Microplastics Are Everywhere. How Dangerous Are They?

Plastic is a lifesaving 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 accidents. My bike helmet is plastic. My smoke detector is plastic. Safety gates for babies: plastic.

But in the last few months, several studies have demonstrated the astonishing ubiquity of microplastics and the potential danger they pose to our bodies—especially our endocrine and cardiovascular systems. Today’s guest is Philip Landrigan, an epidemiologist and pediatrician, and a professor in the biology department of Boston College. We start with the basics: What is plastic? How does plastic become microplastic or nanoplastic? How do these things get into our bodies? Once they’re in our bodies, what do they do? How sure are we that they’re a contributor to disease? What do the latest studies tell us—and what should we ask of 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 that governments can take to limit our risk.

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In the following excerpt, Philip Landrigan and Derek lay out the definitions for plastics, microplastics, and nanoplastics and explain how they enter our bodies.

Derek Thompson: What are plastics?

Philip Landrigan: Plastics are manufactured chemical materials made for the most part, 99 percent, from fossil carbon, from gas, from oil, from coal. All plastics have two main components. First is the polymer, which is the structure, the skeleton of the plastic, and the polymers include some familiar names like polyvinyl chloride, polystyrene, polyurethane, and so on. And then secondly are the chemical additives. At least 16,000 different chemicals, most of them petrochemicals that come from fossil carbon, are inserted into the polymer matrix to give the plastic particular properties like color, like stability, like water resistance, like flame resistance. And there are some familiar names among these additives. For example: phthalates, which are plasticizers that give the plastic flexibility; bisphenol A, BPA; PFAS, the forever chemicals. Some of them are used in plastics. Others are used elsewhere: Flame retardants, like brominated flame retardants to make the plastic fire resistant, those go into plastics destined 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: So microplastics and nanoplastics are the materials that are formed when plastic breaks down in the environment. So, for example, when a large piece of plastic, let’s say a plastic detergent bottle, goes into the ocean, it’s hit with wave action, with sunlight, with heat, with cold, with erosion against rocks and beaches. And over time, it breaks down into smaller and smaller particles. If the particles are 1 micron in diameter or less, they’re known as microplastics. And if they’re 1,000 times smaller than that, they’re known as nanoparticles.

Thompson: Before we get into how these get into our bodies, is the only way that plastic becomes microplastic or nanoplastic confrontation with elements like an ocean or sunlight? Or if I buy a bottle of water, or if I buy a thing of yogurt, is it possible that the sheer passage of time, or the rubbing up of the food against the plastic will create micro- or nanoplastics by the time I consume whatever is in those containers?

Landrigan: Yeah. The short answer to that question is yes. The erosion in the oceans is only one source of microplastics. Whenever you drink bottled water, whenever you eat yogurt out of a plastic container, whenever you heat something in a plastic cup in the microwave, you’ll be pushing plastics into the water, into the food. And that’s a common path of entry.

Thompson: And let’s continue the story. We’ve explained how plastic becomes micro- or nanoplastic. How does that micro-/nanoplastic get into our bodies and cause the kind of disruption that scientists are starting to fear?

Landrigan: So microplastics and nanoplastics can get into our body by two routes. The most common route is by ingestion in food, in water, but also some of them are airborne. They get lofted into the air, and then you can inhale them. And so they’re taken into the lungs. Once those particles get into the gastrointestinal tract or into the lung, some of them have the ability to cross the membrane into the bloodstream. And the basic rule of thumb here is that the smaller the particle, the more easily it can traverse the membrane and get into the bloodstream. And then once the particle is in the bloodstream, it can basically go anywhere in the body. To the heart, the lungs, the reproductive organs, the liver, anywhere at all. And if it’s small enough, it can then pass from the bloodstream into the cells of the organ.

Thompson: There’s a lot of research right now on the possible danger of nano- and microplastics. I wonder, why do you think we haven’t quite paid closer 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 quite have the same level of popularly understood alarm that, say, carcinogens have, cigarettes have. Why has it taken so long, do you think, for people to pay closer attention to the danger of micro- and nanoplastics?

Landrigan: Yeah, I think there are several reasons. I think firstly, it’s been invisible until recently, when it’s just become more and more obvious that there’s an awful lot of plastic pollution out there. Secondly, the life cycle of plastics is long and complex, and the harms associated with plastics occur at different points along this complex life cycle. People haven’t put the pieces together until recently. And then thirdly, it’s been overshadowed by other big issues: most notably, climate change, which is quite rightfully at the forefront of many people’s minds these days.

This excerpt was edited for clarity. Listen to the rest of the episode here and follow the Plain English feed on Spotify.

Host: Derek Thompson
Guest: Philip Landrigan
Producer: Devon Baroldi

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