Science - March 31, 2005

Yet another worry for toxicologists

We already have PCBs, dioxins and flame-retardants to be worried about, and now we have perfluorinated compounds as well. Researchers at Wageningen UR are participating in European researcher projects on this new category of potentially dangerous substances in the environment.

In the late Nineties an American research laboratory discovered that the substances might cause environmental problems in the western world. Traces of the compound perfluoro-octane sulfonate were found in the blood of production workers at chemical giant 3M. This is a substance used to make water and dirt repellent clothing materials such as Gore-Tex and Teflon.

It was not that surprising that employees had traces in their blood, as 3M produces the substance. But when the lab also analysed blood samples from people who had nothing to do with 3M, they found that the compound was present in the blood samples. Samples flown in from the Netherlands gave the same results, and so it seemed as though a synthetic compound had crept unnoticed into human bodies over the whole world.

‘These perfluorinated compounds (PFCs) accumulate at the top of the food chain, in the same way as PCBs,’ explains Professor Jacob de Boer of the Toxicology group and head of Environmental Research at Rivo. ‘The compounds attach themselves to sediments and cell walls in organisms.’ PFCs are found in some plastics and also in protective sprays for leather jackets, shoes and furniture.

PFCs are not substances that are attracted to fats, as PCBs are. Scientists have found them mainly in kidneys and livers of animals. De Boer emphasises that just because scientists suddenly seem to be finding PFCs everywhere does not mean that they have only just arrived in the environment. ‘Perfluorinated compounds attach themselves to glass, so you only find them in blood if you have been using plastic test tubes. When we did not know that, we were not aware of the problem.’

It is not yet known how dangerous PFCs are. ‘If you give rats large quantities you do not see much effect, other than their eyes start to run,’ says De Boer, who also works for the European Food Safety Authority. Together with other colleagues he is now trying to find out more about the toxic effects of perfluorinated compounds. / WK