One dramatic source of man-made radioactivity is a nuclear weapons test. The glassy trinitite created by the first atom bomb contains radioisotopes formed by neutron activation and nuclear fission. In addition some natural radioisotopes are present. A recent paper reports the levels of long-lived radioisotopes in the trinitite. The trinitite was formed from feldspar and quartz which were melted by the heat. Two samples of trinitite were used, the first (left-hand-side bars in the graph) was taken from between 40 and 65 meters of ground zero while the other sample was taken from further away from the ground zero point.