New pesticide discovery closes two waterworks in Copenhagen area

Pesticide residue Dimethylsulfamide found in capital area’s water supply

Two waterworks in the Copenhagen area have been shut down following the discovery of the pesticide residue Dimethylsulfamide in eight out of 14 HOFOR waterworks.

The waterworks in Hvidovre and Dragør have been hit particularly hard and have been temporarily closed. Dimethylsulfamide isn’t on the list of pesticides that waterworks must test for, but the capital region’s water supplier HOFOR decided to test for the relatively unknown residue anyway.

“The residue probably stems from fungicidal products that have been used for fruit and plant development and in the wood product industry. It hasn’t been found in Danish waterworks before and therefore hasn’t been among those tested for by the waterworks,” HOFOR wrote.

“We have asked the Danish Patient Safety Authority to come up with a health-orientated evaluation of the residue.”

READ MORE: Drinking water in several areas of Denmark contaminated with pesticide

Long-term consequences?
HOFOR wrote that it expects the residue will be included on the list of components tested for by waterworks as of July 1.

Dimethylsulfamid will therefore become the third residue added to the obligatory testing program within the past year after other surprising finds in groundwater and drinking water well samples.

The Danish Patient Safety Authority doesn’t believe the water presents a serious health risk, but because of the lack of tests available on the residue, it’s difficult to say what the long-term health impact might be.

“We don’t know much about this residue. It’s probably not carcinogenic, but outside that we don’t really know much,” Hans Sanderson, a senior researcher at Aarhus University, told DR Nyheder.