Historic Atmospheric Organochlorine Pesticide and Halogenated Industrial Compound Inputs to Glacier Ice Cores in Antarctica and the Arctic

Abstract

Ice cores collected from polar ice sheets at Site M, Dronning Maud Land, East Antarctica (Lat 75.00 S, Long 15.00 E), and Holtedahlfonna, Svalbard (Lat 79.13 N, Long 13.27 E), were analyzed for a net deposition of 25 organochlorine pesticides (OCPs) and 16 organohalogen (chlorine/bromine) industrial compounds (OHICs). Long-range atmospheric transport (LRAT) delivers contaminants to both sites, but the processes are different: Site M is affected by subsidence of air from the stratosphere to the Antarctic Plateau, while Holtedahlfonna is affected by air moving through the free troposphere. The sample from Site M is a composite core covering 1958–2000, while the Holtedahlfonna sample includes a historic record from 1953 to 2005 in six discrete samples. The five highest OCPs at Site M were chlorpyrifos, trans-chlordane, 4,4′-dichlorodiphenyl trichloroethane (DDT), ß-hexachlorocyclohexane (HCH), and dieldrin, while at Holtedahlfonna, they were chlorpyrifos, γ-HCH, α-HCH, ß-HCH, and dieldrin. The five most abundant OHICs at Site M were three dichlorobenzenes (diCBs), 1,3-diCB, 1,4-diCB, 1,2-diCB, and 1,3,5-trichlorobenzene and 1,2,4,5-tetrachlorobenzene (tetraCB) and at Holtedahlfonna, they were the same three diCB, pentachloroanisole (PCA), and 1,2,4,5-tetraCB. Of the OHICs, only hexachlorobutadiene, PCA, and hexachlorobenzene were found in all six Holtedahlfonna ice-core segments. Principal component analysis of the OCP percent of total flux values shows no similar variance among the Holtedahlfonna core segments, the whole-core value, or Site M. The principal component analysis of OHIC shows no consistent variance among any of the samples except for two Holtedahlfonna segments with the lowest OHIC values in the core.