Variation of selenium concentration in toenails following long-term storage, washing and reactor irradiation

Neutron activation analysis of toenails is often used to monitor body selenium in studies looking for an association between selenium deficiency and an increased cancer risk. In this study, 87 toenail samples were analyzed for Se four times, using neutron activation with 17.4-second 77mSe, to determine the possible systematic effects of long-term storage, the washing procedure, and irradiation in a nuclear reactor. The mean Se concentration found was 0.92 μg/g, standard deviation 0.14 μg/g. The results showed that the Se concentrations are unaffected by washing and neutron irradiation, but the samples lost moisture during storage causing a 2% increase in the mean Se concentration. (author)