Effects of Radiation from Fukushima Daiichi
on the U.S. Marine Environment
Eugene H. Buck
Specialist in Natural Resources Policy
Harold F. Upton
Analyst in Natural Resources Policy
Peter Folger
Specialist in Energy and Natural Resources Policy
April 5, 2011
Congressional Research Service
7-5700
www.crs.gov
R41751
CRS Report for Congress
P
repared for Members and Committees of Congress
Effects of Radiation from Fukushima Daiichi on the U.S. Marine Environment
Summary
The massive Japanese earthquake and tsunami of March 11, 2011, caused extensive damage to
the Fukushima Daiichi nuclear power installation in northeastern Japan, resulting in the release of
radiation. Concerns have arisen about the potential effects of this released radiation on U.S.
marine environment and resources.
Both ocean currents and atmospheric winds have the potential to transport radiation over and into
marine waters under U.S. jurisdiction. It is unknown whether marine organisms that take up
radiation in Japanese waters may subsequently migrate to where they may be harvested by U.S.
commercial fishermen.
High levels of radioactive iodine-131 (with a half-life of about 8 days), cesium-137 (with a half-
life of about 30 years), and cesium-134 (with a half-life of about 2 years) have been measured in
seawater adjacent to the Fukushima Daiichi site.
EPA rainfall monitors in California, Idaho, and Minnesota have detected trace amounts of
radioactive iodine, cesium, and tellurium consistent with the Japanese nuclear incident, with
current concentrations below any level of concern. It is uncertain how precipitation of radioactive
elements from the atmosphere may affect radiation levels in the marine environment.
Scientists have stated that radiation in the ocean will very quickly become diluted and should not
be a problem beyond the coast of Japan. The same is true of radiation carried by winds. Unless
radioactivity from Fukushima finds its way directly to another part of the world through food or
other commercial products, it should become sufficiently dispersed over time that it will not
prove to be a serious health threat elsewhere.
Currently, it appears that radioactive contamination of seafood from the recent nuclear disaster in
Japan is not a food safety problem for consumers in the United States. According to the U.S. Food
and Drug Administration (FDA), the damage to infrastructure in Japan has limited food
production and associated exports from areas near the Fukushima nuclear facility. Food products
from the areas near the Fukushima nuclear facility, including seafood, are also to be tested by
FDA before they can enter the U.S. food supply.
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Effects of Radiation from Fukushima Daiichi on the U.S. Marine Environment
Contents
Situation ..................................................................................................................................... 1
Concerns..................................................................................................................................... 3
Are there implications for U.S. seafood safety? ..................................................................... 3
How likely is it that radiation will reach U.S. marine waters, either through ocean
currents or atmospheric transport?...................................................................................... 4
What are the likely responses if radiation is detected? ........................................................... 5
Figures
Figure 1. Ocean Currents............................................................................................................. 1
Figure 2. Atmospheric Radiation Forecast for March 18, 2011..................................................... 3
Contacts
Author Contact Information ........................................................................................................ 5
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Effects of Radiation from Fukushima Daiichi on the U.S. Marine Environment
Situation
The massive Japanese earthquake and tsunami of March 11, 2011, caused extensive damage to
the Fukushima Daiichi nuclear power installation in northeastern Japan, resulting in the release of
radiation.1 Concerns have arisen about the potential effects of this released radiation on U.S.
marine environment and resources.
The North Pacific Current is formed by the collision of the Kuroshio Current, running northward
off the East coast of Japan in the eastern North Pacific, and the Oyashio Current, running
southward from Russia (Figure 1). As it approaches the West coast of North America, the North
Pacific Current splits into the southward California Current and the northward Alaska Current.
Although these currents have the potential for bringing radiation from the Japanese Fukushima
Daiichi nuclear accident to U.S. waters, their flow is slow and no radiation above background
levels has yet been detected in marine waters under U.S. jurisdiction.
Figure 1. Ocean Currents
Source: American Meteorological Society.
Seawater is monitored by the Tokyo Electric Power Company (TEPCO) near the discharge points
of the Fukushima Daiichi plant. Water, with a dose rate of greater than 1,000 millisievert per hour,
was confirmed by TEPCO on April 2, 2011, in a pit located next to Fukushima Daiichi’s Unit 2
seawater inlet point. A cracked sidewall of this pit is leaking water from the pit directly into the
ocean.2 Analyses of seawater taken from near the discharge from Fukushima Daiichi Units 1-4
1 For additional background on this incident, see CRS Report R41694, Fukushima Nuclear Crisis, by Richard J.
Campbell and Mark Holt.
2 Fukushima Nuclear Accident Update Log (April 2, 2011), at http://www.iaea.org/newscenter/news/2011/
fukushima020411.html.
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Effects of Radiation from Fukushima Daiichi on the U.S. Marine Environment
have yielded readings of 130,000 becquerels/liter (bq/l) of iodine-131 (half-life about 8 days),
32,000 bq/l of cesium-137 (half-life about 30 years), and 31,000 bq/l of cesium-134 (half-life
about 2 years).3 The occurrence of cesium-137 is of greater concern because of its much longer
half-life. The natural radioactivity of seawater is 13 or 14 bq/l, of which 95% comes from
potassium-40.4
Atmospheric transport (i.e., winds) also is capable of transporting radiation eastward where it
may settle or precipitate into U.S. marine waters (Figure 2).5 The U.S. Department of Energy and
the U.S. Environmental Protection Agency (EPA) monitor atmospheric radiation. As of April 2,
2011, EPA monitors in California, Idaho, and Minnesota have detected trace amounts of
radioactive iodine, cesium, and tellurium in rainwater consistent with the Japanese nuclear
incident; to date, concentrations have been far below any level of concern.6
It is unknown whether marine organisms that take up radiation in Japanese waters may
subsequently migrate to where they may be harvested by U.S. commercial fishermen.
A British scientist reportedly has stated that “[G]iven the scale of the Pacific—the world’s vastest
body of water—radioactivity in the sea at Fukushima will be flushed out beyond the local area by
tides and currents and dilute to very low levels. It [radiation] will get into the (ocean) food chain
but only in that vicinity. Should people in Hawaii and California be concerned? The answer is
no.”7
Scientists at the Woods Hole Oceanographic Institution advise that radiation levels in seafood
should continue to be monitored, but radiation in the ocean will very quickly become diluted and
should not be a problem beyond the coast of Japan. The same is true of radiation carried by winds
around the globe. Unless radioactivity from Fukushima finds its way directly to another part of
the world through food or other commercial products or a major unanticipated release should
occur, it should become sufficiently dispersed over time that it will not prove to be a serious
health threat elsewhere.8
3 Fukushima Nuclear Accident Update Log (March 31, 2011), at http://www.iaea.org/newscenter/news/2011/
fukushima310311.html.
4 Idaho State University, Radioactivity in Nature, at http://fizisist.web.cern.ch/fizisist/funny/NaturalRadioactivity.pdf.
5 Other projections of atmospheric trajectories can be found at http://www.atmos.umd.edu/~tcanty/hysplit/.
6 See http://www.epa.gov/radiation/data-updates.html; also see http://yosemite.epa.gov/opa/admpress.nsf/
d0cf6618525a9efb85257359003fb69d/3724de8571e1b03f8525785c00041a7a%21OpenDocument.
7 Simon Boxall, a lecturer at Britain’s National Oceanography Centre at the University of Southampton, England,
quoted in http://news.discovery.com/earth/japan-seafood-110330.html.
8 See http://www.whoi.edu/page.do?pid=56076&tid=282&cid=94989.
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Effects of Radiation from Fukushima Daiichi on the U.S. Marine Environment
Figure 2. Atmospheric Radiation Forecast for March 18, 2011
Source: Comprehensive Nuclear Test Ban Treaty Organization, Vienna, Austria.
Notes: This forecast shows how weather patterns might be expected disperse radiation from a continuous
source in Fukushima, Japan. The forecast does not show actual levels of radiation. The colors correspond
to the projected intensity of radiation, with yellow being most intense and progressing to less intensity through
the green, blue, to violet end of the spectrum.
Concerns
Are there implications for U.S. seafood safety?
It does not appear that nuclear contamination of seafood will become a food safety problem for
consumers in the United States. The main reasons include
• damage from the disaster has limited seafood production in the affected areas,
• radioactive material will be diluted before reaching U.S. fishing grounds, and
• seafood imports from Japan are being examined before entry into the United
States.
According to the U.S. Food and Drug Administration (FDA), because of damage from the
earthquake and tsunami to infrastructure, few if any food products are being exported from the
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Effects of Radiation from Fukushima Daiichi on the U.S. Marine Environment
affected region.9 For example, according to the National Federation of Fisheries Cooperative
Associations, the region’s fishing industry has stopped landing and selling fish.10
U.S. fisheries are unlikely to be affected because radioactive material that enters the marine
environment will be greatly diluted before reaching U.S. fishing grounds. However, some
advocate vigilance, especially for seafood from areas near the damaged nuclear facility. It has
been suggested that cesium-137 may move up the food chain and become concentrated in fish
muscle or that radiation hot spots may occur.11 The Fisheries Research Agency (Japan) has tested
samples from areas south of the damaged nuclear facility and it has been reported that radiation
levels are far below the standards set by Japan’s health ministry.12
The most common foods imported from Japan include seafood, snack foods, and processed fruits
and vegetables. In 2010, the United States imported 49.0 million pounds of seafood from Japan
with a value of $258.9 million.13 The FDA has primary responsibility for the safety of all
domestic and imported seafood, under the Federal Food, Drug, and Cosmetic Act (FFDCA), as
amended (21 U.S.C. § 301 et seq.). The FFDCA requires that all foods be safe, wholesome, and
accurately labeled. FDA’s general approach to ensuring the safety of seafood imports is based on
identifying risks from the production process, from specific types of seafood, and from certain
countries or firms.
FDA’s import tracking system is being used to identify all shipments of FDA-regulated products
from Japan with special attention to shipments from companies within the affected area. On
March 25, 2011, an Import Alert was updated for food items from specific regions of Japan, but
seafood was not included.14 Food products not included on the Import Alert, but from the areas
near the Fukushima nuclear facility, including seafood, are also to be tested by the FDA before
they can enter the U.S. food supply. For these products, FDA is to conduct field examinations and
collect samples for radionuclide analysis by FDA laboratories.15 FDA also reports that it is
increasing surveillance for all food products imported from Japan.
How likely is it that radiation will reach U.S. marine waters, either
through ocean currents or atmospheric transport?
Since radiation has been detected reaching various U.S. locations by atmospheric transport,
rainfall is likely to already be introducing radioactive elements from the Fukushima Daiichi
accident into U.S. marine waters. Transport by ocean currents is much slower and radiation from
9 U.S. Dept. of Health and Human Services, Food and Drug Administration, Radiation Safety, March 29, 2011,
http://www.fda.gov/newsevents/publichealthfocus/ucm247403.htm.
10 “Tsukiji wholesaler thinks it may take a year for the market to stabilize,” Reuters, March 23, 2011.
11 Elizabeth Rosethal, “Radiation, Once Free, Can Follow a Tricky Path,” New York Times, March 21, 2011.
12 Frederik Balfour, “Sushi Safe From Japan Radiation as Ocean Dilution Makes Risk Negligible,” Bloomberg, March
31, 2011.
13 U.S. Dept. of Commerce, National Marine Fisheries Service, Fisheries Statistics and Economics Division, “U.S.
Foreign Trade Query,” March 31, 2011, http://www.st.nmfs.noaa.gov/st1/trade/index.html.
14 All products identified by the import alert will not be allowed to enter the United States unless it is shown they are
free from radionuclide contamination.
15 FDA, Radiation Safety, March 29, 2011, http://www.fda.gov/newsevents/publichealthfocus/ucm247403.htm.
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this source might eventually also be detected in North Pacific waters under U.S. jurisdiction,
weeks or even months after its release.
What are the likely responses if radiation is detected?
If only low levels of radiation are detected, continued monitoring of the situation will be the
likely response. In the unlikely event that higher levels of radiation are detected, measures (e.g.,
removal of contaminated products from commerce) may be taken to prevent or minimize human
exposure to the contaminated media.
For background information on radiation and its potential for harm, see CRS Report R41728, The
Japanese Nuclear Incident: Technical Aspects, by Jonathan Medalia.
Author Contact Information
Eugene H. Buck
Peter Folger
Specialist in Natural Resources Policy
Specialist in Energy and Natural Resources Policy
gbuck@crs.loc.gov, 7-7262
pfolger@crs.loc.gov, 7-1517
Harold F. Upton
Analyst in Natural Resources Policy
hupton@crs.loc.gov, 7-2264
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