Tons of PCBs in Deep Oceans

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Toxic chemicals that have been released into the environment have turned up in some rather unexpected places. And while it has long been known that polychlorinated biphenyls (PCBs) and other persistent organic pollutants have been found in the surface waters of the oceans, especially the North Atlantic and Arctic, little was known about the quantity of PCBs that have reached the deep ocean.

In a paper published in Geophysical Research Letters, University of Rhode Island chemical oceanographer Rainer Lohmann and colleagues found that approximately 870 kilograms of PCBs per year make their way to the deep ocean at four subduction zones in the North Atlantic and the Southern Ocean.

According to Lohmann, 600,000 tons of PCBs were produced in Europe and North America in the 1950s and 1960s, and about 10 percent of that total has escaped to the atmosphere, soils, sediments and water column.