The Physics Police

The Physics Police

Monday, December 23, 2013

Scaring Women for Profit

Laura Kiesel is a freelance journalist who recently wrote an article for Salon called Toxic tampons: How ordinary feminine care products could be hurting women. She argues that "dangerous chemicals" inside tampons and pads are being ignored. She's focuses mostly on dioxins.
... products such as maxi pads, tampons and douches ... contain potentially harmful ingredients including ... dioxin, which has been identified by the World Health Organization as a Persistent Organic Pollutant, a toxic chemical that persists in environments for long periods of time.
This information comes from a document titled Chem Fatale compiled by Alexandra Scranton of Women's Voices for the Earth. This document, too, focuses on dioxins but lists several preservatives and other ingredients found in feminine hygiene products that are allegedly bad for you.

I suspect the emphasis on "dioxins" has something to do with the way that word sounds. Even if you don't know what dioxins are, you must know they're dangerous! After all, it rhymes with "toxins". Of course they are actually toxins, as Kiesel and Scranton so forcibly point out.

But the question is, are they found in tampons, and at what concentration? Chem Fatale cites a 2002 study published in the journal Environmental Health Perspectives titled Exposure assessment to dioxins from the use of tampons and diapers.

This study detected very, very small traces of dioxins in both cotton and pulp products.
The refined exposure analysis indicates that exposures to dioxins from tampons are approximately 13,000-240,000 times less than dietary exposures.
It would be astounding if no dioxins could be detected, because these chlorine-containing organic molecules are easily detected in extremely small quantities. For better or for worse, dioxins exist wherever life is found, which is to say the entire surface of the Earth. If you want to live absolutely free of any dioxins, go find a planet without life, or better yet, a universe without chlorine.

Despite the inconsequentially low concentration of dioxins found in tampons, Scranton argues that there is still cause for concern.
However, the study authors did not account for the unique and highly permeable tissues of the vagina, and how that vaginal exposure may be different or even more potent than the dietary route of exposure.
If Scranton had actually read the study, she would have learned that dioxin exposure was calculated using the partition coefficient of dioxins in the tampon. That is, how much of the dioxins can leak out and be absorbed into the body. The study assumed 100% intake of bioavailable dioxins! It made no assumption whatsoever about the permeability of anyone's privates.

Not only is the concentration of dioxins in tampons low compared to dietary sources, but the bioavailability is low, too. Remember that mucous membranes in the gut are highly permeable in order to absorb nutrients! Bioavailability of nutrients and dioxins alike are increased by chewing, saliva, stomach acids, the mechanical churning of the gut, etc.

The study's methods are actually quite sound, and its conclusion is clear. Tampons are safe.
Our analysis indicates that the use of either tampons ... does not contribute significantly to dioxin exposures in the United States.
So, if tampons don't contribute significantly to dioxin exposure, then why make a fuss about it? Such unscientific fear mongering seems designed only to scare women. Now why would a group called the Women's Voices for the Earth (WVE) want to scare women?

Well, you can download their Non-Toxic Shopping Guide, which has 17 pages of reasons, from Archipelago Soy Wax candles to Zulu Lux Gluten-Free lipstick.

Laura Kiesel is correct when she says that WVE are "taking aim at the $3-billion-a-year feminine care industry". But their "aim" isn't to inform or improve women's health.

It's to get in on the profit.

This story is being picked up by websites like Reader Supported News. I find it especially ironic when this crowd, which usually remembers to "follow the money", is so quick to believe lies told to them by this small business.

For-profit lies aren't at all monopolized by big business and the political Right.

Laura Kiesel was kind enough to respond to my email, and put forth a defense of her article.

She argued that the 2002 study is:
... over a decade old. In the world of science, a decade is ancient history. This is why I searched for more recent studies and referred to the EPA report from just last year that concluded that dioxins could have serious health effects at even ultra-low levels of exposure--which you conveniently left out of the recap in your blogpost, probably because it would have completely undermined your stance
As it happens, I left this calculation out for brevity, not because it undermines my anything.

The quote about "ultra-low levels" actually comes from an Environmental Health News article by Marla Cone which, like the link in her article, refers to the 2012 EPA document Reanalysis of Key Issues Related to Dioxin Toxicity.

This document concludes (on page 44) that the No Observed Adverse Effect Level (NOAEL) is greater than 0.32 ng/kg-day. Those are your ultra-low levels, right there.
The 2002 study may be old, but it's the only shred of evidence Kiesel or WVE have cited, so I will continue to address its implications. The tampon brand with the highest concentration of dioxins was sample D from Table 4 on page 26 with 0.247 pg/g dioxin and weight 4.04 g.

Assuming 100% absorption by a 60 kg female, the dose from one tampon per day would be:

(4.04 g) * (0.247 pg/g) / (60 kg-day) = 0.00001663 ng/kg-day

That's about 20,000 times smaller than the NOAEL from the 2012 EPA document.

Nothing to be afraid of.

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