UPTAKE OF RADIOACTIVE MATERIAL FROM A NUCLEAR REACTOR BY SMALL MAMMALS AT THE NEVADA TEST SITE.

Because testing was suspended in October of 1958, it is assumed that there was no detectable thyroid radioiodine in mammals living on Jackass Flats, Nevada Test Site, in February, 1959, prior to the testing of a nuclear reactor designed to serve as a space rocket engine. This assumption is supported by the fact that after the reactor test on July 1, 1959, rabbits collected outside of the fall-out pattern showed no thyroid activity. However, slight thyroid activity (1.7 m mu c/gm in rabbits 0.20 to 3.25 m mu c/gm in rodents) was detected within the fa1l-out pattern, to a distance of about 6 miles from the test site. This increment was attributable to the reactor test. Total beta activity of rodent skins increased 10-fold following the test, rabbit skins about 2.5 times. Rabbit gastrointestinal contents displayed a 15-fold increase in beta activity after the test, that of rodents increased 3.5 times. These increases were also attributable to the test. It is concluded that radioactive particles ingested from the fur contributed a large part of the thyroid radioiodine in kangaroo rats. On the other hand, thyroid radioiodine in jack rabbits was derived largely from contaminated vegetation. Bone beta radioactivity was increasedmore » significantly in both rabbits and rodents because of the reactor test. Muscle radioactivity was increased significantly in rodents but not in rabbits. The radioactivity of kidneys, lungs, and livers showed no significant changes from February to July. This particular reactor test had no detectable deleterious influence on mammals living within the area investigated. (auth)« less