The study is part of a research project, `Radioactivity problems within the food sector` performed in 1991-94 at the request of the National Board of Agriculture in Sweden by The National Research Establishment, Dept. of NBC Defence, and the Dept. of Radioecology and the Dept. of Biosystems and Technology, the latter two belonging to the Swedish Univ. of Agricultural Sciences. The aim of the study was to investigate the contamination levels that may occur in agricultural crop products in Sweden in a situation of radioactive fallout from the use of nuclear weapons. There is a risk for a major nuclide transport in agricultural systems by the feeds, mainly by pasture grass and silage and hay crops but also to some extent by grain crops. For that reason, cattle are expected to be important vectors of the fallout nuclides to the human diet, particularly in milk from dairy cattle but also in beef. The activity transport by grain to pig products may also be of some importance. 8 refs, 7 figs, 25 tabs.