Publication Abstract

Radiological Assessment of Ocean Radioactivity

G.J.Hunt

This chapter begins by setting out the radiological quantities and criteria for protection when assessing ocean radioactivity. The radiological protection standards are those promulgated by the International Commission on Radiological Protection (ICRP). A sophisticated system has evolved to protect man and whilst this has been sufficient in most environments to protect other species, a framework for protection of other species is being considered and this is outlined.

The radiological assessment process is then described using a pathway approach with simple models as examples to describe the consequences of the different marine environmental processes. Ingestion, inhalation and external dose assessments are discussed. For assessment of compliance with dose limits, the selection of an appropriate "critical group" is a central feature, and this is based on the results of habits surveys. Collective dose is also a consideration in the ICRP methodology and this too is described.

There is then a comparative assessment of sources of ocean radioactivity, looking first at doses due to natural radionuclides, then those due to artificially-enhanced natural radioactivity. Artificial sources due to weapons-test fallout, operations of the nuclear industry, ocean dumping of solid radioactive waste, dumping in the Arctic, and the effect of the Chernobyl accident are all compared in terms of critical group dose and collective dose. Though there are fluctuations near particular sources, generally the highest doses from marine sources derive from natural radionuclides, followed by those from artificially-enhanced natural radionuclides. Weapons-test fallout is the next most significant source of dose in collective terms, but being diffuse, individual doses are very low. Doses via marine pathways due to the nuclear industry, waste dumping operations and the Chernobyl accident have also produced low doses by comparison with natural sources. The differences are illustrated with suitable graphs.

Reference:

G.J.Hunt, 2004. Radiological Assessment of Ocean Radioactivity. pp205-236 In: Marine Radioactivity (Hugh Livingston (ed.)) Elsevier Science, Amsterdam. 310pp.