Toxins found in animals in deep ocean trenches

Scientists have discovered high levels of harmful chemicals at the bottom of the ocean, many years after their production on land has ceased.

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Pollutants found in deep-sea amphipod crustaceans
Amphipod tissue was tested for the presence of pollutants © Universal History Archive/Getty

 

High levels of toxic pollutants, commonly used in the 20th century, have recently been found in creatures living in the world’s deepest ocean trenches.

The Mariana Trench (in the North Pacific) and the Kermadec Trench (in the South Pacific) were two of the test sites used by Dr Alan Jamieson, Newcastle University, to sample the level of pollutants in deep-dwelling crustaceans.

Of the pollutants found, two were polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs).

Prior to the ban in the 1970s, both were used extensively in the 20th century for electrical insulation and as flame-retardants.

They were banned because they were found to cause liver damage and multiple other health problems, particularly in children.

The level of contamination in the deep-sea crustaceans was even found to be significantly higher than any documented level of contaminants in regions with heavy industrialisation.

“These data clearly indicate that potent anthropogenic contamination and bioaccumulation has occurred,” said Dr Jamieson, “in a dominant macrofaunal group inhabiting the complete depth range of two of the deepest marine trenches.”

The report, published in the journal Nature Ecology and Evolution, suggests that human influence has extended far greater than commonly thought, into the world’s deepest oceans.

Read more wildlife news stories in BBC Wildlife Magazine

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