Scientists Study Whale Baleen to Monitor Synthetic "Forever Chemicals" in Ocean

July 17, 2024

Baleen whales use a filter-feeding system of fringed plates made from keratin, called "baleen," hanging from the roof of the mouth that strains the seawater for food. Not only does this baleen collect food particles, but researchers have found the baleen also accumulates synthetic chemical substances like per- and polyfluoroalkyl substances (PFAS), providing a possible way to monitor the chemicals in the ocean.

The head, top jaw, and baleen of a humpback whale appear above the waters surface
Baleen whales do not have teeth—they have racks of keratin-based baleen that hang down from the top jaw and are used to filter their food from ocean water. Photo: Liam Waters/NMFS Permit No. 27272-01

PFAS are used in thousands of commercial and industrial products, including aqueous fire-fighting foam, disposable food packaging, furniture, cookware, cleansers, and others. These chemicals flow into the ocean from various point and nonpoint sources of pollution. In high concentrations, PFAS can have adverse effects on the growth and photosynthesis of phytoplankton and toxic effects on zooplankton. These chemicals also accumulate in the food chain, having been found in the tissues of marine plants and animals, including fish that humans eat.

Called "forever chemicals" because they break down so slowly, PFAS are a growing environmental and health concern. Tracking them in ocean ecosystems has so far been difficult. Reliable methods for monitoring PFAS in the ocean are needed. Researchers from Stellwagen Bank National Marine Sanctuary, U.S. Environmental Protection Agency, University of Rhode Island, College of the Atlantic, Stanford University, Center for Coastal Studies, and International Fund for Animal Welfare have found that measuring PFAS in whale baleen proves to be a reliable method for monitoring them in the marine environment.

researcher takes a sample from a baleen plate
Stanford University researcher, Matthew Savoca, takes a sample from a baleen plate. Photo: Matthew Savoca

In the study, researchers sampled baleen from 17 individual whales from the Atlantic and Pacific coasts of North America, representing six different species. They found quantifiable levels of common PFAS in all 220 baleen samples tested. While PFAS have been found in other keratin-based tissues, including bird feathers and human hair, this is the first report of these contaminants in baleen. The study also revealed that these chemicals are possibly being transferred from mothers to calves.

Researchers compared PFAS levels found in five different tissue types from whales, and found that skin and blubber were the least effective tissues for PFAS monitoring. However, due to global and U.S. laws, skin and blubber are the only types of  tissue that can be collected from live cetaceans. In this particular study, large tissue samples were collected during necropsy exams from deceased whales. This was a proof of concept study that shows detection of PFAS from baleen is possible. As this research progresses, much smaller baleen tissue samples could be collected from live whales, which would make baleen a reliable and potentially minimally invasive way to monitor PFAS in the ocean.