Dr. Sherri A. Mason (aka “Sam”) earned her bachelor’s degree from the University of Texas at Austin. She completed her doctorate in Chemistry at the University of Montana as a NASA Earth System Science scholar.
Her research group is among the first to study the prevalence and impact of plastic pollution within freshwater ecosystems. While she continues her research endeavors, she has also recently moved into a new role as Sustainability Coordinator at Penn State Erie, The Behrend College.
I have a special affinity to water in so many ways as a scientist. Water is this incredibly simple molecule—three atoms combined together—and yet it is the essence of life. When we go looking for life on other planets, we look for water—because, to our knowledge, you cannot have life without water.
I study plastic pollution, so when given this topic, I immediately thought of some of the experiments we’ve done in my lab looking at plastic within water.
The first experiment we did was actually with tap water, but the experiment I want to share with you today was a follow-up experiment where we looked at bottled water. We had established that there was plastic in tap water at about five pieces per liter of tap water on average across the globe. I really thought it would spark people to demand change—that there shouldn’t be plastic in our water—yet instead a lot of people were like, “oh, i’ll just drink bottled water.” That was like mentally for me, “so you think that if we wrap it in plastic it’s going to somehow have less plastic?” It is mind boggling to me—so we endeavor to look into the global bottled water assessment.
Looking at plastic within bottled water is what I’m going to share with you here. I’m going to walk you through what we do in our lab. (Sorry for the artists in the room—we’re going to try not to make it too scientific.)
Basically, we chose 11 brands of water from across the globe. We chose 11 brands from, I think, 19 different countries. We videotaped people going to stores, buying entire cases of water, and then taking it to a local place to ship it. It was all shipped to my lab where we had a video camera running 24 hours a day, seven days a week—because if you’re going to take on the bottled water industry, you make sure that you have everything documented.
These are the top selling brands either across the globe or within a particular nation. They were shipped to the lab and we randomly chose a bottle out of a case—which is usually 24 bottles—and brought them into our fume hood. The intention of bringing them into the fume hood is that you have this upward drafted air, like being in a fireplace. You have this upward draft of air so you’re not getting plastic coming in settling into your samples from the air. Within the fume hood we would inject the bottles with a dye that’s called nile red, which absorbs to plastic, specifically to things that are hydrophobic—but which could include other items, except that bottled water is sold as this incredibly pure thing.
The idea is that this dye, then, will stick to the surface of the plastic but not anything else that’s in the water. This is a video showing it, and you’ll see in a minute how we visualize the particles as bright spots. We use this crime light: it’s a blue light and we view it through this orange filter. In this way, the fluorescent particles can be seen. This is our money shot showing the particles actually swirling in a bottle of water.
Then we would take these bottles of water and filter them through a very fine mesh glass fiber. It’s like fibers of glass stacked on top of each other. You get to the pores, which are only a micron in size, which is really small—that’s the scientific definition of one micron: really, really small—then we put these filters in a petri dish and look at them under a microscope. This is our blue prime light, which actually doesn’t shine through the orange filter; it shines behind it, and then we view it through the orange filter. This gives you an idea of what those filters look like through the microscope.
Again, these orange bright spots are all of the plastics that are inherent within these bottled water particles that are bigger than 100 microns. This is about the width of the human hair—so everyone: look at your hair right now. Anything that’s bigger than that we can actually grab with forceps—basically tweezers—and we move those particles on our instrument that we use to analyze them. This is called FDR, which stands for “transform infrared spectroscopy.” Basically, we’re using light in order to probe the particles and confirm that they are in fact plastic—almost like what you would see in CSI.
Particles that are smaller than 100 microns we can’t physically move, so instead we take our filter and photograph it. We actually worked with an astrophysicist to develop this software. He took our filtered images that I showed you earlier and basically turned them into black and whites, then created a computer program that would count all the white spots—you can compare it to counting the stars in the night sky—so that we could then account for particles that were even smaller than 100 microns.
This just kind of summarizes the results; these are different brands of bottled water: Nestle Pure Life was by far the worst of the bottled water, with particle counts up to 10,000 pieces of plastic in one bottle of water, which is just insane.
But, on average, each liter of bottled water is going to have about 325 pieces of plastic, which makes it something like 60 times more plastic within bottled water compared to tap water—so the real conclusion here is don’t drink bottled water if you’re afraid about plastic congestion. I know everyone’s going to say what about Flint, Michigan. Yes, there are exceptions to every rule. Our water treatment processes are, generally speaking, safe here in the United States. Again, there are exceptions to the rule, but we don’t need to be drinking bottled water. In the process of packaging things in plastic, we end up putting plastic in them. There have been multiple studies that have come out since our work was done to support this.
So there’s your science lesson for the day. Let’s get back to the art.