Plastics R Us - Part 2

This rumination on plastic in our water, in our bodies, is the second of two parts. If you missed Part 1, I hope you’ll read it here. This essay is a bit longer than I usually like to post, but I couldn’t find the natural place for a “to be continued”. SOOO…. Here you go.

Image by Szabolcs Molnar from Pixabay

I try to minimize contact with plastic, but there’s no escaping it. I shun bottled water, and the saran wrap I bought in 2009 has barely been touched, but I put contact lenses in my eyes every morning, I’m wearing leggings woven from nylon and Lycra, and I’m typing this on a plastic keyboard, so who am I kidding? Even my tofu floats in a plastic tub. I’m bathed in the stuff. But does it really matter? Any particle too small for me to see – the kinds that slough off during my daily encounters – can’t be a problem for me. Right? Since they can’t be digested, don’t they just pass on through, like the summer corn I ate too quickly?

I can’t remember who or what I was listening to, but a podcast guest last summer got my attention with his summary of a study that linked microplastics to cardiovascular “events” – i.e. heart attack, stroke, or death. It was in the New England Journal of Medicine, so I figured it had to be legitimate. I tracked down the original article and, with the help of a dictionary, was able to boil it down to this: the authors tracked a cohort of patients who came in to have their carotid arteries surgically cleaned out. Normally the harvested plaque, what I prefer to call “crud”, is scraped into a biohazard bag never to be seen again. But for the 304 patients enrolled in the study, the crud was analyzed with fancy scientific equipment to determine how much plastic it contained. Specifically, the authors were looking for microplastics and nanoplastics – the tiniest of particles, so small that you need an electron microscope to see some of them. Lab studies had suggested that these tiny plastics could induce inflammation and even the dreaded foam cells that are associated with hardening of the arteries, but would that hold true in vivo, in living human beings?

The researchers found that some of these patients – more than half – had “detectable” microplastics (less than half a millimeter in diameter) and nanoplastics (so tiny you’d think they don’t matter) in their arterial plaque. Perhaps that’s not surprising because, after all, plastic is everywhere. But here’s what got me to rewind the podcast and make sure I’d heard correctly. The patients that had micro- and nanoplastics – MNP for short – in their plaque were significantly more likely to have a cardiac event in the three years following surgery compared to those with virtually no MNP content. In fact, they had a “hazard ratio” – an adjustment that accounts for people dying early in the study – of more than four times what the “clean” patients had.

Why would that be? Who knows, but the authors hypothesized that the MNPs caused inflammation from physical irritation at the microscopic level – mirroring the results from lab experiments - which in turn increased the risk of a cardiac event. Said more simply, teensy, tiny bits of plastic – entering the body through eating, drinking, inhaling, absorbing – has a huge impact on the likelihood of having a heart attack, a stroke, or even death. Even in young adults. Plastic suddenly moved up on my anxiety top hits list.

If it were just this one study, maybe I could shrug it off as a fluke, but there is a growing body of similar evidence. Yet another podcast – Living on Earth – corroborated the cardiac disease-MNP correlation and took it further. Knowing that plastic food containers, when heated, release the contaminants public health officials worry about, researchers in China found that people with high-frequency exposure – i.e. those who frequently ate hot take-out meals packaged in plastic containers – had a higher incidence of congestive heart failure. Knowing that there could be other lifestyle reasons for that, the researchers ran an experiment on rats.

Over three months, rats were given one of four types of water – one where boiling water sat in a plastic container for one minute and then cooled, another group where the hot water sat for five minutes, another for fifteen minutes, and a control group where water had no contact with plastic. The rats that drank plastic leachate had biochemical markers associated with heart damage. Even more shocking was the physical changes in the heart muscle as seen through a microscope. The muscle cells lined up with textbook regularity in the rodents raised on untainted water. All systems “go” for these clean-water guys. Not so with the ones who drank the plastic tea. As the concentration of plastic leachate increased, the cells got more and more disordered, as if the traffic cop had taken the day off when those hearts were made.

To be clear, hearts and arteries aren’t the only places where flotsam from our “better living through chemistry” lives is accumulating. Other studies have shown that MNP particles are in all parts of our bodies – testicles, placentas, livers, basically everything. But the brain has the motherload, with ten to twenty times more microplastics than other organs. The impact on these organs isn’t yet known, but a reasonable person would suspect that it’s not good.

Where did all this plastic come from? How did we get in this predicament? While there is no single answer, certainly the invention of the plastic bottle played a role. Most people alive today don’t even remember a time before plastic bottles, that’s how ubiquitous they’ve become. It all started with well-intentioned Dupont engineer Nathaniel Wyeth – brother to the famed artist Andrew Wyeth – who was convinced he could develop a synthetic, lightweight alternative to glass. The plastics available at the time – i.e. the ones used for detergent bottles – couldn’t handle the pressure of carbonated beverages. But, after years of inspired tinkering, Wyeth developed a method for extruding polyethelene-terphthalate – what we now know as “PET”, or “number one” recyclable plastics - in a way that aligned the molecules in two directions rather than one, which gave the plastic polymer the strength he was looking for while also being lightweight, affordable, and recyclable. For better or worse, PET rapidly revolutionized packaging for carbonated beverages and soon helped catalyze the market for bottled water. Whereas in 1976 the average American consumed one-and-a-half gallons of bottled water per year, by 2021 the number skyrocketed to 47 gallons per person. And PET started showing up in all manner of food and beverage packaging, as well as a wide range of industrial applications.

Along with the plastics themselves came chemical additives – plasticizers (i.e. phthalates), flame retardants, stabilizers and antioxidants, pigments, antistatic agents, thermal stabilizers. The list goes on. Microplastics are also able to absorb and even concentrate many pollutants including heavy metals, PCBs, antibiotics, endocrine disruptors, and even bacteria and viruses. It’s often hard to distinguish between the effects of plastics themselves versus the things they carry. Probably because of the high surface area compared to volume, the smaller the particle size the higher the impact.

But how do these tiny trouble-makers get into us? The routes are so numerous that it’s impossible to enumerate them, but an easy place to start looking is bottled water. I’ve got a long list of reasons for steering clear of bottled water – the expense, the energy footprint, the impact on local watersheds, the inconvenience of lugging it home from the grocery store – but basic human health might trump all of those reasons combined. Think about it. Most containerized water is shipped in plastic bottles, which puts water and PET in close contact for probably months or even years before the cap is unscrewed. Between warehouses, long-haul trucks, and sunbaked cars, the cargo has perhaps spent at least some time in the temperature zones that accelerate the creation of microplastics and concerning leachate.

Researchers have looked into this very question and found that, indeed, bottled water is chock full of plastic debris. In fact, there have been enough such studies that there is now at least one “review” article – i.e. a study which reviewed and summarized other people’s work. Whether looking at the individual studies, or the bundled conglomerate, the answer is clear: bottled water has lots of plastic in it, and it seems that plastic is coming from the packaging itself. Contrary to my expectation, this is true even for water in glass bottles or cartons though the effect is significantly attenuated. Tap water, not surprisingly, had less plastic than bottled water, and, thanks to filtration at the treatment plant, also had less than natural sources of water.

More recently, scientists from Columbia University looked deeper. They developed a new technique that allowed them to get a better handle on the nanoplastic component, the tiniest particles. They found – brace yourself – that a typical liter of bottled water has nearly 250,000 bits of plastic in it.

Some of those plastics get into the water from leaching. It just happens. But we now know that a big contribution comes from the act of opening and closing the cap. With every on-and-off cycle of the bottle’s lid, roughly 500 tiny pieces of plastic are scraped off and fall into the liquid you’re about to drink. Presumably this is true of bottled soda as well, and a million other food products that come in bottles with screw-on tops. The moral of this story is that if you must drink bottled water, don’t fiddle with the cap. Just leave the bottle open and drink it down. In fact, I think I’m going to take mayonnaise off my grocery list because I can just make it at home and store it in a glass jar with a metal lid. My Diet Pepsi habit presents a larger challenge.

But let’s be real. Bottled water isn’t the only way to ingest plastic. At home, my morning coffee is always in a large, white ceramic mug. Nothing fancy, just a Crate and Barrel standard that my husband and I have come to love. We like the way it feels in our hands, and it’s big, so the coffee stays hot longer. The flip side is that the mug itself absorbs heat, a problem we take care of by pre-heating it with boiling water or microwaving the mug of java for a few seconds. Most coffee shops, however, don’t pre-heat their cups, don’t offer a microwave, and rarely have giant mugs. Which is why I usually ask for a paper cup. I know it’s better for the environment to opt for a ceramic mug, but tepid coffee is a total bummer, and coffee-shop coffee is almost always tepid in a ceramic mug, especially if you add half-and-half, which I do.

On a recent morning, I treated myself with a stop into the French bakery that’s mid-way between our house and the highway. When my name was called, I noticed that the paper cup with my very hot decaf skim latte was decorated with the green outline of a leaf, signaling that the cup was compostable. You’d think that all paper cups are compostable, but you’d think wrong. They’re not recyclable either, but that’s another topic. To keep cups from getting soggy, the paper needs to be coated with a waterproofing substance. Back in the old days paper cups were coated with wax. When I remember back to the Dixie Cups from childhood birthday parties and Girl Scout meetings, I can still feel the wax that would accumulate under my fingernails as I scraped the bottom of the cup.

These days most paper cups are lined with a thin layer of polyethylene, the same material that plastic bags are made of. You can’t see it, but it’s what gives the cup a slick feel on the inside. It’s probably not all that bad for cold drinks, but hot drinks are another matter. When hot beverages or soups come in contact with the polyethylene, plastic particles leach into the contents. The good news is that most of them come out the other end of your digestive tract, but the bad news is that the other 10% or so end up in your arterial “crud” and pretty much every other body part. If you’ve got a daily coffee-to-go habit, maybe it’s time to carry an insulated steel coffee mug with you.

But back in the bougie French bakery I could drink my latte without fear because my paper cup was constructed without plastic. By following the URL printed on the cup’s bottom lip, I learned that the compostable cups are lined with a plant-based polymer that biodegrades right along with the paper. Though the manufacturer doesn’t make any health claims, I breathe a sigh of relief. But maybe at my next coffee shop visit, I should give the ceramic mug another chance.

Most adults get to choose what and how they drink. Not so with infants. The preponderance of baby bottles – a bit more than 80% from what I can tell – are made of polypropylene, a form of plastic. A few years back, scientists in Ireland asked the question “How much plastic is going from those bottles into babies?” The answer, not surprisingly, is “a gob-smacking awful lot.” It’s not just that the bottle is plastic. It’s because, to kill off any lurking bacteria, it’s recommended that the formula be heated to 158 degrees Fahrenheit and then cooled back down a bit before giving it to the baby. Plus, there’s a lot of shaking to dissolve the powdered formula. All told, a bottle-fed baby could be getting well over 2 million microplastic particles per day. At the time the research was published, folks were still waffling over the health impacts of microplastics. Not so anymore.

It's too late for my sons and millions of kids raised on plastic – we can’t turn back the clock. But fortunately for parents today who are paying attention, there are options. Pediatricians love to say, “Breast is best,” and it is. But that’s not always possible. Even breastfed babies occasionally take their milk from a bottle, but it need not be a plastic bottle. Glass baby bottles never fully disappeared, and in some countries, including China, glass has long been the preferred option. I haven’t shopped for baby bottles for at least three decades, and when I did, they were plastic ones. Today, knowing what I know now, even though they’re a bit pricier, I would opt for glass.

In what is perhaps the most quoted piece of career-launching advice ever given, Walter Brooke, playing the role of wise, middle-aged white dude in the 1967 film “The Graduate”, has one word for newly minted college graduate Dustin Hoffman. “Plastics.” Adding a few more words, he continues, “There’s a great future in it.” My guess is that the screenplay writers had no idea just how right they’d be. Or how wrong. Plastics have wormed into our lives in ways beyond the wildest 1960’s imagination, not all of which are appreciated. Maybe if there were to be a remake of the film, Brooke’s one word of advice would be “Glass.”

Splash Zone

The summer issue of UCSF Magazine has the best overview of plastics and health that I’ve come across. “The Plastic Inside Us” addresses plastic in clothes and car tires, the challenges with recycling, health implications, fertility, and things you can do to reduce one’s exposure, and includes simple graphics that hammer the message home.

Ever wonder how much a cloud weighs? Printed on the mylar snack mix bag of my weekend Delta flight was this interesting factoid: “A typical fair weather cumulus cloud weighs about 1.4 billion pounds.” Proof that water really IS heavy!