Researchers find six common plastics generate reactive chemicals in water
A study published in Nature by researchers at Columbia University and the University of California, Berkeley found that six common plastics spontaneously generate hydroxyl radicals when in water. In laboratory tests, the radicals were associated with protein clumping and damage to mouse red blood cells, but the researchers have not established whether the process harms people.
Bottom line — Polyethylene and polypropylene produced the most radicals; human health effects remain unproven.
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The study tested polyethylene, polypropylene, polystyrene, PVC, PET and acrylic.
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According to the researchers, the most water-repelling plastics—polyethylene and polypropylene—generated the most radicals; PET and acrylic generated the least.
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The researchers found that lysozyme, a test protein, clumped on polystyrene particles; adding caffeine, which can neutralise radicals, reduced the clumping.
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In experiments reported by Ars Technica, mouse red blood cells exposed to polystyrene fragmented, and haemoglobin leaked out.
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The study’s simulations suggested that water molecules at hydrophobic plastic surfaces make it easier for hydroxide ions to form hydroxyl radicals.
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The researchers have not established how particle size, environmental ageing or exposure levels affect the reaction in people.
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The Columbia team and collaborators are studying where micro- and nanoparticles travel in tissues and whether they pass from mothers to offspring in animal models.