The World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP) provides data and information about the earth´s major groundwater resources. The WHYMAP Viewer provides access to the topics “Groundwater Resources of the World", "World-wide River and Groundwater Basins", "World-wide Groundwater Vulnerability", "Karst Aquifers of the World", and to the “World-wide Hydrogeological Map Information System (WHYMIS)”.

Considering water as the primary resource necessary for social life, agriculture, industry, and wealth, the importance of groundwater investigation is clear. Apart from many other pollutants, this work focusses on geogenic uranium (U) and radium (Ra), which both stand for natural radionuclides (NORM) that need to be considered frame of groundwater exploration and monitoring programmes due to their specific mobility and chemo-/radiotoxicity. As investigation of U and – to a lesser extent - Ra is done by an increasing number of scientific working groups, the global dataset is improving continuously. In order to give a summarized overview on available and recent literature, scientific papers, reports, and governmental documents have been reviewed for U-238 mass concentrations and Ra-226 and Ra-228 activity concentrations and collected in tables and global maps. Further natural isotopes of U and Ra have been rarely subject of investigation. The collected data were evaluated and interpreted in frame of an associated scientific publication (see citation). From the available data it can be concluded that high geogenic U occur mainly under oxidizing conditions and carbonate rich groundwater, which might be seen as indicator for elevated U concentrations. Certain geological formations, as for example sedimentary, granitic, and volcanic host rocks, promote high U concentrations in groundwater. For geogenic Ra, the search for definite indications proved difficult, since less clear correlation is given for any observed factor. In a global perspective, the most promising evidence for elevated Ra are highly reducing redox conditions, as well as the occurrence of Fe/Mn mineral phases. Furthermore, barite represents a sink for Ra due to its ability to incorporate Ra isotopes. Dissolution of those mineral phases eventually results in co-dissolution of Ra, when Ra is found in host rocks of investigated aquifers, or downstream of such groundwater reservoirs. Furthermore, cation exchange might enhance Ra mobility process, especially in case of sedimentary aquifers with low sorption capacity and/or aquifers with high salinity. Given those chemical requirements for the occurrence of U and Ra, a negative correlation between mother and daughter nuclide can be established. When knowledge on present geological and geochemical constraints is available, elevated U and Ra concentrations might be predictable, as long as anthropogenic influence is excluded.

The World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP) provides data and information about the earth´s major groundwater resources. The River and Groundwater Basins Map shows the areal extent of the global groundwater and surface water basins.

The World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP) provides data and information about the earth´s major groundwater resources. The Groundwater Resources Map shows various characteristic groundwater environments in their areal extent and classified by their aquifer productivity and recharge potential. Additional groundwater related features such as wetlands and areas of low rainfall are included in the dataset.

The World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP) provides data and information about the earth´s major groundwater resources. The Map of Global Groundwater Vulnerability to Floods and Droughts indicates the vulnerability level of groundwater resources of the earth. It presents the intrinsic vulnerability of groundwater systems and the sensitivity or resistance of those systems to natural disasters.

The World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP) provides data and information about the earth´s major groundwater resources. The Map of Global Groundwater Vulnerability to Floods and Droughts indicates the vulnerability level of groundwater resources of the earth. It presents the intrinsic vulnerability of groundwater systems and the sensitivity or resistance of those systems to natural disasters.

The World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP) provides data and information about the earth´s major groundwater resources. The River and Groundwater Basins Map shows the areal extent of the global groundwater and surface water basins.

The World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP) provides data and information about the earth´s major groundwater resources. The Groundwater Resources Map shows various characteristic groundwater environments in their areal extent and classified by their aquifer productivity and recharge potential. Additional groundwater related features such as wetlands and areas of low rainfall are included in the dataset.

Considering water as the primary resource necessary for social life, agriculture, industry, and wealth, the importance of groundwater investigation is clear. Apart from many other pollutants, this work focusses on geogenic uranium (U) and radium (Ra), which both stand for natural radionuclides (NORM) that need to be considered frame of groundwater exploration and monitoring programmes due to their specific mobility and chemo-/radiotoxicity. As investigation of U and – to a lesser extent - Ra is done by an increasing number of scientific working groups, the global dataset is improving continuously. In order to give a summarized overview on available and recent literature, scientific papers, reports, and governmental documents have been reviewed for U-238 mass concentrations and Ra-226 and Ra-228 activity concentrations and collected in tables and global maps. Further natural isotopes of U and Ra have been rarely subject of investigation. The collected data were evaluated and interpreted in frame of an associated scientific publication (see citation). From the available data it can be concluded that high geogenic U occur mainly under oxidizing conditions and carbonate rich groundwater, which might be seen as indicator for elevated U concentrations. Certain geological formations, as for example sedimentary, granitic, and volcanic host rocks, promote high U concentrations in groundwater. For geogenic Ra, the search for definite indications proved difficult, since less clear correlation is given for any observed factor. In a global perspective, the most promising evidence for elevated Ra are highly reducing redox conditions, as well as the occurrence of Fe/Mn mineral phases. Furthermore, barite represents a sink for Ra due to its ability to incorporate Ra isotopes. Dissolution of those mineral phases eventually results in co-dissolution of Ra, when Ra is found in host rocks of investigated aquifers, or downstream of such groundwater reservoirs. Furthermore, cation exchange might enhance Ra mobility process, especially in case of sedimentary aquifers with low sorption capacity and/or aquifers with high salinity. Given those chemical requirements for the occurrence of U and Ra, a negative correlation between mother and daughter nuclide can be established. When knowledge on present geological and geochemical constraints is available, elevated U and Ra concentrations might be predictable, as long as anthropogenic influence is excluded.

The World-wide Hydrogeological Map Information System (WHYMIS) offers information on the availability of hydrogeological and other groundwater related maps at national (country) and international (continent) level.