This digital document is a journal article from Journal of Environmental Radioactivity, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: Bikini Island was contaminated on March 1, 1954 by the Bravo detonation (U.S. nuclear test series, Castle) at Bikini Atoll. About 90% of the estimated dose from nuclear fallout to potential island residents is from cesium-137 (^1^3^7Cs) transferred from soil to plants that are consumed by residents. Thus, radioecology research efforts have been focused on removing ^1^3^7Cs from soil and/or reducing its uptake into vegetation. Most effective was addition of potassium (K) to soil that reduces ^1^3^7Cs concentration in fruits to 3-5% of pretreatment concentrations. Initial observations indicated this low concentration continued for some time after K was last applied. Long-term studies were designed to evaluate this persistence in more detail because it is very important to provide assurance to returning populations that ^1^3^7Cs concentrations in food (and, therefore, radiation dose) will remain low for extended periods, even if K is not applied annually or biennially. Potassium applied at 300, 660, 1260, and 2070kgha^-^1 lead to a ^1^3^7Cs concentration in drinking-coconut meat that is 34, 22, 10, and about 4% of original concentration, respectively. Concentration of ^1^3^7Cs remains low 8-10y after K is last applied. An explanation for this unexpected result is discussed.