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A study showing that tampons contained measurable concentrations of 16 toxic metals including lead, cadmium, and arsenic has been making headlines this week.

However, it's still unclear -- and some say unlikely -- that the levels found would harm regular tampon users.

Elevated levels of lead, cadmium, and arsenic -- with geometric means of 120, 6.74, and 2.56 ng/g, respectively -- were found in 30 tampons from 14 different brands, researchers led by Jenni Shearston, PhD, MPH, of the University of California Berkeley, reported in .

"It was surprising to see that most metals were in measurable quantities in tampons. Also, we were surprised to find lead, which has 'no safe' level," co-author Kathrin Schilling, MSc, PhD, of Columbia University Mailman School of Public Health in New York City, told 麻豆传媒 in an email.

Metals may make their way into tampons through several pathways. Metals from the atmosphere or wastewater can contaminate raw materials like cotton, rayon, or viscose, along with water during manufacturing. Further, metals may be added intentionally to tampons as antimicrobial agents, for odor control, or as lubricants for smoother insertion.

Metal concentrations differed slightly by region of tampon purchase: lead, cadmium, and cobalt were lower in tampons from the E.U. and the U.K. compared to the U.S. and for store brand versus name brand tampons. No differences were found between tampons with cardboard and plastic applicators. Lead concentrations were higher in non-organic tampons, but arsenic concentrations were higher in organic tampons.

"While lead and arsenic are strictly regulated in drinking water -- arsenic levels shouldn't exceed 10 mcg/L, and lead should be at zero -- similar regulations for personal care products would be beneficial," Schilling continued. "Ensuring our cosmetics are free from harmful metals can contribute to overall better health and well-being."

The authors wrote, however, that they "cannot speculate on potential harm to the health of menstruators" partially because of a "lack of data on the absorption of chemicals through the vaginal mucosa." The bio-accessibility of tampon metals is not known, but several metals can be absorbed from similar products, including cosmetics, they noted.

"That's something we definitely need to know -- and it's disappointing that we don't," Shearston wrote in an email to 麻豆传媒.

"Here's a comparison that might be helpful: the average amount of lead we found in a tampon is about 25% of the lead found in a single cigarette," Shearston said.

The FDA does set specific limits for contaminants, including metals, in foods. However, tampons are classified as a medical device in the United States. The FDA says it requires quality assurance testing of tampons that includes identifying some metals and "assessing the risk of those substances ... being absorbed by the human body and causing adverse health effects at that level."

"It could lead to a public health concern in the future, just like we learned that lead levels for infants cause problems. I honestly believe that [there will] be more to come out of this," commented Monique De Four Jones, MD, MBA, an ob/gyn with Northwell Health in New Hyde Park, New York, who was not involved with the study.

Still, she told 麻豆传媒, "I don't think it's [so] harmful that we need to pull things off of the market or anything like that." Tampons and tampon-like components have been used for years, "and we haven't seen any major adverse events at this point," she added.

Others were similarly cautious in condemning the personal care products.

"While it's true that there are probably some heavy metals in tampons, the quantities of these contaminants are incredibly low," Gideon Meyerowitz-Katz, PhD, an epidemiologist from the University of Wollongong, Australia, wrote in a Substack in response to the study.

He noted that 173 ng/g, the median amount of lead found in the tampons, translates to a total of 0.0000007-0.000002 grams of lead in each one.

This, he said, is "about the same as the concentration of lead in dried apples," referring to a study that tested vegetables and fruits.

But "menstruators may use more than 7,400 tampons ... over their reproductive years, with each tampon being retained in the vagina for several hours," the authors of the study noted. The vagina is an efficient absorber, with a "highly permeable and vascularized mucosal membrane" and small folds that increase surface area and can allow chemicals directly into systemic circulation without passing through the liver.

Given that menstruators make up half the population, the researchers said more research is key to helping the public feel safe.

"It would be good to see better labeling on tampons and other menstrual and personal care products," Schilling said. "Importantly, our findings highlight the need and urgency for testing tampons (and other products that we use daily) for toxic chemicals before they hit the supermarket shelves."

To conduct the study, researchers analyzed roughly 0.2-g samples from 30 tampons (60 samples) using microwave-acid digestion and inductively coupled plasma mass spectrometry. This allowed them to determine concentrations of arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, manganese, mercury, nickel, lead, selenium, strontium, vanadium, and zinc in each sample.

Each sample contained parts of the inner core and outer covering of the tampon. The researchers compared concentrations of metals by tampon characteristics including brand, organic material, and region of purchase (the U.S., Greece, and England).

Correction: The FDA does require manufacturers to test tampons before they are sold.

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