114 Health Physics 160° E August 2010, Volume 99, Number 2 164° E 168° E 172° E | | | | | Bikar | 12°N -------------------- Tocco crc rrr ree eer qt —y@ = = = = = HH HH He K- KKK 4 ---- 74 12°N E tak o-, NEWETA | Bikini 8 se Rongelap - Arai Ailinginae | | ¥ w. Ujelang | au | vs ‘ ae) ] | Kwajalein Jemo . es ikiep A * Ailuk | ~, 7! iy! > Erikub “a | Lib | _ Namu I it - . Mejit | Wot cme otje Sod a ae . AR | Q? Taka | | Wotho . Ujae Utrik Rongérik ‘ ] | | ! | Maloelap ~ | * Aur | y % “¢ BN L------------------- -o--------------- ~~ i 4-----] 8°N Cesium-137 Deposition Density Majuro and southern- 41-3 kB Kwajalein and mid- 3-8 kB latitude atolls latitude atolls Utrik Rongelap Island and other northern atolls q q m2 | m2 -2 Northern Rongelap _ atch, MA 180-1,300 kBg m -2 0 75 150k m : : es 0 75 150mi | 160° E _Jabwot "ofa ¢ A ar Ailinglaplap 164° E a ! salut es I t Ny, | Ie | Namorik : | 168° E ’ Arno ae Ae | | | ] Majuro | 20-30 kBq m™ 50-180 kBgq m | Epon we, ~ Kil : ay vn ili “liq ‘wp | K | | sllox : ! | | 172° E Fig. 2. Geographical variation of total (cumulative) '*’Cs deposited (kBq m~”) from all Marshall Islands nucleartests (see Table 5) illustrating four areas with similar deposition. Taongi Atoll, located beyond the boundaries of the mapat 14° 32’ north latitude, is not shown and notincludedin the range of depositions shownin the key for the northern atolls. Shaded areas also describe groups of atolls with similar values of organ dose (Table 5) and cancer risk (Table 11). by integration of the exposure rate from theinitial time of fallout arrival rather than from the time when the exposure rate wasat its peak. The doses from external irradiation were estimated in three basic steps (Bouville et al. 2010): 1. estimation of the outdoor exposure rates at 12 h after each test and of the variation in the exposure rates with time at each atoll after each test; 2. estimation of the annual exposure from 1948 through 1970 and of the total exposure from TOAto infinity, obtained by integrating the estimated exposure rates residence on the atoll (with corrections for temporarily resettled populations). The outdoor exposure rates at each atoll were assessed in one of two ways depending on whether reliable measurements of exposure rates were available for a particular nuclear test and atoll combination. If measurement data were available, they were assessed and a best estimate of the average exposure rate at 12 h post detonation (termed £12) on the atoll or reef island was made. If no reliable exposure rate data were available over time; and to estimate E12 directly, then the assessment of E12 conversion factors from free-in-air (outdoor) exposure each atoll and each test. The method relating the 3. estimation of the annual and cumulative absorbed doses to tissues and organs of the body by applying was derived from the estimates of '*’Cs deposition to tissue absorbed dose and by assuming continuous estimates of '*’Cs deposition densities and TOA to £12 densities and TOA provided in Becket al. (2010) for