Food Wrapper Coating Found in Human Blood

May 15, 2009 -- To the growing list of chemicals showing up in human blood, a new study adds compounds that make food wrappers grease-proof.

Called diPAPs, these chemicals are fairly new and scientists don't yet know if they are harmful to human health. But diPAPs break down into another worrisome chemical, called PFOA, which may be carcinogenic.

"The take-home message is that some chemicals that make our lives easier, better and more satisfying end up in our bloodstream with unknown toxicological consequences," said Scott Mabury, a chemist at the University of Toronto. "We should be smart enough to design chemicals that do what we want them to do without causing a chemical pollution problem."

The new study builds on accumulating and worrisome research into a class of compounds called perfluorochemicals. PFOA (perfuorooctanoic acid) is a major one. PFOS (perfluorooctane sulfonate) is another.

PFOA and PFOS are resistant to oil and water, which makes them perfect for use as liners on carpets, nonstick pans, microwave popcorn bags, clothes, electronics and pizza boxes, among many other applications. The problem is that these compounds end up in the environment, our food and our bodies.

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Scientists have found perfluorochemicals in every human blood sample they've tested, Mabury said, often at relatively high levels. In animal experiments, PFOA and PFOS have been linked to cancer, developmental problems and other issues.

Polar bears in the Arctic harbor particularly high levels of PFOA, which confused scientists at first but then led them to discover a large number of precursor chemicals that can escape their sources, fly through the air and end up in animals in remote locations, where the chemicals break down into PFOA.

Mabury was interested in learning more about an overlooked precursor: diPAPs (polfluoroalkyl phosphoric acid diesters), which are used to make food wrappers resistant to grease. These chemicals were designed to stick to the paper, but Mabury suspected that they were getting out of the wrappers and into the food. Because diPAPs break down quickly, he thought that evidence of human contamination would be difficult to find.

The researchers used a highly sensitive, $500,000 mass spectrometer to analyze 20 samples that combined the blood of 10 people. To their surprise, their results, showed levels of diPAPs that were just as high as levels of PFOA in human blood.

It's the first time anyone has found these chemicals in our bodies. And the findings, published in the journal Environmental Science & Technology, suggest that diPAPs are contributing a significant portion of the PFOA found in human blood, Mabury said -- maybe 10 percent or more.