URINARY-EXCRETION OF PU-239 BY THE GENERAL-POPULATION - MEASUREMENT TECHNIQUE AND RESULTS

A technique for measuring ultra-low levels of Pu-239 in urine samples from persons without any occupational exposure has been developed in t his laboratory. We have analysed urine samples ranging from 200 ml to 81. Briefly, the technique involves co-precipitation of plutonium, dis solution in 8N HCl + Cl2 and separating plutonium through anion exchan ge columns. Plutonium is eluted directly onto lexan slides in four dro ps. The slides are dried, packed in a 'rabbit' and sent to a well ther malised research reactor for irradiation to a fluence of 10(17) n.cm-2 . Subsequent to irradiation, tracks are elicited by etching in caustic solution and optically counted. The mean recovery of plutonium was 72 % and the detection limit for a 4 litre urine sample was 0.2 muBq.l-1. The results suggest that urinary excretion of plutonium in persons bo rn in 1958 or earlier which range from -0.08 to 3.4 muBq.l-1 with a me an of 0.6 muBq.l-1 and median of 0.4 muBq.l-1, exceeds that from perso ns born after 1961 which showed a mean of 0.3 muBq.l-1.