Marine Wildlife Contaminated with Harmful Levels of Banned Chemicals
New research led by the Zoological Society of London (ZSL) has found pollutants, including banned chemicals, in the bodies of marine wildlife at levels above toxic thresholds. The project’s lead researcher urges that we “learn from past mistakes”.
A team of scientific researchers, led by ZSL, examined one of the largest datasets taken from stranded marine mammals worldwide. The data were collected over 30 years as part of a long-term Defra-funded study called Cetacean Stranding Investigation Programme (CSIP), and provided information on the pollutant levels in tissue samples from over 1,000 deceased marine mammals.
The study looked at six classes of persistent pollutants in 11 species of whales, dolphins and seals found stranded along UK coasts. The term ‘persistent’ refers to the longevity of a substance in the environment.
Researchers found that from 2014-2018, almost half of the animals studied had levels of pollutants in their bodies that were above toxic thresholds.
In bottlenose dolphins, chemicals called PBDEs (often used in products such as electronics and furniture as flame retardants) were found at levels that were on average 200% over the threshold at which scientists would expect to see negative health effects. ZSL highlights that PBDEs have been linked to a weakened immune system, therefore increasing susceptibility to disease.
PCBs were found in orcas at levels that were over 30 times higher than the toxic threshold for marine mammals. PCBs are a family of chemicals that have been banned globally for over two decades but were previously widely used in products like paints, electronics and adhesives. They have been linked to negative effects on marine mammal’s immune and reproductive systems and their extreme persistence means that they can bioaccumulate (build up) in the bodies of animals over time.
Despite these global bans, these chemicals continue to have detrimental health effects on marine mammals today due to their persistence in the environment.
PFAS chemicals, a group of over 10,000 chemicals frequently used in a range of industrial processes and everyday products such as waterproof clothing, non-stick cookware and food packaging, are similarly renowned for their extreme persistence.
Many PFAS are known or suspected to be detrimental to human health and the health of particular marine mammals. Like PCBs, PFAS can bioaccumulate in the bodies of wildlife and people.
Whale and Dolphin Conservation previously stated that emerging pollutants such as PFAS could be ‘equally or more harmful than more studied pollutants such as PCBs’. However, only a few PFAS chemicals have been banned.
Lead researcher of the study Dr Rosie Williams said “We’re still cleaning up the mess of historic pollutants that were banned over two decades ago. We need to act now, learn from our past mistakes and employ stronger, science-backed measures to curb pollution”.
A universal PFAS restriction, addressing the entire group of chemicals, is fundamental to ensuring that we do not repeat past mistakes made with PCBs. PFAS pollution to date will already impact generations to come and we must act now to ensure we do not add to this toxic legacy of PFAS pollution.