Selenium determination in cereal plants and cultivation soils by radiochemical neutron activation analysis

Selenium (Se) is an essential micronutrient for human health but it is deficient in at least 1 billion people around the globe. Cereals are by far the most significant agricultural crops, not only on a gross tonnage basis, but also by what they represent in terms of energy supply and dietary intake for human nutrition worldwide. Portugal is no exception to such pattern. The Portuguese situation is difficult to assess though, due to scarce information and lack of consistent studies on the subject. In these terms, the Se status of major cereals and their cultivation soils are dealt with herein. Two species of wheat-bread and durum wheat-were sown at the end of November 2009, and then sampled in different growth stages. Rye was collected during harvest season, and cultivation soils were analyzed as well. Se results were within the range of: 100-225 ng g(-1) for soils; 3-55 ng g(-1) for durum wheat; 6-80 ng g(-1) for bread wheat; and 4-30 ng g(-1) for rye. Accuracy of the RNAA procedure was proved by analysis of reference materials NIST-SRM 1515 and NIST-SRM 8433.