How our toothbrushes pollute paradise

"Welcome to paradise," says the welcome center of the Cocos Islands (or Keeling). The archipelago is popular with Australian vacationers and it's easy to know why.

The photographs of the chain of twenty-seven islands, only two of which are inhabited, show oceans which are only swirls of transparent turquoise, cobalt and cerulean colors, and a sand so virgin that they look like virgin beaches.

However, a study conducted in 2017 by researchers from the University of Tasmania and Victoria University, both in Australia, revealed that the islands are covered with approximately 414 million pieces of plastic weighing a total of 238 tonnes (about the same). weight of a blue whale). The results were published May 16 in the journal Scientific Reports.

The use of plastics, especially single-use plastics, has exploded since the 1990s, according to Jennifer Lavers, a researcher at the Institute of Marine and Antarctic Studies at the University of Tasmania and lead author of the study. . "This plastic has to go somewhere and a good part ends here, unfortunately, in countries where waste management can not be treated, and ends up in our rivers and oceans," he said.

The problem of plastic in the oceans is twofold: there are many – the study's authors estimate that there are more pieces of plastic in the ocean than stars in the Milky Way – and this causes the death of marine life.

Fish, birds, sea turtles and marine mammals can be caught in plastic packaging of soda and discarded fishing nets, or drown with leftovers if ingested. Studies indicate that some species of marine life not only accidentally ingest plastic, but are also looking for it. Indeed, over time, marine plastic can absorb aquatic odors that make it almost identical to the food of some species of fish and birds. When these animals eat plastic instead of food, they receive a dose of chemicals such as polychlorinated biphenyls (also called polychlorinated biphenyls) and heavy metals that plastic absorbs from the environment.

A study published separately this week in the journal Communications Biology revealed that plastics found in oceans also damaged the prochlorococcus, the marine bacterium responsible for producing 10% of the planet 's oxygen.

Lavers has chosen these islands for study because their relatively isolated location means that there are relatively fewer sources of local pollution and less human activities than beach cleaning. This allowed the team to see how much plastic the world's oceans had deposited on the islands.

Part of the plastic found by researchers was easily identifiable: toothbrushes, food packaging, straws or straws and plastic bags. Single-use plastics made up about 25% of the material found by researchers.

However, about 60% were microplastics, or fragments that break when a piece of plastic is shaken on all sides. These microplastics can only measure 2 millimeters, almost half the size of a grain of rice.

"This would serve as an additional warning: yes, our local actions could have long-range effects," said Thomas Ballatore, a professor at Harvard University, who studied plastic pollution and did not think it would be a problem. did not participate in the study, in an email. to study

Copyright: 2019 New York Times News Service