Multiple banned pollutants are still being discovered in the Pacific Ocean
The scavenging shrimp-like crustaceans have built up high levels of toxins in their systems after feasting on the bodies of polluted creatures that had sunk to the sea-bed.
Scientists say the inch-long marine animals called amphipods living the dark, high-pressure waters at the bottom of the Pacific had ten times the levels of industrial pollution seen in the average earthworm.
The astonishing way toxic chemicals known as POPs – Persistent Organic Pollutants – were discovered in the remotest places on Earth is stark evidence of the “devastating impact that mankind is having on the planet,” say researchers from Newcastle University.
This is the first time that POPs, including the notorious and banned PCBs (polychlorinated biphenyls) and PBDEs (polybrominated diphenyl ethers), have been found at such depths, but what is causing greater consternation is that have been found at sites thousands of miles apart.
The polluted creatures were recovered using deep sea landers from the Mariana Trench off the Philippines and the Kermadec Trench, 4,400 miles to the south.
PCBs and PBDEs have been used in the manufacture of electrical insulators and flame retardants linked to infertility.
Chemicals found in pollutants included PCBs which are carcinogens and take a long time to break down
It's not a great legacy that we're leaving behind
The USA banned PCB production as long ago as 1979 and a global clampdown came into force in 2001, after the chemicals were proven to be cancer-causing, notwithstanding the 1.3 million tons that had been produced over the previous seven decades.
Industrial accidents and leakage from landfill have seen these pollutants that are invulnerable to nature degradation work their invidious way into environment.
Yet the discovery of pollutant levels higher than at places matching some of the most polluted places in the Pacific came as a shock to Dr Alan Jamieson from Newcastle University’school of Marine Science and Technology.
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He said: “We still think of the deep ocean as being this remote and pristine realm, safe from human impact, but our research shows that, sadly, this could not be further from the truth.
Scientists believe contaminated plastic debris has contributed towards the pollutants
“In fact, the amphipods we sampled contained levels of contamination similar to that found in Suruga Bay, one of the most polluted industrial zones of the northwest Pacific.
“What we don’t yet know is what this means for the wider ecosystem and understanding that will be the next major challenge.”
Dr Jamieson was the lead author of the research produced by the study team from Newcastle University, University of Aberdeen and the James Hutton Institute and published today in Nature Ecology & Evolution.
Once pristine oceans are showing increasing evidence of man’s activities, with synthetic substances finding their way into complex but fragile ecological systems that exist under the surface waters.
Microbeads used in cosmetics have been found inside the bodies of invertebrates and levels of plastic bag consumption by whales and turtles was one of the driving factors behind the levy on their use.
Crustaceans were found to contain 10 times the level of industrial pollution than an earthworm
Just how invasive man-made pollution has become is highlighted by Dr Jamieson, who says he has seen video of a Canadian beer can lying on the sea floor four miles down, off New Zealand, while a friend told him about a raincoat found in the Mariana Trench, intact, at almost seven miles.
As the ocean depths become a sink for pollution and litter, harmful chemicals accumulate through the food chain and reach much higher levels than on the surface.
Dr Jamieson said: “The fact that we found such extraordinary levels of these pollutants in one of the most remote and inaccessible habitats on earth really brings home the long term, devastating impact that mankind is having on the planet.
“It’s not a great legacy that we’re leaving behind.”
Japan Earthquake and Tsunami in pictures
Fri, March 11, 2011
A massive earthquake has struck off the north east coast of Japan, causing a 33ft tsunami in the Pacific Ocean
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A whirlpool is seen near Oarai City, Ibaraki Prefecture, northeastern Japan, The biggest earthquake to hit Japan on record struck the northeast coast on Friday, triggering a 10-metre tsunami
He added: “We’re very good at taking an ‘out of sight out of mind’ approach when it comes to the deep ocean but we can’t afford to be complacent.
“This research shows that far from being remote the deep ocean is highly connected to the surface waters.”
Publishing their findings in Nature Ecology & Evolution, the study team – from Newcastle University, University of Aberdeen and the James Hutton Institute – will now investigate the consequences for the wider ecosystem.
They will also look to see if microbeads have been swallowed by the deep sea creatures.