BACKGROUND C-14 LEVELS IN UK FOODSTUFFS, 1981-1995, BASED UPON A 1992SURVEY

Knowledge of the current 'natural' background level is important to C- 14-related studies, especially dose assessments in the vicinity of and distant from nuclear establishments since its value must be subtracte d from measured levels to determine local enhancement. Although measur ements have been made world-wide to monitor the decline of the backgro und level, from its peak in the early 1960s to the present, there exis ts a paucity of precise data for UK natural materials. Accordingly thi s study was carried out to establish an average figure for the 'natura l' C-14 level in foodstuffs in 1992 from a survey of materials collect ed from a wide range of sites over England and Wales, using this singl e year value, to infill missing years prior to 1992 and to extrapolate d for some years afterwards. Results are presented from the survey, an d from the derived extrapolation with comparison made with measurement s from other laboratories. Copyright (C) 1996 Elsevier Science Ltd.