Unusual pollution research: Earwax-environment link studied

Whale secretion used to gain information on environment

By Kayla Reeves

Whale earwax is not a topic that usually comes up on a walk to get coffee, but it did for Baylor researchers Dr. Stephen Trumble, assistant professor of biology, and Dr. Sascha Usenko, assistant professor of environmental science.

They were trying to answer one student’s question, which led them to recently come up with a new way to study contaminants in the ocean using whale earwax.

A student had been looking at some bowhead whale sample, and asked how to determine a whale’s age, Trumble said.

He was thinking about it during a walk to Starbucks, began discussing it with Usenko and came up with ear plugs — the built-up wax that whales develop during their lifetime.

Since whales keep their earwax in their skull from birth until death, it can act like the rings in a tree trunk for aging.

Trumble wondered if the plugs could be used for other purposes too, he said.

He called a colleague from the Smithsonian in Washington, D.C., and together with the Santa Barbara Museum of Natural History they agreed to donate some samples of ear plugs for research.

Trumble, Usenko and graduate student Eleanor Robinson discovered that by examining the wax, they can measure the whale’s exposure to pollutants and know if the contaminants affected its physiology, Trumble said.

“You have to cut it in half, shave off layer after layer, do a lot of lipid extraction,” Trumble said. “It’s not easy; it’s very tedious.”

He also said it is difficult to find samples because they have to be removed from a dead whale’s skull, while blubber can be sampled in a biopsy.

“But the ear wax gives a lifetime profile from birth to death, and blubber only gives a snapshot from the last couple months,” Trumble said.

“You can’t get something this detailed from any other living organism that I know of,” he said.

So far, the team has found several pesticides and polychlorinated biphenyls (PCBs) in the wax.

Usenko said that some pesticides are natural and some are man-made, and they can travel through the environment into the oceans.

They are studying the possible correlation between these chemicals and the whales’ stress levels and physiology using cortisol, a stress hormone.

Trumble has been studying the cortisol levels to see if the increase in chemicals has an impact on the whale’s life, or if whales that migrate through shipping routes and have more contact with humans and contaminants are more stressed than normal, he said.

The main conclusion that can be drawn right now is that ear wax can be used to study the things that blubber is usually used for, Usenko said, but the researchers are hoping it will lead to more information about the chemical profiles in the environment.

Trumble has been studying the hormones in the wax. Cortisol, a stress hormone, can be measured to see if the increase in contaminants has an impact on the whale’s life, or if whales that migrate through shipping routes and have more contact with humans and contaminants are more stressed than normal, he said.

There is a finite number of samples, Trumble said, but the team is hoping to find more wax sample donors so that they can continue their research.

“We’ve already gotten the okay from national museums in London, and we’re looking at Japan and Russia,” he said. “I suspect people will try to jump on the band wagon, but we’re trying to strike the sample world now and get what we can.”

Trumble also said the researchers are entertaining the idea of doing a similar study in humans, but it will be different because humans’ ear wax is exposed to the environment and a lifetime sample can’t be obtained. They would have to study short term samples instead of a lifelong history.

Their research has been featured in Science Magazine, a national publication for the scientific world.

“It’s a unique opportunity [to be in Science],” Usenko said. “It shows that high quality research can happen at Baylor, and puts us on a national stage. It’s a big deal.”