- Scientists have detected parabens, a common cosmetic preservative, in marine mammals from coastal areas of the United States.
- The chemical concentrations were highest in coastal animals like dolphins and sea otters, but also showed up in polar bears in remote regions.
- Researchers don’t yet know how toxic these chemicals are, but parabens can disrupt hormones in the body.
Compounds from our makeup and bathrooms are winding up in the bodies of dolphins, sea otters, and polar bears – sometimes thousands of miles away. For the first time, research in Environmental Science & Technology reports a common cosmetic preservative in marine mammals from the United States coastal waters. Scientists don’t yet know whether these substances will harm animals, but similar chemicals like PCBs and DDT have shown that our industrial products can cause damage.
“These chemicals are not as persistent as PCBs and DDT, so for that reason, people probably didn’t pay attention to looking at them in marine mammals,” said senior author Kurunthachalam Kannan, a research scientist at the State University of New York in Albany and the New York State Department of Public Heath.
Parabens are a class of chemicals added to perfumes, processed foods, cosmetics, and pharmaceuticals since the 1950s. They extend the shelf lives of products and prevent bacteria from growing.
About 15 years ago, a controversial study linked human breast cancer with cosmetics containing parabens. The effects of parabens on people remain unclear and debated. But scientists do know that parabens are estrogenic: they mimic female hormones. In males, this causes feminization.
Recently, Kannan and his colleagues found that parabens accumulate in the fatty tissue of humans. This happens when we apply products to our skin, such as lotions and perfumes, he said.
“This led us to think that if these chemicals are accumulating in fat, probably they are out there in many others places we have never looked before,” said Kannan.
Chemicals discharged from urban areas and into oceans that don’t break down will infiltrate the food chain, working their way up from plankton to carnivores. Marine mammals are top predators with a fatty layer of blubber, making them a logical group to examine for parabens.
Kannan had the raw materials: he has studied marine mammals for more than 25 years, accumulating a freezer full of archived tissues. His team analyzed parabens in 121 tissue samples from eight species of sea mammals, including sea otters, dolphins, and polar bears. The specimens came from the coastal waters of Florida, California, Washington and Alaska.
Kannan and his colleagues didn’t just look at the parent compound. They also analyzed the metabolites — the chemical byproducts that arise when an animal’s body processes a compound. Metabolites can be more dangerous than parent compounds, said Juan Jose Alava, a postdoctoral fellow at the University of British Columbia and adjunct professor at Simon Fraser University, Canada, who was not involved in the study.
The results were unambiguous: “To our surprise, we found high levels,” Kannan told Mongabay. “We never expected these levels. It’s cause for concern.”
The team found six different parabens and four different paraben metabolites in the mammal tissues. The majority of tissues analyzed contained methyl paraben (MeP). The highest concentrations, up to 865 nanograms per gram (wet weight), were found in livers of coastal bottlenose dolphins in Sarasota Bay, Florida.
The primary metabolite detected was 4-hydroxybenzoic acid (4-HB). Trace amounts of 4-HB showed up in remote polar bears, but high levels appeared in dolphins and sea otters.
“It is important baseline information,” said Peter Ross, director of the Vancouver Aquarium’s Ocean Pollution Research Program, also not involved in the study. These chemicals might not kill animals, but they could alter the development and growth of the exposed individuals, said Ross. How to determine the risks of these chemicals to wildlife and humans is “probably the preeminent question for toxicologists and regulators in this century,” Ross told Mongabay.
Scientists agree that we need a more “precautionary approach” and to study chemicals before applying them, he noted. “This is yet another reminder that our own actions have unintended consequences for the health of the oceans,” said Ross.
Jingchuan Xue, Nozomi Sasaki, Madhavan Elangovan, Guthrie Diamond, and Kurunthachalam Kannan. (2015). Elevated Accumulation of Parabens and their Metabolites in Marine Mammals from the United States Coastal Waters. Environmental Science & Technology 2015 49 (20), 12071-12079.
Bethany Augliere is a graduate student in the Science Communication Program at the University of California, Santa Cruz. Other Mongabay stories produced by UCSC students can be found here