A survey of present levels of radiocesium in Swedish pulp mill liquors and the implications for wood radiocesium transfer factors

Assessments of the impact from radioactive fallout on the pulp industry and the accumulation processes for radionuclides in such industries, using wood and water as primary raw materials, have been conducted in previous studies. Hitherto, there is a general lack of data on present levels of radioactivity in pulp mill liquors apart from the few mills studied by Nilsson (1992); Ravila and Helm (1992); Manjon et al. (1996); Krosshavn et al. (1997). A survey was therefore initiated to describe and compare the present activity levels in pulp mill liquors from various mill locations in Sweden. The Cs-137 activity in pulp mill liquors were compared with the mill location and the deposition pattern of the Chernobyl fallout and nuclear weapons fallout. The large input of wood (approx 2500 m(3) day(-1)) to an average Nordic Kraft mill and the relatively long-term retention time for radiocesium in the Kraft mill recovery cycle enables representative sampling of substances directly related to the activity concentration in wood. (C) 1998 Elsevier Science B.V. All rights reserved.