Toxic chemicals from plastics found in Norwegian marine mammals

Ever wondered about the vibrant colors, flexibility, and durability of plastics? These traits are shaped by “plasticizers,” chemicals added to alter plastics’ properties. Unfortunately, many of these chemicals find their way into oceans, posing a threat to wildlife. Despite some being banned, others are still being used in plastic production resulting in ocean contamination. A new study reported the presence of these chemicals in several marine mammal species from Norway, sparking concerns about their lasting impact on the environment. Let’s find out more about it!

Plastics in the ocean

When plastics are not disposed of properly, they can end up in the ocean. Aside from causing problems such as entanglement, or digestive occlusions, chemicals contained in the plastics themselves can begin to leach out. Many of these chemicals can cause harmful effects on the reproduction and the endocrine system in mammals. Yet, these chemicals are still in use today. There is very little research on how much of these chemicals enter ocean organisms or how they affect these same organisms.

Arctic marine mammals are also at risk

The Arctic is often assumed to be a pristine environment, with little pollution because it is so isolated. Plastics and chemicals do, however, make their way into the Arctic due to air and ocean currents. There, they can be eaten by Arctic marine mammals. A recently published study measured a group of plastic chemicals (“phthalates”) in several marine mammal species from Norway. The scientific team sampled seven stranded marine mammals (one long-finned pilot whale, two killer whales, one sperm whale, one harbor porpoise, one white-beaked dolphin, and one harbor seal) as well as nine live killer whales (that were biopsy sampled).

A 10-day-old killer whale was one of the stranded animals sampled in this study. Photo: Norwegian Orca Survey

Five different phthalates were found. One of the stranded killer whales was a 10-day-old calf. Whilst this calf had previously been found to have high levels of other chemicals, no phthalates were found. This is good news for the calf, and a hopeful indicator that his mother had low phthalate levels and/or these chemicals cannot be transferred to calves through the mother’s milk. We know it can be the case for other contaminants such as PCBs, DDTs, and flame retardants.

Highest levels in white-beaked dolphins, lowest in killer whales

White-beaked dolphins had the most phthalates, and the tested individual had high levels – some of the highest ever seen. On the flip side, killer whales, sperm whales, and long-finned pilot whales had the least phthalates. These differences could be because these animals have different diets or live in different areas. We need to study more about how these chemicals might affect the health of marine mammals, especially how they might mix with other harmful substances we already know are in their bodies.

Samples being taken from a stranded killer whale. Photo: Steve Truluck

What can we do to help?

In our mission to protect whales and dolphins from plastic pollution, we can adopt simple yet impactful measures. As a society, we can embark on a collective journey towards mindful plastic consumption and responsible disposal practices. At home, let’s inspire change by choosing reusable items such as water bottles, bags, straws, and coffee cups while prioritizing recycling. Together, we can advocate for and support policies aimed at reducing plastic usage and prohibiting harmful chemicals. When we vote, let’s consider leaders committed to these initiatives. Through our combined efforts, the small changes we make as individuals can lead to significant transformations, fostering the protection of whales, dolphins, and other marine life.

Sources & Further Reading

Andvik, Clare, Pierre Bories, Mikael Harju, Katrine Borgå, Eve Jourdain, Richard Karoliussen, Audun Rikardsen, Heli Routti, and Pierre Blévin. 2023. “Phthalate Contamination in Marine Mammals off the Norwegian Coast.” Marine Pollution Bulletin 199: 115936. https://doi.org/10.1016/J.MARPOLBUL.2023.115936.

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