High levels of industrial pollution have been found in animals living in the deepest reaches of the Pacific Ocean.

The production of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) — toxic, non-biodegradable pollutants — was phased out in the 1970s. Alan Jamieson, now at Newcastle University, UK, and his colleagues captured amphipods, a type of crustacean, at depths of between about 7,000 metres and 10,000 metres in the Kermadec and Mariana trenches of the Pacific Ocean. The team found PCBs and PBDEs in all samples at all depths. The highest levels of PCBs in the amphipods were 50 times greater than levels found in a survey of crabs in a highly polluted river in China.

The pollutants may have reached these remote areas by way of long-range atmospheric and oceanic transport, and through association with particulate matter and sinking carrion that are consumed by animals, the authors suggest.

Nature Ecol. Evol. 1, 0051 (2017)