Pathways of PFOA to the Arctic: variabilities and contributions of oceanic currents and atmospheric transport and chemistry sources

I Stemmler,G Lammel

doi:10.5194/acp-10-9965-2010

Abstract

Abstract. Perfluorooctanoic acid (PFOA) and other perfluorinated compounds are industrial chemicals in use for decades which resist degradation in the environment and seem to accumulate in polar regions. Transport of PFOA was modeled using a spatially resolved global multicompartment model including fully coupled three-dimensional ocean and atmosphere general circulation models, and two-dimensional top soil, vegetation surfaces, and sea ice compartments. In addition to primary emissions, the formation of PFOA in the atmosphere from degradation of 8:2 fluorotelomer alcohol was included as a PFOA source. Oceanic transport, delivered 14.8±5.0 (8–23) t a−1 to the Arctic, strongly influenced by changes in water transport, which determined its interannual variability. This pathway constituted the dominant source of PFOA to the Arctic. Formation of PFOA in the atmosphere led to episodic transport events (timescale of days) into the Arctic with small spatial extent. Deposition in the polar region was found to be dominated by wet deposition over land, and shows maxima in boreal winter. The total atmospheric deposition of PFOA in the Arctic in the 1990s was ≈1 t a−1, much higher than previously estimated, and is dominated by primary emissions rather than secondary formation.

Highlights

Perfluorooctanoic acid (PFOA) and its ammonium salt have been used for over 50 years as processing aids in the production
Recent studies have demonstrated the importance of interannual variability of the atmospheric dynamics (AMAP, 2004); Halsall et al, 1998) and episodic long-range transports in air (Halsall et al, 1998; Eckhardt et al, 2003, 2007; Wang et al, 2010) on the exposure of the Arctic environment towards pollutants
Large-scale transport of primary emitted and secondarily formed PFOA was modeled for the first time with a global coupled atmosphere-ocean circulation model

Summary

Introduction

Perfluorooctanoic acid (PFOA) and its ammonium salt have been used for over 50 years as processing aids in the production. The aims of this study are to quantify the significance of oceanic and atmospheric transport routes to the Arctic and of primary and main secondary PFOA sources, and to explore how atmosphere and ocean dynamics variabilities are reflected in the poleward contaminant flow. To this end and in contrast to previous studies, a multicompartment chemistry-transport model based on a coupled atmosphere-ocean general circulation model (AOGCM) is used.

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Conclusion