 |
Water from glass bottles might contain up to 3x more microplastics than plastic bottles.
A recent study tested common beverages in France and consistently found glass bottles had the highest microplastic contamination, significantly exceeding plastic bottles and cans.
Beer topped the list, with small glass bottles averaging 134 microplastics per liter (MPs/L), compared to ~32 MPs/L in cans or large bottles. Lemonades (112 MPs/L), colas (103 MPs/L), and cold teas (86 MPs/L) followed (all in glass), with far fewer MPs (1.5–2.4 MPs/L) in plastic bottles or cans.
Even plain bottled water wasn’t exempt. Glass bottles averaged 4.5 MPs/L. That's 181% higher than plastic bottles, which averaged 1.6 MPs/L.
Most surprising of all? The contamination wasn't from the glass itself. Rather, it came from the bottle caps. Researchers discovered that flakes of polyester-based paint on metal caps shed into the beverages. Uncleaned caps drove contamination levels as high as 287 MPs/L, while cleaning caps greatly reduced microplastic contamination by up to 70%.
These findings were both surprising and eye-opening, revealing hidden sources of contamination and challenging common assumptions (even some of my own!) about beverage safety.
|
| |
You just missed this in your inbox
Every week, Dr. Rhonda Patrick and the FoundMyFitness team distill the latest research into clear, actionable insights on health, longevity, and performance, delivered free to your inbox.
Water is Still Safe, But The Source Matters A Lot
The study was conducted by France’s national food safety agency (ANSES). Researchers systematically analyzed microplastic contamination across popular drinks sold in France, including water, cola, tea, lemonade, beer, and wine. Until now, this type of formal assessment had not been conducted in France.
Testing occurred in a specialized laboratory designed specifically to prevent external contamination. Researchers evaluated microplastic levels, particle types (such as polyethylene, polyester, and polypropylene), particle sizes (ranging from 30–50 μm, 50–100 μm, to 100–500 μm), and contamination sources, particularly from packaging materials and caps.
Water generally contained the lowest levels of microplastics compared to other beverages, averaging 2.9 microparticles per liter (MPs/L), but packaging type mattered. Glass bottles had higher contamination (4.5 MPs/L) compared to plastic bottles (1.6 MPs/L).
Differences among water sources were also uncovered. Mineral water had higher microplastic levels (3.7 MPs/L) compared to spring water (1.6 MPs/L) and sparkling water had higher microplastic levels (3.4 MPs/L) compared to still water (2.4 MPs/L)—a small difference that didn't quite reach statistical significance. Particle size distribution was consistent across water samples, meaning that small, medium, and large particles were, for the most part, not different among the different beverage and packaging types.
How did microplastic levels fare among the remaining beverages studied?
-
Beer had the highest levels of microplastics detected across all beverage types, averaging 82.9 MPs/L regardless of packaging. Small glass bottles were the worst offenders (133.7 MPs/L), followed by large glass bottles (32.8 MPs/L) and then cans (31.8 MPs/L).
-
Cold tea averaged 28.5 MPs/L, but levels were higher in glass bottles (86.3 MPs/L) than in cans (16.3 MPs/L) and plastic bottles (2.2 MPs/L).
-
Lemonade averaged 45.2 MPs/L across the board, with levels that were highest in glass bottles (111.6 MPs/L), moderate in cans (10.9 MPs/L), and lowest in plastic bottles (1.5 MPs/L).
-
Cola (soft drinks) averaged 31 MPs/L across all samples but varied dramatically by packaging type.
- Glass bottles contained extremely high levels of microplastics (103 MPs/L), cans contained 3.4 MPs/L, and plastic bottles contained 2.1 MPs/L.
- Sugar-sweetened colas contained fewer microplastics on average (14.3 MPs/L) than unsweetened ones (48.5 MPs/L).
-
Wine, on the other hand, generally had lower contamination than other beverages, averaging only 8.2 MPs/L. Boxed wine contained high levels of microplastics (30 MPs/L) while other packaging types including small plastic bottles, large plastic bottles, and glass bottles contained relatively lower levels (2.1–8.7 MPs/L).
On the surface, these results might run contrary to what many of us think—how do microplastics "sneak into" water packaged in glass? Well, it isn't the glass itself that's the source of microplastic contamination. That comes from another culprit—bottle caps.
|
|
|
Painted Bottle Caps As Hidden Source of Contamination
The researchers discovered a critical yet unexpected contributor to microplastic contamination: the metal caps on glass bottles.
Caps were typically coated with polyester-based paint, which easily scraped off during packaging and storage, introducing substantial microplastic contamination into the beverages. Analysis showed that the color and chemical composition of the paint on the caps was identical to the microplastic particles found in the drinks!
To confirm this, researchers tested several cleaning methods to remove microplastic contamination from the caps prior to placing them on freshly-bottled (microplastic-free) water.
- First, they tested a new set of glass-bottled beverages without clearing the caps. This resulted in high microplastic contamination, with drinks containing an average of 287.3 MPs/L.
- Next, they treated the caps by blowing them clean with air, a process that reduced contamination by 63% (to 105.8 MPs/L), significantly less than the untreated caps.
- Finally, they blew the caps clean and rinsed them with water and an alcohol solution. This further reduced microplastic levels to 86.7 MPs/L—an 18% drop compared to the air-blown caps and a 70% drop from the uncleaned caps.
When the researchers looked at the rinsing solutions used for cleaning, they found it contained, on average, 47.8 particles per rinsed cap, a clear indication that storage conditions and abrasion during handling contribute to contamination.
|
|
| |
Considering Other Contaminants in Water (And Which Packaging Contains the Fewest)
This study raises some alarms and questions our assumptions about the perceived safety of glass versus plastic. Especially because of the mixed evidence on other plastic-associated chemicals including PFAS, BPA, and BPS.
Two public data sets published in the last few years have been informative in showing levels of PFAS—otherwise known as "forever chemicals"—in bottled water from various sources in the United States.
A Consumer Reports analysis in 2020–2022 found that noncarbonated beverages (most of which were bottled in plastic with a few exceptions) had detectable levels of PFAS, including several with total PFAS over the "safe" limit of 1ppt. Only two still water brands had undetectable PFAS levels, and both of them (Mountain Valley spring water and Saratoga spring water) are bottled in glass. However, all carbonated water (including three brands packaged in glass) tested had measurable amounts of PFAS, ranging from 1.1 ppt to 9.76 ppt (a level detected in the popular Topo Chico sparkling water).
In the FDA's 2023–2024 analysis, most still waters packaged in plastic (specifically, polyethylene terephthalate or PET tested below detection of 0.3 ppt or below the "safe" limit of 1 ppt. In fact, the analysis of bottled water products revealed that none of the samples exceeded the EPA limits for PFAS and only ten had detectable levels—all were below 2 ppt.
The takeaway here is the PFAS shows up in both container types, but peak values come from certain glass-bottled sparkling waters—the highest result from the U.S.-sold waters was Topo Chico's 9.76 ppt; the typical range of glass-bottled waters is not detectable up to 5 ppt. Among plastic bottles, levels range from not detectable to 2 ppt. Still water is generally less microplastic-laden than sparkling (carbonated).
For a short dive into 4 potential ways to detox your body from topic microplastics and their associated chemicals, check out this clip on the FoundMyFitness Clips channel on YouTube.
|
| |
|
| |
 |
| |
I also go in depth on common sources of microplastics and the best ways to limit your exposure in Premium Member Q&A episodes #63 and #64:
Q&A #63 with Dr. Rhonda Patrick (10/12/2024)
-
13:21 - Which water filters effectively reduce microplastic exposure?
-
14:30 - Do I avoid drinking out of plastic bottles?
-
19:18 - The supplement that may boost BPA excretion
-
23:41 - Why I stopped cooking with silicone
Q&A #64 with Dr. Rhonda Patrick (11/2/2024)
-
05:05 - Which plastic-free coffee makers are best on a budget?
-
16:56 - Do plastic remineralization filters reduce reverse osmosis benefits?
-
21:04 - What are the worst offenders for microplastic exposure?
-
22:10 - The hidden risks of canned foods and beverages
-
22:56 - Is water from plastic filter pitchers like Brita worse than tap water?
|
|
What about BPA and BPS?
Bottled water in glass generally delivers the very lowest bisphenol exposure (less than 2 ng/L) because glass bottles are chemically inert. But as we've seen with the French study, caps, liners, and the bottling lines can add traces of BPA that carries some estrogen-like activity (but it's still 3x lower than plastic). Plastic bottles stored cool and at room temperature are close behind in terms of BPA levels (ranging from 0–20 ng/L). However, these levels can climb when bottles are heated or exposed to the sun—rising to 10–270 ng/L.
Since I'm sure it's on everyone's mind, let's talk about contaminant exposure from cans—specifically canned sparkling water and soft drinks. Canned beverages generally contain 1–2 MPs/L of microplastics, around 200 ng/L of BPA (although modern BPA-non-intent liners greatly reduce this number to less than 50 ng/L), and only ~2–3 ppt PFAS—orders of magnitude below the EPA's strict regulatory limit of 4 ppt. So, while they're not totally microplastic-, BPA/BPS-, or PFAS-free, cans reside somewhere between glass and plastic in terms of their levels of contamination, depending on the contaminant studied.
What does this mean?
Overall, drinking water—whatever the container—is a source of plastic-associated chemicals but it might contribute only a sliver of total bisphenol, PFAS, or microplastic intake—especially if you don't drink a lot of bottled water or canned seltzer or soda. Canned foods (like soup), thermal-paper receipts, and many household plastics are far larger sources.
|
|
| |
Final thoughts
If you're like me, these findings may seem somewhat jarring—they fundamentally go against what my gut tells me is right. Drinking from glass should be a safer option than drinking from plastic. And maybe it still is.
What can you do as a conscious consumer who might be thinking there's really no easy way out? Avoiding drinking out of bottled and canned beverages entirely—while ideal—just isn't possible for most people.
Microplastic contamination is certainly a concern, but when weighing potential risks, exposure to endocrine-disrupting chemicals or persistent "forever chemicals" like PFAS may pose even greater threats. In that context, choosing glass packaging, despite its higher microplastic levels, might still be the safer overall option.
This consideration is particularly important for pregnant women, infants and young children, and individuals with autoimmune or reproductive conditions. Endocrine-disrupting chemicals can interfere with the body’s hormonal systems, potentially affecting growth, development, and long-term health outcomes. For instance, research has linked prenatal BPA exposure to altered brain development and behavioral changes in children. Similarly, PFAS exposure has been associated with adverse outcomes such as low birth weight and neurodevelopmental disorders.
Perhaps the most important takeaway is that the only reliable way to significantly reduce microplastic exposure is by taking control of your home's water quality.
Reverse osmosis (RO) filtration systems are among the most effective solutions available, capable of removing up to 99.9% of microplastics. They also eliminate heavy metals, bacteria, and harmful chemicals like PFAS, making them a comprehensive solution for safer drinking water. Additionally, RO-purified water isn’t just for drinking—it's versatile enough to wash produce, removing microplastics and other contaminants from fruits and vegetables, offering an extra layer of protection.
Ultimately, microplastics may be unavoidable, and choosing glass packaging doesn't necessarily guarantee safety. Practicing "imperfect avoidance" involves doing our best to limit exposure, selecting cleaner sources when possible, and recognizing the power we have to offset potential harm through a healthy, active, and vibrant lifestyle.
|
|
|
|
|
|
|
|