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Abstract:
Concentrations of neutral poly- and perfluoroalkyl substances (PFASs),
such as fluorotelomer alcohols (FTOHs), perfluoroalkane sulfonamides
(FASAs), perfluoroalkane sufonamidoethanols (FASEs), and fluorotelomer
acrylates (FTACs), have been simultaneously determined in surface
seawater and the atmosphere of the North Sea. Seawater and air samples
were taken aboard the German research vessel Heincke on the cruise 303
from 15 to 24 May 2009. The concentrations of FTOHs, FASAs, FASEs, and
FTACs in the dissolved phase were 2.6-74, < 0.1-19, < 0.1-63, and <
1.0-9.0 pg L-1, respectively. The highest concentrations were determined
in the estuary of the Weser and Elbe rivers and a decreasing
concentration profile appeared with increasing distance from the coast
toward the central part of the North Sea. Gaseous FTOHs, FASAs, FASEs,
and FTACs were in the range of 36-126, 3.1-26, 3.7-19, and 0.8-5.6 pg
m(-3), which were consistent with the concentrations determined in 2007
in the North Sea, and approximately five times lower than those reported
for an urban area of Northern Germany. These results suggested
continuous continental emissions of neutral PFASs followed by transport
toward the marine environment. Air-seawater gas exchanges of neutral
PFASs were estimated using fugacity ratios and the two-film resistance
model based upon paired air-seawater concentrations and estimated
Henry's law constant values. Volatilization dominated for all neutral
PFASs in the North Sea. The air-seawater gas exchange fluxes were in the
range of 2.5 x 10(3)-3.6 x 10(5) pg m(-2) for FTOHs, 1.8 x 10(2)-1.0 x
10(5) pg m(-2) for FASAs, 1.1 x 10(2)-3.0 x 10(5) pg m(-2) for FASEs and
6.3 x 10(2)-2.0 x 10(4) pg m(-2) for FTACs, respectively. These results
suggest that the air-seawater gas exchange is an important process that
intervenes in the transport and fate for neutral PFASs in the marine
environment.
