As the population on earth increases beyond six billion, the demands for clean water are rising and therefore, groundwater utilisation as source for drinking water has been increasingly used in many parts around the world.
The increased groundwater utilization has caused several health issues, due to the presence of geogenic toxic pollutants such as arsenic, uranium, selenium etc. In particular, the contamination of groundwaters with arsenic is a worldwide problem with millions of affected people.
In South East Asia (Bangladesh, Vietnam, West Bengal, Nepal, Cambodia, Mongolia) over 50 million people depend on groundwater with arsenic concentrations higher than the local limits of 50 µg/L and over 500 million people might consume water with arsenic over the WHO, USA and EU limits of 10 µg/L. In the USA more than 13 million people, mostly in Western States, consume drinking water with more than 10 µg/L arsenic.
In Europe, many regions are affected by elevated arsenic concentrations (Hungary, Romania, Greece, Spain, Finland, Germany). The situation is particularly severe in some regions of Eastern and Southeastern Europe where smaller communities depend on local ground water resources that are contaminated with arsenic and according to the EU directive 98/83 , all drinking water sources within the European Union should have complied with the new limits by 12/2003. However, until to date, in Hungary and West Romania, almost 400 thousand people depend on drinking water contaminated with arsenic concentrations over 50 µg/L . In Northern Greece more than 150 thousand people use groundwater, which contains arsenic concentrations between 40-140 µg/L, whereas the respective tap water was found to contain arsenic in the range 15-30 µg/L .
 Nordstrom, D.K. (2002) Worldwide occurrences of arsenic in groundwater. Science 296, 2143-2145.
 European Commission Directive, (1998), 98/83/EC, related with drinking water quality intended for human consumption, Brussels, Belgium.
. Mitrakas, M., 2001. A survey of arsenic levels in tap, undergroundand thermal mineral waters of Greece. Fresenius Environ. Bull. 10 (9), 717-721.
Yiannis Katsoyiannis ist Gastwissenschaftler an der Technischen Universität Berlin im Fachgebiet für Wasserreinhaltung und beim Umweltbundesamt Abteilung Trinkwasser. Als Stidpendiat der Alexander-von-Humboldt-Stiftung entwickelt er Methoden zur Uran- und Arsenentfernung aus dem Grundwasser mit Hilfe biologischer Behandlungsmethoden.