as wall as combine to make evaluations of local fallout contriou- tions from U. S. Pacific tests indistinguishable from the contributicens of the world-wide Many small-scale radiological * > fallout. survevs were . ° conducted during n areas, the greater distance of th o the 1950's and 1960's at or near the Pacific testing areas in the northern Marshall Islands; nowever, definitive evaluations of the impacts of residual fallout radicactivity were not made wn or suspected to be contaminated by tropo- o. J oO those island " (1-3). ot] until the 1970's These evaluations were conducted on spheric fallout from the tests at Bikini and Enewetak Atolls. Environmental studies of peripheral areas in the central Pacilic were conducted on a small scale during the testing years 1958) by the University of Washington, 1979, (1945- and thereafter in 1975, and 1980 by Brookhaven National Laboratory as well. Those studies vielded significant data on background radiation levels in these areas, and form the basis for this report. The Marshall Islands are all comprised of coral atolls or partially drowned atolls formed by coral limestone accretions on subsiding volcanic bases. rilling studies at Enewetak established that the limestone cap may exceed 1280 meters in As and thorium series the contributions of the uranium to the radiation environment in the Marshalls i es are dominate a. st ct + from th ented by small contributions ea] rv QO &. i Oo So ye Go a by cosmic rad @ ot he < those islands which are remotes wa External background radiation levels on cb are virtually nil a result, ct (6). fv thickness fron °°K,