The concentrations of the chemical GenX in tap water in Zuid Holland remains under the legal limits, the public health institute RIVM said on Friday.

However, any increase in the amount of GenX being discharged into the rivers will lead to the legal limit being broken, the RIVM said, adding that this means ‘close monitoring is necessary’.

In July the AD published research showing the chemical is present in tap water in at least six places in Zuid-Holland province, where a factory using the chemical is located.

GenX is used by the Chemours chemical plant in Dordrecht for the production of the non-stick substance teflon. The company has a permit to pump 6,400 kilos of waste water containing GenX into the river but moves are underway to reduce the discharge to 2,000 kilos and then a stop altogether.

In May it emerged that blood tests on people living close to the former DuPont chemical plant showed that some have too much of another toxic chemical, C8, in their blood. C8 was used in the production of Telfon until 2012 when it was replaced by GenX.