The ocean is one of the biggest mysteries on earth, and not only in terms of physical size. According to the NOAA, we’ve only truly explored about five percent of the ocean. We know more about the moon than we do about the deepest reaches of the sea. We do, however, leave a trail of shit nearly everywhere we go–and it seems that trail of shit extends even to places we’ve barely been to in person. Researchers collecting crustaceans from the Mariana Trench and the Kermadec Trench, the deepest parts of the world’s oceans, found harmful, banned chemicals produced by humans in a variety of different species.
Dr. Alan Jamieson, an Honorary Lecturer from the University of Aberdeen, used traps set by deep-sea landers in the Mariana Trench, he found a staggering amount of both polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). PCBs were widely used in everything from TVs and microscopes to refrigerators and electrical insulators for decades. They were even sprayed on dirt roads to keep the dust down. Then, in the late ’70s, it was discovered that they were pretty much the worst things on earth, and they were either outright banned or heavily restricted. PBDEs, although still relatively widely used, are just as bad, if not worse. Usually used in flame retardants, they’re mostly banned in the EU and parts of the US.
PCBs and PBDEs are scary for a couple of reasons. First, they do not degrade naturally, so most of what humans made is still floating around somewhere–and we made a lot. Between the late 1920s and the eventual ban of PBCs, nearly 1.5 million tons were released into the environment. In the ’60s, when researchers really started studying the effects, traces of them were found in humans, plants, and animals all around the world. “Not only in heavily populated areas such as New York City, but also in remote areas as far as the Arctic,” explained the NOAA. They build up in living organisms, getting stored in fatty tissues.
So how much did Jamieson find in the deepest parts of the ocean? “In the Mariana, the highest levels of PCBs were fifty times more contaminated than crabs from paddy fields fed by the Liaohe River, one of the most polluted rivers in China,” he wrote in Nature Ecology and Evolution. “Our proximity to these extreme locations is far from remote, which is why even the deepest chasms of the ocean are no longer pristine. The challenge moving forward is to determine the physiological consequences of such contamination.”