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> Home > Water and soil > Water-quality

Water quality

Studies of the transport and transformation of xenobiotics in the aquatic environment and the soil for use in groundwater protection.

The composition of geological formations is crucial for the quality of the groundwater flowing through the geological layers. Anthropogenic activity on the Earth's surface also affects the groundwater, in that chemical substances may leach down into the groundwater and affect the quality of the water..

GEUS’ activities in brief

In its capacity as the national geospecialist data centre, GEUS collects data on groundwater quality through monitoring programmes. GEUS also conducts research into factors that can lead to undesirable water quality in the groundwater zone. This includes natural geochemical processes which influence the chemical composition of the water, the transformation of nitrates from farmland, leaching of pesticides, as well as leaching of xenobiotics.


Geological processes and water quality

In Denmark, groundwater is pumped up from geological layers that differ considerably in composition. The content of minerals in these geological formations, as well as the organic substances embedded there, are vital for the quality of the groundwater pumped up. For a number of years now, GEUS has been carrying out studies in this field. For example, GEUS has examined the increased oxidation of the reduced layers in chalk reservoirs and the subsequent release of sulphate and nickel with the formation of hard groundwater. Furthermore, GEUS has carried out a study of naturally occurring arsenic in groundwater resources in Denmark and in Vietnam. For more, see Capacity building ((LINK)).


Xenobiotic substances in groundwater

Modern society utilises a number of chemical compounds in industrial production, food production, energy generation and in households. Experience has shown that we are not always able to manage these substances without some waste, so residues may occur in the groundwater. GEUS has considerable expertise in the fate of xenobiotics in groundwater. For example, GEUS has considerable knowledge about how pesticides or their degradation products are degrated and how they are bound up to soil particles and sediment particles. GEUS runs a warning system which monitors whether pesticides are leaching into the groundwater. The Danish Pesticide Leashing Assessment Programme is part of GEUS’ monitoring programmes. Leaching, transport and transformation of nutrients such as nitrate are also areas which GEUS addresses in its research. GEUS also examines the risks associated with the use of new chemical compounds. Most recently, GEUS has examined the risk of leaching of residues of medicines in vulnerable groundwater aquifers.


Water quality