Analysis of environmental contaminants in human biological material for moni- toring calls for precise specification and standardization of all sampling methods before the activities proper are started. Selection of relevant biomarkers (analy- tes) in the appropriate matrices, assessment of the required number of specimens, selection of the method and time of sampling, suitable receptacles, storage of samples and all further manipulations must be recorded in writing, consistent with requirements of proper laboratory practice.

        Key words: biological monitoring - sampling - trace elements