Lab Fish Fed Plastic More Likely To Develop Tumors, Liver Problems

Nov 22, 2013

Scientists have photographed dead whales and seabirds, their stomachs filled with plastic bags and bottle caps. But those larger chunks eventually break down. In fact, the majority of plastic pollution in the ocean, by volume, comes in the form of tiny confetti-sized particles. They’re commonly found in Puget Sound. And new research shows that when fish eat particles of plastic the results aren’t good.

The plastic in the ocean acted sort of like a poison pill for fish, sopping up those pollutants.
Credit epSos .de/Flickr

Chelsea Rochman compared three groups of Japanese medaka, the “lab rat” of fish. Rochman is a postdoctoral researcher at the University of California, Davis in the School of Veterinary Medicine. She fed one group regular fish food. In the other 2 groups Rochman substituted in 10% clean plastic and 10% plastic that had been submerged in San Diego Bay for several months. In the ocean chemicals – like flame-retardants and PCBs – latch on to floating plastic. After two months the fish in Rochman’s lab were analyzed for levels of those chemicals in their bodies.

Rochman: “We did find that the chemicals do transfer from the plastic to the fish and we saw a greater concentration in the fish that ate the plastic that had been in the ocean than the fish that had eaten the virgin plastic or the controlled diet.”

In other words, the plastic in the ocean acted sort of like a poison pill for fish, sopping up those pollutants. Rochman found that the fish that were fed plastic developed liver problems and showed signs of tumor development. It’s unclear if these health effects are happening in fish in the Northwest, but Rochman’s research suggests these chemicals could be making their way into the food chain. Her research was published in the journal Nature Scientific Reports.

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