GeoHint: Hydrochemical Geogenic Background Values of Arsenic

The hydrochemical composition of groundwater results from the geochemical makeup of the aquifer and from anthropogenic input.

Map of hydrochemical geogenic background values of near-surface groundwater bodies of arsenic.
Arsenic: Hydrochemical geogenic background values of near-surface groundwater bodies. Simplified after: Hobiger, G. et al. (2007)
© BMLFUW (Ed.) Hydrological Atlas of Austria

To evaluate groundwater quality and to detect possible anthropogenic contamination requires the separation of these two sources of input.

Arsenic: toxic and trace element

Rock of different colors, especially striking a dark red.
Realgar, also known as ruby sulphur, is a commonly occurring arsenic-sulfur mineral and cause of geogenic arsenic in water.
© Geological Survey of Austria

After subtraction of the anthropogenic part, the hydrochemical content of groundwater reflects geological background levels. Arsenic occurs mainly in crystalline rocks and can find its way into the groundwater in such areas.