Chemical pollutants seem to have made their way in the deepest trenches of the ocean -- a place that scientists initially thought to be untouched by human influence.
In fact, BBC News noted that scientists were particularly surprised by high concentrations of pollutants like PCBs and PBDEs in deep sea ecosystems. These chemicals have been widely used for much of the 20th century and were found to be toxic as they build up in different ecosystems.
In a report published in the journal Nature Ecology and Evolution, the team led by Dr. Alan Jamieson of the University of Newcastle retrieved crustaceans from deep below the Pacific Ocean's surface. They found that these have PCBs and PBDEs in their systems. These materials were commonly used as electrical insulators and flame retardants, although PCB production has been banned in the U.S. since 1979 and by a UN treaty in 2001.
Despite the significant reduction in their use, these materials can still be detected in marine organisms today, as both had the ability to remain intact for long periods. Also, they can often bind with other particles that help carry them throughout the ocean. Their ability to "bioaccumulate" or build up in marine organisms over time also suggested that they are widespread in fish around the globe.
The Washington Post reported that it is still unclear how contaminants can get into the trenches and why they appear in high levels in the Mariana Trench, although researchers suspect that the chemicals originated around the "great Pacific garbage patch," which is a body of debris in the northern part of the Pacific. The chemical pollutants from the region could have easily clung to the plastic waste as it drops to the bottom of the ocean.
More research is necessary to understand how these contaminants can move throughout the food chain. But it does remain clear that these results are enough proof that human activities can have jarring consequences for the planet.