[Vou. 91 reentage of icles < 88 it activity* amount of r drops at uo 200 miles rted device 1.2% of the similar balseal fallout letonations, fallout pat, produced. ions at the strontium ) ‘tion and dis96 9 5 4 2 24.9 72.4 1.9 0.8 160 1964] 295 manycases, single rainfalls deposited 1-3 curies of beta activity per square mile. On July 9 & 10, 1957, the rain falling on Jefferson City, Missouri contained 7.6 ¢/mi*® of fresh fission product activity (U. 8. Atomic Energy Commission 1959b). In the same year, increased levels of Sr-90 were observed in North Dakota milk (Pfeiffer 1958) and in Minnesota wheat (Cas- 35 5 O = e ~~ 30 r " 20 «= . 14. ss NAN fz f= BE 10 - P “~N So oO “ 54 mably, the deposition 0 = ; 80° » the tropo- 60° T 499 T 1 200 N 0° s T T 20° 40° 60° DEGREES OF LATITUDE 9 ; across the 30° to 60° ircumnavi- \ARTIN : RADIOECOLOGY AND STUDY OF ENVIRONMENTAL RADIATION Fig. 3. Millicuries of Sr-90 deposited on soil at different latitudes, After Alexander iome tropo- (1960). 2 deposited jor part is precipita- ter 1959), and small quantities of fallout were detected on vegetation in New England (Bormann et al. 1958). Since these areas are also in the band of maximum world-wide fallout, there is some doubt as to what fraction of these mecreases was due to tropospheric and what fraction to stratospheric fallout. In general, these temporary, usually localized increases of environmental radiation and of the radionuclide content of foods have not been regarded as particularly hazardous (U. 8. Atomie Energy Commission 1959a). They eky Mounsoduets. In ! per kiloton