Banned Chemicals from the 70s found in Deepest Reaches of the Ocean
A study led by Newcastle University’s Dr Alan Jamieson has uncovered the first evidence that man-made pollutants have now reached the farthest corners of our Earth. Sampling amphipods from the Pacific Ocean’s Mariana and Kermadec Trenches – which are over 10 kilometres deep and 7,000 kilometres apart – the team found extremely high levels of Persistent Organic Pollutants in the organism’s fatty tissue. These include polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) which are commonly used as electrical insulators and flame retardants.
From the 1930s to when PCBs were banned in the 1970s, the total global production of these chemicals was in the region of 1.3 million tonnes. Released into the environment through industrial accidents and discharges and leakage from landfills, these pollutants are invulnerable to natural degradation and so persist in the environment for decades.
“This research shows that far from being remote, the deep ocean is highly connected to the surface waters,” says Dr Jamieson. “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.”
In April, the study “Human footprint in the abyss: 30 year records of deep-sea plastic” found a plastic bag in the Mariana Trench, 10,898 metres deep. “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,” says Dr Jamieson.