Microplastics: Meant to last, just not forever and not in our bodies

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Megan Hill is an assistant professor of chemistry and leader of the Hill Lab in Colorado State University's College of Natural Sciences. Her research leverages organic chemistry to design advanced polymeric materials for applications in sustainability, catalysis and soft materials. She recently sat down with SOURCE to answer some common questions.

What are microplastics?

Given their name, they are micro-sized bits of plastic. There are even smaller nanoplastics that are below that (.5 mm in diameter) threshold (about the size of a grain of rice). They are pieces of plastic that have broken down but never fully degraded.

How long has synthetic, mass-produced plastic been around?

Let's say about 100 years. Chemists spent a lot of time and effort optimizing polymerization techniques, eventually making catalysts that enabled extremely fast, cheap and easy production of plastic materials. Once the industry realized how useful these lightweight, durable and cheap materials were, then it just kind of exploded.

It's much more complex than that because there was government assistance in making these types of products more affordable. Within the last 10 to 20 years, people started to realize, "Wow, this stuff is still around, and it doesn't seem like it's going away anytime soon."

Have we had better living through chemistry, i.e., plastics, in the past century?

You absolutely have to take that into account. Plastics make cars and airplanes lighter, reducing the amount of fuel that is needed. Wind turbines are made from epoxy resins, crosslinked polymer networks. Polyethylene is used in hip replacements, and Kevlar is something that saves people's lives. These are all plastic materials.

What are the unintended consequences?

We've never had to deal with materials that have such a long lifetime. Every material that we've worked with in the past has been environmentally degradable over at least long periods of time. People didn't realize how long it would actually take these materials to degrade. But now we are facing the fact that nearly every piece of plastic that has ever been made still exists, except for a small percentage that has been incinerated.

Is it bad that microplastics are found in virtually every part of human bodies?

We still have a lot to learn about how microplastics affect our health. Initially, it was thought that it wouldn't be that big of an issue because particles have to be really small to pass through your esophagus or digestive tract, so we assumed microplastics would not persist in the body.

But as these particles have become smaller and smaller, now they're accumulating in tissues and throughout our bodies. We are still not sure what this means to our health. Plastics are designed to be inert, so the chemical structures are not likely interacting with anything in our body, but they are foreign objects that your body will likely react to.

There's still a lot unknown about the severity or what might actually happen as these particles accumulate more in animals and then humans as they go up the food chain.

What's an example of your lab's research in polymers?

One area of research our lab focuses on is integrating reversible or degradable bonds into polymer networks and backbones. By making some of the bonds reversible, we can improve the ability for the materials to be broken and reformed, without compromising their material properties—a big problem plastic recycling is currently facing.

Another CSU group has pioneered polymer materials that can be chemically recycled, a route that enables polymers to be broken down to their starting materials so they can be remade into the high-quality materials that are needed in industry.

What does it mean for a polymer to be sustainable?

It means finding starting materials that aren't derived from oil. It means using processes that are less energy intensive. It means thinking about the end-of-life of the materials we are making. We still aren't exactly sure how long it's OK for something to persist in the environment, and the answer will certainly depend on several different circumstances, but it needs to be addressed.

Something I find hopeful and inspiring is how the whole polymer community, and chemistry community, has refocused our attention on these issues. I wouldn't say that anyone's doing research now without thinking about the end fate of the materials they are making, which is something that people just didn't consider before.

What are some positive developments?

Scientists have teamed up and come up with some really promising solutions. They have developed new recycling methods, they have engineered enzymes that are more efficient at breaking down plastics, they have developed catalysts that can convert plastics into useful chemicals, etc.

There is also funding for researchers to develop sustainable materials, figure out creative methods to tackle the abundance of plastic waste, and for people to start companies. So I see a very bright future in this. It would help if the government would make plastic a little more expensive or have some sort of incentives to get companies to stop using it. It's incredibly difficult for individual consumers to avoid all the plastic that is cheap and easy.

What can people do to help?

Every little action helps. Support companies that try to steer away from plastics, vote for politicians who support research, and if you can, spend or give a little extra money to show it's something you care about.

You know that quote from "The Graduate" where the dad says there's a great future in plastics? The new quote that we all tell each other is there's a great future in sustainable plastics.

Provided by Colorado State University