Mother Seals Are Transferring Dangerous Environmental Pollutants to Their Pups

Researchers have discovered that hooded seal mothers are inadvertently passing on environmental pollutants to their newborn offspring. The toxins are transferred through the placenta and the mother’s milk. The details are in a paper that was just published in the journal Environmental Toxicology and Chemistry.

Perfluoroalkyl substances (PFASs) are common environmental contaminants that are only just now being properly studied. Many of these chemicals have been banned but some are still used in carpets, textiles, packaging, and other products. They persist in the environment and can be toxic to the native wildlife. PFASs and similar chemicals frequently end up in the systems of marine organisms. Predators such as marine mammals are especially at risk because they eat contaminated prey, resulting in a build-up of chemicals in their bodies.

Hooded seals (Cystophora cristata) are large marine mammals found throughout the Arctic region. Adult males have an odd inflatable bladder on the top of their head. The bladder is normally used during mating displays or territorial disputes. Females lack the head ornament and have silver fur with black spots. Hooded seal mothers nurse their young for a short 3 to 4 days. Since the pups feed exclusively on milk during this time, the species is a good model for studying the possibility of PFAS transfers to offspring.

The research team captured 15 lactating hooded seals and their pups. Blood and milk samples were taken and the animals were then released. The samples were analyzed in a laboratory at the Norwegian University of Life Sciences.

The researchers found PFASs in all of the samples, showing that the chemicals were being passed through the mothers’ milk. PFASs were also capable of transferring through the placenta before the pups were born. The most common PFAS in the samples was perfluorooctane sulfonate, a chemical that is being phased out of use in most countries.

The team’s findings show the danger of PFASs and similar compounds. The chemicals were transferred to seal pups through the placenta and mother’s milk. PFAS concentrations have been linked to low birth rates in seals and other marine mammals. The study highlights the importance of studying the effects of these environmental contaminants, which are still used in some countries.


Grønnestad et al. Maternal transfer of perfluoroalkyl substances in hooded seals. Environmental Toxicology and Chemistry (2016).

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