Plastics don’t decay in the environment like organic material; they just break up into smaller and smaller pieces. And those pieces are turning up in the bodies of shellfish, seabirds, and terrestrial animals like earthworms. And a small pilot study led by an Austrian researcher recently found bits of plastic in every sample of feces from the eight people from around the world who took part in it.
This has raised concerns about human health as well. Harmful chemicals known as persistent organic pollutants such as dioxins, PCBs, and DDT can bind to plastics.
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The United Nations Food and Agriculture Organization has called the human health risk “negligible,” since people remove the digestive tracts from most fish before eating them. But some species of shellfish or small fish like sardines are eaten whole. And Dave Love, an environmental scientist at the Johns Hopkins University Center for a Livable Future in Baltimore, points out that there are many unanswered questions about microplastics.
“We don’t really know enough to understand the implications for human health,” Love told Seeker. “We need to do a lot more work around human exposure.”
The risks may be “quite low” for people, he said, but it will take scientists some time to know that for sure — and in the meantime, they’re still harmful to wildlife like birds and turtles.
“Most of the work has been done on an individual organism level, and there hasn’t been a lot of work understanding the impacts on population, such as a school of fish,” Love said.
He recently co-authored a paper that laid out a list of these unanswered questions concerning the sources of microplastics, their chemical properties, how they degrade in the environment, their impact on ecosystems, and their toxicity to humans.
When it comes to plastics, the biggest contribution citizens can make to help mitigate the pollution crisis is to make sure that their plastic materials are properly disposed of or recycled — and to use less of it in the first place.
“After writing this paper, when I go grocery shopping, I specifically look for foods that don’t have a whole lot of packaging because I know that will end up in a landfill,” Love remarked. “I try to get low packaging, and if I can, compostable or recyclable packaging.”