By Elena Walter
Peer-Reviewed Study: https://doi.org/10.1016/j.envint.2024.108849
News Article: https://www.npr.org/2024/07/11/nx-s1-5036484/tampons-heavy-metals-study
Background
Heavy toxic metals, such as lead, mercury, or arsenic, are able to cause poisoning of varying degrees, depending on the metal itself, the dosage, and how the metals got into the body. Metals can enter the body through inhalation, ingestion, or absorption. (1) Some metals have safe levels of dosage, such as copper, which is present in all cells for cellular respiration and is used in certain birth control products, but others, such as lead, have no safe dosage. (2, 5) Certain metals, such as zinc or cobalt, in certain circumstances may even be antibacterial. (4)
Tampons are used by an estimated 52-86% of menstruating adults in the US, and one person may use roughly 7,400 tampons total throughout their life to manage their periods, assuming they use 4 tampons/day and each cycle is 4 days long for 39 years. (3) Prior to this study on metals in tampons, 15 other studies have been conducted which determined the presence of other chemicals, such as dioxins, polycyclic aromatic hydrocarbons, and volatile organic compounds (VOCs). (3)
Cotton, one of the primary materials used in the absorbent layer of tampons along with viscose and rayon, can readily take up metals present in soil. Metals may also be added to tampons for purposes of pigmentation or antibacterial properties. (3)
Peer-reviewed article
This article’s primary focus was to determine if there were any detectable levels of heavy metals in tampons. 16 metals were tested for: arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, mercury, manganese, nickel, lead, selenium, strontium, vanadium, and zinc. A range of variability in tampons were also considered, including organic vs nonorganic, European vs American, whether there was an applicator or not, if the applicator was cardboard or plastic, and name brand vs store brand. Researchers took ~0.2 g of the inner absorbent material and acid digested them before running the samples through ICP-MS.
Figure 1. Boxplots of metal distributions in tampon samples. Machine-read values were used for 90% of chromium concentrations and 91% of mercury concentrations. (1)
Of the 60 samples taken, representing 24 tampons, all 16 metals tested for were found in measurable quantities. 4 of the 16 metals, mercury, chromium, arsenic, and selenium, concentrations were found above the MDL (method detection limit) in at least 8.3% of samples. Anything below the MDL was determined using machine-read values. Important to note, though, is that the other 12 metals were found above the MDL in 100% of samples. The highest concentrations were found for zinc and calcium. Of the metals with the highest toxicity, arsenic, cadmium, chromium, lead, and vanadium, lead was found to have the highest concentration across samples. Across different brands, there was high variability. Certain brands had higher concentrations of arsenic, but lower concentrations of lead than the geometric mean.
Figure 2. Comparison of metal concentrations in organic (yellow) vs nonorganic (green) tampons.
The article discusses certain adverse health effects to metals such as lead and arsenic, as they may lead to negative neurological effects, dermal impacts, or cancer, among other things. These two metals are highlighted because there is no safe dosage for lead, and because a previous study has been conducted linking vaginal arsenic exposure in rats to impacts on the uterus and ovaries. (6) The authors go on to consider potential sources of metals in tampons. These range from atmospheric deposition, to wastewater contamination. It’s noted that the organic tampons tested were all 100% cotton, and cotton is particularly susceptible to uptaking metals through soil. Additionally, they were unable to accurately determine the sources of all of the raw ingredients used in the tampons. It is also highlighted that certain metals may be added purposefully to the tampons during manufacturing. Zinc, the metal with the overall highest concentration found, does have antibacterial properties, and were found with concentrations higher than those reported for textiles in other studies, which further implies its addition during the manufacturing process.
Overall, the study positions itself firmly as an exploratory study, as nothing similar to it has ever been conducted. While there are limits for other chemicals in tampons set by different governmental bodies, none of them clearly limit metal concentrations. The study, while finding metal concentrations in all tampon samples analyzed, does acknowledge that certain metals are likely added purposefully. The lack of sample size from each brand and product is also acknowledged, as well as the limitation that not enough studies have been done to assess the bio-accessability of these metals through the vaginal membrane. In future studies, the leaching of these metals through the vagina needs to be quantified to properly link the presence of metals in tampons to any adverse health effects.
News Article
The news article by Rachel Treisman for NPR covers these findings. The article first introduces the negative health effects of toxic metal exposure. It goes on to cover the peer-reviewed study, beginning with quotes from the lead author, Jenni Shearston. It then discusses the findings that measurable levels of metal had been found in all of the samples, and notably that high levels of lead, arsenic, and cadmium were detected. Treisman also mentions the sources from which the metals may have come from that Shearston discusses in the study. The article includes a call to action from Shearston herself, saying that it would be “exciting” for the public to call for manufacturer testing or better labeling on products. Treisman also has a representative from the FDA comment that although there are lingering questions about whether metals are actually released into the bloodstream from tampons, they are reviewing the research. Additionally, industry representatives from both the US and UK were asked to comment, to which they understandably reassured the safety of their products. More researchers from similar fields also commented, on both the previous studies that have also found harmful chemicals in tampons, but also that it’s not clear yet if harmful dosages of metals are occurring due to tampons. The article concludes by advising readers to choose tampons without plastics or fragrances, or by choosing alternatives to tampons such as menstrual cups, but that there isn’t yet a clear risk associated with tampons for heavy metal exposure.
Assessment
I would rate this article a 10/10. I think the author does a wonderful job of conveying the scientific results of the study. Although they do not go into specifics on the methodology, I do not believe that it is wholly necessary to do so for a general audience. They not only ask for comments from the lead author and other experts in the field, but also from a governmental body as well as industry representatives. This wide breadth of backgrounds provides for a well balanced discussion that acknowledges the study’s findings, while also not over-dramatizing it and causing panic. It even goes as far as to recommend next steps if people are concerned about the heavy metals, but reaffirms that the actual health impacts of the heavy metals in tampons is not clear and requires more studying to properly identify. Overall, the news article did a great job.
References
1. Cleveland Clinic. (2022, July 7). Heavy Metal Poisoning (Toxicity). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/23424-heavy-metal-poisoning-toxicity
2. Mayo Clinic. (2019). ParaGard (copper IUD) - Mayo Clinic. Mayoclinic.org. https://www.mayoclinic.org/tests-procedures/paragard/about/pac-20391270
3. Shearston, J. A., Upson, K., Gordon, M., Do, V., Balac, O., Nguyen, K., Yan, B., Kioumourtzoglou, M.-A., & Schilling, K. (2024). Tampons as a source of exposure to metal(loid)s. Environment International, 190(108849), 108849–108849. https://doi.org/10.1016/j.envint.2024.108849
4. Zhang, E., Zhao, X., Hu, J., Wang, R., Fu, S., & Qin, G. (2021). Antibacterial metals and alloys for potential biomedical implants. Bioactive materials, 6(8), 2569–2612. https://doi.org/10.1016/j.bioactmat.2021.01.030
5. Nordberg GF, Costa M. Handbook on the toxicology of metals: volume II: specific metals. Academic press; 2021.
6. Irnawati, I., Idroes, R., Akmal, M., Suhartono, E., Rusyana, A., & Seriana, I. (2022). The Effect and Activity of Free Radical Enzymes Due to Arsenic Exposure Through the Vulva and Vagina. Open Access Macedonian Journal of Medical Sciences, 10(B), 2279–2285. https://doi.org/10.3889/oamjms.2022.10306
Hi Elena! This was a very interesting blog post to read. I agree that the news article did a great job summarizing the main findings of the study and what the implications are. Specifically, I appreciated how it highlighted that there is not enough information to "definitively link the metals to negative health effects." Also, using several different reliable interviews is definitely helpful for the credibility of the article. Providing alternatives to tampons additionally shows care for the reader, as some may be reasonably concerned about the use of tampons. Do you know how they chose which metals to test for? The news article mentioned that the study did not name the brands and product lines of the tampons they studied. Why do you think that is? Is there a way to determine the source of all the raw materials used in the tampons from the manufacturers, or would this call for a separate study?
ReplyDeleteHi Kristen! The researchers did not specify exactly why or how they chose the metals that they did to study, but I would assume that they chose metals that were likely to be present and ones that had the highest toxicity. Further, I think they chose to not disclose the brands they studied to avoid legal backlash, because large brands may consider the study to be a direct attack against their reliability and thus impact sales. The study itself, though, mentioned the limitations in sourcing raw materials. The main issue is that often the tampons would be listed as "assembled in the US with international products" and then not disclose where those raw ingredients came from.
DeleteHey Elena, great analysis. I found this especially interesting and especially terrifying as a female. Even knowing there is no current quantitative findings connecting the metals to poor health, the presence itself of such heavy metals in tampons is concerning. I do wonder if there is a difference in presence and concentration of certain heavy metals in different types of tampons and/or dependent on the size of the company and warehouse. I would think a larger company might pay less attention to such facts in individual production, but larger overall findings to avoid poor public imaging. This also makes me wonder about whether there are heavy metals present in other feminine products such as pads since many companies make both. Do you know if the sources of these heavy metals is due to accidental exposure during manufacturing or if it is something innate that appears or sticks to regardless of preventive measures?
ReplyDeleteHi Elizabeth! The study itself didn't disclose brands, and only postulated on sources but didn't quantifiably test possible ones, but the study did mention that concentrations of copper, nickel, and selenium were higher in store-brand tampons compared to name-brand, but that name-brand tampons had higher concentrations of zinc. This study was centered on tampons, specifically, but if certain metal concentrations are able to be traced back to the cotton materials, I wouldn't be surprised if pads also had metal contamination. The study doesn't suggest any accidental exposure during manufacturing, but rather pre-contamination in raw materials or the purposeful addition during manufacturing (such as zinc for antibacterial properties, or other metals for pigments/fragrances).
DeleteHi Elena, thank you for sharing this very important article with us and for your great analysis of it. First of all, I wonder whether not enough studies have been done because this product is primarily used by women; in general, research on women-related health issues is still far behind research focused on men. So, I’m grateful that Shearston and her colleagues are shedding light on this topic.
ReplyDelete1. You also mentioned that soil is the main source of metals that are then taken up by cotton. I wonder whether soil-free cotton cultivation, such as through hydroponic methods, could be a better option - assuming the water used is properly treated for these metals.
2. I know that “below limit of detection” means we cannot fully trust the data. What does the machine-read value indicate in this context?
3. You also mentioned that there are no government-established limits for metal concentrations in tampons. What other equivalent measures could be used to create a preliminary scale or guideline for acceptable limits?
Thank you!
Hi Frozan! The paper states that they calculated their MDL (method detection limit) as being 3.33 times the standard deviation of blank measurements, and then corrected for the dilution factor. So from my understanding, any data that was above zero but fell below this limit was then handled without as much statistical processing, and is less reliable because it falls within the standard deviation of the blanks. As for regulation, I don't think many preliminary scales would be effective, because it would mean relying on large companies to independently choose to make their testing more stringent, which means a loss of profit. I think the only truly reliable path is for the FDA to instate official policy.
DeleteThank you Elena!
DeleteGreat job Elena! I agree with your assessment of a 10/10. You did an excellent job explaining how the article balanced clarity with scientific accuracy, and I appreciate how you highlighted the range of perspectives—from researchers to regulators to industry representatives. I also thought your point about avoiding unnecessary alarm while still stressing the need for more research was especially important for responsible science communication. The part of the news article I found the most simultaneously interesting and horrifying is that while the FDA regulates tampons as a medical device, manufacturers are not required to test them for chemical contaminants. Do you think the article could have gone further by connecting the presence of metals in tampons to regulatory gaps in consumer product safety, and would that have helped the public better understand the broader policy implications?
ReplyDeleteHi Sarea! I'm not sure if the article should've connected the study even more to gaps in consumer product safety. They already have a statement from Shearston calling for policy change and a statement from and FDA representative that they would be looking into the situation. I worry that going further to point our these broad gaps in the lack of heavy metal testing for these products would cause unnecessary panic. Manufacturers do have to test for certain chemical contaminants, like dioxins, which have been shown to have high toxicities, but it is challenging to regulate so many contaminants if a direct health impact hasn't been shown.
DeleteHi Elena, thank you for sharing this study, and I appreciate your analysis. I completely agree with your 10/10 rating for the news article. It’s so refreshing to see a topic this sensitive handled without sensationalism. It's easy to just write a 'toxic tampon' scare headline. Also, it’s great to have different perspectives from the leading scientists, the FDA, the BAHP, and ACOG in one news article. This article focuses on 'here’s what we know' (metals are present) and 'here’s what we don’t know yet' (the actual health impact), which is exactly what good science journalism should be.
ReplyDeleteAnd it’s interesting to see that in organic tampons, some metals are higher than in non-organic ones, which is similar to the previous cacao product study. I wonder whether the organic criteria should be updated in light of these studies, or if we should set up another criterion for metal labels on the packaging. Also, what do you think the most important next step should be? Tracing the origin of metals and setting up regulations, or testing for leaching and linking them to health effects?
Hi Siyu, I definitely think the next step should be testing for leaching and proving the link between the heavy metals in tampons and negative health effects. I worry that without evidence definitively showing that link, policymakers won't feel that it's truly necessary to make the regulations.
DeleteHi Elena, great analysis of peer reviewed paper and news article. I did not know that there was not FDA regulations to test tampons for chemical contamination, so I found it especially interesting since users of tampons often have ability to give birth to children and I've so frequently seen in drug advertisements or in chemical/lab safety information, many warnings specifically for people with childbearing abilities. I also agree with your rating of the news article as I also liked how the article included advice for tampon users that may be concerned and reported the findings clearly with balanced writing (not too conservatively or using sensationalized language) that represents the research well to a general audience.
ReplyDeleteHi Elena, great analysis! I really enjoyed reading this overview. The note about cotton absorbing metals from the soil reminded me of the slide from lecture saying that the greatest pesticide use in the US is on cotton. Are pesticides some of the chemicals that the government has put limits on? I was also curious if the authors mentioned which metals would be added for pigmentation like whitening the cotton?
ReplyDeleteI wonder if other forms of cotton used in the body like cotton rolls used at the dentist would have similar amounts of metals. Though these cotton rolls for example are likely used much less frequently and for a shorter duration than tampons, so the health risk is likely smaller.
Great analysis Elena! I completely agree with your rating of the article. It was delightful to read an article about such a concerning topic that didn't sugarcoat or try and discredit the findings, while also not trying to sensationalize the findings. However, it was shocking to me that the US, EU and UK have not established regulations for consumer protections from tampon contaminants and that there are no requirements for these companies to test their products for these either. In addition, a lot of these studies cited in the discussion section of the paper that look into vaginal exposure and toxicology are from the 2020s. Do you have any idea why this is the case? Is this just a matter of women's health being understudied, or is knowledge about heavy metal contaminants and prevalence more recent? In addition, considering the lack of regulation for such a popular period item, it makes me curious about if there's any regulation for alternative period products such as menstrual cups or period underwear. If the advice is for concerned consumers to shift items, but there's a similar potential unknown and/or threat with other items, it seems like a call to action for greater regulation and study is sorely needed.
ReplyDeleteHi Elena,
ReplyDeleteI enjoyed reading your analysis of the peer-reviewed paper and agree with the 10/10 ranking you gave the news article. While the authors of the peer-reviewed paper note that this is an exploratory study and that little is known about how toxic heavy metals might enter the reproductive system through tampon use, there are previous rat studies that suggest possible toxicity. Do the authors discuss these studies in more depth or use them to potentially extrapolate negative effects in humans. For instance, effects that could, in turn, be used to caution tampon use until their safety can be more firmly established?
Hi Elena, I really enjoyed reading your analysis of the peer reviewed article and your analysis of the news article. I think that it is really interesting that it can be concluded that these metals were added purposefully. I noticed a spike in Iron within the data presented, but I'm assuming that it is not very harmful. Lead being detected is interesting because public opinion around lead is very negative, the article could have totally leveraged this for clicks, but did not. Stuff like that, and the point that you highlighted in your analysis make this conclusively a 10/10 article.
ReplyDeleteThis was a really interesting post and a great analysis! I'm somewhat surprised that this research hadn't been done before, but I do know that there's a bit of a blind spot in medical research regarding feminine hygiene. I'm glad that this topic is finally being investigated, and I'm very curious to see the findings regarding any possible medical consequences of these heavy metals being in tampons. Did the article mention whether or not it would be possible to completely remove some of these metals, particularly lead, from tampons? I agree with your rating on the article, it was very informative while not being overly complex. Do you think these findings could provide any sort of pressure towards the companies to either be more transparent with the metals in their products or remove them? I'm very curious to see the list of brands they tested and the amount of metals they found.
ReplyDeleteGreat analysis, Elena! Thank you for sharing this study. It is so disappointing that one of the most widely used period products has so many harmful chemicals in it that have very dangerous health impacts. I heard about this study last year, but it was striking to hear that all 16 chemicals were detected across all samples. This was a great example of how pollutants that enter the environment have widespread impacts on every aspect of our lives. What surprised me was that the researchers had to make a guess that the zinc was intentionally added for its antibacterial properties. This highlights the lack of transparency between manufacturers and users. It is great to hear the news article had so many expert opinions from the researchers and others in the field to enhance their credibility. The calls to action from the author are a great first step to getting more research into the often-overlooked women’s health issues in medical research. Are there any current regulatory standards for metals in products? Especially for lead, which has no safe exposure limit, is it legal for these brands to have heavy metals in their products without any transparency? If the contaminants are coming from the soil, could changing agricultural practices be a realistic way to reduce metal contamination in cotton? What would that look like?
ReplyDeleteHey Elena! I think this is a very good topic and you did a great job summarizing it. I particularly like how the paper talked about the possible limitations of the study and directions for future research. I also am curious if any negative health impacts can be linked to the presence of these heavy metals in tampons. I also agree with your assessment of the article. I found that it was very detailed and gave a lot of insight into the study. It did a good job explaining the results in an understandable manner for people.
ReplyDeleteGreat analysis and honestly a great news article all around, common for NPR in my opinion but I digress. The levels found in this study are absolutely absurd in that so many were found to be above MDL in all samples, including some that were found to be of the most toxic character like lead and cadmium. Based on figure 1 some like lead, copper, and cobalt had really concentrated samples that more than double the MDL as well. This implies that inherently some brands were significantly worse at limiting heavy metals than others or possibly certain types or properties such as the organic cotton as you mentioned may cause greater susceptibility to metal uptakes. I understand the choice not to put the brand names on the study, especially without having a clear study yet quantifying how tampons transfer the metals to the bloodstream/body. However, I think it would possibly be better to have brand names included in possible health risk studies in the future as to provide people with the most safe options and understanding of risks with different types and the such. It's also scary to hear manufactorers not have clearly defined sources for things made to go in the human body as that implies to me they likely already know about the adverse health already as seen with cigarette industry.
ReplyDeleteHi Elena! This is a very shocking study to me. This remindedme of something talked about in my immunology class on how certain brands of tampons were found to cause toxic shock syndrome in women. This makes me question on how well tampons are regulated. Did they say anything about the effects of being exposed to these metals overtime? I think that’ll be an interesting follow up study. Also, I am very curious on what brands they used. Was there a noticeable difference between brands or was only a single one used for continuity results?
ReplyDeleteGreat job with your analysis Elena! Exploratory research like this is critical as far as suggesting future areas for research and is especially effective when authors thoroughly address limitations. I would be curious to know the potential reasons for the differences in concentration between non-organic and organic brands. If specific differences in manufacturing are found to be associated with the difference in metal concentrations, then there would be a clear path forward in understanding the causes of the contamination for metals that are not added intentionally. I am also curious if companies that manufacture tampons that do add metals like zinc for its antibacterial properties had done any in-house research or considered the potential health impacts before deciding to add them.
ReplyDeleteHi Elena! Your post really opened my eyes to how common metal contamination might be in products people use all the time without thinking about it. It was shocking to read that all 16 metals showed up in every sample, or that lead was one of the highest—especially since there’s no safe level of exposure. It also surprised me how much the levels varied between brands and how even organic cotton wasn’t necessarily better. I agree that the lack of data on how much metal can actually be absorbed is a huge gap, and it makes sense why the study calls itself exploratory.
ReplyDeleteHi Elena! Thanks for your post. I have heard about heavy metals being found in menstrual products before, but I didn't realize how many types of metals have been identified! I was wondering if you or the authors believe that there is a risk of absorbing the metals into the body. I've heard that the risk is low, but I'm not sure how accurate that is. I think this study really highlights the need to study whether or not metals in tampons and other menstrual products are harmful to those who need them.
ReplyDelete