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There is increasing alarm about the extent of micro plastic pollution, which has been found everywhere from Everest to the Arctic. However, it turns out there’s an even smaller and more poisonous form of plastic pollution entering remote reaches of the globe. A new study published in Environmental Research found significant quantities of nanoplastics in ice samples from both the North and South Poles.

“Now we know that nanoplastics are transported to these comers of the Earth in these quantities. This indicates that nanoplastics are really a bigger pollution problem than we thought,” study lead author Dusan Materic said in a press release.

Nanoplastics are plastics that are smaller than a micrometer in size. Their small size means they are more difficult to study than microplastics, or plastics between five millimeters and a micrometer. But they maybe even more dangerous.

“Nanoplastics are very toxicologically active compared to, for instance, microplastics, and that’s why this is very important” Materic said.

Materic and his team used new methods to measure nanoplastic pollution in ice samples from Greenland and Antarctica. They sampled a 14-meter-deep ice core (核) from the Greenland icecap and sea ice from Antarcia’s McMurdo Sound. They found that there were an average of 13.2 nanograms per milliliter of nanoplastics in the Greenland ice and an average of 52.3 nanograms per milliliter in the Antarctic ice.

But what was even more surprising than the amount of nanoplastics in the remote ice was just how long they had sat there. “In the Greenland core, we see nanoplastic pollution happening all the way from the 1960s. So organisms, despite the lack of the solid evidence, likely all over the world, have been exposed to it for quite some time now,” Materic said.

The study also looked at the types of plastic present in the samples. Half of the Greenland nanoplastics were polyethylene (PE), the kind of plastic used for plastic bags and packaging. A quarter came from tires and a fifth were polyethylene terephthalate (PET), which is, used for clothing and bottles.