Accelerator mass spectrometry as a powerful tool for the determination of 129I in rainwater

129I is a very long-lived radionuclide (T(1/2) = 15.7 x 10(6) years) that is present in the environment both because of natural and anthropogenic sources. Its environmental interest, for example, as a tracer of geological processes, makes it the research target of a growing scientific community. However, its detection in environmental samples by radiometric methods is very difficult because of its long half-life. In this work, we present the methodology developed for its detection by Accelerator Mass Spectrometry (AMS) in rainwater.