher.

Ken Buesseler, senior scientist of marine chemistry and geochemistry at Woods Hole Oceanographic Institution is one of the primary sources used in regards to research on the spread of radionuclides from Fukushima into the Pacific. Online sources such as National Geographic and Think Progress have cited Dr. Buesseler’s research.

FAQ from Dr. Buesseler:
Where does radiation from Fukushima go once it enters the ocean?

The streaks [of radionuclides] became longer and narrower as they move off shore, where diffusive processes began to homogenize and dilute the radionuclides…With distance and time; radionuclide concentrations become much lower in the ocean, something that our measurements confirm.

But more recently, the ratio of radioactive materials has shifted:

The initial leak had a high concentration of cesium isotopes, but the water flowing from the plant into the ocean now is likely to be proportionally much higher in strontium-90. The tanks (on the plant site) have 100 times more strontium than cesium. He believes that the cesium is retained in the soil under the plant, while strontium and tritium, another radioactive substance, are continuing to escape…Buesseler thinks the process occurs a bit more rapidly, and estimates it might take three years for contamination to reach the U.S. coastline.

You can read more of the FAQ here.

Are Our Oceans Safe?
The second part of Fukushima & Our Oceans will be published tomorrow. Check back to learn about the state of the oceans now and in the future.

Click here to see the complete list of sources.

Copyright © 2013 by Marine Science Today, a publication of Marine Science Today LLC.

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