Key Takeaways
We are exposed to microplastics frequently; one study has suggested we consume a credit card’s weight of it each week.
Many plastics are endocrine-disrupting chemicals, which can interfere with delicate processes within the human body.
While the level of microplastics found in individual sources may be negligible, there is limited research to indicate the combined effects of regular plastic exposure from a range of sources, which is a cause for significant concern.
I must preface this article with a warning: Prepare to feel uneasy.
Plastic is ubiquitous. In most cases, we dislike it, just as we feel we can’t escape it. In few cases, we have an idea of how much of it is circling our systems.
As a relatively new health threat (this article won’t even touch on its unanimously accepted environmental threat), plastic has only been widespread since the mid 20th century, when it was lauded as an inexpensive, sanitary and versatile material that could be used to manufacture products for all types of purposes and desires.
Now, microplastics are being identified in the placentas of newborn babies, proving just how invasive it has become.
In fact, an early study suggests that people could be ingesting 5 grams of plastic each week – that’s the weight of a credit card!
From canned beverages to receipts, our contact with plastic can come in surprising places, but first, let’s take a look at the threat plastic poses to human health.
Plastics Are Endocrine Disruptors
Something about the term ‘endocrine disruptor’ just sounds ominous. Considering the endocrine system is in charge of the production, circulation and regulation of our hormones, something that interferes with these vital processes should certainly be regarded with concern.
The chemicals found in many plastics disrupt this delicate system, which has been linked to[1]:
· Reproductive issues (such as PCOS, reduced sperm count)
· Developmental malformities.
· Increased cancer risk; and
· Immune system disturbances.
Note: Endocrine-disrupting chemicals are also frequently found in personal care products such as cosmetics, body and skincare and sunscreen.
Microplastics have been identified in placentas which confirms that they are able to pass through the placental barrier.[2] Of course, that means it must first be possible for microplastics to enter the human bloodstream, and even before that, the digestive system, where if these microplastics aren’t excreted, they can pass through the intestinal lining to be transported to other organs.
Bisphenol-a (BPA), an endocrine-disrupting plastic commonly used in the manufacture of daily use products has a molecular structure similar to the female sex hormone estradiol (estrogen), allowing it to mimic its function at receptor sites throughout the body, in both females and males.[3]
Consider an estrogen receptor a keyhole. The right key is, of course, an estradiol molecule, which opens it to conduct normally scheduled processes. But when a BPA key comes along that is similar enough in shape to open the estrogen keyhole, it interferes with those normal processes. When a BPA molecule acts on an estrogen receptor, it’s like receiving a phishing email dressed up as an existing and reputable brand, but once you follow the link, you download a whole load of virusware!
The discovery of BPA as an artificial estrogen is, in large, why exposure to it has been so strongly linked to reproductive and developmental disturbances in women. Further, males are not exempt; their exposure to BPA has also been found to have estrogenic effects and contribute to infertility[5].
While there is not yet enough research to fully understand the effect of plastic exposure on various health indicators, the body of research in this area is rapidly expanding, due to the disastrous implications which have been identified so far.
It's best to be aware of where you might be frequently exposed to plastic, so you can reduce your exposure accordingly.
A Preliminary Note
The following list of sources where we might be exposed to microplastics is not an exhaustive list. In fact, most sources are less widely known ones that have been included to draw awareness to them.
It is important to note that the use of known toxins, such as BPA, in manufacturing are heavily regulated. While the level of plastic which we are exposed to via the following individual sources will not exceed dangerous thresholds, the concern is both the additive and multiplicative health effects of plastic exposure from the combination of these sources. These combined effects are not yet well documented in research literature.
Additive effects refer to the combined individual effects of exposure to plastic from multiple sources. This is the health impact that being exposed to microplastics from a range of sources will have on you overall. While you may consume negligible amounts of microplastics from each individual source, like drinking from a plastic water bottle, if you are also frequently drinking from takeaway cups and handling receipts, then your combined level of exposure may pass the threshold for concern.
Multiplicative effects are even more problematic than additive effects and refer to any interactions of endocrine-disrupting chemicals arising from exposure to multiple plastic sources, which may amplify or attenuate endocrine-disrupting effects that would not be observed in isolation.
An upside of the following list is that by reducing your contact with each of these sources, you will inevitably reduce your environmental impact, as most involve single-use products.
Water Bottles
The obvious one to kick the list off. On top of avoiding single-use plastic water bottles for almost every reason, you can also reduce your exposure to BPA by saying goodbye to them.
This is likely not news to many - but here is the caveat:
Most plastic bottles which claim they are ‘BPA free’, use other bisphenols like BPS and BPF…which are, yes, also endocrine disruptors and likely just as bad!
Your safest bet is always stainless-steel or glass water bottles.
Canned Food & Beverages
Canned food may be the primary route in which humans are exposed to plastic as historically cans have been lined with a coating of BPA. This is concerning as several studies have confirmed that BPA can readily migrate to the food it’s in contact with[6].
While consumer disapproval has been raised about this practice, most substitute coatings currently used in manufacturing have not been adequately assessed for safety. This suggests that the claim ‘BPA free’ cannot be indicative of safety, especially if companies do not state what coating they use as a substitute.
Canned beverages also pose a problem, as many of them are also lined with BPA and it is unclear how prevalent this practice is across the manufacturing processes of major beverage companies. While this coating prevents your drinks from tasting like aluminium, the microplastic infusion you’re getting instead may be flavourless, but certainly not desirable.
Takeaway Coffee Cups
Here’s another reason to give up single-use takeout cups. Most of these mugs are lined with plastic which can leak into their incumbent hot liquid. If you can’t go a day without your barista-made coffee fix, then you’re also accepting a daily dose of microplastic if you’re not drinking in-café or bringing your own cup.
If you are bringing your own coffee mug, ensure it’s not made from plastic, though!
Receipts
Receipts are coated with BPA, which means that they:
a). can’t be recycled
b). should be avoided!
If you handle receipts frequently, BPA can be absorbed through the skin on your hands - another reason to say ‘no’ when the cashier asks if you’d like one with your purchase. If you do have to handle them, make sure you wash your hands afterwards.
Teabags
A warm cup of tea infused with microplastics. Doesn’t sound too tasty. Most teabags are made up of approximately 25% plastic which can leak into the hot beverage, or otherwise, paper teabags often use plastic in the glue used to seal them.[7] But don’t give up the brew just yet! You can switch to loose leaf tea and use food-safe reusable tea bags to get the same benefit, minus the plastic.
Dust
Have you ever seen little particles drifting through the air on a sunny day? Microplastics can easily accumulate in dust and make their way into our bodies through the air, where scientists warn they certainly do not belong. These microplastics may originate from the synthetic fibres in our clothes which are shed when washed or worn. For this reason, it is best practice to dust your living environments frequently.
Final Thoughts
To restate, the level of plastic exposure from each of these individual sources is inconsequential, but it is the combined consumption from all that poses a health concern. Because a large body of research does not yet exist to support the health implications of consistent exposure to everyday plastics over time, beyond the worrying outcomes that have already been identified, it is advisable to consciously reduce your exposure where possible.
Questions to Ponder
Why do you think clear evidence to support links between plastic exposure and various health outcomes is yet to exist? What barriers do you think researchers face?
What are the main ways you are being exposed to plastic? Can you reduce this?
A Note on Sources: In these articles, links to web pages are included as anchor text – that is body text you can click to visit a link. Footnotes are used to cite research papers, as appropriate.
[1] EPA. https://www.epa.gov/endocrine-disruption/what-endocrine-disruption
[2] Ragusa, A., Svelato, A., Santacroce, C., Catalano, P., Notarstefano, V., Carnevali, O., ... & Giorgini, E. (2021). Plasticenta: First evidence of microplastics in human placenta. Environment International, 146, 106274. Retrieved from https://www.sciencedirect.com/science/article/pii/S0160412020322297
[3] LaFee, S. (2012). BPA’s Real Threat May Be After Its Metabolized. UC San Diego. Retrieved from https://ucsdnews.ucsd.edu/pressrelease/bpas_real_threat_may_be_after_it_has_metabolized#:~:text=BPA%20is%20too%20short%20to,fetuses%2C%20infants%20and%20young%20children.
[4] Steinmetz, R., Brown, N. G., Allen, D. L., Bigsby, R. M., & Ben-Jonathan, N. (1997). The environmental estrogen bisphenol A stimulates prolactin release in vitro and in vivo. Endocrinology, 138(5), 1780-1786. Retrieved from https://www.researchgate.net/publication/14106531_The_Environmental_Estrogen_Bisphenol_A_Stimulates_Prolactin_Release_in_Vitro_and_in_Vivo_1
[5] Liu, X., Miao, M., Zhou, Z., Gao, E., Chen, J., Wang, J., ... & Li, D. K. (2015). Exposure to bisphenol-A and reproductive hormones among male adults. Environmental toxicology and pharmacology, 39(2), 934-941. Retrieved from https://www.sciencedirect.com/science/article/pii/S138266891500071X?casa_token=Yab05OlejG8AAAAA:RlSkn9KH2debhvtDG97A8VG7kHHBKcZcLkE3mauQjok9flIx7NE-0DcLnfneVriCRICCAvZBew
[6] Brotons, J. A., Olea-Serrano, M. F., Villalobos, M., Pedraza, V., & Olea, N. (1995). Xenoestrogens released from lacquer coatings in food cans. Environmental health perspectives, 103(6), 608-612. Retrieved from https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.95103608
[7] Hernandez, L. M., Xu, E. G., Larsson, H. C., Tahara, R., Maisuria, V. B., & Tufenkji, N. (2019). Plastic teabags release billions of microparticles and nanoparticles into tea. Environmental science & technology, 53(21), 12300-12310. Retrieved from https://pubs.acs.org/doi/abs/10.1021/acs.est.9b02540