Plastic additives found in the eggs of herring gulls

Herring gulls are passing along chemicals used in plastic production to their offspring, according to new research from the University of Exeter. The study adds to a growing collection which shows that coastal environments are hit particularly hard by plastic pollution. 

Phthalates are chemical compounds that are added to plastics to keep them flexible. In collaboration with experts at the University of Queensland, the Exeter team found up to six types of phthalates in newly laid herring gull eggs.

“Herring gull mothers pass on vital nutrients to their offspring via their eggs,” said Professor Jon Blount.

“This includes lipids that nourish developing embryos, and vitamin E, which helps to protect chicks from oxidative stress that can occur during development and at hatching.”

“Unfortunately, our findings suggest that mothers are inadvertently passing on phthalates and products of lipid damage.” 

Professor Blount noted that eggs with higher phthalate contamination also contained greater amounts of lipid damage and less vitamin E. Further research is needed to investigate the consequences this may have for baby chicks. 

The team collected 13 herring gulls eggs from various sites in Cornwall. All of the contained phthalates, which are now found in almost every environment on Earth. The compounds tend to accumulate in the fatty tissues of living organisms. Previous studies have discovered phthalates in birds that herring gulls are known to prey upon. 

“Research on the impact of plastic on animals has largely focussed on entanglement and ingestion of plastic fragments,” said Professor Blount. “Far less is known about the impacts of plastic additives on the body.”

“By testing eggs, our study gives us a snapshot of the mother’s health – and it appears phthalate contamination could be associated with increased oxidative stress, and mothers transfer this cost to their offspring via the egg.”

“More research is now needed to discover how developing offspring are affected by being exposed to phthalates before they have even emerged as a hatchling.”

“We need to look more deeply into the pervasive threats of plastics – not just the breakdown of plastic items themselves, but also the dispersal of the multiple chemicals they contain.

“Where do these end up, and what effects are they having on wildlife and ecosystems?”

The study is published in the journal Marine Pollution Bulletin.

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By Chrissy Sexton, Earth.com Staff Writer