Evidence for Dynamic Air−Water Coupling and Cycling of Persistent Organic Pollutants over the Open Atlantic Ocean

• Published in: Environmental science & technology 2004-05, Vol.38 (9), p.2617-2625
• Main Authors: Jaward, Foday M, Barber, Jonathan L, Booij, Kees, Dachs, Jordi, Lohmann, Rainer, Jones, Kevin C
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Air pollution; Applied sciences; Atlantic Ocean; Atmospheric pollution; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring; Environmental Pollutants - analysis; Exact sciences and technology; Insecticides - analysis; Marine; Natural water pollution; Ocean currents; PCB; Phytoplankton; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Pollution, environment geology; Polychlorinated biphenyls; Polychlorinated Biphenyls - analysis; Seawaters, estuaries; Solubility; Trends; Water Pollutants, Chemical - analysis; Water pollution; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es049881q

Ship-board air samples collected between The Netherlands and South Africa in January−February 2001 were analyzed for PCBs and selected organochlorine compounds. Broad latitudinal trends in compound concentrations were influenced by proximity to source areas, land, and air mass origin. Lowest concentrations were observed in the remote south Atlantic (1−32° S), where ∑7PCB concentra tions were ∼10 pg m-3. Here, a diurnal cycle was noted for some PCB congeners, with the daytime concentrations higher than the nighttime concentrations, typically by a factor of 1.5−2.5. The data are consistent with a close coupling of air−open ocean concentrations, which has important implications for future rates of POP removal from the global “recyclable pool”. The observations are discussed in the context of the potential controlling variables. Interactions between the phytoplankton and the dissolved phase are implicated in controlling the observations made here and a hypothesis to explain the cycling trends is presented. However, the precise mechanisms remain unclear; further studies are urgently required to elucidate them.