The recommendations are based on the conservative assumption of a nonthreshold linear relationship between radiological dose and the health effect. The assumption of no threshold means that any nonzero dose yields a nonzero effect detrimental to health. Evaluation of risks using this assumption probably results in overestimates of risks. Values for annual dose limits in various situations are jlisted in Table 5-2. These limits represent the recommendations of the FRC. For application to the Enewetak Atoll, the United States Atomic Energy Commission Task Group Report recommends that the values needed to evaluate cleanup alternatives should be the FRC guides, reduced by 50 percent for annual doses to individuals, and by 20 percent for the 30-year gonadal doses, because of uncertainties in field measurements. These values are shown in Table 5-3. These reductions in the average population dose are made because of the uncertainty concerning dose estimates which depend greatly on the foods that the people will choose to eat and the way they will choose to live. In addition, these recommendations follow the general guidance of the FRC to provide allowances for exposures from beneficial nonmedical uses of radioactive materials. 5.4 LIMITING AND CONTROLLING HAZARDS The methods examined for limiting radiological hazards on Enewetak Atoll are: (1) the control of the diet of the Enewetak people and, by implication, their agricultural and food gathering practices; (2) the control of residence of the population throughout the islands of the atoll; and (3) the cleanup of radioactive materials. 5.4.1 Control! of Diet and Food Sources : §.4.1.1 Internal Dose and Food Source. Radiocontaminants in foods come directly from the soil in which food plants are growing. Radiological gyrveys of Enewetak Atoll have found evidence of uptake of 37Cs and Sr, among other radionuclides, in both edible and inedible plants. Indigenous plants used for food that incorporate radionuclides from the soil include coconuts, pandanus, breadfruit, and arrowroot. Human internal radiation exposure is directly related to the amount of fruit of these plants ingested by the individual. The surveys also report radionuclides in the flesh and organs of indigenous fauna, such as terns, rats and land crabs. Internal doses will increase as a result of eating flesh from local birds and crabs, or from domestic animals such as poultry and swine, which have foraged on radioactive plants. Consequently, an effective dose reduction procedure would be simply to restrict the islanders' use of these foods. Lacking such controls, the penalty would be the accumulation of large radioactive doses for the individual utilizing such food sources.