Dolphins are dying from toxic chemicals banned since the 1980s

Polychlorinated biphenyls (PCBs) are commonly found in the bodies of short-beaked common dolphins that get stranded on UK beaches, and are linked to the animals’ risk of infectious diseases

By Melissa Hobson

11 April 2025

A common dolphin stranded on a UK beach

Waves & Wellies Photography

Dolphins in seas around the UK are dying from a combination of increased water temperatures and toxic chemicals that the UK banned in the 1980s.

Polychlorinated biphenyls (PCBs) are a long-lasting type of persistent chemical pollutant, once widely used in industrial manufacturing. They interfere with animals’ reproduction and immune response and cause cancer in humans.

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In a new study, researchers showed that higher levels of PCBs in the body and increased sea surface temperatures are linked to a greater mortality risk from infectious diseases for short-beaked common dolphins , a first for marine mammals.

The ocean is facing “a triple planetary crisis” – climate change, pollution and biodiversity loss – but we often look at threats in isolation, says Rosie Williams at Zoological Society of London.

Williams and her colleagues analysed post-mortem data from 836 common dolphins stranded in the UK between 1990 and 2020 to assess the impact of these interlinked threats.