New 3D maps released at the 2014 Ocean Sciences Meeting in Honolulu show that a huge mass of Atlantic seawater is infused with traces of lead – a pollutant that was widely used in the automobile industry until a few decades ago. Although using this hazardous substance has been banned in the United States and Europe, maps show that there are places where lead contamination is a continuing problem – especially near southern Africa and Gibraltar.
Until a few decades ago, toxic metal lead was widely emitted by cars running on leaded gasoline. In the 1970s many countries banned gasoline containing lead additives. Since then the lead levels in the Atlantic have dropped dramatically, butnew, remarkably detailed maps and animations show spots with high traces of lead.
The maps are part of GEOTRACES, an electronic atlas showing hydrographic and marine geochemical data on the presence of trace metals and other chemicals in the world’s oceans. The data compiled during more than 30 scientific crusises over the past three years is based on over 30,000 water samples collected at 787 sites. The system tracks over 200 elements, including lead, traces of which were found in central Atlantic as a huge mass of subsurface seawater; lead levels are higher at the surface than in deeper waters. After collecting all the lead particles, the surface water slowly sank and became a kind of “time capsule” recording the impact of human action on the environment.
Although there are places where lead contamination presents a local problem, the concentrations don’t pose a major threat to humans or wildlife, according to MIT ocean scientist Edward Boyle. However, the data does show persisting consequences of pollution caused by humans and may act as a warning tool for future practices.