What we know about the health effects of microplastics

We live in a world where microplastics are everywhere — and that’s not hyperbole. From rainwater, to the bottom of the Mariana Trench, inside our own bodies, and even in the air we breathe, researchers have been alarmed to find microplastics pretty much everywhere they’ve looked. Microplastics are tiny pieces of plastic less than five millimeters in length that come from a variety of sources, including the breakdown of plastic products, cosmetics and industrial processes.

Plastic particles can take hundreds or even thousands of years to break down, leading to massive amounts of environmental contamination that we see. Most recently, an Oxford study found that microplastics were even present in male testicles, and not just a few samples: in every single participant tested.

GBH’s All Things Considered host Arun Rath spoke about the potential health implications of these microplastics with Dr. Phil Landrigan, a pediatrician, epidemiologist and director of the Program for Global Public Health and the Common Good at Boston College. What follows is a lightly edited transcript.

Arun Rath: So to start off, what do we know at this point about how microplastics are entering the human body? Is there any way to avoid it?

Phil Landrigan: So microplastics get into us by two main routes. First is ingestion, if we eat food — for example, seafood or meat — that is contaminated with microplastics. And second is we can also absorb them by inhalation because a certain number of microplastics are in the atmosphere, in the air we breathe. They’re invisible and we can take them in through the lungs.

And once the microplastic particles come into our body, through the gastrointestinal tract or through the lungs, they can get into the bloodstream, especially the smaller pieces. The smaller they are, the more easily they can pass into the bloodstream. From there they can go to all the organs in the body.

Rath: What do we know so far about the health effects of microplastics?

Landrigan: Well, to answer that question, let me take just a quick moment and tell you what’s in a microplastic. Basically, microplastics, like plastics themselves, have two main components. Firstly, there is the polymer — the structure that holds the thing together. That would be polyvinyl chloride, polystyrene or polyurethane. Then there are thousands of chemicals — an estimated 16,000 different chemicals — that are stuck into the polymer to give the plastic particular properties like color, flexibility or flame resistance.

Many of those 16,000 chemicals are very toxic. They include chemicals that can cause cancer — carcinogens — neurotoxicants, and endocrine disruptors that can disrupt the functioning of the endocrine system.

When plastics get into the human body, they can harm human health in two ways. Firstly, they can act like Trojan horses and release those toxic chemicals into the bloodstream. Secondly, the particles themselves can get into cells and clog things up.

We know a fair bit about the toxic properties of the leading chemicals. We know a lot less at this stage of the game about what damage the particles themselves might do.

Rath: I think a lot of people have a sense that these are relatively new substances we’re talking about, but this goes all the way back to artificial fibers and all kinds of modern products right?

Landrigan: That’s right. Plastic production began after World War II in the 1950s. But in the last 20 years, it’s really taken off. Half of all the plastic ever made has been made since the year 2000 and production is accelerating. Even as we speak, it’s going up exponentially. And once the plastic is made and it’s used and it’s thrown away, it starts breaking down. The end result is microplastics.

Rath: With people and the whole environment having been exposed to microplastics for so long now, and especially that increased period of the last 20 years, do we have a sense of long-term effects?

Landrigan: No, it’s still early stages, but there was a very worrisome article published in March in the New England Journal of Medicine looking at the impacts of microplastic particles on the cardiovascular system. These researchers from Italy found that about 60% of 300 people whom they examined had microplastics in their heart and their great vessels. And they found that the folks that had microplastics in their bodies were four times — that is to say, 400% — more likely to have a heart attack, have a stroke, or to die in the following three years compared to people that had no microplastics.

That’s only one study. It doesn’t prove cause and effect, but it’s a strong signal and as I said, very worrisome.

Rath: Where do we need to see research concentrated to be able to find out what these microplastics are doing to us?

Landrigan: I think we need two things. We absolutely need research looking at the impacts of microplastics not only on the heart, but on the brain, the kidneys, the immune system, and the other tissues in the human body. But at the same time, even as we’re waiting for that research to be done — which could take years, in some cases — we need to act now on the basis of what we already know about plastics.

We know that plastics are already causing harm to human health at every stage of their production, their use and their disposal. We simply cannot sit around and wait until we have every detail of the research completed. We need to act on this on the basis of what we know, or things are going to get worse.

Fortunately, the United Nations is well aware of this. Negotiations are proceeding now to draft a global plastics treaty like the Paris Climate Agreement. If this treaty is as strong as we would like it to be, its centerpiece will be a global cap on plastic production that limits the amount of plastics that countries will make. That way, countries can still continue to make the plastics that they really need for medicine, engineering, and aerospace, for example, but make less of the pointless, unnecessary single-use plastics that we simply use, rip off the package, and throw away. It’s those single-use plastics that are really driving the plastic waste problem.

Rath: I know that it doesn’t always mean anything, but is there a consensus that we need to move towards that kind of structuring in how we deal with plastic?

Landrigan: Well, the the UN negotiations are moving forward, and a number of countries around the world have formed what they called a high ambition coalition with the intent of driving a strong treaty. The problem is that there’s very serious pushback from the fossil fuel industry.

The fossil fuel industry are the major producer of plastics. 99% of plastics are made from coal, oil and gas. The last thing that the industry wants is any kind of a cap on global production.