For the third year in a row, residues of pesticides, better known as sprays, have been found in more than half of the wells tested. The proportion of positive pesticide tests related to water wells has more than doubled since 2016, the figures show. However, this is mainly due to the fact that significantly more substances were analysed this year. 

Alarming results for drinking water quality
‘De Nationale Geologiske Undersøgelser for Danmark og Grønland’ (GEUS), which was responsible for the drilling, examined 1,431 wells this year. Pesticide residues were found in 55.3 percent of them. The limit values were exceeded in 13.5 percent of the cases.

According to Maria Reumert Gjerding, the head of ‘Danmarks Naturfredningsforening’, this shows that groundwater is not sufficiently controlled and that the protection of drinking water in Denmark is insufficient.

“It is a very clear signal that we need to increase protection significantly,” said Gjerding. However, pesticide residues in Denmark are so low that they do not pose a health risk.

Groundwater parks as a possible solution
Gjerding believes there is a need for what in other countries are called groundwater parks. These are large areas underground where groundwater is formed, which are completely protected from pesticides.

Pesticide residues usually come from farms spraying their fields. Over time, the pesticide residues can seep through the soil into the groundwater. This is why Gjerding also believes that the use of pesticides in areas where groundwater is formed should be banned in the future.