Regional geochemical, hydrogeological and hydrochemical studies are one of the important directions of geological mapping. Analytical geochemical and hydrochemical works are the most important source of information when compiling mineral maps and their regularities and forecasts, ecological and geological schemes, lithological maps of the bottom surface of the water area. Compiling the leading geochemical basis and a scheme of geochemical knowledge is a mandatory methodological requirement for GK-1000/3 and GK-200/2. Geochemical and radiogeochemical studies are also carried out as part of research projects (including international ones) performed by VSEGEI in cooperation with geological services of world countries. Work on regional geochemistry, hydrogeology and hydrogeochemistry is carried out by the regional geochemistry department.