Plastic is a life-saving technology. Plastic medical equipment, like disposable syringes and IV bags, reduces deaths in hospitals. Plastic packaging keeps food fresh longer. Plastic parts in cars make cars lighter, which could make them less deadly in a crash. My bicycle helmet is made of plastic. My smoke detector is made of plastic. Baby safety gates: plastic.
But in recent months, several studies have demonstrated the surprising ubiquity of microplastics and the potential danger they represent for our bodies, particularly our endocrine and cardiovascular systems. Today’s guest is Philip Landrigan, an epidemiologist and pediatrician and professor in the Department of Biology at Boston College. Let’s start with the basics: what is plastic? How does plastic become microplastic or nanoplastic? How do these things get into our bodies? Once in our body, what do they do? Are we sure they contribute to disease? What do the latest studies tell us and what should we ask from future research? Along the way, we discuss why plastic recycling doesn’t actually work, the small steps we can take to limit our exposure, and the big steps governments can take to limit our risks.
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In the following excerpt, Philip Landrigan and Derek present the definitions of plastics, microplastics and nanoplastics and explain how they enter our bodies.
Derek Thompson: What are plastics?
Philippe Landrigan: Plastics are manufactured chemical materials made mostly, 99%, from fossil carbon, gas, oil and coal. All plastics have two main components. The first is the polymer, which is the structure, the skeleton of the plastic, and polymers include familiar names like polyvinyl chloride, polystyrene, polyurethane, etc. And then, secondly, chemical additives. At least 16,000 different chemicals, mostly petrochemicals derived from fossil carbon, are inserted into the polymer matrix to give the plastic special properties such as color, stability, water resistance, resistance to flames. And there are some familiar names among these additives. For example: phthalates, which are plasticizers that give flexibility to plastic; bisphenol A, BPA; PFAS, the forever chemicals. Some of them are used in plastics. Others are used elsewhere: flame retardants, such as brominated flame retardants to make plastic fire resistant, these are included in the composition of plastics intended to be included in computers. And then chemicals that make the plastic resistant to water and grease.
Thompson: And what are microplastics or nanoplastics?
Landrigan: Microplastics and nanoplastics are therefore materials that form when plastic breaks down in the environment. So, for example, when a large piece of plastic, say a plastic detergent bottle, ends up in the ocean, it is hit by wave action, by sunlight, by heat, by cold, by the erosion of rocks and beaches. And over time, it breaks down into smaller and smaller particles. If the particles are 1 micron or less in diameter, they are called microplastics. And if they’re 1,000 times smaller than that, they’re called nanoparticles.
Thompson: Before we get into how these enter our bodies, is the only way for plastic to become microplastic or nanoplastic through confrontation with elements like the ocean or sunlight? Or if I buy a bottle of water, or if I buy a yogurt, is it possible that the simple passage of time, or the rubbing of food against plastic, creates micro- or nanoplastics by the time I consume anything. is in these containers?
Landrigan: Yeah. The short answer to this question is yes. Ocean erosion is just one source of microplastics. Every time you drink bottled water, every time you eat yogurt from a plastic container, every time you heat something in a plastic cup in the microwave, you’re pushing plastic into the water , in food. And it’s a common route of entry.
Thompson: And let’s continue the story. We explained how plastic becomes micro- or nanoplastic. How do these micro/nanoplastics get into our bodies and cause the kind of disruption that scientists are beginning to fear?
Landrigan: Microplastics and nanoplastics can therefore enter our body via two routes. The most common route is through ingestion of food, water, but some of these are also airborne. They are thrown into the air and you can then inhale them. And so they are transported to the lungs. Once these particles enter the gastrointestinal tract or lungs, some of them have the ability to cross the membrane to reach the bloodstream. And the basic rule here is that the smaller the particle, the more easily it can pass through the membrane and enter the bloodstream. And then, once the particle is in the bloodstream, it can go anywhere in the body. To the heart, to the lungs, to the reproductive organs, to the liver, anywhere. And if it’s small enough, then it can pass from the bloodstream to the organ’s cells.
Thompson: Much research is currently being carried out on the possible danger of nano and microplastics. I wonder why you think we haven’t paid more attention to this? We’re talking about a technology, at least in terms of basic synthetic plastics. It’s been around for a century, but I feel like it doesn’t raise the same level of commonly understood alarm as, say, carcinogens or cigarettes. Why do you think it took so long for people to pay more attention to the danger of micro- and nanoplastics?
Landrigan: Yes, I think there are several reasons. First of all, I think it was invisible until recently, when it became increasingly clear that there is a huge amount of plastic pollution in nature. Second, the life cycle of plastics is long and complex, and damages associated with plastics occur at different points in this complex life cycle. People didn’t put the pieces together until recently. And then, thirdly, it has been overshadowed by other major issues: notably climate change, which is rightly at the forefront of many people’s minds these days.
This excerpt has been edited for clarity. Listen to the rest of the episode here and follow it Pure English food on Spotify.
Host: Derek Thompson
Guest: Philippe Landrigan
Producer: Devon Baroldi
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