“Extraordinary” amounts of toxic chemicals that were banned in the 1970s have been discovered in the bodies of sea creatures living at the bottom of the deepest ocean trench in the world.
Scientists were stunned to discover that such high levels of polychlorinated biphenyls (PCBs) and other persistent organic pollutants were to be found more than 10km (six miles) below sea level in the Mariana Trench in the Pacific Ocean. It is about 1,300km from the nearest major land mass, Japan.
Persistent organic pollutants, known as POPs, include PCBs and polybrominated diphenyl ethers (PBDEs), which can be used as electrical insulators and flame retardants.
“The spotlight has hovered over these pollutants due to their capacity to remain viable over long time periods and for long-range transport in material such as soil, water and air. This has increased their pervasiveness in a variety of environments including the Arctic and now the deepest ocean.
“At the same time they can accumulate at up to 70,000 times background levels in the fatty tissue of living organisms with significant magnification at higher levels in the food chain.
“These factors, together with their devastating effects on the hormonal, immune and reproductive systems, have been major drivers in their regulation and elimination.”
Written by Ian Johnston Environment Correspondent