The experimentsat Eneu Island at ikini Atoll significance of the four radionuclides via the using potassium-rich fertilizers (1qN-16P-16K) or KC, show a reduction greater 10 fold in the concentration of 137Cs in cocon$t meat and fluid; the 197Cs concentrationsin f ingestion pathway (Table 18). The MAI for Rongelap is the maximum annual intake that would occur based on the model described reviously. For example, the intake of 137Cs would be less in any year after 1995 decreasing exponentially by the 30-y radioactive half-life 0.74 to 1.5 Bq g-! (20 to 40 pCi g-1) workers as defined by the ICRP, is that annual using potassium-rich fertilizer ar (i.e., 2.3% per year). The ALI for occupational while the 137Cs concentrations in intake of each radionuclide that would lead to an effective dose of rate 20 mSv y—! (2000 mrem y-!). In Table 18, we have reduced the ICRP ALI for occupational exposure by a factor of 20.to correspond to the adopted annual guideline of 1 mSv y—! (100 mrem y-!) effective dose rate for the public. As indicated in Table Eneu Island, we fe began a similar ex the adjusted ALI; it would of course decrease are about 8 to 10 times higher Bikini Island where the 137Cs conc 18, the MAI on Rongelapfor 137Csis about 22% of with each succeeding year. On the other hand, Island. The results of that experi 9S, 239+240Py, and 241Am are only 0.57%, 0.22%, and 0.17% of the ALI, respectively. weight to about 0.56 to 0. (15 to 20 pCi g-!) wet weight. In Mitigation of Food-Chain Dose wherethe initial concentration was We have conducted many experiments at etween 1.9 to 3.7 Bq g-! (50 to 100 pCi g-!) wet weight, the potassium treatment has reduced [the 137Cs Bikini Atoll to evaluate methods to mitigate concentration to less than 0.37 Bq g-! (10 pCi g-}). eee ce nH the 137Cs dose from the terrestrial food chain. Table 18. Comparison of the maximum annual intake (MAI) on Rongelap Island with the sifted ICRP annual limit on intake (ALI) for 137Cs, ®Sr, 39+240Py, and 241Am. Nuclide B7Cs_ Sr MAI on Rongelap@ Imported foods Imported foods available unavailable (Bq) (Bq) 1.1 x 104 1.7x 102 2.8 x 104 Adjusted ICRP ALIb (Bq) 5.0 x 104 5.5 x 102 3.0 x 104 MAI asia fraction of the ALI when imported foods are avdilable 0.22 0.0057 239+240Py (ingestion) 4.4 11 2.0 x 103 0.0032 241Am (ingestion) 2.6 4.7 1.5 x 108 0.0047 239+240Py (inhalation) 0.037 0.037 15 . 0.0035 241Am (inhalation) 0.028 0.028 15 0.0099 a Maximum annual intake based on data and models described in text. This value becomes legs each year, declining exponentially with the 30-y half-life of 137Cs (2.3% per year). b The ICRP ALI (ICRP, 1991b) is divided by 20 to adjust the ALI, which is based on an effective dose of 20 mSv y-! (2000 mrem y-1), to a general population ALI based on aneffective dose of mSv y~! (100 mrem y-!) (ICRP, 1991a; NCRP, 1987b). 35