A global inventory of groundwater quality : first results

Groundwater quality is deteriorating worldwide due to anthropogenic impacts and it may be limited naturally as well. We present a first overview of groundwater quality at a global scale as part of the Global Groundwater Information System of the International Groundwater Resources Assessment Centre. The groundwater quality overview consists of 11 attributes that refer to individual compounds, occurrence of anthropogenic pollution and other quality problems. It considers individual countries or other large administrative units and is qualitative because source material is qualitative. The latter complicates intercomparison and limits true insight into the current status. However, global patterns can be recognized. A need exists to transform the insights per country into hydrogeochemical insights in order to identify the poor-quality regions within an identified country as well as to identify probable problem areas in not-yet identified countries. Such a process-based probability approach is developed for F-rich groundwater.