Deep in the Mariana Trench, at depths lower than the Rockies are high, rests a tin of reduced-sodium Spam.
NOAA scientists caught sight of it last year near the mouth of the Mariana’s Sirena Deep. It isn’t an isolated incursion, but it was nevertheless startling, the sight of those timeless golden letters bright against the deep ocean bottom.
Shortly after came news from another team of scientists who had found in the Mariana an innovation less familiar than shelf-stable meat, but far more significant. In the bodies of deep-dwelling creatures were found traces of industrial chemicals responsible for the rise of modern America—polychlorinated biphenyls.
PCBs had been detected in Hirondellea gigas, tiny shrimp-like amphipods scooped up by deepwater trawlers. Results from the expedition, led by Newcastle University’s hadal-zone expert Alan Jamieson, were preliminarily released last year and then published in February.
PCBs have been found the world over—from the bed of the Hudson River to the fat of polar bears roaming the high Arctic—but never before in the creatures of the extreme deep, a bioregion about which science knows relatively little.
How PCBs reached the Mariana is still under investigation. Jamieson and colleagues speculated on multiple, regional sources. A nearby military base. The industrial corridors along the Asian coastline. And the Great Pacific Garbage Patch, where PCBs glom onto plastic particles caught in the current. Over time, the plastic degrades and descends into the depths, ferrying PCBs with them.
But the true origin of PCBs lies in another time and place, in Depression-era Alabama, and before that, 19th-century Germany at the pinnacle of German chemistry.
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PCB production began in late 1929 in a factory east of Birmingham. The same era that gave us New York’s Chrysler Building, The Little Engine That Could, and eventually Spam brought mass-made PCBs to market.
General Electric and Westinghouse were early adopters. Both firms formulated PCBs into dielectric fluids, the insulating liquids added to capacitors and other electrical components to keep them cool and to prevent fires. With PCBs’ aid, the electric grid spread from the industrialized north into the rural regions of the Deep South and the American West. By mid-century, PCBs had a bird’s-eye view of any block in America with a utility pole and PCB-bathed transformer.
Soon PCBs were added to paints, caulks, plastics, even floor finishes and dish detergents. They were branded, and assigned names like Aroclor. That commercial products contained PCBs was never advertised, explained Ellen Griffith Spears, who wrote the definitive book on PCBs’ genesis.
PCBs slipped into the world, becoming ubiquitous while remaining anonymous. Until the mid-1960s, when the Danish-born scientist Sören Jensen detected PCBs in the bodies of pike taken from the waters off Sweden.