Last week, the news was all about the deterioration of Dutch groundwater quality and the resulting stress on drinking water production. This was the perfect reason for me to attend the 10th International Groundwater Quality Conference (GQ19) in Liège together with three of my colleagues (Arnaut van Loon, Bas van der Grift, and Niels Hartog).
GQ19 is, after ISMAR10 in Madrid, the second conference I attended as a starting researcher this year. The main thing I liked about both conferences is meeting people from the same field of research and discussing the groundwater problems and solutions in their countries.
Geogenic arsenic contamination
I presented a case study about a well field of Brabant Water in Tilburg, where the drinking water production from shallow groundwater is mainly threatened by high concentrations of sulfate resulting from anthropogenic contamination. Partly due to this quality issue, groundwater extraction wells were also placed in deeper groundwater. However, geogenic arsenic mobilisation from glauconite weathering threatens the drinking water production at these depths. Thus, we should not only be aware of anthropogenic contamination affecting the groundwater quality from above but also look for potential geogenic hazards in the deeper subsurface. It was interesting to see in another talk that De Watergroep conducted a parallel study where they found the same arsenic problem in Lommel, close to the Dutch border in Belgium.
In the Netherlands, we are currently planning to adapt four-dimensional groundwater protection: by surface area (2D), depth, and time. There are already strict regulations for drilling activities. Thereby, the Dutch government has quite good control of what happens in the subsurface. This is not the case in, for example, Brazil or Mozambique, where almost all groundwater extraction wells are private and not registered. Consequently, protection of groundwater sources might seem a mission impossible. If our groundwater quality is already deteriorating, what might be the status of groundwater in densely populated second and third world countries?