[en] Aquatic sediment sampling and conservation procedures are dependant on the problems of investigation, and thus require both for radionuclide and geochemical studies special consideration. A general rule is that upon sampling the natural sediment composition and structure should be optimally preserved. Conservation of bottom sediments at 4 deg. C is a good method for material to be used for experiments (e.g. sorption studies), while deep-freezing (-20 deg. C) is best for geochemical and biological analysis of the sediments. Freeze-drying preserves most of its structure and the geochemical speciation of substances. For studies on migration of radionuclides in bottom sediments, investigations on dominant factors are important, among which are mentioned microbiological activities, effective sediment properties like base-exchange capacities and the presence of benthic fauna. Field studies combine with selective experiments and analysis, present opportunities for optimal results. (author)