ABSTRACT
UK maximum concentrations allowed – no individual standard set in legislation, but there is a total indicative dose for radioactivity (including gross alpha and gross beta activity) of 0.1 mSv/year. Radon and its decay products however, are specifically excluded from this standard along with tritium and potassium-40. There is a separate standard for the radioactive element tritium (100 Bq/l) but not others. WHO Guideline Value: Gross alpha activity 0.1Bq/l, gross beta activity 1Bq/l.
There is a general degree of public concern about risks from radioactivity and there are regular calls for increased safety within the nuclear industry. However, the most significant risk from radioactivity to human health comes from natural radionuclides. In fact, the nuclear industry’s contribution to average human annual exposure is trivial (O’Riordan and O’Riordan, 1991). The United Nations Scientific Committee on the Effects of Atomic Radiation has estimated that exposure to natural sources contributes more than 98 per cent of the radiation dose of the population, excluding medical exposure. Thus less than 2 per cent of radiation exposure comes from nuclear activities. When medical exposure is included (which is about 11 per cent) natural radiation provides 87 per cent of the total contribution, with radon’s contribution alone being 32 per cent (Castle, 1988).
