Residents, tourists advised not to swim in pond near Dordrecht Chemours factory

The province of Zuid-Holland has extended its advice not to swim in the recreational lake Merwelanden, which is a few kilometers from the Chemours factory in Dordrecht, until at least October. The province has extended this warning after a follow-up study by the RIVM into the risks of swimming in the lake.

On July 14, the province issued negative swimming advice for Merwelanded because of PFAS, a collective name for chemical substances that can be harmful to health, found in the water. After the initial findings, the RIVM conducted a follow-up study on behalf of the province and the Ministry of Infrastructure and Water Management.

The RIVM calculated how much PFAS people can ingest when swimming in Merwelanden. For children, exposure can be as high as half the tolerable daily intake (TDI) of PFAS. That is based on 25 swimming days per year. For adult swimmers, it is 10 percent of the tolerable intake within 25 swimming days. “If people ingest more PFAS for a long time than this health-based limit value, harmful effects on health are possible. Because people also ingest PFAS through food and drinking water, for example, regular swimming in the recreational lake Merwelanden makes the total intake of PFAS too high,” said the RIVM.

In a July report, the RIVM assessed 13 swimming and recreation locations in the Hollandse Delta and Rivierenland water boards. The RIVM concluded that swimming was okay in twelve places, but Merwelanden required further investigation.

Responsible deputy Frederik Zevenbergen cannot yet say when swimming in Merwelanden will be safe again. “We will continue to monitor the safety quality closely. And the province will continue to ensure that parties continue to talk to each other to improve the situation where possible.”

The chemical factory Chemours, a producer of plastics, has been in the news in recent months. Zembla revealed after an investigation that the management of Chemours and predecessor DuPont had concealed for years that the groundwater around the factory had become contaminated with PFAS. The broadcast sparked outrage among political parties and locals.