Chemicals from plastics leak into seabird stomachs over time

Seabirds often mistake plastic debris for food, and ingestion poses many health risks to the animals such as intestinal blockages. A new study has shown, for the first time, that plastic waste can release potentially harmful chemicals into the stomach fluid of seabirds for extended periods of time.

The findings highlight the urgent need to reduce plastic pollution in our oceans and to dispose of our waste more responsibly. As levels of marine plastic pollution continue to grow, so do the threats to wildlife.

Pieces of plastic can remain in birds’ intestines for long periods of time, and scientists are now concerned that the plastic is capable of releasing harmful chemicals.

“I’ve been working on northern fulmars for almost 10 years,” said study lead author Susanne Kühn of the Wageningen Marine Research in the Netherlands. “As these seabirds ingest plastics regularly, and 93% of the fulmars from the North Sea have some plastic in their stomachs, it is important to understand the potential harm this could cause.”

The researchers set out to investigate whether plastics may release chemicals after being eaten by fulmars. 

The team replicated the conditions found in the fulmar stomach, as well as the plastic debris that the seabirds ingest. The experts collected stomach oil, a nutrient-rich liquid found in the fulmar stomach, from hunters in the Faroe Islands.

“Previous studies have typically used uniform plastic pellets, sometimes artificially contaminated, which is not representative of plastic found in the sea,” explained Kühn. “Instead, we went beach combing and found a variety of plastic types and shapes to create a marine plastic sample that a fulmar might realistically ingest.”

After covering the plastic samples in stomach oil, the researchers mimicked the temperature and levels of agitation that can be found in the fulmar stomach. Next, the team chwmically analyzed the oil at different points in time to determine whether chemicals had leached out of the plastic.

The study revealed that the plastic released a variety of chemicals in the stomach oil over time. In some cases, foreign chemicals leaked from the plastics for more than three months. The chemicals turned out to be additives such as plasticizers, flame retardants, and stabilizers.

The team was shocked to find that the stomach oil of fulmar chicks already contained plastic-derived chemicals before the experiments, indicating that their parents had mistakenly feed them plastic waste.

While the long-term health implications are unclear, previous studies have shown that several of the leached chemicals can disrupt hormones and reproduction among seabirds and may have genetic effects in birds.

The research suggests that the impacts of plastic pollution on birds are not limited to immediate effects, such as entanglement, but have the potential to be much longer lasting.

“I hope that these results will increase awareness of the various negative effects of plastic debris in the oceans,” said Kühn. “We urgently need to reduce the amount of plastic in the marine environment.”

The study is published in the journal Frontiers in Environmental Science.

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By Chrissy Sexton, Earth.com Staff Writer