Swimming in Dordrecht lake possible again after PFAS reduction

Swimming in lake Merwelanden in Dordrecht is now permitted again, as measurements showed that the PFAS concentrations are far below the RIVM's advice values. Over a year ago, the province of Zuid-Holland gave negative swimming advice for the lake, which is close to the Chemours factory.

After additional "flushing" of the lake, Waterschap Hollandse Delta determined that the PFAS values ​​have dropped significantly, and the province has withdrawn the negative advice. "We are pleased that we have succeeded in reducing the PFAS concentrations to well below the RIVM limit value and that people can swim responsibly in the lake again this summer," says provincial executive Arne Weverling.

"This is very good news, especially if you are not going on holiday or cannot go to the swimming pools," adds Dordrecht alderman Tanja de Jonge. But there is still work to be done. "We need to investigate further where the PFAS comes from, and it needs to be cleaned up because we are talking about the health of residents here."

The popular recreational lake was flushed in early June, which is also done when there is blue-green algae, for example. The PFAS levels in the water then slowly decreased, after which the flushing was accelerated. As a result, the PFAS values ​​decreased more sharply. In the last two weeks of July, they were at about one-sixth of what the RIVM considers irresponsible for swimming water. The institute determines these values ​​based on the effects of the various types of PFAS has on a person's health.

Swimming in the lake is possible until September 30, the end of the swimming season. Until then, the water will be flushed. Meanwhile, the investigation into the source of the pollution continues. Once that is done, further steps will follow if necessary.

Chemours has previously promised to contribute to the cleaning of the Merwelandenplas. The municipalities of Dordrecht, Papendrecht, Sliedrecht, and Molenlanden have held the plastics manufacturer liable for the pollution of the groundwater by PFAS on their territory. The judge considers this proven for at least the period between 1984 and 1998.