Rusty nails adsorb trace plutonium from the environment

Discarded rusty iron objects in the environment adsorb trace plutonium mobilized by oxygenated surface waters (e.g. rain, snow melt). Radiochemical and mass spectrometric analysis of the surface oxide coating of modest collections of rusty nails retrieved from remote locations provides a global fallout plutonium signal of up to 2 x 1010 atoms of 239Pu per sample. The median 239Pu measurement for 10 samples from five locations was 2.82 x 109 atoms. The average 240Pu/239Pu atom ratio was 0.176 ± 0.012, consistent with the value accepted for global fallout. (author)