The RIVM public health institute has known for years that the chemical PFAS was in eggs all over the country, but it was not until December that people in the Dordrecht region who keep chickens as a hobby were warned not to eat their eggs, broadcaster NOS said on Friday.

Wageningen University research dating back to 2015 showed that PFAS was in eggs produced by hens that were being kept as a hobby, NOS said. The chemicals are linked to cancer and other health issues.

Last December, the local Dordrecht health board and the RIVM said people in the region should not eat the eggs produced by their own hens because of the risks. That decision was taken after research showed the concentrations of PFAS in the eggs were higher than considered responsible by the European Union.

That research was carried out on farms near the Chemours chemical plant which had been releasing PFAS into the environment for decades. 

However, two weeks ago, NOS said its own research had revealed the presence of PFAS in eggs from hens as far away as Friesland, Utrecht and Limburg, leading the RIVM to call for nationwide research.

But, NOS said, almost 10 years ago a researcher at Wageningen University carried out checks on eggs from 73 different hen keepers and 22 professional farms. In eggs from the farms, there was virtually no PFAS but concentrations were much higher in the eggs produced as a hobby. 

Under current limits, half of the eggs from the hobby farmers would not have been approved for sale because the concentrations were too high, NOS said.

A spokesman for the RIVM said recommending that people who kept a few chickens not eat the eggs is a decision not to be taken lightly. “If we give such a recommendation, we need to be sure it is necessary,” he said. The food safety board, he pointed out, is currently working on a risk assessment on PFAS in eggs.