“What we’re trying to learn is where the pollutants come from and how those pollutants vary by where the seals feed,” said Lohmann, who has conducted studies of marine pollutants around the world. “Fur seals that have given birth have lower pollutant levels than those that have not, because they pass their pollutants on to their pups in their milk.”
All of the seals the researchers are studying breed on the South Shetland Islands of Antarctica, but some spend the winter off the coast of Argentina while others winter off Chile. The two groups are thought to be exposed to different pollutants in the food they eat at their wintering grounds.
Lohmann’s lab is analyzing 60 samples of seal milk collected between 2000 and 2010. He expects to find a wide variety of pollutants in the samples, including mercury, pesticides, flame retardants, PCBs, and other organic pollutants.
“These are all pollutants that degrade very slowly, so some may have been in the environment for decades while others, like flame retardants, are relatively new compounds that are still used by industry today,” Lohmann said.
“The seals can’t avoid the pollutants, so the best we can hope for is that the concentration of pollutants will decrease in their system over time, so that whatever harm there was is less harmful in the future,” Lohmann said. “But some data suggests that pollutant concentrations haven’t declined in the last ten years, even though most of the compounds were banned 40 years ago.”
The results of Lohmann’s analysis are expected in late February. His research is funded by a grant from the National Marine Sanctuary Foundation.
For more information, please see the related press release.
