Accumulation of wet-deposited radiocaesium and radiostrontium by spring oilseed rape (Brássica napus L.) and spring wheat (Tríticum aestívum L.)

The accumulation of 134Cs and 85Sr within different parts of spring oilseed rape and spring wheat plants was investigated, with a particular focus on transfer to seeds after artificial wet deposition at different growth stages during a two-year field trial. In general, the accumulation of radionuclides in plant parts increased when deposition was closer to harvest. The seed of spring oilseed rape had lower concentrations of 85Sr than spring wheat grain. The plants accumulated more 134Cs than 85Sr. We conclude that radionuclides can be transferred into human food chain at all growing stages, especially at the later stages. The variation in transfer factors during the investigation, and in comparison to previous results, implies the estimation of the risk for possible transfer of radionuclides to seeds in the event of future fallout during a growing season is still subject to considerable uncertainty. -- Highlights: •Accumulation of 134Cs and 85Sr in plants increased the closer to harvest the nuclides were deposited. •134Cs and 85Sr concentrations in seeds were highest when deposited after flowering. •Activity concentrations of 134Cs in spring oilseed rape were higher than the activity concentrations of 85Sr. •Oilseed rape redistributes 134Cs and 85Sr to seed at a lower rate than wheat redistributes 134Cs and 85Sr to grain. -- Intercepted radionuclides can be transferred into the food chain for humans