Results of monitoring for polychlorinated dibenzo-p-dioxins and dibenzofurans in ambient air at McMurdo Station, Antarctica

This paper presents the results of ambient air monitoring for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) performed during the 1992-1993 and 1993-1994 austral summers in the vicinity of McMurdo Station, Antarctica. Twenty-eight air samples were collected from four different locations to determine the identity and concentration of PCDD/PCDF compounds. PCDD/PCDF compounds were not detected at either the predominantly upwind location or a more remote site on Black Island. Trace levels of only a few PCDD/PCDF congeners were detected sporadically at a location approximately 500 m downwind of the station. The most frequent, most varied, and highest levels of PCDDs/PCDFs were measured at a downtown location, where concentrations of total PCDDs ranged from 0.12 to 1.80 pg/m 3 and total PCDFs ranged from less than 0.02 to 2.77 pg/m 3 . The data indicate that there are combustion sources at McMurdo other than the solid waste incinerator (power plants, vehicles, heating furnaces, etc.) that contribute PCDD/PCDF compounds to the ambient air. The greatest variety and highest concentration of PCDD/PCDF congeners measured in 1992-1993 during incineration of selected solid wastes implicates the interim incinerator as the likely source of the increased presence of these compounds in air. Results from the remote Black Island site indicate that the background Antarctic air is still free of PCDD/PCDF compounds (not detectable at current method detection limits in the sub-pg/m 3 range).