New 3D maps from a $300 million international collaboration use vivid color to reveal the presence of various metal and chemical pollutants in the world’s oceans, Science reported.
Creating the GEOTRACES project required the collection of nearly 30,000 water samples from 787 study sites. Researchers collected the samples over the past few years, tracking about 200 elements and other substances.
The maps revealing lead levels show how past pollution contributes to modern contamination. Most lead pollution originated from leaded gasoline emissions. Although leaded gas has been banned in the U.S. and Europe for decades, huge volumes of lead-infused seawater still exist at a kilometer below the surface of the Atlantic.