ANALYSIS OF HALOGENATED METHOXYBENZENES AND HEXACHLOROBENZENE (HCB) IN THE PICOGRAM M(-3) RANGE IN MARINE AIR

Halogenated methoxybenzenes (halogenated anisoles) and hexachlorobenze ne (HCB) have been analyzed in marine air samples from the lower tropo sphere of the East Atlantic Ocean, taken on the German research vessel 'Polarstern' during two cruises in 1993 and 1994, and in air samples from the North Pacific Ocean (1995). The high-volume sampling method, sample preparation and analysis by HRGC-ECD and HRGC-MSD;SIM are descr ibed. The effectiveness of a new graphitized-carbon-covered silica sor bent (ANGI-Sorb B) for the sampling of semi-volatiles is demonstrated. Eight congeners of the halogenated anisoles and HCB were detected in almost all marine air samples. The concentrations of the chloroanisole s, which show a distinct north-south interhemispherical gradient, were between 0.2 and 145 pg m(-3): for the bromoanisoles concentrations we re between 0.2 and 42 pg m(-3). Only a weak inter-hemispheric gradient was observed for HCB at levels of 10-40 pg m(-3). Levels of HCB were approximately 100 pg m(-3) in continentally influenced air. Biogenic a nd indirect anthropogenic sources of the halogenated anisoles are disc ussed.