In order to understand the interaction between groundwater, surface water and sediments, there is a need for speciation analysis of trace elements in the mentioned matrices. This could be done experimentally or by calculation with e.g. thermodynamic codes. This article will give a short overview of methods with some examples and results. Speciation in water could be determined by thermodynamic calculations with e.g. PHREEQC or Visual MINTEQ. Experimental speciation in water could be done by ultrafiltration or dialysis in situ. If applicable, in situ dialysis in the field is simple with little need of equipment. Speciation of trace elements in drinking water is of special interest to assess possible health effects. Speciation of trace elements in sediments and soils can be done by any one of the numerous selective extractions. Which speciation approach depends on which trace elements are of interest. A common need is to get information about plant uptake of specific elements.