Remediation and rehabilitation programmes in the Marshall Islands

Following cessation of nuclear testing in the Marshall Islands in 1958 the northern atolls have been subject to extensive studies of their radiological status with a view to the return of displaced residents. In the case of Bikini an assessment was most recently carried out at the request of the Marshall Islands Government by the IAEA, based on data obtained through the DOE funded studies of Lawrence Livermore National Laboratory and the Nationwide Radiological Study undertaken for the Marshall Islands Government. For a diet of entirely local foodstuffs the mean adult annual dose to residents could be about 15 mSv, and greater than a generic reference level for intervention of 10 mSv/a. A more likely diet with some imported foods, however, would incur annual doses of about 4 mSv. Remediation in the form of potassium fertilizer application, which suppresses the uptake of Cs-137 in plants, has been recommended. In the case of Rongelap Atoll, conditions for resettlement were established in a Memorandum of Understanding (MOU) between US Government agencies and the Rongelap community. This required that annual doses to the maximally exposed resident not exceed I mSv. A number of independent evaluations and reviews found that some residents could exceed this compliance level and again remediation measures have been recommended, primarily the application of potassium to soil. It is, however, doubtful whether any remediation is justifiable on solely radiological grounds. The Rongelap MOU also specified an activity concentration limit for transuranics in soil, but this additional constraint could be considered confusing and unnecessary, particularly when it appeared to have no derivable connection to the compliance dose value. (author)