Answer to Question #966 Submitted to "Ask the Experts"

Q

Were there any studies done on radiation fallout and health effects for the Island of Guam in the 1950s, 1960s, or 1970s? I am researching ⁹⁰Sr and ¹³⁷Cs that was carried from the Marshall Islands through the Pacific areas after 67 nuclear detonations.

A

Your question is an interesting one because of the extensive amount of nuclear testing conducted in the Pacific and because Guam is located far enough away from the Marshall Islands to have received little research attention. Although you ask about the nuclear tests conducted in the Marshall Islands, you might also be interested to know that there was nuclear testing conducted at other locations in the Pacific, including Johnston Island and Christmas Island (Kiribati) in the northern hemisphere and Malden Island (Kiribati), French Polynesia, and Australia in the southern hemisphere. Also, as you might know, nuclear testing was conducted at other locations in the world, including Nevada, Russia, Kazakhstan, etc., and those tests also spread radioactivity throughout the world. Literally, no place was exempt from receiving what was has been termed "global fallout." Though you ask specifically about ⁹⁰Sr and ¹³⁷Cs from the nuclear tests conducted in the Marshall Islands (1946-1958), it is important that when you evaluate measurement data on long-lived radionuclides like those, you are aware that some of the radioactivity measured (depending on the point in time of the measurement) was partially due to fallout from nuclear tests conducted at places other than in the Marshall Islands or even in the Pacific. To answer your questions more specifically, I don't know of any detailed studies of radioactive fallout and/or related health effects on Guam, although there are various measurements of fallout radioactivity reported for Guam. In particular, the Atomic Energy Commission's Health and Safety Laboratory (HASL) made many measurements of fallout radioactivity at Guam and other western Pacific locations as part of its Pacific and worldwide surveillance efforts. For example, the cumulative ⁹⁰Sr was reported through 1957 by Eisenbud and Harley—two of the most important researchers in that field—in Science in 1957. They gave the cumulative deposition for Guam to be 78 mCi mi^-1. The ¹³⁷Cs deposition is not given, but you can estimate it by considering that cesium is produced by nuclear explosions in the ratio of about 1.6 times that of strontium. You can make the approximation that the depositions of the two radionuclides were also about in that ratio, primarily because their half-lives are so close to being equal. Hence, the cumulative deposition of ¹³⁷Cs in Guam might have been about 125 mCi mi^-2. In evaluating these data, remember that was the deposition in June of 1957. Today it has decayed considerably. There may also have been additional deposition after that time as well. If you are interested in researching the rather extensive historical documents that are available on fallout, some which provide data for Guam and other nearby locations, you should search the online archives provided by the Department of Energy (DOE). You can use Guam as a searching keyword, but many times it is listed as part of the Caroline Islands. Go to the DOE International Health Program's Marshall Islands Program Web page and then click on HISTORICAL DOCUMENTS. This will take you to the IHP Marshall Islands Document Search Web page. There you will find a search engine where you can use key words of your choosing. Here are a few documents that I know you will find interesting. You can locate them by title and/or author.

• RADIOACTIVE DEBRIS FROM OPERATION CASTLE ISLANDS OF THE MID-PACIFIC, Author: BRESLIN A J, CASSIDY M E
   
• RADIOACTIVITY IN THE BIOTA AT ISLANDS OF THE CENTRAL PACIFIC 1954-1958, Author: DONALDSON L R
   
• LONG-TERM FALLOUT, Author: EISENBUD M, HARLEY J H
   
• SUMMARY OF GUMMED FILM RESULTS THROUGH DECEMBER 1959, Author: HARLEY J H, HALLDEN N A, ONG L D Y
   
• RADIOACTIVE FALLOUT THROUGH SEPTEMBER 1955 BY M EISENBUD AND J H HARLEY (SCIENCE, AUGUST 10, 1956, VOL 124, NO. 3215 ), Author: EISENBUD M, HARLEY J H
   
• ENVIRONMENTAL CONTAMINATION FROM WEAPON TESTS, Author: HARDY E P, HARLEY J H

Good luck with your literature searching. Steven L. Simon, Ph.D. National Cancer Institute Rockville, MD