Air-sea exchange fluxes of synthetic polycyclic musks in the North Sea and the Arctic

Abstract

Synthetic polycyclic musk fragrances galaxolide (HHCB) and tonalide (AHTN) were measured simultaneously in air and sea water in the Arctic, the North Sea and in the rural air of northern Germany. Median concentrations of gas-phase HHCB and AHTN were 4 and 18 pg m-3 in the Arctic, 28 and 18 pg m-3 in the North Sea, and 71 and 21 pg m-3 in northern Germany, respectively. Various ratios of HHCB/AHTN indicated that AHTN is more persistent than HHCB in the atmosphere. In the North Sea, concentrations of dissolved HHCB and AHTN ranged from 12 to 2030 pg L-1 for HHCB and from below the method detection limit (3 pg L-1) to 965 pg L-1 for AHTN with median values of 59 and 23 pg L-1, respectively. The medians of volatilization fluxes for HHCB and AHTN were +27.2 and +14.2 ng m-2 day-1 and the depositional fluxes were –5.9 and –3.3 ng m-2 day-1, indicating the dominance of the water-side concentration gradient at the coast. In the Arctic, the depositional fluxes ranged within -1.0 - -1.5 ng m-2 day-1 for HHCB and -3.8 - -6.2 ng m-2 day-1 for AHTN, which dominated the air-sea gas exchange process.