Measurement of curium in marine samples

Measurements of environmentally small but detectable amounts of curium requires reliable, accurate, and sensitive analytical methods. The radiochemical separation developed at Woods Hole is briefly reviewed with specific reference to radiochemical interferences in the alpha spectrometric measurement of curium nuclides and to the relative amounts of interferences expected in different oceanic regimes and sample types. Detection limits for 242Cm and 244Cm are ultimately limited by their presence in the 243Am used as curium yield monitor. Environmental standard reference materials are evaluated with regard to curium. The marine literature is reviewed and curium measurements are discussed in relation to their source of introduction to the environment. Sources include ocean dumping of low-level radioactive wastes and discharges from nuclear fuel reprocessing activities. In particular, the question of a detectable presence of 244Cm in global fallout from nuclear weapons testing is addressed and shown to be essentially negligible. Analyses of Scottish coastal sediments show traces of 242Cm and 244Cm activity which are believed to originate from transport from sources in the Irish Sea. (orig.)