Photo/Illutration Tristram’s storm petrel (Provided by the Wild Bird Society of Japan)

Dwelling precariously on wave-battered, remote islands of the Pacific, Tristram’s storm petrel seems to inhabit a world untouched by human commotion, embodying the raw, untamed essence of nature.

But recent research has cast a troubling pall over this idyllic image. A joint study by Tokyo University of Agriculture and Technology and the Wild Bird Society of Japan (WBSJ) found that the birds have excessive concentrations of plastic-derived chemical compounds. The likely cause is accidental ingestion of miniscule bits of plastic debris.

Tristram’s storm petrel, a highly pelagic, dark-plumaged seabird that measures about 25 centimeters and has a wingspan of roughly 55 cm, breeds on remote offshore islands in the northwestern Pacific, including Japan’s Izu Islands. It primarily feeds on shrimp and other small organisms drifting near the ocean surface.

Researchers analyzed oil secreted from specialized glands located at the base of the birds’ tail feathers. A colony on an uninhabited island near Kozushima--one of the seven islands that make up the Izu chain--was selected for the study.

Among the 13 birds examined, four exhibited an absorption rate exceeding 500 nanograms per gram of fat of a class of plastic-derived chemicals known as benzotriazole ultraviolet stabilizers (BUVSs). These additives are commonly used in plastics and other materials to prevent degradation from ultraviolet (UV) light. One nanogram equals one-billionth of a gram.

As BUVSs are classified as persistent organic pollutants, they do not break down naturally in the environment, meaning they can accumulate in marine organisms upon which seabirds and fish feed. The toxic effect on the food chain and risk to both marine life and human health is of growing concern.

“We were surprised to find such high concentrations,” said Yutaka Yamamoto, chief of the Conservation Division at the WBSJ, an organization dedicated to protecting wild birds and their habitats.

Notably, the detected BUVSs include compounds regulated under international treaties due to their known biological toxicity. Some were found at levels comparable to those previously documented in seabirds from other parts of the North Pacific, including Hawaii.

Although other synthetic substances known to bioaccumulate through the food chain were also identified, no correlation was found between their levels and those of BUVSs. This suggests that the storm petrels were likely ingesting plastic fragments directly, rather than merely absorbing the chemicals through their prey.

Kaoruko Mizukawa, a lecturer in environmental chemistry at Tokyo University of Agriculture and Technology, explained that the North Pacific is among regions with the highest concentrations of drifting plastics worldwide.

“Although the birds’ habitat is on a remote uninhabited island, we still anticipated we would detect these man-made substances. It’s disheartening to confirm our suspicions,” he said.

Mizukawa said efforts to prevent more waste from entering the ocean are “crucial” and that consumers should have greater opportunities to learn about the additives used in the plastic products they regularly use.

The research findings were published in the international journal Marine Pollution Bulletin.

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