Chemicals in Soap Are Killing Coral Reefs

They could be killing the wildlife in your favorite local waterway, too.

January 21, 2014
Is Your Soap Toxic to Ocean Coral?

If you love swimming in open waters, whether on a tropical island or in your favorite backyard river or stream, it might be time to rethink your soap. A new study has found that common chemicals in soap and other personal care products, as well as cleaning products, are destroying coral reefs—and could be doing similar damage to the ecosystem of your local river.

The study, published in the journal Ecotoxicology, looked at the damage to coral reefs caused by a chemical called benzophenone-2 by exposing baby coral and coral cells to this potent chemical. "The biggest problem we saw was with coral recruitment," says Craig Downs, PhD, executive director of the Haereticus Environmental Laboratory, which led the study. Coral recruitment is the process by which baby coral attach themselves to new reefs, and they didn't do that when they were exposed to benzophenone-2. "That means, from an evolutionary perspective, that the coral reef is effectively dead. With no new young individuals in a reef, the reef is going to disappear within a couple decades," he says.


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Benzophenone-2 is used in soaps, colognes, perfumes, shampoos, and a dozen other types of personal care products; it's also used in cleaning products, auto paints, and a myriad of other industrial applications (it's related to another chemical called oxybenzone, which is used in sunscreens and is also guilty of killing coral). Yet it's considered a pseudo persistent-organic pollutant: Once in enters the environment it takes anywhere from three to nine months to break down, Downs says. "But people are always using it," he adds. "It's constantly being released into the environment," from our showers, drains, and washing machines. Most wastewater-treatment plants aren't equipped to remove it, and once it's in waterways and their drainage areas, it has the potential to bind to sediment and soil. So they never really become free of the chemical.

Since oceans are never able get rid of benzophenone-2, it has the added disastrous downside of preventing coral reefs from recovering. In truly clean waters, Downs says, damaged or destroyed coral can rebound within a decade. But "80 to 90 percent of coral reefs in the Caribbean are gone," he says. That's because development of coastal areas there has led to improperly treated wastewater that finds its way into the ocean, only to wreak havoc on reefs.

And although he specifically analyzed its damage to coral reefs, Downs suspects that benzophenone-2 could be damaging U.S. rivers and waterways. He says U.S.-based studies on the chemical are rare (he blames a heavily influential chemical industry that has lobbied to prevent the federal government from funding such studies), but researchers in Switzerland and Spain, which use water-treatment technologies similar to ours, have shown high levels of it in fresh waterways in those countries.


"Bezophenone-2 is a known endocrine disruptor," Downs says. In addition to interfering with thyroid hormones in people, it causes sterility in fish, and it doesn't discriminate based on whether those fish live in coral reefs or in freshwater streams. In fact, Downs says that benzophenone-2 and chemicals like it could be compounding the damage that overfishing is doing to wild fish stocks. "We've noticed a big problem with fish that grow in mangroves; they're just not reproducing," he says. "So we know something else is impacting them. When we do chemical analyses of wild fish, they're just loaded with chemicals, from old problems like DDT to synthetic musk," another component of artificial fragrances used in personal care products and cleaners.

Not only that, but bezophenone-2 also readily absorbed through skin. When you're swimming in water that's been contaminated with it, whether it was released from a wastewater-treatment plant or by a swimmer who just used a toxic soap, your skin could absorb it.

By far, Downs says, it's consumer products like soap and cleaners that are contributing the highest levels of the pollutant to oceans and waterways, so you can do your part by choosing less-toxic products:

• Buy "free & clear" everything. Benzophenone-2 is used to keep scents and colors from being broken down by UV light, and because manufacturers aren't required to list all the ingredients in colors and fragrances, you might not see it in the ingredients list on your favorite soap. It's also used in plastic packaging as an additional UV filter. Stick with dye-free and non-artificially scented products. You can find personal-care products without the ingredient on the Environmental Working Group's Skin Deep database.


• Find cleaner cleaners. Cleaning-product manufacturers aren't required to disclose all their ingredients, either, yet benzophenone-2 keeps those neon-green sprays bright and those "sunshine breeze"–scented fabric softeners smelling nice. Find commercial cleaners that are kind to fish (and benzophenone free) in the Environmental Working Group's Guide to Healthy Cleaning Products database.