[en] In generating data to assess the migratory behaviour of radionuclides in groundwaters travelling through 'soil', it is necessary that laboratory experiments are designed to simulate field conditions as closely as possible. This paper aims to place in perspective the relative importance of test parameters, e.g. pH, temperature, groundwater composition, contact-time, which require definition in order to arrive at meaningful distribution coefficients. Experimental procedures are outlined and results for fission products, plutonium, uranium and thorium contacted with a variety of soil types are reported and discussed. 4 refs.; 6 figs.; 4 tabs