Scientists say man-made cancer-causing chemicals, which have been banned since the 1970s, have been found in the deepest recesses of the Pacific Ocean.

Traces of high levels of the pollutants were found in scavenging shrimp-like amphipods living more than 10km (6 miles) below the surface in two trenches 7,000km (4,300 miles) apart.

Residue of polychlorinated biphenyls, better known as PCB's was found in the creatures' bodies at the bottom of the deepest oceans.

Shock as pollutants found in deep ocean life

Researchers were shocked to find contamination levels similar to those found in a heavily polluted area just off Japan.

The findings are being published in Nature Ecology and Evolution, and now the study team is to investigate if microbeads have been swallowed by the deep sea creatures.


Report author Alan Jamieson 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.

Image: The pollutants were found deep in the Mariana and Kermadec trenches

He told Sky News: "We can't assume now there are any places in the world that are still pristine."

The findings come after Sky's Ocean Rescue campaign was launched to raise awareness of the damage being done to our marine environment worldwide.

Chemicals found in the 2-3cm long crustaceans included polychlorinated biphenyls (PCBs), which have been defined as carcinogens and do not break down for decades.

Documentary: Plastic pollution in our oceans

Around 1.3 million tons of PCBs were widely used in industry from the 1930s until they were banned in the 1970s.

:: You can find out more about Sky Ocean Rescue and get involved by visiting the campaign's website and you can also watch our documentary, A Plastic Tide.

PCBs were used in plastics and carbonless copy paper as well as electrical equipment, glues and engine oils.

Why the oceans are under threat

Industrial accidents and leakage from landfill have seen them released into the sea and they are extremely slow to break down.

Scientists also discovered polybrominated diphenyl ethers (PBDEs) which were used as flame retardants and are known to reduce fertility.

The team used deep-sea landers to search the Mariana Trench, east of the Philippines, and the Kermadec Trench, north of New Zealand.

Image: A Greenpeace protest in 2009 against PCB contamination

The Mariana Trench is the deepest part of the world's oceans.

In 2012, Titanic director James Cameron made a record-breaking solo dive to the bottom of the trench in a submersible.

Scientists believe the pollutants have found their way into the remote trenches through contaminated plastic debris and dead animals sinking to the ocean floor.

Image: Dr Jamieson says the research shows the devastating effect man is having on the planet

The voracious amphipods then live off what they can scavenge.

Dr Jamieson, of Newcastle University's School of Marine Science and Technology, 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."