Marine Environmental Radioactivity-The Missing Science?

摘要

In paying attention to the specific needs of radiological protection and the protection of man and the environment from ionizing radiation, insufficient attention has been paid to the identification of prime processes which control the distributions of radionuclides. A major omission has been a failure to optimize the use of cost effective direct observational data for the in situ distribution of radionuclides in sediments by autoradiographic techniques. Here I consider the distribution of alpha particle radioactivity, together with some actinides in marine/ estuarine sediments of the Cumbrian coast, England. Today, the alpha particle radioactivity from Pu, Am and Cm, originating from authorized low level discharges of effluents into the NE Irish Sea from the British Nuclear Fuels plc plant at Sellafield, is associated with three main phases: BNFL hot particles, the minerals haematite and magnetite and hydrated iron oxide flecks which are associated with quartz grains. The receiving environment contains large quantities of industrial iron together with other elements, from haematite mining, blast furnace production of iron, coal mining and phosphogypsum wastes. These wastes have interacted with the radionuclides, but as the industrial activities have now ceased, future distributions of alpha emitters are likely to be different and existing transport-dispersion models may not be suitable. Preliminary evidence indicates that the rate of loss of stable and radioactive elements from coastal waters may have increased. This applies to most of the UK coastal waters. In order to understand the behaviour of radionuclides in marine and estuarine systems, site specific characteristics must be recognized. The use of global values and vague operational concepts in order to account for radionuclide distributions has limited scientific meaning.