Researchers make disturbing discovery after analyzing hundreds of dolphin autopsies: 'A nightmare to get rid of'

Dolphins around the United Kingdom are dying at alarming rates, and scientists have traced the cause to a dangerous combination of rising ocean temperatures and lingering chemical pollution.

What's happening?

Short-beaked common dolphins, one of the most widely distributed marine mammals in U.K. waters, are dying in large numbers from infections that are more likely to become fatal because of toxic chemicals called PCBs, or polychlorinated biphenyls. These pollutants were banned in the U.K. back in 1981, yet they're still showing up in disturbing quantities in dolphin blubber.

A similar U.K. study in 2021 also found alarming amounts of PCBs in otherwise healthy male harbour porpoises.

This recent dolphin study looked at the post-mortem records of 836 dolphins found between 1990 and 2020. Researchers said that for every 1 milligram per kilogram increase in PCBs, the dolphins' risk of dying from an infection increased by 1.6%. And with every 1 degree Celsius rise in ocean temperature (1.8 degrees Fahrenheit), the risk jumped another 14%.

"Because [PCBs are] so persistent, they're a nightmare to get rid of," Rosie Williams of the Zoological Society of London said.

Why is this discovery important?

Dolphins are at the top of the ocean food chain, which means toxic chemicals such as PCBs accumulate in their bodies at much higher concentrations than in other species.

This research highlights how pollution and overheating oceans aren't just problems in isolation. Together, they make marine life even more vulnerable. That includes risks to animals we rely on for food, along with the ripple effects on coastal communities that depend on healthy oceans to survive and thrive.

It also sounds the alarm on other persistent pollutants, including PFAS, or perfluoroalkyl and polyfluoroalkyl substances, which are still widely used and just as difficult to eliminate from the environment.

These so-called "forever chemicals" show up in everything from drinking water to wildlife and have been linked to health risks such as cancer, hormonal disruptions, and immune system issues.

What's being done about these issues?

While the U.K. banned PCBs decades ago, the chemicals are still reaching waterways through old industrial stockpiles and byproducts of modern manufacturing.

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Efforts to address the issue include removing remaining equipment that utilizes these PCBs and upgrading water treatment systems to better filter out long-lasting pollutants.

Persistent pollution may feel overwhelming, but staying informed is one of the best ways to drive change. Learning more about these issues and taking conscious action helps build a cleaner, healthier future for all of us.

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