Large amounts of toxic pollution found in deepest trenches

It's mankind's dirty secret that its garbage eventually find their way to the open seas. Given the vastness and almost unimaginable depths of the world's oceans, man might assume that some parts of the ocean remain safe from human indifference. Scientists are proving, however, that it is sadly not the case. By studying amphipods leaving at the world's deepest trenches, scientists discovered worrying levels of "persistent organic pollutants" inside the crustaceans' bodies. This means that our toxic waste has already reached places where man itself has barely set foot. To add insult to injury, these are pollutants that have been banned for decades already.

Persistent organic pollutants are a special class of organic material that are impervious to environmental degradation. They would be the organic equivalent of non-biodegradable compounds and can last for decades. Because of their harmful properties, these POPs, as they are called, have been banned since the 70s. However, they have been in use long enough, since the 30s, to have long-lasting effects.

These POPs are usually released through accidents, discharges, improper disposal, and the like. While it is believed that more than half of these still existing POPs are trapped in landfills, about 35% may have already been deposited in coastal sediments and in the open oceans. But before this study, it was generally believed that it only affected the "deep sea", meaning levels higher than 2,000 m.

Scientists studied these scavenging amphipods to determine how much, if any, POPs have ended up inside these creatures. The high levels of toxic pollution are, indeed, disturbing. Thanks to the downward movement of water and the movement of the ocean floor itself, POPs can reach the deepest places of the ocean through contaminated sediments, dead animals, and even plastic materials.

Some of the amphipods examined came from the famous Mariana trench, as deep as 10,250 m down. This and the other Kermadec trench are so far from any industrial area that it is almost inconceivable that our toxic pollution from decades ago would reach that far and that deep. It is almost ironic that our pollution have settled in what many consider the final frontier, even before man itself has.

SOURCE: Nature