Radioactivity of137Cs of plant samples taken in former Semipalatinsk Nuclear Test Site (SNTS) was determined. The radioactivity ranged from 0.3 to 81.1 Bq/kg, most of them were under background level but the distribution was localized. Compared to the soil, the plants did not have strong radioactivity, suggesting a potential that plants in this site absorbs radiocesium from soil when the chemical situation of the soil might change, causing fixed Cs turn to be available.
Using ESR spectroscopy, we revealed various free radicals in a Japanese commercially available black pepper before and after γ-irradiation. The representative ESR spectrum of the pepper is composed of a sextet centered at g=2.0, a singlet at the same g-value and a singles at g=4.0. The first one is attributable to a signal with hyperfine interactions of Mn2+ion (7.4 mT) . The second one is due to an organic free radical. The third one may be originated from Fe3+ ion of the non-hem Fe in proteins. A pair of signals appeared in the black pepper after γ-irradiation. The progressive saturation behavior reconfirmed the signal identification for the radicals in the black pepper.