Interhemisphere exchange of hexachlorocyclohexanes, hexachlorobenzene, polychlorobiphenyls, and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane in the lower troposphere
- Univ. of Ulm (Germany)
Two nearly independent hemispheric compartments exist in the atmosphere for hexachlorobenzene (HCB; south/north (S/N) ratio of 0.06) and {alpha}-hexachlorocyclohexane ({alpha}-HCH; S/N = 0.09), as a base-line measurements in both hemispheres indicate. The interhemispheric differences in the profile of the {alpha} and {gamma} isomers of hexachlorocyclohexane can be explained best by the different HCH products applied worldwide. Both isomers occur in technical HCH, the so-called benzene hexachloride (BHC), which is preferably used in the Northern Hemisphere, and the purified HCH lindane, consisting of > 99% {gamma}-HCH, which is used worldwide. The distribution of the PCB congeners between gas phase and aerosol particles in dependence of the degree of chlorination is examined in urban air at a temperature of {minus}8C, which is close to the global medium temperature of {minus}11C at 4,000 m. In clean air the interhemispheric contrast, the south/north ratio, is {approximately}0.7 or even close to unity for the PCB. 4,4{prime}-DDT is detected at 8 times higher levels in the southern as compared to the Northern Hemisphere. 4,4{prime}-DDE, the transformation product of 4,4{prime}-DDT, follows the same pattern (S/N = 3). The quotient of Henry constant and octanol-water distribution coefficient H/K{sub ow} correlates to the S/N ratio of semivolatiles in the troposphere. These results require the conclusion that the interhemispheric exchange of other compounds with similar physicochemical data as given by HCB and {alpha}-HCH must be very slow in the atmosphere if it occurs at all at a significant level. This can have far-reaching consequences in the understanding of both the interhemispheric and finally the global distribution of xenobiotics, as the oceanic system has to be discussed as the major long-range transport medium.
- OSTI ID:
- 5016587
- Journal Information:
- Environmental Science and Technology; (United States), Vol. 25:6; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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CHLORINATED ALIPHATIC HYDROCARBONS
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AEROSOLS
AIR POLLUTION
AIR SAMPLERS
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DDT
GAS CHROMATOGRAPHY
LINDANE
MASS SPECTROSCOPY
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ADSORBENTS
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CHLORINATED ALICYCLIC HYDROCARBONS
CHROMATOGRAPHY
COLLOIDS
DISPERSIONS
EARTH ATMOSPHERE
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HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENATED AROMATIC HYDROCARBONS
INSECTICIDES
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PARTICLES
PESTICIDES
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SEPARATION PROCESSES
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SPECTROSCOPY
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)