Microplastics are a growing problem in the world’s oceans. They originate largely with packaging and drink bottles and break up into tiny pieces in the environment. Of the 9 billion-plus tons of plastic produced since the 1950s, about 7 billion have ended up as waste, much of which ends up in pieces smaller than 5 millimeters (about 3/16 of an inch), according to the US Environmental Protection Agency.
The findings — published March 5 in the research journal Environmental Pollution — show that microplastics can pass up the food chain, from fish to a mammalian predator. And those findings raise questions for human health, the authors concluded.
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Microplastics have turned up in seafood like shellfish, which humans consume whole — and the authors of the new study say more study needs to go into how ingesting those substances affect people. Nelms said that’s the planned follow-up to her seal study.
"Given that most of our food is packaged in plastic, it is highly likely we are consuming small amounts of plastic as a result of contamination on a regular basis,” Nelms said. By comparison, the amount of plastic humans end up eating directly through their food “probably makes up a small proportion of the plastic we eat.” But she said even if animals eventually pass the plastic, long-lived toxins can latch onto the particles and enter the body.
“Persistent chemicals, such as PCBs, are known to adhere to the surface of microplastics,” she said. “They can cause endocrine disruption and alterations to immune system function if ingested.” Those chemicals “are more of a concern than the particles themselves,” she said.