Vertical eddy diffusion as a key mechanism for removing perfluorooctanoic acid (PFOA) from the global surface oceans

• Published in: Environmental pollution (1987) Vol. 179; pp. 88 - 94
• Main Authors: Lohmann, Rainer, Jurado, Elena, Dijkstra, Henk A., Dachs, Jordi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2013; Elsevier
• Subjects: Accounting; Applied sciences; Atlantic Ocean; Caprylates - analysis; Diffusion; Eddies; Environmental Monitoring; Exact sciences and technology; Fluorocarbons - analysis; Global sink; Marine; Models, Chemical; Natural water pollution; Ocean models; Oceans; Organic pollutants; PFOA; Pollution; Pollution abatement; Seawater - chemistry; Seawaters, estuaries; Stores; Water circulation; Water Pollutants, Chemical - analysis; Water treatment and pollution; Atlantic Ocean; A, Atlantic; Global sink; Organic pollutants; Oceans; Diffusion; PFOA; Organic perhalocompound; Deep water; Mechanism; Pelagic zone; Persistent organic pollutant; Marine environment; Eddy diffusion; Perfluorooctanoic acid; Carboxylic acid; Long range pollutant transport; Vertical profile; Emerging pollutant; Planetary scale; Ocean; Fluorine Organic compounds
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2013.04.006

Here we estimate the importance of vertical eddy diffusion in removing perfluorooctanoic acid (PFOA) from the surface Ocean and assess its importance as a global sink. Measured water column profiles of PFOA were reproduced by assuming that vertical eddy diffusion in a 3-layer ocean model is the sole cause for the transport of PFOA to depth. The global oceanic sink due to eddy diffusion for PFOA is high, with accumulated removal fluxes over the last 40 years of 660 t, with the Atlantic Ocean accounting for 70% of the global oceanic sink. The global oceans have removed 13% of all PFOA produced to a depth greater than 100 m via vertical eddy diffusion; an additional 4% has been removed via deep water formation. The top 100 m of the surface oceans store another 21% of all PFOA produced (∼1100 t). [Display omitted] •Eddy diffusion has removed ∼660 t of PFOA from surface oceans over the last 40 years.•Atlantic Ocean accounts for 70% of the global oceanic sink of PFOA.•Vertical eddy diffusion has moved ∼13% of PFOA to oceans deeper than 100 m.•Around 4% of PFOA has been removed via deep water formation.•The top 100 m of global oceans contain ∼21% of historical PFOA production. Vertical eddy diffusion is an important removal process for hydrophilic organic pollutants such as PFOA from the surface ocean.