Assessment of environmental risks of granular wastes, immobilised in monolithic bodies implies at least three independent, preferably standardised, tests: Weight variations during drying and wetting; leaching with water or dilute acid and determination of the available fraction of the micro-constituent involved. Their accuracy, precision and minimal turn-over time depend on the dimensions of the test specimen and the experimental procedure. They are considered here in relation to the inevitable underlying assumptions and the practical limitation of the turn-over time. Two standard geometries of test aliquots are considered in detail. The use of radioanalysis in the determination of some of the characterising parameters is summarised.