Dandruff Shampoo Could Mess Up Waterways

Scientific American

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Every time you wash your hair, a lot of shampoo goes down the drain. And if you're bothered by tiny white flakes, odds are you use a shampoo that deals with dandruff.

Such medicinal shampoos often include a fungicide. A fair amount of fungicide thus ends up at the local wastewater treatment plant. Those industrial facilities remove a lot of stinky stuff. But they mostly fail to grab the drugs in soaps, shampoos, toothpastes, perfumes, sunscreen and other skincare products that our daily habits add to wastewater.

Now a study has detected fungicides from anti-dandruff shampoos in the water. And even at concentrations as low as 0.5 micrograms per liter of H2O such fungicides can hurt many organisms, from tiny algae to big plants and fish. The study is in the journal Environmental Toxicology and Chemistry.

Exposure to the fungicide is chronic: It gets repeated day after day after day. The algae just die. But bigger plants suffer retarded growth. And animals like fish are affected, too, since they share similar cellular mechanisms with their distant relatives. We might want to start coming up with ways to get our dandruff shampoo—and other personal care products—out of the drink.

—David Biello

[The above text is a transcript of this podcast.]

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