PCBs and other organic pollutants reach the deep ocean

An alphabet soup of persistent organic pollutants—including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs)—is carried by the wind and rivers into the ocean. A new study bolsters findings from scant prior sampling showing that these compounds riding on ocean currents have penetrated as far as 2,500 meters deep in the Atlantic Ocean (Environ. Sci. Technol. 2016, DOI: 10.1021/acs.est.5b05891). Rainer Lohmann of the University of Rhode Island and colleagues deployed samplers at various depths at mooring sites in the North Atlantic and in the tropical Atlantic to measure organic pollutants dissolved in the water. The samplers contained polyethylene films that sorb dissolved organic contaminants. After a year, the researchers collected the films, extracted the compounds, and analyzed them using gas chromatography-mass spectrometry, searching for 78 target pollutants that included PCBs, PBDEs, and PAHs. The deep ocean is “clearly not highly polluted” with these compounds, Lohmann says, but they are surprisingly prevalent “for what we thought of as being a fairly pristine body of water.”